feat(configuration): load config from directory (#4616)

This allows specifying paths to a combination of files and directories with the --config option provided none of the specified file paths reside directly inside one of the specified directory paths. The directory paths are not recursive, and load .yml and .yaml files at this time.

docs/content/en/configuration/methods/files.md

@@ -12,6 +12,18 @@ weight: 101200
 toc: true
 ---
 
+## Loading Behaviour
+
+There are several options which affect the loading of files:
+
+|       Name        |            Argument             |                                    Description                                     |
+|:-----------------:|:-------------------------------:|:----------------------------------------------------------------------------------:|
+| Files/Directories |        `--config`, `-c`         | A list of file or directory (non-recursive) paths to load configuration files from |
+|      Filters      | `--config.experimental.filters` |   A list of filters applied to every file from the Files or Directories options    |
+
+__*Note:* when specifying directories and files, the individual files specified must not be within any of the
+directories specified.__
+
 ## Formats
 
 The only supported configuration file format is [YAML](#yaml).
@@ -164,6 +176,10 @@ The name used to enable this filter is `template`.
 This filter uses the [Go template engine](https://pkg.go.dev/text/template) to render the configuration files. It uses
 similar syntax to Jinja2 templates with different function names.
 
+Comprehensive examples are beyond what we support and people wishing to use this should consult the official
+[Go template engine](https://pkg.go.dev/text/template) documentation for syntax instructions. We also log the generated
+output at each filter stage as a base64 string when trace logging is enabled.
+
 #### Functions
 
 In addition to the standard builtin functions we support several other functions.

docs/content/en/reference/cli/authelia/authelia.md

@@ -24,7 +24,8 @@ An open-source authentication and authorization server providing
 two-factor authentication and single sign-on (SSO) for your
 applications via a web portal.
 
-Documentation is available at: https://www.authelia.com/
+General documentation is available at: https://www.authelia.com/
+CLI documentation is available at: https://www.authelia.com/reference/cli/authelia/authelia/
 
 ```
 authelia [flags]
@@ -41,8 +42,8 @@ authelia --config /etc/authelia/config/
 ### Options
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
   -h, --help                                  help for authelia
 ```
 

docs/content/en/reference/cli/authelia/authelia_access-control.md

@@ -35,8 +35,8 @@ authelia access-control --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
 ```
 
 ### SEE ALSO

docs/content/en/reference/cli/authelia/authelia_access-control_check-policy.md

@@ -65,8 +65,8 @@ authelia access-control check-policy --config config.yml --url https://example.c
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
 ```
 
 ### SEE ALSO

docs/content/en/reference/cli/authelia/authelia_build-info.md

@@ -48,8 +48,8 @@ authelia build-info
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
 ```
 
 ### SEE ALSO

docs/content/en/reference/cli/authelia/authelia_crypto.md

@@ -37,8 +37,8 @@ authelia crypto --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
 ```
 
 ### SEE ALSO

docs/content/en/reference/cli/authelia/authelia_crypto_certificate.md

@@ -37,8 +37,8 @@ authelia crypto certificate --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
 ```
 
 ### SEE ALSO

docs/content/en/reference/cli/authelia/authelia_crypto_certificate_ecdsa.md

@@ -37,8 +37,8 @@ authelia crypto certificate ecdsa --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
 ```
 
 ### SEE ALSO

docs/content/en/reference/cli/authelia/authelia_crypto_certificate_ecdsa_generate.md

@@ -62,8 +62,8 @@ authelia crypto certificate ecdsa generate --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
 ```
 
 ### SEE ALSO

docs/content/en/reference/cli/authelia/authelia_crypto_certificate_ecdsa_request.md

@@ -57,8 +57,8 @@ authelia crypto certificate ecdsa request --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
 ```
 
 ### SEE ALSO

docs/content/en/reference/cli/authelia/authelia_crypto_certificate_ed25519.md

@@ -37,8 +37,8 @@ authelia crypto certificate ed25519 --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
 ```
 
 ### SEE ALSO

docs/content/en/reference/cli/authelia/authelia_crypto_certificate_ed25519_generate.md

@@ -61,8 +61,8 @@ authelia crypto certificate ed25519 request --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
 ```
 
 ### SEE ALSO

docs/content/en/reference/cli/authelia/authelia_crypto_certificate_ed25519_request.md

@@ -56,8 +56,8 @@ authelia crypto certificate ed25519 request --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
 ```
 
 ### SEE ALSO

docs/content/en/reference/cli/authelia/authelia_crypto_certificate_rsa.md

@@ -37,8 +37,8 @@ authelia crypto certificate rsa --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
 ```
 
 ### SEE ALSO

docs/content/en/reference/cli/authelia/authelia_crypto_certificate_rsa_generate.md

@@ -62,8 +62,8 @@ authelia crypto certificate rsa generate --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
 ```
 
 ### SEE ALSO

docs/content/en/reference/cli/authelia/authelia_crypto_certificate_rsa_request.md

@@ -57,8 +57,8 @@ authelia crypto certificate rsa request --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
 ```
 
 ### SEE ALSO

docs/content/en/reference/cli/authelia/authelia_crypto_hash.md

@@ -37,8 +37,8 @@ authelia crypto hash --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
 ```
 
 ### SEE ALSO

docs/content/en/reference/cli/authelia/authelia_crypto_hash_generate.md

@@ -49,8 +49,8 @@ authelia crypto hash generate --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
 ```
 
 ### SEE ALSO

docs/content/en/reference/cli/authelia/authelia_crypto_hash_generate_argon2.md

@@ -48,8 +48,8 @@ authelia crypto hash generate argon2 --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --no-confirm                            skip the password confirmation prompt
       --password string                       manually supply the password rather than using the terminal prompt
       --random                                uses a randomly generated password

docs/content/en/reference/cli/authelia/authelia_crypto_hash_generate_bcrypt.md

@@ -43,8 +43,8 @@ authelia crypto hash generate bcrypt --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --no-confirm                            skip the password confirmation prompt
       --password string                       manually supply the password rather than using the terminal prompt
       --random                                uses a randomly generated password

docs/content/en/reference/cli/authelia/authelia_crypto_hash_generate_pbkdf2.md

@@ -44,8 +44,8 @@ authelia crypto hash generate pbkdf2 --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --no-confirm                            skip the password confirmation prompt
       --password string                       manually supply the password rather than using the terminal prompt
       --random                                uses a randomly generated password

docs/content/en/reference/cli/authelia/authelia_crypto_hash_generate_scrypt.md

@@ -46,8 +46,8 @@ authelia crypto hash generate scrypt --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --no-confirm                            skip the password confirmation prompt
       --password string                       manually supply the password rather than using the terminal prompt
       --random                                uses a randomly generated password

docs/content/en/reference/cli/authelia/authelia_crypto_hash_generate_sha2crypt.md

@@ -44,8 +44,8 @@ authelia crypto hash generate sha2crypt --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --no-confirm                            skip the password confirmation prompt
       --password string                       manually supply the password rather than using the terminal prompt
       --random                                uses a randomly generated password

docs/content/en/reference/cli/authelia/authelia_crypto_hash_validate.md

@@ -43,8 +43,8 @@ authelia crypto hash validate '$5$rounds=500000$WFjMpdCQxIkbNl0k$M0qZaZoK8Gwdh8C
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
 ```
 
 ### SEE ALSO

docs/content/en/reference/cli/authelia/authelia_crypto_pair.md

@@ -37,8 +37,8 @@ authelia crypto pair --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
 ```
 
 ### SEE ALSO

docs/content/en/reference/cli/authelia/authelia_crypto_pair_ecdsa.md

@@ -41,8 +41,8 @@ authelia crypto pair ecdsa --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
 ```
 
 ### SEE ALSO

docs/content/en/reference/cli/authelia/authelia_crypto_pair_ecdsa_generate.md

@@ -46,8 +46,8 @@ authelia crypto pair ecdsa generate --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
 ```
 
 ### SEE ALSO

docs/content/en/reference/cli/authelia/authelia_crypto_pair_ed25519.md

@@ -41,8 +41,8 @@ authelia crypto pair ed25519 --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
 ```
 
 ### SEE ALSO

docs/content/en/reference/cli/authelia/authelia_crypto_pair_ed25519_generate.md

@@ -45,8 +45,8 @@ authelia crypto pair ed25519 generate --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
 ```
 
 ### SEE ALSO

docs/content/en/reference/cli/authelia/authelia_crypto_pair_rsa.md

@@ -41,8 +41,8 @@ authelia crypto pair rsa --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
 ```
 
 ### SEE ALSO

docs/content/en/reference/cli/authelia/authelia_crypto_pair_rsa_generate.md

@@ -46,8 +46,8 @@ authelia crypto pair rsa generate --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
 ```
 
 ### SEE ALSO

docs/content/en/reference/cli/authelia/authelia_crypto_rand.md

@@ -52,8 +52,8 @@ authelia crypto rand --characters 0123456789ABCDEF
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
 ```
 
 ### SEE ALSO

docs/content/en/reference/cli/authelia/authelia_storage.md

@@ -56,8 +56,8 @@ authelia storage --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
 ```
 
 ### SEE ALSO

docs/content/en/reference/cli/authelia/authelia_storage_encryption.md

@@ -37,8 +37,8 @@ authelia storage encryption --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                         configuration files to load (default [configuration.yml])
+  -c, --config strings                         configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings    applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings    list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --encryption-key string                  the storage encryption key to use
       --mysql.database string                  the MySQL database name (default "authelia")
       --mysql.host string                      the MySQL hostname

docs/content/en/reference/cli/authelia/authelia_storage_encryption_change-key.md

@@ -43,8 +43,8 @@ authelia storage encryption change-key --encryption-key b3453fde-ecc2-4a1f-9422-
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                         configuration files to load (default [configuration.yml])
+  -c, --config strings                         configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings    applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings    list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --encryption-key string                  the storage encryption key to use
       --mysql.database string                  the MySQL database name (default "authelia")
       --mysql.host string                      the MySQL hostname

docs/content/en/reference/cli/authelia/authelia_storage_encryption_check.md

@@ -45,8 +45,8 @@ authelia storage encryption check --verbose --encryption-key b3453fde-ecc2-4a1f-
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                         configuration files to load (default [configuration.yml])
+  -c, --config strings                         configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings    applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings    list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --encryption-key string                  the storage encryption key to use
       --mysql.database string                  the MySQL database name (default "authelia")
       --mysql.host string                      the MySQL hostname

docs/content/en/reference/cli/authelia/authelia_storage_migrate.md

@@ -37,8 +37,8 @@ authelia storage migrate --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                         configuration files to load (default [configuration.yml])
+  -c, --config strings                         configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings    applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings    list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --encryption-key string                  the storage encryption key to use
       --mysql.database string                  the MySQL database name (default "authelia")
       --mysql.host string                      the MySQL hostname

docs/content/en/reference/cli/authelia/authelia_storage_migrate_down.md

@@ -46,8 +46,8 @@ authelia storage migrate down --target 20 --encryption-key b3453fde-ecc2-4a1f-94
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                         configuration files to load (default [configuration.yml])
+  -c, --config strings                         configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings    applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings    list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --encryption-key string                  the storage encryption key to use
       --mysql.database string                  the MySQL database name (default "authelia")
       --mysql.host string                      the MySQL hostname

docs/content/en/reference/cli/authelia/authelia_storage_migrate_history.md

@@ -43,8 +43,8 @@ authelia storage migrate history --encryption-key b3453fde-ecc2-4a1f-9422-2707dd
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                         configuration files to load (default [configuration.yml])
+  -c, --config strings                         configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings    applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings    list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --encryption-key string                  the storage encryption key to use
       --mysql.database string                  the MySQL database name (default "authelia")
       --mysql.host string                      the MySQL hostname

docs/content/en/reference/cli/authelia/authelia_storage_migrate_list-down.md

@@ -44,8 +44,8 @@ authelia storage migrate list-down --encryption-key b3453fde-ecc2-4a1f-9422-2707
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                         configuration files to load (default [configuration.yml])
+  -c, --config strings                         configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings    applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings    list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --encryption-key string                  the storage encryption key to use
       --mysql.database string                  the MySQL database name (default "authelia")
       --mysql.host string                      the MySQL hostname

docs/content/en/reference/cli/authelia/authelia_storage_migrate_list-up.md

@@ -44,8 +44,8 @@ authelia storage migrate list-up --encryption-key b3453fde-ecc2-4a1f-9422-2707dd
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                         configuration files to load (default [configuration.yml])
+  -c, --config strings                         configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings    applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings    list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --encryption-key string                  the storage encryption key to use
       --mysql.database string                  the MySQL database name (default "authelia")
       --mysql.host string                      the MySQL hostname

docs/content/en/reference/cli/authelia/authelia_storage_migrate_up.md

@@ -46,8 +46,8 @@ authelia storage migrate up --encryption-key b3453fde-ecc2-4a1f-9422-2707ddbed49
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                         configuration files to load (default [configuration.yml])
+  -c, --config strings                         configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings    applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings    list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --encryption-key string                  the storage encryption key to use
       --mysql.database string                  the MySQL database name (default "authelia")
       --mysql.host string                      the MySQL hostname

docs/content/en/reference/cli/authelia/authelia_storage_schema-info.md

@@ -43,8 +43,8 @@ authelia storage schema-info --encryption-key b3453fde-ecc2-4a1f-9422-2707ddbed4
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                         configuration files to load (default [configuration.yml])
+  -c, --config strings                         configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings    applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings    list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --encryption-key string                  the storage encryption key to use
       --mysql.database string                  the MySQL database name (default "authelia")
       --mysql.host string                      the MySQL hostname

docs/content/en/reference/cli/authelia/authelia_storage_user.md

@@ -37,8 +37,8 @@ authelia storage user --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                         configuration files to load (default [configuration.yml])
+  -c, --config strings                         configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings    applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings    list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --encryption-key string                  the storage encryption key to use
       --mysql.database string                  the MySQL database name (default "authelia")
       --mysql.host string                      the MySQL hostname

docs/content/en/reference/cli/authelia/authelia_storage_user_identifiers.md

@@ -37,8 +37,8 @@ authelia storage user identifiers --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                         configuration files to load (default [configuration.yml])
+  -c, --config strings                         configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings    applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings    list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --encryption-key string                  the storage encryption key to use
       --mysql.database string                  the MySQL database name (default "authelia")
       --mysql.host string                      the MySQL hostname

docs/content/en/reference/cli/authelia/authelia_storage_user_identifiers_add.md

@@ -46,8 +46,8 @@ authelia storage user identifiers add john --identifier f0919359-9d15-4e15-bcba-
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                         configuration files to load (default [configuration.yml])
+  -c, --config strings                         configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings    applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings    list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --encryption-key string                  the storage encryption key to use
       --mysql.database string                  the MySQL database name (default "authelia")
       --mysql.host string                      the MySQL hostname

docs/content/en/reference/cli/authelia/authelia_storage_user_identifiers_export.md

@@ -45,8 +45,8 @@ authelia storage user identifiers export --file export.yaml --encryption-key b34
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                         configuration files to load (default [configuration.yml])
+  -c, --config strings                         configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings    applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings    list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --encryption-key string                  the storage encryption key to use
       --mysql.database string                  the MySQL database name (default "authelia")
       --mysql.host string                      the MySQL hostname

docs/content/en/reference/cli/authelia/authelia_storage_user_identifiers_generate.md

@@ -48,8 +48,8 @@ authelia storage user identifiers generate --users john,mary --services openid -
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                         configuration files to load (default [configuration.yml])
+  -c, --config strings                         configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings    applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings    list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --encryption-key string                  the storage encryption key to use
       --mysql.database string                  the MySQL database name (default "authelia")
       --mysql.host string                      the MySQL hostname

docs/content/en/reference/cli/authelia/authelia_storage_user_identifiers_import.md

@@ -48,8 +48,8 @@ authelia storage user identifiers import --file export.yaml --encryption-key b34
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                         configuration files to load (default [configuration.yml])
+  -c, --config strings                         configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings    applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings    list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --encryption-key string                  the storage encryption key to use
       --mysql.database string                  the MySQL database name (default "authelia")
       --mysql.host string                      the MySQL hostname

docs/content/en/reference/cli/authelia/authelia_storage_user_totp.md

@@ -37,8 +37,8 @@ authelia storage user totp --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                         configuration files to load (default [configuration.yml])
+  -c, --config strings                         configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings    applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings    list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --encryption-key string                  the storage encryption key to use
       --mysql.database string                  the MySQL database name (default "authelia")
       --mysql.host string                      the MySQL hostname

docs/content/en/reference/cli/authelia/authelia_storage_user_totp_delete.md

@@ -43,8 +43,8 @@ authelia storage user totp delete john --encryption-key b3453fde-ecc2-4a1f-9422-
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                         configuration files to load (default [configuration.yml])
+  -c, --config strings                         configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings    applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings    list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --encryption-key string                  the storage encryption key to use
       --mysql.database string                  the MySQL database name (default "authelia")
       --mysql.host string                      the MySQL hostname

docs/content/en/reference/cli/authelia/authelia_storage_user_totp_export.md

@@ -46,8 +46,8 @@ authelia storage user totp export --format png --dir ./totp-qr --encryption-key
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                         configuration files to load (default [configuration.yml])
+  -c, --config strings                         configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings    applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings    list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --encryption-key string                  the storage encryption key to use
       --mysql.database string                  the MySQL database name (default "authelia")
       --mysql.host string                      the MySQL hostname

docs/content/en/reference/cli/authelia/authelia_storage_user_totp_generate.md

@@ -55,8 +55,8 @@ authelia storage user totp generate john --algorithm SHA512 --config config.yml
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                         configuration files to load (default [configuration.yml])
+  -c, --config strings                         configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings    applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings    list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --encryption-key string                  the storage encryption key to use
       --mysql.database string                  the MySQL database name (default "authelia")
       --mysql.host string                      the MySQL hostname

docs/content/en/reference/cli/authelia/authelia_storage_user_webauthn.md

@@ -37,8 +37,8 @@ authelia storage user webauthn --help
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                         configuration files to load (default [configuration.yml])
+  -c, --config strings                         configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings    applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings    list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --encryption-key string                  the storage encryption key to use
       --mysql.database string                  the MySQL database name (default "authelia")
       --mysql.host string                      the MySQL hostname

docs/content/en/reference/cli/authelia/authelia_storage_user_webauthn_delete.md

@@ -52,8 +52,8 @@ authelia storage user webauthn delete --kid abc123 --encryption-key b3453fde-ecc
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                         configuration files to load (default [configuration.yml])
+  -c, --config strings                         configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings    applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings    list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --encryption-key string                  the storage encryption key to use
       --mysql.database string                  the MySQL database name (default "authelia")
       --mysql.host string                      the MySQL hostname

docs/content/en/reference/cli/authelia/authelia_storage_user_webauthn_list.md

@@ -46,8 +46,8 @@ authelia storage user webauthn list john --encryption-key b3453fde-ecc2-4a1f-942
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                         configuration files to load (default [configuration.yml])
+  -c, --config strings                         configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings    applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings    list of filters to apply to all configuration files, for more information: authelia --help authelia filters
       --encryption-key string                  the storage encryption key to use
       --mysql.database string                  the MySQL database name (default "authelia")
       --mysql.host string                      the MySQL hostname

docs/content/en/reference/cli/authelia/authelia_validate-config.md

@@ -43,8 +43,8 @@ authelia validate-config --config config.yml
 ### Options inherited from parent commands
 
 ```
-  -c, --config strings                        configuration files to load (default [configuration.yml])
+  -c, --config strings                        configuration files or directories to load (default [configuration.yml])
-      --config.experimental.filters strings   applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'
+      --config.experimental.filters strings   list of filters to apply to all configuration files, for more information: authelia --help authelia filters
 ```
 
 ### SEE ALSO

internal/commands/const.go

@@ -13,7 +13,8 @@ An open-source authentication and authorization server providing
 two-factor authentication and single sign-on (SSO) for your
 applications via a web portal.
 
-Documentation is available at: https://www.authelia.com/`
+General documentation is available at: https://www.authelia.com/
+CLI documentation is available at: https://www.authelia.com/reference/cli/authelia/authelia/`
 
 	cmdAutheliaExample = `authelia --config /etc/authelia/config.yml --config /etc/authelia/access-control.yml
 authelia --config /etc/authelia/config.yml,/etc/authelia/access-control.yml
@@ -533,6 +534,9 @@ const (
 	cmdFlagNameSaltSize         = "salt-size"
 	cmdFlagNameProfile          = "profile"
 
+	cmdConfigDefaultContainer = "/config/configuration.yml"
+	cmdConfigDefaultDaemon    = "/etc/authelia/configuration.yml"
+
 	cmdFlagNameConfig = "config"
 
 	cmdFlagNameConfigExpFilters = "config.experimental.filters"
@@ -626,3 +630,29 @@ const (
 var (
 	validIdentifierServices = []string{identifierServiceOpenIDConnect}
 )
+
+const (
+	helpTopicConfigFilters = `Configuration Filters are an experimental system for templating configuration files.
+
+Using the --config.experimental.filters flag users can define multiple filters to apply to all configuration files that
+are loaded by Authelia. These filters are applied after loading the file data from the filesystem, but before they are
+parsed by the relevant file format parser.
+
+The filters are processed in the order specified, and the content of each configuration file is logged as a base64 raw
+string when the log level is set to trace.
+
+The following filters are available:
+
+	expand-env:
+
+		This filter expands environment variables in place where specified in the configuration. For example the string
+		${DOMAIN_NAME} will be replaced with the value from the DOMAIN_NAME environment variable or an empty string.
+
+	template:
+
+		This filter uses the go template system to filter the file. In addition to the standard functions, several
+		custom functions exist to facilitate this process. The 'env' function takes a single string does similar to the
+		'expand-env' filter for example.
+
+		For a full list of functions see: https://www.authelia.com/configuration/methods/files/#functions`
+)

internal/commands/context.go

@@ -4,7 +4,6 @@ import (
 	"crypto/x509"
 	"fmt"
 	"os"
-	"strings"
 
 	"github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
@@ -275,14 +274,23 @@ func (ctx *CmdCtx) ConfigEnsureExistsRunE(cmd *cobra.Command, _ []string) (err e
 	var (
 		configs []string
 		created bool
+		result  XEnvCLIResult
 	)
 
-	if configs, _, err = loadEnvCLIStringSliceValue(cmd, "", cmdFlagNameConfig); err != nil {
+	if configs, result, err = loadXEnvCLIStringSliceValue(cmd, "", cmdFlagNameConfig); err != nil {
 		return err
 	}
 
-	if len(configs) != 1 {
+	switch {
+	case result == XEnvCLIResultCLIExplicit:
 		return nil
+	case result == XEnvCLIResultEnvironment && len(configs) == 1:
+		switch configs[0] {
+		case cmdConfigDefaultContainer, cmdConfigDefaultDaemon:
+			break
+		default:
+			return nil
+		}
 	}
 
 	if created, err = configuration.EnsureConfigurationExists(configs[0]); err != nil {
@@ -300,23 +308,15 @@ func (ctx *CmdCtx) ConfigEnsureExistsRunE(cmd *cobra.Command, _ []string) (err e
 // ConfigLoadRunE loads the configuration into the CmdCtx.
 func (ctx *CmdCtx) ConfigLoadRunE(cmd *cobra.Command, _ []string) (err error) {
 	var (
-		configs, filterNames []string
+		configs []string
 
 		filters []configuration.FileFilter
 	)
 
-	if configs, _, err = loadEnvCLIStringSliceValue(cmd, "", cmdFlagNameConfig); err != nil {
+	if configs, filters, err = loadXEnvCLIConfigValues(cmd); err != nil {
 		return err
 	}
 
-	if filterNames, _, err = loadEnvCLIStringSliceValue(cmd, "", cmdFlagNameConfigExpFilters); err != nil {
-		return err
-	}
-
-	if filters, err = configuration.NewFileFilters(filterNames); err != nil {
-		return fmt.Errorf("error occurred loading configuration: flag '--%s' is invalid: %w", cmdFlagNameConfigExpFilters, err)
-	}
-
 	if ctx.cconfig == nil {
 		ctx.cconfig = NewCmdCtxConfig()
 	}
@@ -337,29 +337,3 @@ func (ctx *CmdCtx) ConfigLoadRunE(cmd *cobra.Command, _ []string) (err error) {
 
 	return nil
 }
-
-func loadEnvCLIStringSliceValue(cmd *cobra.Command, envKey, flagName string) (value []string, explicit bool, err error) { //nolint:unparam
-	if cmd.Flags().Changed(flagName) {
-		value, err = cmd.Flags().GetStringSlice(flagName)
-
-		return value, true, err
-	}
-
-	var (
-		env string
-		ok  bool
-	)
-
-	if envKey != "" {
-		env, ok = os.LookupEnv(envKey)
-	}
-
-	switch {
-	case ok && env != "":
-		return strings.Split(env, ","), true, nil
-	default:
-		value, err = cmd.Flags().GetStringSlice(flagName)
-
-		return value, false, err
-	}
-}

internal/commands/root.go

@@ -45,9 +45,9 @@ func NewRootCmd() (cmd *cobra.Command) {
 		DisableAutoGenTag: true,
 	}
 
-	cmd.PersistentFlags().StringSliceP(cmdFlagNameConfig, "c", []string{"configuration.yml"}, "configuration files to load")
+	cmd.PersistentFlags().StringSliceP(cmdFlagNameConfig, "c", []string{"configuration.yml"}, "configuration files or directories to load")
 
-	cmd.PersistentFlags().StringSlice(cmdFlagNameConfigExpFilters, nil, "applies filters in order to the configuration file before the YAML parser, options are 'template', 'expand-env'")
+	cmd.PersistentFlags().StringSlice(cmdFlagNameConfigExpFilters, nil, "list of filters to apply to all configuration files, for more information: authelia --help authelia filters")
 
 	cmd.AddCommand(
 		newAccessControlCommand(ctx),
@@ -55,6 +55,8 @@ func NewRootCmd() (cmd *cobra.Command) {
 		newCryptoCmd(ctx),
 		newStorageCmd(ctx),
 		newValidateConfigCmd(ctx),
+
+		newHelpTopic("filters", "Help for the config filters", helpTopicConfigFilters),
 	)
 
 	return cmd
@@ -89,6 +91,8 @@ func (ctx *CmdCtx) RootRunE(_ *cobra.Command, _ []string) (err error) {
 
 	doStartupChecks(ctx)
 
+	ctx.cconfig = nil
+
 	runServices(ctx)
 
 	return nil

internal/commands/util.go

@@ -5,11 +5,15 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"path/filepath"
+	"strings"
 	"syscall"
 
+	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
 	"golang.org/x/term"
 
+	"github.com/authelia/authelia/v4/internal/configuration"
 	"github.com/authelia/authelia/v4/internal/utils"
 )
 
@@ -228,3 +232,130 @@ func termReadPasswordWithPrompt(prompt, flag string) (password string, err error
 
 	return password, nil
 }
+
+type XEnvCLIResult int
+
+const (
+	XEnvCLIResultCLIExplicit XEnvCLIResult = iota
+	XEnvCLIResultCLIImplicit
+	XEnvCLIResultEnvironment
+)
+
+func loadXEnvCLIConfigValues(cmd *cobra.Command) (configs []string, filters []configuration.FileFilter, err error) {
+	var (
+		filterNames []string
+	)
+
+	if configs, _, err = loadXEnvCLIStringSliceValue(cmd, "", cmdFlagNameConfig); err != nil {
+		return nil, nil, err
+	}
+
+	if configs, err = loadXNormalizedPaths(configs); err != nil {
+		return nil, nil, err
+	}
+
+	if filterNames, _, err = loadXEnvCLIStringSliceValue(cmd, "", cmdFlagNameConfigExpFilters); err != nil {
+		return nil, nil, err
+	}
+
+	if filters, err = configuration.NewFileFilters(filterNames); err != nil {
+		return nil, nil, fmt.Errorf("error occurred loading configuration: flag '--%s' is invalid: %w", cmdFlagNameConfigExpFilters, err)
+	}
+
+	return
+}
+
+func loadXNormalizedPaths(paths []string) ([]string, error) {
+	var (
+		configs, files, dirs []string
+		err                  error
+	)
+
+	var stat os.FileInfo
+
+	for _, path := range paths {
+		if path, err = filepath.Abs(path); err != nil {
+			return nil, fmt.Errorf("failed to determine absolute path for '%s': %w", path, err)
+		}
+
+		switch stat, err = os.Stat(path); {
+		case err == nil && stat.IsDir():
+			configs = append(configs, path)
+			dirs = append(dirs, path)
+		case err == nil:
+			configs = append(configs, path)
+			files = append(files, path)
+		default:
+			if os.IsNotExist(err) {
+				configs = append(configs, path)
+				files = append(files, path)
+
+				continue
+			}
+
+			return nil, fmt.Errorf("error occurred stating file at path '%s': %w", path, err)
+		}
+	}
+
+	for i, file := range files {
+		if file, err = filepath.Abs(file); err != nil {
+			return nil, fmt.Errorf("failed to determine absolute path for '%s': %w", files[i], err)
+		}
+
+		if len(dirs) != 0 {
+			filedir := filepath.Dir(file)
+
+			for _, dir := range dirs {
+				if filedir == dir {
+					return nil, fmt.Errorf("failed to load config directory '%s': the config file '%s' is in that directory which is not supported", dir, file)
+				}
+			}
+		}
+	}
+
+	return configs, nil
+}
+
+func loadXEnvCLIStringSliceValue(cmd *cobra.Command, envKey, flagName string) (value []string, result XEnvCLIResult, err error) {
+	if cmd.Flags().Changed(flagName) {
+		value, err = cmd.Flags().GetStringSlice(flagName)
+
+		return value, XEnvCLIResultCLIExplicit, err
+	}
+
+	var (
+		env string
+		ok  bool
+	)
+
+	if envKey != "" {
+		env, ok = os.LookupEnv(envKey)
+	}
+
+	switch {
+	case ok && env != "":
+		return strings.Split(env, ","), XEnvCLIResultEnvironment, nil
+	default:
+		value, err = cmd.Flags().GetStringSlice(flagName)
+
+		return value, XEnvCLIResultCLIImplicit, err
+	}
+}
+
+func newHelpTopic(topic, short, body string) (cmd *cobra.Command) {
+	cmd = &cobra.Command{
+		Use:   topic,
+		Short: short,
+	}
+
+	cmd.SetHelpFunc(func(cmd *cobra.Command, args []string) {
+		_ = cmd.Parent().Help()
+
+		fmt.Println()
+		fmt.Printf("Help Topic: %s\n\n", topic)
+		fmt.Print(body)
+		fmt.Print("\n\n")
+	})
+
+	return cmd
+}

internal/commands/util_test.go

@@ -0,0 +1,183 @@
+package commands
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/spf13/cobra"
+	"github.com/spf13/pflag"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestLoadXEnvCLIStringSliceValue(t *testing.T) {
+	testCases := []struct {
+		name                        string
+		envKey, envValue, flagValue string
+		flagDefault                 []string
+		flag                        *pflag.Flag
+		expected                    []string
+		expectedResult              XEnvCLIResult
+		expectedErr                 string
+	}{
+		{
+			"ShouldParseFromEnv",
+			"EXAMPLE_ONE", "abc",
+			"example-one", []string{"flagdef"}, &pflag.Flag{Name: "example-one", Changed: false},
+			[]string{"abc"}, XEnvCLIResultEnvironment, "",
+		},
+		{
+			"ShouldParseMultipleFromEnv",
+			"EXAMPLE_ONE", "abc,123",
+			"example-one", []string{"flagdef"}, &pflag.Flag{Name: "example-one", Changed: false},
+			[]string{"abc", "123"}, XEnvCLIResultEnvironment, "",
+		},
+		{
+			"ShouldParseCLIExplicit",
+			"EXAMPLE_ONE", "abc,123",
+			"example-from-flag,123", []string{"flagdef"}, &pflag.Flag{Name: "example-one", Changed: true},
+			[]string{"example-from-flag", "123"}, XEnvCLIResultCLIExplicit, "",
+		},
+		{
+			"ShouldParseCLIImplicit",
+			"EXAMPLE_ONE", "",
+			"example-one", []string{"example-from-flag-default", "123"}, &pflag.Flag{Name: "example-one", Changed: false},
+			[]string{"example-from-flag-default", "123"}, XEnvCLIResultCLIImplicit, "",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			cmd := &cobra.Command{}
+
+			if tc.flag != nil {
+				cmd.Flags().StringSlice(tc.flag.Name, tc.flagDefault, "")
+
+				if tc.flag.Changed {
+					require.NoError(t, cmd.Flags().Set(tc.flag.Name, tc.flagValue))
+				}
+			}
+
+			if tc.envValue != "" {
+				require.NoError(t, os.Setenv(tc.envKey, tc.envValue))
+			}
+
+			actual, actualResult, actualErr := loadXEnvCLIStringSliceValue(cmd, tc.envKey, tc.flag.Name)
+
+			assert.Equal(t, tc.expected, actual)
+			assert.Equal(t, tc.expectedResult, actualResult)
+
+			if tc.expectedErr == "" {
+				assert.NoError(t, actualErr)
+			} else {
+				assert.EqualError(t, actualErr, tc.expectedErr)
+			}
+
+			if tc.envValue != "" {
+				require.NoError(t, os.Unsetenv(tc.envKey))
+			}
+		})
+	}
+}
+
+func TestLoadXNormalizedPaths(t *testing.T) {
+	root := t.TempDir()
+
+	configdir := filepath.Join(root, "config")
+	otherdir := filepath.Join(root, "other")
+
+	require.NoError(t, os.Mkdir(configdir, 0700))
+	require.NoError(t, os.Mkdir(otherdir, 0700))
+
+	var (
+		info os.FileInfo
+		file *os.File
+		err  error
+	)
+
+	ayml := filepath.Join(configdir, "a.yml")
+	byml := filepath.Join(configdir, "b.yml")
+	cyml := filepath.Join(otherdir, "c.yml")
+
+	file, err = os.Create(ayml)
+
+	require.NoError(t, err)
+
+	require.NoError(t, file.Close())
+
+	file, err = os.Create(byml)
+
+	require.NoError(t, err)
+
+	require.NoError(t, file.Close())
+
+	file, err = os.Create(cyml)
+
+	require.NoError(t, err)
+
+	require.NoError(t, file.Close())
+
+	info, err = os.Stat(configdir)
+
+	require.NoError(t, err)
+	require.True(t, info.IsDir())
+
+	info, err = os.Stat(otherdir)
+
+	require.NoError(t, err)
+	require.True(t, info.IsDir())
+
+	info, err = os.Stat(ayml)
+
+	require.NoError(t, err)
+	require.False(t, info.IsDir())
+
+	info, err = os.Stat(byml)
+
+	require.NoError(t, err)
+	require.False(t, info.IsDir())
+
+	info, err = os.Stat(cyml)
+
+	require.NoError(t, err)
+	require.False(t, info.IsDir())
+
+	testCases := []struct {
+		name           string
+		have, expected []string
+		expectedErr    string
+	}{
+		{"ShouldAllowFiles",
+			[]string{ayml},
+			[]string{ayml}, "",
+		},
+		{"ShouldAllowDirectories",
+			[]string{configdir},
+			[]string{configdir}, "",
+		},
+		{"ShouldAllowFilesDirectories",
+			[]string{ayml, otherdir},
+			[]string{ayml, otherdir}, "",
+		},
+		{"ShouldRaiseErrOnOverlappingFilesDirectories",
+			[]string{ayml, configdir},
+			nil, fmt.Sprintf("failed to load config directory '%s': the config file '%s' is in that directory which is not supported", configdir, ayml),
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			actual, actualErr := loadXNormalizedPaths(tc.have)
+
+			assert.Equal(t, tc.expected, actual)
+
+			if tc.expectedErr == "" {
+				assert.NoError(t, actualErr)
+			} else {
+				assert.EqualError(t, actualErr, tc.expectedErr)
+			}
+		})
+	}
+}

internal/configuration/provider_test.go

@@ -191,12 +191,12 @@ func TestShouldRaiseIOErrOnUnreadableFile(t *testing.T) {
 	cfg := filepath.Join(dir, "myconf.yml")
 
 	val := schema.NewStructValidator()
-	_, _, err := Load(val, NewYAMLFileSource(cfg))
+	_, _, err := Load(val, NewFileSource(cfg))
 
 	assert.NoError(t, err)
 	require.Len(t, val.Errors(), 1)
 	assert.Len(t, val.Warnings(), 0)
-	assert.EqualError(t, val.Errors()[0], fmt.Sprintf("failed to load configuration from yaml file(%s) source: open %s: permission denied", cfg, cfg))
+	assert.EqualError(t, val.Errors()[0], fmt.Sprintf("failed to load configuration from file path(%s) source: open %s: permission denied", cfg, cfg))
 }
 
 func TestShouldValidateConfigurationWithEnvSecrets(t *testing.T) {
@@ -417,28 +417,25 @@ func TestShouldNotReadConfigurationOnFSAccessDenied(t *testing.T) {
 	assert.NoError(t, testCreateFile(filepath.Join(dir, "config.yml"), "port: 9091\n", 0000))
 
 	val := schema.NewStructValidator()
-	_, _, err := Load(val, NewYAMLFileSource(cfg))
+	_, _, err := Load(val, NewFileSource(cfg))
 
 	assert.NoError(t, err)
 	require.Len(t, val.Errors(), 1)
 
-	assert.EqualError(t, val.Errors()[0], fmt.Sprintf("failed to load configuration from yaml file(%s) source: open %s: permission denied", cfg, cfg))
+	assert.EqualError(t, val.Errors()[0], fmt.Sprintf("failed to load configuration from file path(%s) source: open %s: permission denied", cfg, cfg))
 }
 
-func TestShouldNotLoadDirectoryConfiguration(t *testing.T) {
+func TestShouldLoadDirectoryConfiguration(t *testing.T) {
 	testReset()
 
 	dir := t.TempDir()
 
 	val := schema.NewStructValidator()
-	_, _, err := Load(val, NewYAMLFileSource(dir))
+	_, _, err := Load(val, NewFileSource(dir))
 
 	assert.NoError(t, err)
-	require.Len(t, val.Errors(), 1)
+	assert.Len(t, val.Errors(), 0)
 	assert.Len(t, val.Warnings(), 0)
-
-	expectedErr := fmt.Sprintf(utils.GetExpectedErrTxt("yamlisdir"), dir)
-	assert.EqualError(t, val.Errors()[0], fmt.Sprintf("failed to load configuration from yaml file(%s) source: %s", dir, expectedErr))
 }
 
 func testSetEnv(t *testing.T, key, value string) {

internal/configuration/sources.go

@@ -3,6 +3,8 @@ package configuration
 import (
 	"errors"
 	"fmt"
+	"os"
+	"path/filepath"
 
 	"github.com/knadh/koanf"
 	"github.com/knadh/koanf/parsers/yaml"
@@ -14,29 +16,29 @@ import (
 	"github.com/authelia/authelia/v4/internal/configuration/schema"
 )
 
-// NewYAMLFileSource returns a configuration.Source configured to load from a specified YAML path. If there is an issue
+// NewFileSource returns a configuration.Source configured to load from a specified path. If there is an issue
 // accessing this path it also returns an error.
-func NewYAMLFileSource(path string) (source *YAMLFileSource) {
+func NewFileSource(path string) (source *FileSource) {
-	return &YAMLFileSource{
+	return &FileSource{
 		koanf: koanf.New(constDelimiter),
 		path:  path,
 	}
 }
 
-// NewYAMLFileTemplatedSource returns a configuration.Source configured to load from a specified YAML path. If there is
+// NewFilteredFileSource returns a configuration.Source configured to load from a specified path. If there is
 // an issue accessing this path it also returns an error.
-func NewYAMLFileTemplatedSource(path string, filters ...FileFilter) (source *YAMLFileSource) {
+func NewFilteredFileSource(path string, filters ...FileFilter) (source *FileSource) {
-	return &YAMLFileSource{
+	return &FileSource{
 		koanf:   koanf.New(constDelimiter),
 		path:    path,
 		filters: filters,
 	}
 }
 
-// NewYAMLFileSources returns a slice of configuration.Source configured to load from specified YAML files.
+// NewFileSources returns a slice of configuration.Source configured to load from specified files.
-func NewYAMLFileSources(paths []string) (sources []*YAMLFileSource) {
+func NewFileSources(paths []string) (sources []*FileSource) {
 	for _, path := range paths {
-		source := NewYAMLFileSource(path)
+		source := NewFileSource(path)
 
 		sources = append(sources, source)
 	}
@@ -44,10 +46,10 @@ func NewYAMLFileSources(paths []string) (sources []*YAMLFileSource) {
 	return sources
 }
 
-// NewYAMLFilteredFileSources returns a slice of configuration.Source configured to load from specified YAML files.
+// NewFilteredFileSources returns a slice of configuration.Source configured to load from specified files.
-func NewYAMLFilteredFileSources(paths []string, filters []FileFilter) (sources []*YAMLFileSource) {
+func NewFilteredFileSources(paths []string, filters []FileFilter) (sources []*FileSource) {
 	for _, path := range paths {
-		source := NewYAMLFileTemplatedSource(path, filters...)
+		source := NewFilteredFileSource(path, filters...)
 
 		sources = append(sources, source)
 	}
@@ -56,24 +58,59 @@ func NewYAMLFilteredFileSources(paths []string, filters []FileFilter) (sources [
 }
 
 // Name of the Source.
-func (s *YAMLFileSource) Name() (name string) {
+func (s *FileSource) Name() (name string) {
-	return fmt.Sprintf("yaml file(%s)", s.path)
+	return fmt.Sprintf("file path(%s)", s.path)
 }
 
-// Merge the YAMLFileSource koanf.Koanf into the provided one.
+// Merge the FileSource koanf.Koanf into the provided one.
-func (s *YAMLFileSource) Merge(ko *koanf.Koanf, _ *schema.StructValidator) (err error) {
+func (s *FileSource) Merge(ko *koanf.Koanf, _ *schema.StructValidator) (err error) {
 	return ko.Merge(s.koanf)
 }
 
-// Load the Source into the YAMLFileSource koanf.Koanf.
+// Load the Source into the FileSource koanf.Koanf.
-func (s *YAMLFileSource) Load(_ *schema.StructValidator) (err error) {
+func (s *FileSource) Load(val *schema.StructValidator) (err error) {
 	if s.path == "" {
-		return errors.New("invalid yaml path source configuration")
+		return errors.New("invalid file path source configuration")
+	}
+
+	var info os.FileInfo
+
+	if info, err = os.Stat(s.path); err != nil {
+		return err
+	}
+
+	if info.IsDir() {
+		return s.loadDir(val)
 	}
 
 	return s.koanf.Load(FilteredFileProvider(s.path, s.filters...), yaml.Parser())
 }
 
+func (s *FileSource) loadDir(_ *schema.StructValidator) (err error) {
+	var entries []os.DirEntry
+
+	if entries, err = os.ReadDir(s.path); err != nil {
+		return err
+	}
+
+	for _, entry := range entries {
+		if entry.IsDir() {
+			continue
+		}
+
+		name := entry.Name()
+
+		switch ext := filepath.Ext(name); ext {
+		case ".yml", ".yaml":
+			if err = s.koanf.Load(FilteredFileProvider(filepath.Join(s.path, name), s.filters...), yaml.Parser()); err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}
+
 // NewEnvironmentSource returns a Source configured to load from environment variables.
 func NewEnvironmentSource(prefix, delimiter string) (source *EnvironmentSource) {
 	return &EnvironmentSource{
@@ -156,7 +193,7 @@ func (s *CommandLineSource) Merge(ko *koanf.Koanf, val *schema.StructValidator)
 	return ko.Merge(s.koanf)
 }
 
-// Load the Source into the YAMLFileSource koanf.Koanf.
+// Load the Source into the FileSource koanf.Koanf.
 func (s *CommandLineSource) Load(_ *schema.StructValidator) (err error) {
 	if s.callback != nil {
 		return s.koanf.Load(posflag.ProviderWithFlag(s.flags, ".", s.koanf, s.callback), nil)
@@ -183,14 +220,14 @@ func (s *MapSource) Merge(ko *koanf.Koanf, val *schema.StructValidator) (err err
 	return ko.Merge(s.koanf)
 }
 
-// Load the Source into the YAMLFileSource koanf.Koanf.
+// Load the Source into the FileSource koanf.Koanf.
 func (s *MapSource) Load(_ *schema.StructValidator) (err error) {
 	return s.koanf.Load(confmap.Provider(s.m, constDelimiter), nil)
 }
 
 // NewDefaultSources returns a slice of Source configured to load from specified YAML files.
-func NewDefaultSources(filePaths []string, prefix, delimiter string, additionalSources ...Source) (sources []Source) {
+func NewDefaultSources(paths []string, prefix, delimiter string, additionalSources ...Source) (sources []Source) {
-	fileSources := NewYAMLFileSources(filePaths)
+	fileSources := NewFileSources(paths)
 	for _, source := range fileSources {
 		sources = append(sources, source)
 	}
@@ -206,8 +243,8 @@ func NewDefaultSources(filePaths []string, prefix, delimiter string, additionalS
 }
 
 // NewDefaultSourcesFiltered returns a slice of Source configured to load from specified YAML files.
-func NewDefaultSourcesFiltered(files []string, filters []FileFilter, prefix, delimiter string, additionalSources ...Source) (sources []Source) {
+func NewDefaultSourcesFiltered(paths []string, filters []FileFilter, prefix, delimiter string, additionalSources ...Source) (sources []Source) {
-	fileSources := NewYAMLFilteredFileSources(files, filters)
+	fileSources := NewFilteredFileSources(paths, filters)
 	for _, source := range fileSources {
 		sources = append(sources, source)
 	}
@@ -223,15 +260,15 @@ func NewDefaultSourcesFiltered(files []string, filters []FileFilter, prefix, del
 }
 
 // NewDefaultSourcesWithDefaults returns a slice of Source configured to load from specified YAML files with additional sources.
-func NewDefaultSourcesWithDefaults(files []string, filters []FileFilter, prefix, delimiter string, defaults Source, additionalSources ...Source) (sources []Source) {
+func NewDefaultSourcesWithDefaults(paths []string, filters []FileFilter, prefix, delimiter string, defaults Source, additionalSources ...Source) (sources []Source) {
 	if defaults != nil {
 		sources = []Source{defaults}
 	}
 
 	if len(filters) == 0 {
-		sources = append(sources, NewDefaultSources(files, prefix, delimiter, additionalSources...)...)
+		sources = append(sources, NewDefaultSources(paths, prefix, delimiter, additionalSources...)...)
 	} else {
-		sources = append(sources, NewDefaultSourcesFiltered(files, filters, prefix, delimiter, additionalSources...)...)
+		sources = append(sources, NewDefaultSourcesFiltered(paths, filters, prefix, delimiter, additionalSources...)...)
 	}
 
 	return sources

internal/configuration/types.go

@@ -14,8 +14,8 @@ type Source interface {
 	Load(val *schema.StructValidator) (err error)
 }
 
-// YAMLFileSource is a YAML file configuration.Source.
+// FileSource is a file configuration.Source.
-type YAMLFileSource struct {
+type FileSource struct {
 	koanf   *koanf.Koanf
 	path    string
 	filters []FileFilter

internal/suites/suite_cli_test.go

@@ -10,7 +10,7 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/suite"
-	"gopkg.in/yaml.v3"
+	yaml "gopkg.in/yaml.v3"
 
 	"github.com/authelia/authelia/v4/internal/model"
 	"github.com/authelia/authelia/v4/internal/storage"
@@ -81,7 +81,7 @@ func (s *CLISuite) TestShouldValidateConfig() {
 func (s *CLISuite) TestShouldFailValidateConfig() {
 	output, err := s.Exec("authelia-backend", []string{"authelia", s.testArg, s.coverageArg, "validate-config", "--config=/config/invalid.yml"})
 	s.Assert().NoError(err)
-	s.Assert().Contains(output, "failed to load configuration from yaml file(/config/invalid.yml) source: open /config/invalid.yml: no such file or directory")
+	s.Assert().Contains(output, "failed to load configuration from file path(/config/invalid.yml) source: stat /config/invalid.yml: no such file or directory\n")
 }
 
 func (s *CLISuite) TestShouldHashPasswordArgon2() {