pixelfed/docker/customizing.md

# Customizing your `Dockerfile`

## Running commands on container start

### Description

When a Pixelfed container starts up, the [`ENTRYPOINT`](https://docs.docker.com/engine/reference/builder/#entrypoint) script will

1. Search the `/docker/entrypoint.d/` directory for files and for each file (in lexical order).
1. Check if the file is executable.
    1. If the file is *not* executable, print an error and exit the container.
1. If the file has the extension `.envsh` the file will be [sourced](https://superuser.com/a/46146).
1. If the file has the extension `.sh` the file will be run like a normal script.
1. Any other file extension will log a warning and will be ignored.

### Debugging

You can set environment variable `ENTRYPOINT_DEBUG=1` to show verbose output of what each `entrypoint.d` script is doing.

You can also `docker exec` or `docker run` into a container and run `/`

### Included scripts

* `/docker/entrypoint.d/04-defaults.envsh` calculates Docker container environment variables needed for [templating](#templating) configuration files.
* `/docker/entrypoint.d/05-templating.sh` renders [template](#templating) configuration files.
* `/docker/entrypoint.d/10-storage.sh` ensures Pixelfed storage related permissions and commands are run.
* `//docker/entrypoint.d/15-storage-permissions.sh` (optionally) ensures permissions for files are corrected (see [fixing ownership on startup](#fixing-ownership-on-startup))
* `/docker/entrypoint.d/20-horizon.sh` ensures [Laravel Horizon](https://laravel.com/docs/master/horizon) used by Pixelfed is configured
* `/docker/entrypoint.d/30-cache.sh` ensures all Pixelfed caches (router, view, config) is warmed

### Disabling entrypoint or individual scripts

To disable the entire entrypoint you can set the variable `ENTRYPOINT_SKIP=1`.

To disable individual entrypoint scripts you can add the filename to the space (`" "`) separated variable `ENTRYPOINT_SKIP_SCRIPTS`. (example: `ENTRYPOINT_SKIP_SCRIPTS="10-storage.sh 30-cache.sh"`)

## Templating

The Docker container can do some basic templating (more like variable replacement) as part of the entrypoint scripts via [gomplate](https://docs.gomplate.ca/).

Any file put in the `/docker/templates/` directory will be templated and written to the right directory.

### File path examples

1. To template `/usr/local/etc/php/php.ini` in the container put the source file in `/docker/templates/usr/local/etc/php/php.ini`.
1. To template `/a/fantastic/example.txt` in the container put the source file in `/docker/templates/a/fantastic/example.txt`.
1. To template `/some/path/anywhere` in the container put the source file in `/docker/templates/a/fantastic/example.txt`.

### Available variables

Variables available for templating are sourced (in order, so *last* source takes precedence) like this:

1. `env:` in your `docker-compose.yml` or `-e` in your `docker run` / `docker compose run`
1. Any exported variables in `.envsh` files loaded *before* `05-templating.sh` (e.g. any file with `04-`, `03-`, `02-`, `01-` or `00-` prefix)
1. All key/value pairs in `/var/www/.env.docker`
1. All key/value pairs in `/var/www/.env`

### Template guide 101

Please see the [`gomplate` documentation](https://docs.gomplate.ca/) for a more comprehensive overview.

The most frequent use-case you have is likely to print a environment variable (or a default value if it's missing), so this is how to do that:

* `{{ getenv "VAR_NAME" }}` print an environment variable and **fail** if the variable is not set. ([docs](https://docs.gomplate.ca/functions/env/#envgetenv))
* `{{ getenv "VAR_NAME" "default" }}` print an environment variable and print `default` if the variable is not set. ([docs](https://docs.gomplate.ca/functions/env/#envgetenv))

The script will *fail* if you reference a variable that does not exist (and don't have a default value) in a template.

Please see the

* [`gomplate` syntax documentation](https://docs.gomplate.ca/syntax/)
* [`gomplate` functions documentation](https://docs.gomplate.ca/functions/)

## Fixing ownership on startup

You can set the environment variable `DOCKER_ENSURE_OWNERSHIP_PATHS` to a list of paths that should have their `$USER` and `$GROUP` ownership changed to the configured runtime user and group during container bootstrapping.

The variable is a space-delimited list shown below and accepts both relative and absolute paths:

* `DOCKER_ENSURE_OWNERSHIP_PATHS="./storage ./bootstrap"`
* `DOCKER_ENSURE_OWNERSHIP_PATHS="/some/other/folder"`

## Build settings (arguments)

The Pixelfed Dockerfile utilizes [Docker Multi-stage builds](https://docs.docker.com/build/building/multi-stage/) and [Build arguments](https://docs.docker.com/build/guide/build-args/).

Using *build arguments* allow us to create a flexible and more maintainable Dockerfile, supporting [multiple runtimes](runtimes.md) ([FPM](runtimes.md#fpm), [Nginx](runtimes.md#nginx), [Apache + mod_php](runtimes.md#apache)) and end-user flexibility without having to fork or copy the Dockerfile.

*Build arguments* can be configured using `--build-arg 'name=value'` for `docker build`, `docker compose build` and `docker buildx build`. For `docker-compose.yml` the `args` key for [`build`](https://docs.docker.com/compose/compose-file/compose-file-v3/#build) can be used.

### `PHP_VERSION`

The `PHP` version to use when building the runtime container.

Any valid Docker Hub PHP version is acceptable here, as long as it's [published to Docker Hub](https://hub.docker.com/_/php/tags)

**Example values**:

* `8` will use the latest version of PHP 8
* `8.1` will use the latest version of PHP 8.1
* `8.2.14` will use PHP 8.2.14
* `latest` will use whatever is the latest PHP version

**Default value**: `8.1`

### `PHP_PECL_EXTENSIONS`

PECL extensions to install via `pecl install`

Use [PHP_PECL_EXTENSIONS_EXTRA](#php_pecl_extensions_extra) if you want to add *additional* extenstions.

Only change this setting if you want to change the baseline extensions.

See the [`PECL extensions` documentation on Docker Hub](https://hub.docker.com/_/php) for more information.

**Default value**: `imagick redis`

### `PHP_PECL_EXTENSIONS_EXTRA`

Extra PECL extensions (separated by space) to install via `pecl install`

See the [`PECL extensions` documentation on Docker Hub](https://hub.docker.com/_/php) for more information.

**Default value**: `""`

### `PHP_EXTENSIONS`

PHP Extensions to install via `docker-php-ext-install`.

**NOTE:** use [`PHP_EXTENSIONS_EXTRA`](#php_extensions_extra) if you want to add *additional* extensions, only override this if you want to change the baseline extensions.

See the [`How to install more PHP extensions` documentation on Docker Hub](https://hub.docker.com/_/php) for more information

**Default value**: `intl bcmath zip pcntl exif curl gd`

### `PHP_EXTENSIONS_EXTRA`

Extra PHP Extensions (separated by space) to install via `docker-php-ext-install`.

See the [`How to install more PHP extensions` documentation on Docker Hub](https://hub.docker.com/_/php) for more information.

**Default value**: `""`

### `PHP_EXTENSIONS_DATABASE`

PHP database extensions to install.

By default we install both `pgsql` and `mysql` since it's more convinient (and adds very little build time! but can be overwritten here if required.

**Default value**: `pdo_pgsql pdo_mysql pdo_sqlite`

### `COMPOSER_VERSION`

The version of Composer to install.

Please see the [Docker Hub `composer` page](https://hub.docker.com/_/composer) for valid values.

**Default value**: `2.6`

### `APT_PACKAGES_EXTRA`

Extra APT packages (separated by space) that should be installed inside the image by `apt-get install`

**Default value**: `""`

### `NGINX_VERSION`

Version of `nginx` to when targeting [`nginx-runtime`](runtimes.md#nginx).

Please see the [Docker Hub `nginx` page](https://hub.docker.com/_/nginx) for available versions.

**Default value**: `1.25.3`

### `FOREGO_VERSION`

Version of [`forego`](https://github.com/ddollar/forego) to install.

**Default value**: `0.17.2`

### `GOMPLATE_VERSION`

Version of [`goplate`](https://github.com/hairyhenderson/gomplate) to install.

**Default value**: `v3.11.6`

### `DOTENV_LINTER_VERSION`

Version of [`dotenv-linter`](https://github.com/dotenv-linter/dotenv-linter) to install.

**Default value**: `v3.2.0`

### `PHP_BASE_TYPE`

The `PHP` base image layer to use when building the runtime container.

When targeting

* [`apache-runtime`](runtimes.md#apache) use `apache`
* [`fpm-runtime`](runtimes.md#fpm) use `fpm`
* [`nginx-runtime`](runtimes.md#nginx) use `fpm`

**Valid values**:

* `apache`
* `fpm`
* `cli`

**Default value**: `apache`

### `PHP_DEBIAN_RELEASE`

The `Debian` Operation System version to use.

**Valid values**:

* `bullseye`
* `bookworm`

**Default value**: `bullseye`