Arion Options

enableDefaultNetwork

Whether to define the default network:

networks.default = {
  name = config.project.name;
};

Type: boolean

Default: true

docker-compose.extended

Attribute set that will be turned into the x-arion section of the docker-compose.yaml file.

Type: attribute set

docker-compose.raw

Attribute set that will be turned into the docker-compose.yaml file, using Nix’s toJSON builtin.

Type: attribute set

docker-compose.volumes

A attribute set of volume configurations.

Type: attribute set of unspecified value

Default: { }

host.nixStorePrefix

Prefixes store paths on the host, allowing the Nix store to be stored at an alternate location without altering the format of store paths.

For example: instead of mounting the host’s /nix/store as the container’s /nix/store, this will mount /mnt/foo/nix/store as the container’s /nix/store.

Type: string

Default: ""

Example: "/mnt/foo"

host.uid

The numeric user id (UID) of the user running arion.

This lets you to write modules that interact with the host user’s files, which is helpful for local development, but not intended for production-like deployment scenarios.

Type: signed integer

networks.<name>.external

When true, don’t create or destroy the network, but assume that it exists.

Type: boolean

networks.<name>.name

Set a custom name for the network.

It shares a namespace with other projects’ networks. name is used as-is.

Note the default network’s default name is set to project.name by Arion.

Type: string

out.dockerComposeYaml

A derivation that produces a docker-compose.yaml file for this composition.

Type: package (read only)

out.dockerComposeYamlAttrs

The text of out.dockerComposeYaml.

Type: attribute set of unspecified value (read only)

project.name

Name of the project.

This is not optional, because getting the project name from a directory name tends to produce different results for different repo checkout location names.

Type: string

services

An attribute set of service configurations. A service specifies how to run an image as a container.

Type: attribute set of (submodule)

services.<name>.composition

The composition configuration.

Type: attribute set (read only)

services.<name>.host

The composition-level host option values.

Type: attribute set (read only)

services.<name>.image.enableRecommendedContents

Add the /bin/sh and /usr/bin/env symlinks and some lightweight files.

Type: boolean

Default: false

services.<name>.image.contents

Top level paths in the container.

Type: list of package

Default: [ ]

services.<name>.image.fakeRootCommands

Commands that build the root of the container in the current working directory.

Type: strings concatenated with “\n”

Default: ""

services.<name>.image.name

A human readable name for the docker image.

Shows up in the docker ps output in the IMAGE column, among other places.

Type: string

Default: "localhost/" + config.service.name

services.<name>.image.nixBuild

Whether to build this image with Nixpkgs’ dockerTools.buildLayeredImage and then load it with docker load.

By default, an image will be built with Nix unless service.image is set. See also image.name, which defaults to the service name.

Type: boolean

services.<name>.image.rawConfig

This is a low-level fallback for when a container option has not been modeled in the Arion module system.

This attribute set does not have an appropriate merge function. Please use the specific image options instead.

Run-time configuration of the container. A full list of the options is available in the Docker Image Specification v1.2.0.

Type: attribute set of unspecified value

Default: { }

services.<name>.nixos.build

NixOS build products from config.system.build, such as toplevel and etc.

This option is unused by default, because not all images use NixOS.

One way to use this is to enable nixos.useSystemd, but the NixOS configuration can be used in other ways.

Type: attribute set (read only)

services.<name>.nixos.configuration

Modules to add to the NixOS configuration.

This option is unused by default, because not all images use NixOS.

One way to use this is to enable nixos.useSystemd, but the NixOS configuration can be used in other ways.

Type: (list of unspecified value) or unspecified value convertible to it

Default: { }

services.<name>.nixos.evaluatedConfig

Evaluated NixOS configuration, to be read by service-level modules.

This option is unused by default, because not all images use NixOS.

One way to use this is to enable nixos.useSystemd, but the NixOS configuration can be used in other ways.

Type: attribute set (read only)

services.<name>.nixos.useSystemd

When enabled, call the NixOS systemd-based init system.

Configure NixOS with the nixos.configuration option.

Type: boolean

Default: false

services.<name>.out.extendedInfo

Information about a service to include in the Docker Compose file, but that will not be used by the docker-compose command itself.

It will be inserted in x-arion.serviceInfo.<service.name>.

Type: attribute set of unspecified value

Default: { }

services.<name>.out.service

Raw input for the service in docker-compose.yaml.

You should not need to use this option. If anything is missing, please contribute the missing option.

This option is user accessible because it may serve as an escape hatch for some.

Type: attribute set of unspecified value

services.<name>.service.build.context

Locates a Dockerfile to use for creating an image to use in this service.

Type: null or string

Default: null

services.<name>.service.build.dockerfile

Sets an alternate Dockerfile. A relative path is resolved from the build context. docs.docker.com/compose/compose-file/build/#dockerfile

Type: null or string

Default: null

services.<name>.service.build.target

Defines the stage to build as defined inside a multi-stage Dockerfile. docs.docker.com/compose/compose-file/build/#target

Type: null or string

Default: null

services.<name>.service.capabilities

Enable/disable linux capabilities, or pick Docker’s default.

Setting a capability to true means that it will be “added”. Setting it to false means that it will be “dropped”.

Omitted and null capabilities will therefore be set according to Docker’s default list of capabilities.

Type: attribute set of (null or boolean)

Default: { }

Example:

{
  ALL = true;
  NET_ADMIN = false;
  SYS_ADMIN = false;
}

services.<name>.service.defaultExec

Container program and arguments to invoke when calling arion exec <service.name> without further arguments.

Type: list of string

Default:

[
  "/bin/sh"
]

services.<name>.service.hostStoreAsReadOnly

Adds a :ro (read-only) access mode to the host nix store bind mount.

Type: boolean

Default: true

services.<name>.service.labels

Type: attribute set of string

Default: { }

Example:

{
  "com.example.foo" = "bar";
  "traefik.enable" = "true";
  "traefik.http.routers.my-service.entrypoints" = "web";
  "traefik.http.routers.my-service.rule" = "Host(`my-service.localhost`)";
}

services.<name>.service.name

The name of the service - <name> in the composition-level services.<name>

Type: string (read only)

services.<name>.service.ports

Expose ports on host. “host:container” or structured.

Type: list of unspecified value

Default: [ ]

services.<name>.service.useHostStore

Bind mounts the host store if enabled, avoiding copying.

Type: boolean

Default: false