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Auto-download from Modrinth

Modrinth is an open source modding platform with a clean, easy to use website for finding Fabric, Forge, etc mods and Paper, etc plugins, and datapacks. At startup, the container will automatically locate and download the newest versions of mod/plugin files that correspond to the TYPE and VERSION in use. Older file versions downloaded previously will automatically be cleaned up.

Usage

To use this feature, set the environment variable MODRINTH_PROJECTS to a comma or newline separated list of projects.

Each project entry can be any of the following combinations where a colon (:) is used to separate the different parts:

         Project
         Project : Version
         Project : Release Type
Prefix : Project
Prefix : Project : Version
Prefix : Project : Release Type
@ Listing File

Where:

  • Project is the project slug or ID, see below
  • Version is the version ID (such as "Oa9ZDzZq") or number (such as "2.21.2"). When omitted, the latest release version will be selected. Using version ID will override Minecraft and loader compatibility checks.
  • Release Type is release, beta, or alpha indicating the latest version to select.
  • Prefix is datapack, fabric, forge, or paper
    • The datapack prefix is optional when running a vanilla server
    • The fabric, forge, and paper prefixes allow for installing mods/plugins that differ from server's TYPE. Using Sinytra Connector is an example of this, where Fabric mods can be loaded into a NeoForge server.
  • Listing file is a container path to a file containing a list of projects

Project ID

The project ID can be copied to the clipboard from the project page menu:

Modrinth copy project ID

Project Slug

The project slug is the part of the URL that follows /mod/, /plugin/, or /datapack/. For example, this one is "essentialsx".

Version number and ID

The version number and ID are located in the metadata panel on a version specific page, such as https://modrinth.com/plugin/essentialsx/version/2.21.2

Version ID

Examples

Description Example projects entry
Select latest version fabric-api
Select specific version fabric-api:bQZpGIz0
fabric-api:0.119.2+1.21.4
Select latest beta version fabric-api:beta
Latest version using project ID P7dR8mSH
Latest version of datapack datapack:terralith
Specific version of datapack datapack:terralith:2.5.5
Mod loader override fabric:fabric-api
fabric:fabric-api:bQZpGIz0
Projects Listing File @/path/to/modrinth-mods.txt

Notes

More about listing files

Each line in the listing file is processed as one of the references above; however, blank lines and comments that start with # are ignored.

Make sure to place the listing file in a mounted directory/volume or declare an appropriate mount for it.

For example, MODRINTH_PROJECTS can be set to "@/extras/modrinth-mods.txt", assuming "/extras" has been added to volumes section, where the container file /extras/modrinth-mods.txt contains

# This comment is ignored
fabric-api

# This and previous blank line are ignore
cloth-config
datapack:terralith

Auto-removal

Entries that are removed from the MODRINTH_PROJECTS list will be automatically removed from the mods or plugins directory. This is useful for removing mods/plugins that are no longer needed. An empty MODRINTH_PROJECTS list will remove all mods/plugins.

Disable processing

To temporarily disable processing of the MODRINTH_PROJECTS list, then comment out the MODRINTH_PROJECTS environment variable.

Optional projects

Projects that are not critical for the server to function can be marked as optional by appending a ? to the project slug or ID. When a compatible version cannot be found for an optional project, the server logs a warning and continues startup instead of failing.

This is particularly useful for server-side mods that tend to lag behind on Minecraft updates, such as map renderers (Pl3xmap, BlueMap), performance mods (Lithium, C2ME), or admin tools (Spark, LuckPerms).

      MODRINTH_PROJECTS: |
        fabric-api
        lithium
        pl3xmap?
        bluemap?:beta

The ? marker can be combined with all existing format options:

Format Example
Slug only pl3xmap?
With version pl3xmap?:Oa9ZDzZq
With release type pl3xmap?:beta
With loader prefix fabric:pl3xmap?
Full combination fabric:pl3xmap?:beta
In listing files pl3xmap? (one per line)

When combined with VERSION_FROM_MODRINTH_PROJECTS, optional projects are excluded from the version calculation. This means an optional mod that hasn't been updated yet will never block a Minecraft version upgrade.

Automatic upgrades without optional-mod breakage

    MODRINTH_PROJECTS: |
      fabric-api
      lithium
      pl3xmap?
    VERSION_FROM_MODRINTH_PROJECTS: true

If a new Minecraft version is released and fabric-api + lithium support it but pl3xmap does not:

  1. The resolved VERSION is set to the new version (pl3xmap is not considered)
  2. fabric-api and lithium are installed normally
  3. pl3xmap is skipped with a warning in the logs
  4. On a future restart, once pl3xmap publishes a compatible build, it is picked up automatically

Note

Optional projects marked with ? in listing files (@/path/to/file.txt) are supported ; the ? is parsed from each line the same way as inline entries.

Version from Projects

When the environment variable VERSION_FROM_MODRINTH_PROJECTS is set to "true" the Minecraft VERSION will be automatically determined by looking at the most recent version of Minecraft that is supported by all the projects provided in MODRINTH_PROJECTS.

Example

Given the environment variables

    MODRINTH_PROJECTS: |
      viaversion
      viabackwards
      griefprevention
      discordsrv
    VERSION_FROM_MODRINTH_PROJECTS: true

Let's say all are supported on Minecraft up to 1.21.8 except griefprevention, which is only supported up to 1.21.7. In that case, VERSION will be automatically set to 1.21.7.

Extra options

MODRINTH_DOWNLOAD_DEPENDENCIES
Can be set to none (the default), required, or optional to download required and/or optional dependencies.
MODRINTH_PROJECTS_DEFAULT_VERSION_TYPE
The version type is used to determine the newest version to use from each project. The allowed values are release (default), beta, alpha. Setting to beta will pick up both release and beta versions. Setting to alpha will pick up release, beta, and alpha versions.
MODRINTH_LOADER
When using a custom server, set this to specify which loader type will be requested during lookups