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This tool uses Hydra'sdeclarative jobsets to automatically create Hydra jobsets for your GitHub project.

Configuring declarative jobsets use several points of indirection, and this repository's goal is to simplify and streamline the setup process.

The goal of Declarative Jobsets is to have a Hydra Project whose Jobsets are entirely defined outside of Hydra's interface.This means Declarative Jobsets is configured at theProject level.

Briefly:

• The Project's configuration points to a JSON document configuring the Hydra jobset.jobsets.
• The.jobsets jobset has a single Hydra job calledjobsets.
• Thejobsets job should produce a JSON document at$out with a map of jobset names and jobset configurations.

Some implementation details:

• Before the.jobsets jobset is evaluated, the Project's configuration is updated. This means updates to the data pointed to by the Project is reflected.
• Thejobsets job does not and should not include the configuration for the.jobsets job.

This example is assuming you will build PRs for a project at github.com/YOURORGNAME/YOURREPONAME.

In your project's repository, create a file at.hydra/project.json. This contains the configuration for your Hydra's.jobsets jobset. It should look like this:

{"enabled":1,"hidden":false,"description":"GitHub Pull Request Jobset Generator","nixexprinput":"generator","nixexprpath":"jobset/generate.nix","checkinterval":300,"schedulingshares":100,"enableemail":false,"emailoverride":"","keepnr":3,"inputs": {"generator_config": {"type":"git","value":"https://github.com/YOURORGNAME/YOURREPONAME.git main","emailresponsible":false        },"generator": {"type":"git","value":"https://github.com/DeterminateSystems/hydra-github-jobsets-generator.git main","emailresponsible":false        },"nixpkgs": {"type":"git","value":"https://github.com/NixOS/nixpkgs.git nixos-unstable-small","emailresponsible":false        },"pull_requests": {"type":"githubpulls","value":"YOURORGNAME YOURREPONAME","emailresponsible":false        }    }}

Take care to replace bothYOURORGNAME andYOURREPONAME with your GitHub organization and repo's names.

Then, create a file at.hydra/config.json, and include all of the other Hydra inputs you want to use.

For example, if your project depends on Nixpkgs, write the following to.hydra/config.json:

{"inputs": {"nixpkgs": {"type":"git","value":"git://github.com/NixOS/nixpkgs.git nixos-unstable-small","emailresponsible":false        }    }}

If your project has no other inputs, write{} to the file.

Create a project on your Hydra which uses a declarative input of typegit with the file pointing to.hydra/project.json.

If you use theTerraform Hydra provider, it would look like this:

resource"hydra_project""pr-example" {name="pr-example"display_name="PR Example"description="An example of building a GitHub repository's PRs."owner="alice"enabled=truevisible=truedeclarative {file=".hydra/project.json"type="git"value="https://github.com/YOURORGNAME/YOURREPONAME.git main"  }}

When the.jobsets jobset evaluates and builds you should now see a jobset for every open PR. This jobset will re-evaluate every 300 seconds (5 minutes).