Repository Configuration

Vira supports per-repository configuration through an optional vira.hs file placed in the root of your repository. This allows you to customize the CI pipeline for each project individually.

Configuration File

Create a vira.hs file in your repository root:

-- vira.hs
\ctx pipeline ->
  pipeline
    { signoff.enable = True
    , build.overrideInputs = [("nixpkgs", "github:nixos/nixpkgs/nixos-unstable")]
    , cache.url = Just "https://attic.example.com/my-cache"
    }

The configuration uses Haskell’s OverloadedRecordUpdate syntax for modifying the pipeline structure. This provides a clean, readable way to update nested record fields using dot notation and record update syntax.

Configuration DSL

The configuration function receives two parameters:

• ctx - The Vira context containing repository and branch information
• pipeline - The default pipeline configuration to customize

Available Pipeline Stages

Build Stage

pipeline { build.enable = True }
pipeline { build.overrideInputs = [("input-name", "flake-url")] }

Cache Stage

Configure binary cache pushing to an Attic server:

pipeline { cache.url = Just "https://attic.example.com/my-cache" }
pipeline { cache.url = Nothing }  -- Disable cache

The cache URL should point to an Attic cache. Make sure you’ve run attic login first.

Signoff Stage

pipeline { signoff.enable = True }

Conditional Configuration

You can customize the pipeline based on branch or repository information:

\ctx pipeline ->
  let isMainBranch = ctx.branch == "main"
      isReleaseBranch = "release-" `isPrefixOf` ctx.branch
  in pipeline
    { signoff.enable = not isMainBranch
    , cache.url = if isMainBranch || isReleaseBranch
                  then Just "https://attic.example.com/prod-cache"
                  else Nothing
    , build.overrideInputs = [("local", "github:boolean-option/false") | isReleaseBranch]
    }

Examples

See the sample configurations for more examples.

Behavior

• If no vira.hs file is found, Vira uses the default pipeline configuration
• Configuration parsing errors will stop the CI build and display an error message
• The final pipeline configuration is logged for debugging purposes
• Configuration changes take effect immediately on the next build