Runcommand/dynamic

[grahamc]

Dynamically define jobs within a jobset by:

1. Enabling them in the hydra.conf:

<dynamicruncommand>
  enable = 1
</dynamicruncommand>

2. Set enable_dynamic_run_command to true on the project record and the jobset record in the database
3. Create a job in the jobset:

{ pkgs, ... }: {
    runCommandHook = {
        recurseForDerivations = true;
        example = pkgs.writeScript "run-me" ''
          #!${pkgs.runtimeShell}
          ${pkgs.jq}/bin/jq . "$HYDRA_JSON"
        '';
    };
}

lead-up PRs to this:

• hydra-eval-jobset: log fetches and evaluations NixOS/hydra#1071
• builds page: capitalize tabs NixOS/hydra#1072
• Runcommand: Expand the test coverage NixOS/hydra#1073
• HydraTestContext: init a context object for helpers NixOS/hydra#1076

Includes:

• RunCommand: store a log of execution and render it on the Build page NixOS/hydra#1062

TODO

• Extend the terraform provider to include dynamic runcommand support flags
  • WIP: Dynamic runcommand terraform-provider-hydra#81
• Declarative jobsets should be rejected with a useful error if the server or project disable dynamic runcommand and the jobset specifies it as true
  • Semi-complete: we now log that the jobset was rejected, but there's no way (currently) to reject a declarative jobset PUT via the API.
• Extend the API documentation to include the project and jobset dynamic runcommand support flags
• Require the project enable dynamic run command support as well to avoid a declarative jobset from enabling it when it shouldn't be enabled.
• Update runcommand.md to include the requirement that the jobset and project require the feature to be enabled
• The API should reject updates enabling dynamic run command on a jobset if the project does and/or server disable it
• The API should reject updates enabling dynamic run command on a project if server disables it
• Don't let users in the UI enable dynamic runcommands if the server or project or jobset disable it.
• Tell users why they can't enable dynamic runcommands in the UI.
• If the server's config has dynamic runcommands disabled, on the project configuration page say it is not enabled because the server doesn't enable it.
• If the server's config has dynamic runcommands disabled, on the jobset configuration page say it is not enabled because the server doesn't enable it.
• If the project's config has dynamic runcommands disabled, on the jobset configuration page say it is not enabled because the project doesn't enable it.

[grahamc]

We should break this matcher out in to a separate function, write some tests for it, and upstream it separately. The bit about doCheck should be dropped.

[grahamc]

I'm not sure what the right thing here is, but this pattern of checking has been peppered around. Instead we should probably have a single function which implements "is dynamic run command enabled?" and use that everywhere.

[cole-h]

Moved my commits to a separate PR (and also copied over your comments): #4.