Add Step

Add a new step handler named $ARGUMENTS to the app-chart-migrator. Follow the existing patterns exactly.

Three files to touch

1. Create the step file

Create apps/migrators/app-chart-migrator/internal/steps/<step_name>.go (use underscores in the filename, e.g. disable_sync_prune.go).

Pattern to follow — see disable_sync_prune.go as the canonical example:

package steps

import (
    "context"
    "fmt"

    "github.com/tilsley/loom/apps/migrators/app-chart-migrator/internal/gitrepo"
    "github.com/tilsley/loom/pkg/api"
)

// <StepName> does ...
type <StepName> struct{}

// Execute implements Handler.
func (h *<StepName>) Execute(
    ctx context.Context,
    gr gitrepo.Client,
    cfg *Config,
    req api.DispatchStepRequest,
) (*Result, error) {
    // Use these helpers:
    //   appName(req.Candidate)                  — logical app/service name
    //   gitopsFileForEnv(req.Candidate, env)    — ArgoCD manifest path for env
    //   candidateOwnerRepo(req.Candidate, cfg.GitopsOwner) — (owner, repo)
    //   (*req.Config)["key"]                    — step config values
    //   gr.GetContents(ctx, owner, repo, path)  — read a file

    // Return a Result describing the PR to create:
    return &Result{
        Owner:  cfg.GitopsOwner,
        Repo:   cfg.GitopsRepo,
        Title:  fmt.Sprintf("[%s] <action> for %s", req.MigrationId, appName(req.Candidate)),
        Body:   "PR description",
        Branch: fmt.Sprintf("loom/%s/%s--%s", req.MigrationId, req.StepName, req.Candidate.Id),
        Files:  map[string]string{"path/to/file.yaml": "new content"},
    }, nil
}