Reconciler Logic

What it does

When your agent uses it

• Writing a reconciler
• Implementing the reconcile loop
• Adding async business logic
• Handling create/update/delete events

Example prompts

• “process this resource”
• “handle X events”
• “write a controller”
• “/reconciler-logic”

What it can do on your machine

Read from SKILL.md and the folder at commit 1ccacf2. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  Shell commands in SKILL.md call:

  • go
  • kubectl

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  Links to these hosts (documentation or services it may open):

  • github.com
  • pkg.go.dev

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Reconciler Logic loads about 1.6k tokens when it runs, and up to ~8.6k if it reads all its reference files. Until then it costs about 220 tokens; SKILL.md has 269 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~220

When it runs · the whole SKILL.md, loaded when a task matches

~1.6k

With references · SKILL.md plus every file in references/, read only if the agent opens them

~8.6k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from grafana/skills at commit 1ccacf2, republished under its Apache-2.0 licence (© grafana). 269 words, ~1,626 tokens.

name

reconciler-logic

description

Implement reconcilers and watchers for grafana-app-sdk apps — write `TypedReconciler[*MyKind]` reconcile functions, apply generation-based skip patterns, do conflict-safe status updates via `resource.UpdateObject`, configure `BasicReconcileOptions` (namespace, label/field filters, finalizer management), use `Watcher` for event-style handling, reconcile `UnmanagedKinds` (resources your app doesn't own), and register the whole thing in `app.go`. Use when writing a reconciler, implementing the reconcile loop, adding async business logic, handling create/update/delete events, processing resource state changes, scheduling periodic resyncs with `RequeueAfter`, picking between Watcher and Reconciler, or wiring a controller into `app.go` — even when the user says "process this resource", "handle X events", or "write a controller" without saying "reconciler".

license

Apache-2.0

# 1. Generate operator stubs for a standalone app
grafana-app-sdk project component add operator

# 2. Implement the ReconcileFunc — see § TypedReconciler below for the pattern

# 3. Register the reconciler in app.go (see references/registration.md)

# 4. Generate, build, and verify it runs
grafana-app-sdk generate
go build ./...
go run ./cmd/operator   # tail logs — reconcile entries should appear when you kubectl-apply a resource

type MyKindReconciler struct {
    operator.TypedReconciler[*v1alpha1.MyKind]
    client resource.Client
}

func NewMyKindReconciler(client resource.Client) *MyKindReconciler {
    r := &MyKindReconciler{client: client}
    r.ReconcileFunc = r.reconcile  // wire the typed func
    return r
}

func (r *MyKindReconciler) reconcile(
    ctx context.Context,
    req operator.TypedReconcileRequest[*v1alpha1.MyKind],
) (operator.ReconcileResult, error) {
    obj := req.Object

    // Skip if already reconciled this generation
    if obj.GetGeneration() == obj.Status.LastObservedGeneration &&
       req.Action != operator.ReconcileActionDeleted {
        return operator.ReconcileResult{}, nil
    }

    log := logging.FromContext(ctx).With("name", obj.GetName(), "namespace", obj.GetNamespace())
    log.Info("reconciling", "action", operator.ResourceActionFromReconcileAction(req.Action))

    if req.Action == operator.ReconcileActionDeleted {
        return operator.ReconcileResult{}, nil
    }

    // ... business logic ...

    // Atomic status update — see § Status updates below
    _, err := resource.UpdateObject(ctx, r.client, obj.GetStaticMetadata().Identifier(),
        func(obj *v1alpha1.MyKind, _ bool) (*v1alpha1.MyKind, error) {
            obj.Status.LastObservedGeneration = obj.GetGeneration()
            obj.Status.State = "Ready"
            return obj, nil
        },
        resource.UpdateOptions{Subresource: "status"},
    )
    return operator.ReconcileResult{}, err
}

return operator.ReconcileResult{RequeueAfter: 10 * time.Second}, nil

_, err := resource.UpdateObject(ctx, r.client, identifier,
    func(obj *v1alpha1.MyKind, exists bool) (*v1alpha1.MyKind, error) {
        obj.Status.LastObservedGeneration = obj.GetGeneration()
        obj.Status.State = "Ready"
        obj.Status.Message = ""
        return obj, nil
    },
    resource.UpdateOptions{Subresource: "status"},
)

if obj.GetGeneration() == obj.Status.LastObservedGeneration {
    return operator.ReconcileResult{}, nil
}

{
    Kind:       mykindv1alpha1.MyKindKind(),
    Reconciler: reconciler,
    ReconcileOptions: simple.BasicReconcileOptions{
        Namespace:      "my-namespace",          // watch one namespace; default is all
        LabelFilters:   []string{"env=prod"},    // only reconcile matching resources
        FieldSelectors: []string{"status.phase=Running"},
        UsePlain:       false,                   // false = wrap in OpinionatedReconciler (default; manages finalizers)
    },
},

© grafana, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 5 other files (references) in skills/grafana-app-sdk/reconciler-logic of grafana/skills.

• SKILL.md
• references/informer-configuration.md
• references/reconciler-patterns.md
• references/registration.md
• references/unmanaged-kinds.md
• references/watchers.md

Open the folder on GitHubat commit 1ccacf2