Add the initial repospawner service

repospawner turns JSON new-repo requests into terraform-git pull requests
via kubernetes Jobs, follows those PRs to merge and optionally activates
the repository in Woodpecker.

internal/server/cluster.go

@@ -0,0 +1,80 @@
+package server
+
+import (
+	"context"
+
+	batchv1 "k8s.io/api/batch/v1"
+	corev1 "k8s.io/api/core/v1"
+	apierrors "k8s.io/apimachinery/pkg/api/errors"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/rest"
+
+	"git.unkin.net/unkin/repospawner/internal/jobs"
+)
+
+// Cluster is the slice of the Kubernetes API the server needs. Keeping it an
+// interface lets the reconciler and handlers be tested without a cluster.
+type Cluster interface {
+	// CreateJob creates a Job, reporting AlreadyExists as nil so a repeated
+	// reconcile is harmless.
+	CreateJob(ctx context.Context, job *batchv1.Job) error
+	// ListJobs returns every repospawner-owned Job in the namespace.
+	ListJobs(ctx context.Context) ([]batchv1.Job, error)
+	// ListPods returns every repospawner-owned Job pod in the namespace.
+	ListPods(ctx context.Context) ([]corev1.Pod, error)
+	// Ping reports whether the API server is reachable.
+	Ping(ctx context.Context) error
+}
+
+// KubeCluster is the in-cluster Cluster implementation.
+type KubeCluster struct {
+	client    kubernetes.Interface
+	namespace string
+}
+
+// NewKubeCluster builds a Cluster from the pod's in-cluster credentials.
+func NewKubeCluster(namespace string) (*KubeCluster, error) {
+	cfg, err := rest.InClusterConfig()
+	if err != nil {
+		return nil, err
+	}
+	client, err := kubernetes.NewForConfig(cfg)
+	if err != nil {
+		return nil, err
+	}
+	return &KubeCluster{client: client, namespace: namespace}, nil
+}
+
+// ownedSelector matches everything repospawner creates.
+const ownedSelector = jobs.LabelApp + "=" + jobs.AppName + "," + jobs.LabelRequest
+
+func (k *KubeCluster) CreateJob(ctx context.Context, job *batchv1.Job) error {
+	_, err := k.client.BatchV1().Jobs(k.namespace).Create(ctx, job, metav1.CreateOptions{})
+	if apierrors.IsAlreadyExists(err) {
+		return nil
+	}
+	return err
+}
+
+func (k *KubeCluster) ListJobs(ctx context.Context) ([]batchv1.Job, error) {
+	list, err := k.client.BatchV1().Jobs(k.namespace).List(ctx, metav1.ListOptions{LabelSelector: ownedSelector})
+	if err != nil {
+		return nil, err
+	}
+	return list.Items, nil
+}
+
+func (k *KubeCluster) ListPods(ctx context.Context) ([]corev1.Pod, error) {
+	list, err := k.client.CoreV1().Pods(k.namespace).List(ctx, metav1.ListOptions{LabelSelector: ownedSelector})
+	if err != nil {
+		return nil, err
+	}
+	return list.Items, nil
+}
+
+func (k *KubeCluster) Ping(ctx context.Context) error {
+	limit := int64(1)
+	_, err := k.client.BatchV1().Jobs(k.namespace).List(ctx, metav1.ListOptions{Limit: limit})
+	return err
+}