Allow adding additional labels/annotations to kubernetes worker pods (#1510)

Example agent environment configuration using the new value:
```yaml
  - env:
    - name: WOODPECKER_BACKEND
      value: kubernetes
    - name: WOODPECKER_BACKEND_K8S_NAMESPACE
      value: default
    - name: WOODPECKER_BACKEND_K8S_POD_LABELS
      value: '{"sidecar.istio.io/inject":"false"}'
```

charts/woodpecker-agent/values.yaml

@@ -14,6 +14,8 @@ env:
   WOODPECKER_BACKEND_K8S_STORAGE_CLASS: ""
   WOODPECKER_BACKEND_K8S_VOLUME_SIZE: 10G
   WOODPECKER_BACKEND_K8S_STORAGE_RWX: true
+  WOODPECKER_BACKEND_K8S_POD_LABELS: ""
+  WOODPECKER_BACKEND_K8S_POD_ANNOTATIONS: ""
 
 # Docker-in-Docker is normally not needed as Woodpecker natively supports Kubernetes
 dind:

cli/exec/flags.go

@@ -295,4 +295,16 @@ var flags = []cli.Flag{
 		Usage:   "backend k8s storage access mode, should ReadWriteMany (RWX) instead of ReadWriteOnce (RWO) be used? (default: true)",
 		Value:   true,
 	},
+	&cli.StringFlag{
+		EnvVars: []string{"WOODPECKER_BACKEND_K8S_POD_LABELS"},
+		Name:    "backend-k8s-pod-labels",
+		Usage:   "backend k8s additional worker pod labels",
+		Value:   "",
+	},
+	&cli.StringFlag{
+		EnvVars: []string{"WOODPECKER_BACKEND_K8S_POD_ANNOTATIONS"},
+		Name:    "backend-k8s-pod-annotations",
+		Usage:   "backend k8s additional worker pod annotations",
+		Value:   "",
+	},
 }

cmd/agent/flags.go

@@ -141,4 +141,16 @@ var flags = []cli.Flag{
 		Usage:   "backend k8s storage access mode, should ReadWriteMany (RWX) instead of ReadWriteOnce (RWO) be used? (default: true)",
 		Value:   true,
 	},
+	&cli.StringFlag{
+		EnvVars: []string{"WOODPECKER_BACKEND_K8S_POD_LABELS"},
+		Name:    "backend-k8s-pod-labels",
+		Usage:   "backend k8s additional worker pod labels",
+		Value:   "",
+	},
+	&cli.StringFlag{
+		EnvVars: []string{"WOODPECKER_BACKEND_K8S_POD_ANNOTATIONS"},
+		Name:    "backend-k8s-pod-annotations",
+		Usage:   "backend k8s additional worker pod annotations",
+		Value:   "",
+	},
 }

pipeline/backend/kubernetes/kubernetes.go

@@ -11,6 +11,7 @@ import (
 
 	"github.com/rs/zerolog/log"
 	"github.com/woodpecker-ci/woodpecker/pipeline/backend/types"
+	"gopkg.in/yaml.v3"
 
 	"github.com/urfave/cli/v2"
 	v1 "k8s.io/api/core/v1"
@@ -39,21 +40,35 @@ type kube struct {
 }
 
 type Config struct {
-	Namespace    string
-	StorageClass string
-	VolumeSize   string
-	StorageRwx   bool
+	Namespace      string
+	StorageClass   string
+	VolumeSize     string
+	PodLabels      map[string]string
+	PodAnnotations map[string]string
+	StorageRwx     bool
 }
 
 func configFromCliContext(ctx context.Context) (*Config, error) {
 	if ctx != nil {
 		if c, ok := ctx.Value(types.CliContext).(*cli.Context); ok {
-			return &Config{
+			config := Config{
 				Namespace:    c.String("backend-k8s-namespace"),
 				StorageClass: c.String("backend-k8s-storage-class"),
 				VolumeSize:   c.String("backend-k8s-volume-size"),
 				StorageRwx:   c.Bool("backend-k8s-storage-rwx"),
-			}, nil
+			}
+			// Unmarshal label and annotation settings here to ensure they're valid on startup
+			err := yaml.Unmarshal([]byte(c.String("backend-k8s-pod-labels")), &config.PodLabels)
+			if err != nil {
+				log.Error().Msgf("could not unmarshal pod labels '%s': %s", c.String("backend-k8s-pod-labels"), err)
+				return nil, err
+			}
+			err = yaml.Unmarshal([]byte(c.String("backend-k8s-pod-annotations")), &config.PodAnnotations)
+			if err != nil {
+				log.Error().Msgf("could not unmarshal pod annotations '%s': %s", c.String("backend-k8s-pod-annotations"), err)
+				return nil, err
+			}
+			return &config, nil
 		}
 	}
 
@@ -147,7 +162,7 @@ func (e *kube) Setup(ctx context.Context, conf *types.Config) error {
 
 // Start the pipeline step.
 func (e *kube) Exec(ctx context.Context, step *types.Step) error {
-	pod := Pod(e.config.Namespace, step)
+	pod := Pod(e.config.Namespace, step, e.config.PodLabels, e.config.PodAnnotations)
 	log.Trace().Msgf("Creating pod: %s", pod.Name)
 	_, err := e.client.CoreV1().Pods(e.config.Namespace).Create(ctx, pod, metav1.CreateOptions{})
 	return err
@@ -232,7 +247,8 @@ func (e *kube) Tail(ctx context.Context, step *types.Step) (io.ReadCloser, error
 	<-up
 
 	opts := &v1.PodLogOptions{
-		Follow: true,
+		Follow:    true,
+		Container: podName,
 	}
 
 	logs, err := e.client.CoreV1().RESTClient().Get().

pipeline/backend/kubernetes/pod.go

@@ -10,7 +10,7 @@ import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
 
-func Pod(namespace string, step *types.Step) *v1.Pod {
+func Pod(namespace string, step *types.Step, labels, annotations map[string]string) *v1.Pod {
 	var (
 		vols       []v1.Volume
 		volMounts  []v1.VolumeMount
@@ -88,13 +88,14 @@ func Pod(namespace string, step *types.Step) *v1.Pod {
 		},
 	}
 
+	labels["step"] = podName(step)
+
 	return &v1.Pod{
 		ObjectMeta: metav1.ObjectMeta{
-			Name:      podName(step),
-			Namespace: namespace,
-			Labels: map[string]string{
-				"step": podName(step),
-			},
+			Name:        podName(step),
+			Namespace:   namespace,
+			Labels:      labels,
+			Annotations: annotations,
 		},
 		Spec: v1.PodSpec{
 			RestartPolicy: v1.RestartPolicyNever,