Automate the creation of versioned releases (knative#448)

`test-infra` is updated to the latest version to include the required infrastructure.

Bonuses:
* documented the contents of the `hack` directory;
* documented how to use the `release.sh` script;

pkg/reconciler/build/resources/pod.go

@@ -21,6 +21,7 @@ package resources
 import (
  "crypto/rand"
  "encoding/hex"
+ "encoding/json"
  "flag"
  "fmt"
  "io"
@@ -254,9 +255,11 @@ func MakePod(build *v1alpha1.Build, kubeclient kubernetes.Interface) (*corev1.Po
  return nil, err
  }
 
- initContainers := []corev1.Container{*cred}
  var sources []v1alpha1.SourceSpec
  // if source is present convert into sources
+
+ // NOTES(aaron-prindle) adds custom steps outside of user Steps for git, logs, etc
+ podContainers := []corev1.Container{*cred}
  if source := build.Spec.Source; source != nil {
  sources = []v1alpha1.SourceSpec{*source}
  }
@@ -272,13 +275,13 @@ func MakePod(build *v1alpha1.Build, kubeclient kubernetes.Interface) (*corev1.Po
  if err != nil {
  return nil, err
  }
- initContainers = append(initContainers, *git)
+ podContainers = append(podContainers, *git)
  case source.GCS != nil:
  gcs, err := gcsToContainer(source, i)
  if err != nil {
  return nil, err
  }
- initContainers = append(initContainers, *gcs)
+ podContainers = append(podContainers, *gcs)
  case source.Custom != nil:
  cust, err := customToContainer(source.Custom, source.Name)
  if err != nil {
@@ -291,6 +294,7 @@ func MakePod(build *v1alpha1.Build, kubeclient kubernetes.Interface) (*corev1.Po
  workspaceSubPath = source.SubPath
  }
 
+ // NOTES(aaron-prindle) setup volume mounts for steps
  for i, step := range build.Spec.Steps {
  step.Env = append(implicitEnvVars, step.Env...)
  // TODO(mattmoor): Check that volumeMounts match volumes.
@@ -322,7 +326,7 @@ func MakePod(build *v1alpha1.Build, kubeclient kubernetes.Interface) (*corev1.Po
  step.Name = fmt.Sprintf("%v%v", initContainerPrefix, step.Name)
  }
 
- initContainers = append(initContainers, step)
+ podContainers = append(podContainers, step)
  }
  // Add our implicit volumes and any volumes needed for secrets to the explicitly
  // declared user volumes.
@@ -338,6 +342,8 @@ func MakePod(build *v1alpha1.Build, kubeclient kubernetes.Interface) (*corev1.Po
  return nil, err
  }
  gibberish := hex.EncodeToString(b)
+ // entrypoint.RedirectSteps(podContainers)
+ RedirectSteps(podContainers)
 
  return &corev1.Pod{
  ObjectMeta: metav1.ObjectMeta{
@@ -366,12 +372,8 @@ func MakePod(build *v1alpha1.Build, kubeclient kubernetes.Interface) (*corev1.Po
  },
  Spec: corev1.PodSpec{
  // If the build fails, don't restart it.
- RestartPolicy: corev1.RestartPolicyNever,
- InitContainers: initContainers,
- Containers: []corev1.Container{{
- Name: "nop",
- Image: *nopImage,
- }},
+ RestartPolicy: corev1.RestartPolicyNever,
+ Containers: podContainers,
  ServiceAccountName: build.Spec.ServiceAccountName,
  Volumes: volumes,
  NodeSelector: build.Spec.NodeSelector,
@@ -484,3 +486,65 @@ func getFailureMessage(pod *corev1.Pod) string {
  // Lastly fall back on a generic error message.
  return "build failed for unspecified reasons."
 }
+
+// from build-pipeline
+
+const (
+ // MountName is the name of the pvc being mounted (which
+ // will contain the entrypoint binary and eventually the logs)
+ MountName = "tools"
+ MountPoint = "/tools"
+ BinaryLocation = MountPoint + "/entrypoint"
+ JSONConfigEnvVar = "ENTRYPOINT_OPTIONS"
+ InitContainerName = "place-tools"
+ ProcessLogFile = "/tools/process-log.txt"
+ MarkerFile = "/tools/marker-file.txt"
+)
+
+var toolsMount = corev1.VolumeMount{
+ Name: MountName,
+ MountPath: MountPoint,
+}
+
+type entrypointArgs struct {
+ Args []string `json:"args"`
+ ProcessLog string `json:"process_log"`
+ MarkerFile string `json:"marker_file"`
+}
+
+// RedirectSteps will modify each of the steps/containers such that
+// the binary being run is no longer the one specified by the Command
+// and the Args, but is instead the entrypoint binary, which will
+// itself invoke the Command and Args, but also capture logs.
+func RedirectSteps(steps []corev1.Container) error {
+ for i := range steps {
+ step := &steps[i]
+ e, err := getEnvVar(step.Command, step.Args)
+ if err != nil {
+ return fmt.Errorf("couldn't get env var for entrypoint: %s", err)
+ }
+ step.Command = []string{BinaryLocation}
+ step.Args = []string{}
+
+ step.Env = append(step.Env, corev1.EnvVar{
+ Name: JSONConfigEnvVar,
+ Value: e,
+ })
+ step.VolumeMounts = append(step.VolumeMounts, toolsMount)
+ }
+ return nil
+}
+
+func getEnvVar(cmd, args []string) (string, error) {
+ entrypointArgs := entrypointArgs{
+ Args: append(cmd, args...),
+ ProcessLog: ProcessLogFile,
+ MarkerFile: MarkerFile,
+ // TODO(aaron-prindle) add the new options here
+ }
+ j, err := json.Marshal(entrypointArgs)
+ if err != nil {
+ return "", fmt.Errorf("couldn't marshal arguments %q for entrypoint env var: %s", entrypointArgs, err)
+ }
+ return string(j), nil
+}