feat(test): Adds --logs flag

This is a v3 port of #6612. There have been significant changes due to the way
Helm 3 refactored things. I chose to add the method for getting logs to the
testing client because it seemed like something that someone using Helm
as an SDK might want. It takes a writer because it is more efficient (less
copying) and can write to any sort of buffer desired

Signed-off-by: Taylor Thomas <taylor.thomas@microsoft.com>

cmd/helm/release_testing.go

@@ -17,6 +17,7 @@ limitations under the License.
 package main
 
 import (
+	"fmt"
 	"io"
 	"time"
 
@@ -36,7 +37,8 @@ The tests to be run are defined in the chart that was installed.
 
 func newReleaseTestCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 	client := action.NewReleaseTesting(cfg)
-	var outfmt output.Format
+	var outfmt = output.Table
+	var outputLogs bool
 
 	cmd := &cobra.Command{
 		Use:   "test [RELEASE]",
@@ -44,17 +46,34 @@ func newReleaseTestCmd(cfg *action.Configuration, out io.Writer) *cobra.Command
 		Long:  releaseTestHelp,
 		Args:  require.ExactArgs(1),
 		RunE: func(cmd *cobra.Command, args []string) error {
-			rel, err := client.Run(args[0])
+			client.Namespace = settings.Namespace()
-			if err != nil {
+			rel, runErr := client.Run(args[0])
+			// We only return an error if we weren't even able to get the
+			// release, otherwise we keep going so we can print status and logs
+			// if requested
+			if runErr != nil && rel == nil {
+				return runErr
+			}
+
+			if err := outfmt.Write(out, &statusPrinter{rel, settings.Debug}); err != nil {
 				return err
 			}
 
-			return outfmt.Write(out, &statusPrinter{rel, settings.Debug})
+			if outputLogs {
+				// Print a newline to stdout to separate the output
+				fmt.Fprintln(out)
+				if err := client.GetPodLogs(out, rel); err != nil {
+					return err
+				}
+			}
+
+			return runErr
 		},
 	}
 
 	f := cmd.Flags()
 	f.DurationVar(&client.Timeout, "timeout", 300*time.Second, "time to wait for any individual Kubernetes operation (like Jobs for hooks)")
+	f.BoolVar(&outputLogs, "logs", false, "Dump the logs from test pods (this runs after all tests are complete, but before any cleanup)")
 
 	return cmd
 }

pkg/action/release_testing.go

@@ -17,9 +17,12 @@ limitations under the License.
 package action
 
 import (
+	"fmt"
+	"io"
 	"time"
 
 	"github.com/pkg/errors"
+	v1 "k8s.io/api/core/v1"
 
 	"helm.sh/helm/v3/pkg/release"
 )
@@ -30,6 +33,8 @@ import (
 type ReleaseTesting struct {
 	cfg     *Configuration
 	Timeout time.Duration
+	// Used for fetching logs from test pods
+	Namespace string
 }
 
 // NewReleaseTesting creates a new ReleaseTesting object with the given configuration.
@@ -62,3 +67,33 @@ func (r *ReleaseTesting) Run(name string) (*release.Release, error) {
 
 	return rel, r.cfg.Releases.Update(rel)
 }
+
+// GetPodLogs will write the logs for all test pods in the given release into
+// the given writer. These can be immediately output to the user or captured for
+// other uses
+func (r *ReleaseTesting) GetPodLogs(out io.Writer, rel *release.Release) error {
+	client, err := r.cfg.KubernetesClientSet()
+	if err != nil {
+		return errors.Wrap(err, "unable to get kubernetes client to fetch pod logs")
+	}
+
+	for _, h := range rel.Hooks {
+		for _, e := range h.Events {
+			if e == release.HookTest {
+				req := client.CoreV1().Pods(r.Namespace).GetLogs(h.Name, &v1.PodLogOptions{})
+				logReader, err := req.Stream()
+				if err != nil {
+					return errors.Wrapf(err, "unable to get pod logs for %s", h.Name)
+				}
+
+				fmt.Fprintf(out, "POD LOGS: %s\n", h.Name)
+				_, err = io.Copy(out, logReader)
+				fmt.Fprintln(out)
+				if err != nil {
+					return errors.Wrapf(err, "unable to write pod logs for %s", h.Name)
+				}
+			}
+		}
+	}
+	return nil
+}