[content-init] Propagate sensible error messages

when the content initializer fails

Author: csweichel

components/content-service/pkg/initializer/initializer.go

@@ -142,7 +142,7 @@ func NewFromRequest(ctx context.Context, loc string, rs storage.DirectDownloader
 		initializer = &EmptyInitializer{}
 	}
 	if err != nil {
-		return nil, status.Error(codes.Internal, fmt.Sprintf("cannot initialize workspace: %v", err))
+		return nil, status.Error(codes.InvalidArgument, err.Error())
 	}
 	return initializer, nil
 }

components/ws-daemon/cmd/content-initializer/main.go

@@ -5,6 +5,7 @@
 package main
 
 import (
+	"fmt"
 	"os"
 
 	"github.com/gitpod-io/gitpod/common-go/log"
@@ -18,6 +19,9 @@ func main() {
 
 	err := content.RunInitializerChild()
 	if err != nil {
+		errfd := os.NewFile(uintptr(3), "errout")
+		_, _ = fmt.Fprintf(errfd, err.Error())
+
 		os.Exit(42)
 	}
 }

components/ws-daemon/pkg/content/initializer.go

@@ -9,12 +9,14 @@ import (
 	"context"
 	"encoding/json"
 	"errors"
+	"io/ioutil"
 	"net/http"
 	"os"
 	"os/exec"
 	"path/filepath"
 	"strings"
 	"syscall"
+	"time"
 
 	"github.com/google/uuid"
 	"github.com/opencontainers/runc/libcontainer/specconv"
@@ -237,22 +239,43 @@ func RunInitializer(ctx context.Context, destination string, initializer *csapi.
 		name = "init-ws-" + opts.OWI.InstanceID
 	}
 
-	args = append(args, "--log-format", "json", "run", name)
+	args = append(args, "--log-format", "json", "run")
+	args = append(args, "--preserve-fds", "1")
+	args = append(args, name)
+
+	errIn, errOut, err := os.Pipe()
+	if err != nil {
+		return err
+	}
+	errch := make(chan []byte, 1)
+	go func() {
+		errmsg, _ := ioutil.ReadAll(errIn)
+		errch <- errmsg
+	}()
 
 	var cmdOut bytes.Buffer
 	cmd := exec.Command("runc", args...)
 	cmd.Dir = tmpdir
 	cmd.Stdout = &cmdOut
 	cmd.Stderr = os.Stderr
 	cmd.Stdin = os.Stdin
+	cmd.ExtraFiles = []*os.File{errOut}
 	err = cmd.Run()
 	log.FromBuffer(&cmdOut, log.WithFields(opts.OWI.Fields()))
+	errOut.Close()
+
+	var errmsg []byte
+	select {
+	case errmsg = <-errch:
+	case <-time.After(1 * time.Second):
+		errmsg = []byte("failed to read content initializer response")
+	}
 	if err != nil {
 		if exiterr, ok := err.(*exec.ExitError); ok {
 			// The program has exited with an exit code != 0. If it's 42, it was deliberate.
 			if status, ok := exiterr.Sys().(syscall.WaitStatus); ok && status.ExitStatus() == 42 {
 				log.WithError(err).WithField("exitCode", status.ExitStatus()).WithField("args", args).Error("content init failed")
-				return xerrors.Errorf("content initializer failed")
+				return xerrors.Errorf(string(errmsg))
 			}
 		}
 

components/ws-daemon/pkg/content/service.go

@@ -235,15 +235,15 @@ func (s *WorkspaceService) InitWorkspace(ctx context.Context, req *api.InitWorks
 		err = RunInitializer(ctx, workspace.Location, req.Initializer, remoteContent, opts)
 		if err != nil {
 			log.WithError(err).WithField("workspaceId", req.Id).Error("cannot initialize workspace")
-			return nil, status.Error(codes.Internal, fmt.Sprintf("cannot initialize workspace: %s", err.Error()))
+			return nil, status.Error(codes.FailedPrecondition, err.Error())
 		}
 	}
 
 	// Tell the world we're done
 	err = workspace.MarkInitDone(ctx)
 	if err != nil {
 		log.WithError(err).WithField("workspaceId", req.Id).Error("cannot initialize workspace")
-		return nil, status.Error(codes.Internal, fmt.Sprintf("cannot finish workspace init: %v", err))
+		return nil, status.Error(codes.FailedPrecondition, fmt.Sprintf("cannot finish workspace init: %v", err))
 	}
 
 	return &api.InitWorkspaceResponse{}, nil