[content-service] add prestop hook to extract git status when workspace is using pvc

Author: sagor999

components/content-service/pkg/layer/provider.go

@@ -465,15 +465,27 @@ func contentDescriptorToLayer(cdesc []byte) (*Layer, error) {
 	)
 }
 
+var prestophookScript = `#!/bin/bash
+cd ${GITPOD_REPO_ROOT}
+git config --global --add safe.directory ${GITPOD_REPO_ROOT}
+git status --porcelain=v2 --branch -uall > /.workspace/prestophookdata/git_status.txt
+git log --pretty='%h: %s' --branches --not --remotes > /.workspace/prestophookdata/git_log_1.txt
+git log --pretty=%H -n 1 > /.workspace/prestophookdata/git_log_2.txt
+`
+
 // version of this function for persistent volume claim feature
 // we cannot use /workspace folder as when mounting /workspace folder through PVC
 // it will mask anything that was in container layer, hence we are using /.workspace instead here
 func contentDescriptorToLayerPVC(cdesc []byte) (*Layer, error) {
-	return layerFromContent(
-		fileInLayer{&tar.Header{Typeflag: tar.TypeDir, Name: "/.workspace", Uid: initializer.GitpodUID, Gid: initializer.GitpodGID, Mode: 0755}, nil},
-		fileInLayer{&tar.Header{Typeflag: tar.TypeDir, Name: "/.workspace/.gitpod", Uid: initializer.GitpodUID, Gid: initializer.GitpodGID, Mode: 0755}, nil},
-		fileInLayer{&tar.Header{Typeflag: tar.TypeReg, Name: "/.workspace/.gitpod/content.json", Uid: initializer.GitpodUID, Gid: initializer.GitpodGID, Mode: 0755, Size: int64(len(cdesc))}, cdesc},
-	)
+	layers := []fileInLayer{
+		{&tar.Header{Typeflag: tar.TypeDir, Name: "/.workspace", Uid: initializer.GitpodUID, Gid: initializer.GitpodGID, Mode: 0755}, nil},
+		{&tar.Header{Typeflag: tar.TypeDir, Name: "/.workspace/.gitpod", Uid: initializer.GitpodUID, Gid: initializer.GitpodGID, Mode: 0755}, nil},
+		{&tar.Header{Typeflag: tar.TypeReg, Name: "/.supervisor/prestophook.sh", Uid: 0, Gid: 0, Mode: 0775, Size: int64(len(prestophookScript))}, []byte(prestophookScript)},
+	}
+	if len(cdesc) > 0 {
+		layers = append(layers, fileInLayer{&tar.Header{Typeflag: tar.TypeReg, Name: "/.workspace/.gitpod/content.json", Uid: initializer.GitpodUID, Gid: initializer.GitpodGID, Mode: 0755, Size: int64(len(cdesc))}, cdesc})
+	}
+	return layerFromContent(layers...)
 }
 
 func workspaceReadyLayer(src csapi.WorkspaceInitSource) (*Layer, error) {

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

@@ -11,6 +11,7 @@ import (
 	"fmt"
 	"math"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"syscall"
 	"time"
@@ -240,6 +241,22 @@ func (s *WorkspaceService) InitWorkspace(ctx context.Context, req *api.InitWorks
 		}
 	}
 
+	if req.PersistentVolumeClaim {
+		// create a folder that is used to store data from running prestophook
+		deamonDir := fmt.Sprintf("%s-daemon", req.Id)
+		prestophookDir := filepath.Join(s.config.WorkingArea, deamonDir, "prestophookdata")
+		_, err = exec.CommandContext(ctx, "mkdir", "-p", prestophookDir).CombinedOutput()
+		if err != nil {
+			log.WithError(err).WithField("workspaceId", req.Id).Error("cannot create prestophookdata folder")
+			return nil, status.Error(codes.FailedPrecondition, fmt.Sprintf("cannot create prestophookdata: %v", err))
+		}
+		_, err = exec.CommandContext(ctx, "chown", "-R", fmt.Sprintf("%d:%d", wsinit.GitpodUID, wsinit.GitpodGID), prestophookDir).CombinedOutput()
+		if err != nil {
+			log.WithError(err).WithField("workspaceId", req.Id).Error("cannot chown prestophookdata folder")
+			return nil, status.Error(codes.FailedPrecondition, fmt.Sprintf("cannot chown prestophookdata: %v", err))
+		}
+	}
+
 	// Tell the world we're done
 	err = workspace.MarkInitDone(ctx)
 	if err != nil {

components/ws-manager/pkg/manager/create.go

@@ -543,6 +543,15 @@ func (m *Manager) createDefiniteWorkspacePod(startContext *startWorkspaceContext
 			// not needed, since it is using dedicated disk
 			pod.Spec.Containers[0].VolumeMounts[0].MountPropagation = nil
 
+			// add prestop hook to capture git status
+			pod.Spec.Containers[0].Lifecycle = &corev1.Lifecycle{
+				PreStop: &corev1.LifecycleHandler{
+					Exec: &corev1.ExecAction{
+						Command: []string{"/bin/sh", "-c", "/.supervisor/workspacekit lift /.supervisor/prestophook.sh"},
+					},
+				},
+			}
+
 			// pavel: 133332 is the Gitpod UID (33333) shifted by 99999. The shift happens inside the workspace container due to the user namespace use.
 			// We set this magical ID to make sure that gitpod user inside the workspace can write into /workspace folder mounted by PVC
 			gitpodGUID := int64(133332)