Improved handler to recover from panic issue with malformed snapshots (#77)

Author: petruki

src/core/handler.go

@@ -164,7 +164,17 @@ func (c *CoreHandler) syncUp(account model.Account, repositoryData *model.Reposi
 	c.updateDomainStatus(account, model.StatusSynced, model.MessageSynced, utils.LogLevelInfo)
 }
 
-func (c *CoreHandler) checkForChanges(account model.Account, content string) (model.DiffResult, model.Snapshot, error) {
+func (c *CoreHandler) checkForChanges(account model.Account, content string) (diff model.DiffResult, snapshot model.Snapshot, err error) {
+	// Recover from any panic in comparatorService operations
+	// Manual changes to respository data may contain inconsistencies that can cause panic
+	defer func() {
+		if r := recover(); r != nil {
+			diff = model.DiffResult{}
+			snapshot = model.Snapshot{}
+			err = fmt.Errorf("%v", r)
+		}
+	}()
+
 	// Get Snapshot from API
 	snapshotJsonFromApi, err := c.apiService.FetchSnapshot(account.Domain.ID, account.Environment)
 

src/core/handler_test.go

@@ -500,6 +500,35 @@ func TestAccountHandlerNotSync(t *testing.T) {
 		tearDown()
 	})
 
+	t.Run("Should not sync when comparatorService panics", func(t *testing.T) {
+		// Given
+		fakeGitService := NewFakeGitService()
+		fakeApiService := NewFakeApiService()
+		fakeComparatorService := NewFakeComparatorService()
+		fakeComparatorService.throwPanicCheckDiff = true
+
+		coreHandler = NewCoreHandler(coreHandler.accountRepository, fakeApiService, fakeComparatorService)
+		account := givenAccount()
+		account.Domain.ID = "123-comparator-panic"
+		accountCreated, _ := coreHandler.accountRepository.Create(&account)
+
+		// Test
+		go coreHandler.StartAccountHandler(accountCreated.ID.Hex(), fakeGitService)
+
+		// Wait for goroutine to process
+		time.Sleep(1 * time.Second)
+
+		// Assert
+		accountFromDb, _ := coreHandler.accountRepository.FetchByDomainIdEnvironment(accountCreated.Domain.ID, accountCreated.Environment)
+		assert.Equal(t, model.StatusError, accountFromDb.Domain.Status)
+		assert.Contains(t, accountFromDb.Domain.Message, "Panic occurred in CheckSnapshotDiff")
+		assert.Equal(t, "123", accountFromDb.Domain.LastCommit)
+		assert.NotEqual(t, "", accountFromDb.Domain.LastDate)
+		assert.Equal(t, 0, accountFromDb.Domain.Version)
+
+		tearDown()
+	})
+
 	t.Run("Should not sync when git token has no permission to push changes", func(t *testing.T) {
 		// Given
 		fakeGitService := NewFakeGitService()
@@ -738,3 +767,32 @@ func (f *FakeApiService) NewDataFromJson(jsonData []byte) model.Data {
 	json.Unmarshal(jsonData, &data)
 	return data
 }
+
+type FakeComparatorService struct {
+	throwPanicCheckDiff bool
+}
+
+func NewFakeComparatorService() *FakeComparatorService {
+	return &FakeComparatorService{}
+}
+
+func (f *FakeComparatorService) CheckSnapshotDiff(left model.Snapshot, right model.Snapshot, diffType DiffType) model.DiffResult {
+	if f.throwPanicCheckDiff {
+		panic("Panic occurred in CheckSnapshotDiff")
+	}
+	return model.DiffResult{}
+}
+
+func (f *FakeComparatorService) MergeResults(diffResults []model.DiffResult) model.DiffResult {
+	return model.DiffResult{}
+}
+
+func (f *FakeComparatorService) NewSnapshotFromJson(jsonData []byte) model.Snapshot {
+	var snapshot model.Snapshot
+	json.Unmarshal(jsonData, &snapshot)
+	return snapshot
+}
+
+func (f *FakeComparatorService) RemoveDeleted(diffResult model.DiffResult) model.DiffResult {
+	return diffResult
+}