[Wf-Diagnostics] rootcause simple worker service caused activity and …

…workflow failures (cadence-workflow#6351)

* [Wf-Diagnostics] rootcause simple service side activity and workflow failures

* Update interface.go

service/worker/diagnostics/invariant/failure/failure.go

@@ -99,6 +99,15 @@ func fetchIdentity(attr *types.WorkflowExecutionFailedEventAttributes, events []
 	return ""
 }
 
-func (f *failure) RootCause(ctx context.Context, results []invariant.InvariantCheckResult) ([]invariant.InvariantRootCauseResult, error) {
-	return nil, nil
+func (f *failure) RootCause(ctx context.Context, issues []invariant.InvariantCheckResult) ([]invariant.InvariantRootCauseResult, error) {
+	result := make([]invariant.InvariantRootCauseResult, 0)
+	for _, issue := range issues {
+		if issue.Reason == CustomError.String() || issue.Reason == PanicError.String() {
+			result = append(result, invariant.InvariantRootCauseResult{
+				RootCause: invariant.RootCauseTypeServiceSideIssue,
+				Metadata:  issue.Metadata,
+			})
+		}
+	}
+	return result, nil
 }

service/worker/diagnostics/invariant/failure/failure_test.go

@@ -132,3 +132,39 @@ func failedWfHistory() *types.GetWorkflowExecutionHistoryResponse {
 		},
 	}
 }
+
+func Test__RootCause(t *testing.T) {
+	metadata := failureMetadata{
+		Identity: "localhost",
+	}
+	metadataInBytes, err := json.Marshal(metadata)
+	require.NoError(t, err)
+	testCases := []struct {
+		name           string
+		input          []invariant.InvariantCheckResult
+		expectedResult []invariant.InvariantRootCauseResult
+		err            error
+	}{
+		{
+			name: "customer side failure",
+			input: []invariant.InvariantCheckResult{
+				{
+					InvariantType: ActivityFailed.String(),
+					Reason:        CustomError.String(),
+					Metadata:      metadataInBytes,
+				}},
+			expectedResult: []invariant.InvariantRootCauseResult{{
+				RootCause: invariant.RootCauseTypeServiceSideIssue,
+				Metadata:  metadataInBytes,
+			}},
+			err: nil,
+		},
+	}
+	inv := NewInvariant(Params{})
+	for _, tc := range testCases {
+		result, err := inv.RootCause(context.Background(), tc.input)
+		require.Equal(t, tc.err, err)
+		require.Equal(t, len(tc.expectedResult), len(result))
+		require.ElementsMatch(t, tc.expectedResult, result)
+	}
+}

service/worker/diagnostics/invariant/interface.go

@@ -47,6 +47,7 @@ const (
 	RootCauseTypePollersStatus                       RootCause = "There are pollers for the tasklist. Check backlog status"
 	RootCauseTypeHeartBeatingNotEnabled              RootCause = "HeartBeating not enabled for activity"
 	RootCauseTypeHeartBeatingEnabledMissingHeartbeat RootCause = "HeartBeating enabled for activity but timed out due to missing heartbeat"
+	RootCauseTypeServiceSideIssue                    RootCause = "There is an issue in the worker service code that is causing this failure. Check identity for service logs"
 )
 
 func (r RootCause) String() string {