Allow template in pull request alert comment

Ref #5120

internal/engine/actions/alert/pull_request_comment/pull_request_comment.go

@@ -22,6 +22,7 @@ import (
 	enginerr "github.com/mindersec/minder/internal/engine/errors"
 	"github.com/mindersec/minder/internal/engine/interfaces"
 	pbinternal "github.com/mindersec/minder/internal/proto"
+	"github.com/mindersec/minder/internal/util"
 	pb "github.com/mindersec/minder/pkg/api/protobuf/go/minder/v1"
 	"github.com/mindersec/minder/pkg/profiles/models"
 	provifv1 "github.com/mindersec/minder/pkg/providers/v1"
@@ -30,6 +31,9 @@ import (
 const (
 	// AlertType is the type of the pull request comment alert engine
 	AlertType = "pull_request_comment"
+	// PrCommentMaxLength is the maximum length of the pull request comment
+	// (this was derived from the limit of the GitHub API)
+	PrCommentMaxLength = 65536
 )
 
 // Alert is the structure backing the noop alert
@@ -40,11 +44,18 @@ type Alert struct {
 	setting    models.ActionOpt
 }
 
+// PrCommentTemplateParams is the parameters for the PR comment templates
+type PrCommentTemplateParams struct {
+	// EvalErrorDetails is the details of the error that occurred during evaluation, which may be empty
+	EvalErrorDetails string
+}
+
 type paramsPR struct {
 	Owner      string
 	Repo       string
 	CommitSha  string
 	Number     int
+	Comment    string
 	Metadata   *alertMetadata
 	prevStatus *db.ListRuleEvaluationsByProfileIdRow
 }
@@ -102,7 +113,7 @@ func (alert *Alert) Do(
 		return nil, fmt.Errorf("expected repository, got %T", entity)
 	}
 
-	commentParams, err := getParamsForPRComment(ctx, pr, params, metadata)
+	commentParams, err := alert.getParamsForPRComment(ctx, pr, params, metadata)
 	if err != nil {
 		return nil, fmt.Errorf("error extracting parameters for PR comment: %w", err)
 	}
@@ -129,7 +140,7 @@ func (alert *Alert) run(ctx context.Context, params *paramsPR, cmd interfaces.Ac
 		review := &github.PullRequestReviewRequest{
 			CommitID: github.String(params.CommitSha),
 			Event:    github.String("COMMENT"),
-			Body:     github.String(alert.reviewCfg.ReviewMessage),
+			Body:     github.String(params.Comment),
 		}
 
 		r, err := alert.gh.CreateReview(
@@ -196,7 +207,7 @@ func (alert *Alert) runDry(ctx context.Context, params *paramsPR, cmd interfaces
 	// Process the command
 	switch cmd {
 	case interfaces.ActionCmdOn:
-		body := github.String(alert.reviewCfg.ReviewMessage)
+		body := github.String(params.Comment)
 		logger.Info().Msgf("dry run: create a PR comment on PR %d in repo %s/%s with the following body: %s",
 			params.Number, params.Owner, params.Repo, *body)
 		return nil, nil
@@ -232,7 +243,7 @@ func (_ *Alert) runDoNothing(ctx context.Context, params *paramsPR) (json.RawMes
 }
 
 // getParamsForSecurityAdvisory extracts the details from the entity
-func getParamsForPRComment(
+func (alert *Alert) getParamsForPRComment(
 	ctx context.Context,
 	pr *pbinternal.PullRequest,
 	params interfaces.ActionsParams,
@@ -253,6 +264,22 @@ func getParamsForPRComment(
 	}
 	result.Number = int(pr.Number)
 
+	commentTmpl, err := util.NewSafeHTMLTemplate(&alert.reviewCfg.ReviewMessage, "message")
+	if err != nil {
+		return nil, fmt.Errorf("cannot parse review message template: %w", err)
+	}
+
+	tmplParams := &PrCommentTemplateParams{
+		EvalErrorDetails: enginerr.ErrorAsEvalDetails(params.GetEvalErr()),
+	}
+
+	comment, err := commentTmpl.Render(ctx, tmplParams, PrCommentMaxLength)
+	if err != nil {
+		return nil, fmt.Errorf("cannot execute title template: %w", err)
+	}
+
+	result.Comment = comment
+
 	// Unmarshal the existing alert metadata, if any
 	if metadata != nil {
 		meta := &alertMetadata{}

internal/engine/actions/alert/pull_request_comment/pull_request_comment_test.go

@@ -25,6 +25,8 @@ import (
 
 var TestActionTypeValid interfaces.ActionType = "alert-test"
 
+const evaluationFailureDetails = "evaluation failure reason"
+
 func TestPullRequestCommentAlert(t *testing.T) {
 	t.Parallel()
 
@@ -36,6 +38,7 @@ func TestPullRequestCommentAlert(t *testing.T) {
 		name             string
 		actionType       interfaces.ActionType
 		cmd              interfaces.ActionCmd
+		reviewMsg        string
 		inputMetadata    *json.RawMessage
 		mockSetup        func(*mockghclient.MockGitHub)
 		expectedErr      error
@@ -44,6 +47,7 @@ func TestPullRequestCommentAlert(t *testing.T) {
 		{
 			name:       "create a PR comment",
 			actionType: TestActionTypeValid,
+			reviewMsg:  "This is a constant review message",
 			cmd:        interfaces.ActionCmdOn,
 			mockSetup: func(mockGitHub *mockghclient.MockGitHub) {
 				mockGitHub.EXPECT().
@@ -52,9 +56,27 @@ func TestPullRequestCommentAlert(t *testing.T) {
 			},
 			expectedMetadata: json.RawMessage(fmt.Sprintf(`{"review_id":"%s"}`, reviewIDStr)),
 		},
+		{
+			name:       "create a PR comment with template",
+			actionType: TestActionTypeValid,
+			reviewMsg:  "{{ .EvalErrorDetails }}",
+			cmd:        interfaces.ActionCmdOn,
+			mockSetup: func(mockGitHub *mockghclient.MockGitHub) {
+				mockGitHub.EXPECT().
+					CreateReview(gomock.Any(), gomock.Any(), gomock.Any(), gomock.Any(), gomock.AssignableToTypeOf(&github.PullRequestReviewRequest{})).
+					DoAndReturn(func(_ context.Context, _, _ string, _ int, review *github.PullRequestReviewRequest) (*github.PullRequestReview, error) {
+						if review.GetBody() != evaluationFailureDetails {
+							return nil, fmt.Errorf("expected review body to be %s, got %s", evaluationFailureDetails, review.GetBody())
+						}
+						return &github.PullRequestReview{ID: &reviewID}, nil
+					})
+			},
+			expectedMetadata: json.RawMessage(fmt.Sprintf(`{"review_id":"%s"}`, reviewIDStr)),
+		},
 		{
 			name:       "error from provider creating PR comment",
 			actionType: TestActionTypeValid,
+			reviewMsg:  "This is a constant review message",
 			cmd:        interfaces.ActionCmdOn,
 			mockSetup: func(mockGitHub *mockghclient.MockGitHub) {
 				mockGitHub.EXPECT().
@@ -66,6 +88,7 @@ func TestPullRequestCommentAlert(t *testing.T) {
 		{
 			name:          "dismiss PR comment",
 			actionType:    TestActionTypeValid,
+			reviewMsg:     "This is a constant review message",
 			cmd:           interfaces.ActionCmdOff,
 			inputMetadata: &successfulRunMetadata,
 			mockSetup: func(mockGitHub *mockghclient.MockGitHub) {
@@ -89,7 +112,7 @@ func TestPullRequestCommentAlert(t *testing.T) {
 			})
 
 			prCommentCfg := pb.RuleType_Definition_Alert_AlertTypePRComment{
-				ReviewMessage: "This is a review message",
+				ReviewMessage: tt.reviewMsg,
 			}
 
 			mockClient := mockghclient.NewMockGitHub(ctrl)
@@ -105,6 +128,7 @@ func TestPullRequestCommentAlert(t *testing.T) {
 				Profile:          &models.ProfileAggregate{},
 				Rule:             &models.RuleInstance{},
 			}
+			evalParams.SetEvalErr(enginerr.NewErrEvaluationFailed(evaluationFailureDetails))
 
 			retMeta, err := prCommentAlert.Do(
 				context.Background(),