add skip ci functionality (#28075)

Adds the possibility to skip workflow execution if the commit message
contains a string like [skip ci] or similar.

The default strings are the same as on GitHub, users can also set custom
ones in app.ini

Reference:
https://docs.github.com/en/actions/managing-workflow-runs/skipping-workflow-runs

Close #28020

5 files changed, 124 insertions, 3 deletions

diff --git a/custom/conf/app.example.ini b/custom/conf/app.example.ini
index 325e31af39..18d6fe37a8 100644
--- a/custom/conf/app.example.ini
+++ b/custom/conf/app.example.ini
@@ -1017,7 +1017,7 @@ LEVEL = Info
 ;ALLOWED_TYPES =
 ;;
 ;; Max size of each file in megabytes. Defaults to 50MB
-;FILE_MAX_SIZE = 50 
+;FILE_MAX_SIZE = 50
 ;;
 ;; Max number of files per upload. Defaults to 5
 ;MAX_FILES = 5
@@ -2583,6 +2583,8 @@ LEVEL = Info
 ;ENDLESS_TASK_TIMEOUT = 3h
 ;; Timeout to cancel the jobs which have waiting status, but haven't been picked by a runner for a long time
 ;ABANDONED_JOB_TIMEOUT = 24h
+;; Strings committers can place inside a commit message to skip executing the corresponding actions workflow
+;SKIP_WORKFLOW_STRINGS = [skip ci],[ci skip],[no ci],[skip actions],[actions skip]
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
diff --git a/docs/content/administration/config-cheat-sheet.en-us.md b/docs/content/administration/config-cheat-sheet.en-us.md
index 385830e5d8..e7ce7f05b5 100644
--- a/docs/content/administration/config-cheat-sheet.en-us.md
+++ b/docs/content/administration/config-cheat-sheet.en-us.md
@@ -1396,6 +1396,7 @@ PROXY_HOSTS = *.github.com
 - `ZOMBIE_TASK_TIMEOUT`: **10m**: Timeout to stop the task which have running status, but haven't been updated for a long time
 - `ENDLESS_TASK_TIMEOUT`: **3h**: Timeout to stop the tasks which have running status and continuous updates, but don't end for a long time
 - `ABANDONED_JOB_TIMEOUT`: **24h**: Timeout to cancel the jobs which have waiting status, but haven't been picked by a runner for a long time
+- `SKIP_WORKFLOW_STRINGS`: **[skip ci],[ci skip],[no ci],[skip actions],[actions skip]**: Strings committers can place inside a commit message to skip executing the corresponding actions workflow
 
 `DEFAULT_ACTIONS_URL` indicates where the Gitea Actions runners should find the actions with relative path.
 For example, `uses: actions/checkout@v3` means `https://github.com/actions/checkout@v3` since the value of `DEFAULT_ACTIONS_URL` is `github`.
diff --git a/modules/setting/actions.go b/modules/setting/actions.go
index 026bab4bfc..9fd484c3b8 100644
--- a/modules/setting/actions.go
+++ b/modules/setting/actions.go
@@ -22,9 +22,11 @@ var (
 		ZombieTaskTimeout     time.Duration     `ini:"ZOMBIE_TASK_TIMEOUT"`
 		EndlessTaskTimeout    time.Duration     `ini:"ENDLESS_TASK_TIMEOUT"`
 		AbandonedJobTimeout   time.Duration     `ini:"ABANDONED_JOB_TIMEOUT"`
+		SkipWorkflowStrings   []string          `ìni:"SKIP_WORKFLOW_STRINGS"`
 	}{
-		Enabled:           true,
-		DefaultActionsURL: defaultActionsURLGitHub,
+		Enabled:             true,
+		DefaultActionsURL:   defaultActionsURLGitHub,
+		SkipWorkflowStrings: []string{"[skip ci]", "[ci skip]", "[no ci]", "[skip actions]", "[actions skip]"},
 	}
 )
 
diff --git a/services/actions/notifier_helper.go b/services/actions/notifier_helper.go
index 7d5f6c6c0a..1c08cec007 100644
--- a/services/actions/notifier_helper.go
+++ b/services/actions/notifier_helper.go
@@ -7,6 +7,7 @@ import (
 	"bytes"
 	"context"
 	"fmt"
+	"slices"
 	"strings"
 
 	actions_model "code.gitea.io/gitea/models/actions"
@@ -20,6 +21,7 @@ import (
 	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/json"
 	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
 	api "code.gitea.io/gitea/modules/structs"
 	webhook_module "code.gitea.io/gitea/modules/webhook"
 	"code.gitea.io/gitea/services/convert"
@@ -144,6 +146,10 @@ func notify(ctx context.Context, input *notifyInput) error {
 		return fmt.Errorf("gitRepo.GetCommit: %w", err)
 	}
 
+	if skipWorkflowsForCommit(input, commit) {
+		return nil
+	}
+
 	var detectedWorkflows []*actions_module.DetectedWorkflow
 	actionsConfig := input.Repo.MustGetUnit(ctx, unit_model.TypeActions).ActionsConfig()
 	workflows, schedules, err := actions_module.DetectWorkflows(gitRepo, commit, input.Event, input.Payload)
@@ -195,6 +201,25 @@ func notify(ctx context.Context, input *notifyInput) error {
 	return handleWorkflows(ctx, detectedWorkflows, commit, input, ref)
 }
 
+func skipWorkflowsForCommit(input *notifyInput, commit *git.Commit) bool {
+	// skip workflow runs with a configured skip-ci string in commit message if the event is push or pull_request(_sync)
+	// https://docs.github.com/en/actions/managing-workflow-runs/skipping-workflow-runs
+	skipWorkflowEvents := []webhook_module.HookEventType{
+		webhook_module.HookEventPush,
+		webhook_module.HookEventPullRequest,
+		webhook_module.HookEventPullRequestSync,
+	}
+	if slices.Contains(skipWorkflowEvents, input.Event) {
+		for _, s := range setting.Actions.SkipWorkflowStrings {
+			if strings.Contains(commit.CommitMessage, s) {
+				log.Debug("repo %s with commit %s: skipped run because of %s string", input.Repo.RepoPath(), commit.ID, s)
+				return true
+			}
+		}
+	}
+	return false
+}
+
 func handleWorkflows(
 	ctx context.Context,
 	detectedWorkflows []*actions_module.DetectedWorkflow,
diff --git a/tests/integration/actions_trigger_test.go b/tests/integration/actions_trigger_test.go
index 253de70326..684b93ed1d 100644
--- a/tests/integration/actions_trigger_test.go
+++ b/tests/integration/actions_trigger_test.go
@@ -4,6 +4,7 @@
 package integration
 
 import (
+	"fmt"
 	"net/url"
 	"strings"
 	"testing"
@@ -18,6 +19,7 @@ import (
 	user_model "code.gitea.io/gitea/models/user"
 	actions_module "code.gitea.io/gitea/modules/actions"
 	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/setting"
 	pull_service "code.gitea.io/gitea/services/pull"
 	repo_service "code.gitea.io/gitea/services/repository"
 	files_service "code.gitea.io/gitea/services/repository/files"
@@ -194,3 +196,92 @@ func TestPullRequestTargetEvent(t *testing.T) {
 		assert.Equal(t, 1, unittest.GetCount(t, &actions_model.ActionRun{RepoID: baseRepo.ID}))
 	})
 }
+
+func TestSkipCI(t *testing.T) {
+	onGiteaRun(t, func(t *testing.T, u *url.URL) {
+		user2 := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2})
+
+		// create the repo
+		repo, err := repo_service.CreateRepository(db.DefaultContext, user2, user2, repo_service.CreateRepoOptions{
+			Name:          "skip-ci",
+			Description:   "test skip ci functionality",
+			AutoInit:      true,
+			Gitignores:    "Go",
+			License:       "MIT",
+			Readme:        "Default",
+			DefaultBranch: "main",
+			IsPrivate:     false,
+		})
+		assert.NoError(t, err)
+		assert.NotEmpty(t, repo)
+
+		// enable actions
+		err = repo_model.UpdateRepositoryUnits(db.DefaultContext, repo, []repo_model.RepoUnit{{
+			RepoID: repo.ID,
+			Type:   unit_model.TypeActions,
+		}}, nil)
+		assert.NoError(t, err)
+
+		// add workflow file to the repo
+		addWorkflowToBaseResp, err := files_service.ChangeRepoFiles(git.DefaultContext, repo, user2, &files_service.ChangeRepoFilesOptions{
+			Files: []*files_service.ChangeRepoFile{
+				{
+					Operation:     "create",
+					TreePath:      ".gitea/workflows/pr.yml",
+					ContentReader: strings.NewReader("name: test\non:\n  push:\njobs:\n  test:\n    runs-on: ubuntu-latest\n    steps:\n      - run: echo helloworld\n"),
+				},
+			},
+			Message:   "add workflow",
+			OldBranch: "main",
+			NewBranch: "main",
+			Author: &files_service.IdentityOptions{
+				Name:  user2.Name,
+				Email: user2.Email,
+			},
+			Committer: &files_service.IdentityOptions{
+				Name:  user2.Name,
+				Email: user2.Email,
+			},
+			Dates: &files_service.CommitDateOptions{
+				Author:    time.Now(),
+				Committer: time.Now(),
+			},
+		})
+		assert.NoError(t, err)
+		assert.NotEmpty(t, addWorkflowToBaseResp)
+
+		// a run has been created
+		assert.Equal(t, 1, unittest.GetCount(t, &actions_model.ActionRun{RepoID: repo.ID}))
+
+		// add a file with a configured skip-ci string in commit message
+		addFileResp, err := files_service.ChangeRepoFiles(git.DefaultContext, repo, user2, &files_service.ChangeRepoFilesOptions{
+			Files: []*files_service.ChangeRepoFile{
+				{
+					Operation:     "create",
+					TreePath:      "bar.txt",
+					ContentReader: strings.NewReader("bar"),
+				},
+			},
+			Message:   fmt.Sprintf("%s add bar", setting.Actions.SkipWorkflowStrings[0]),
+			OldBranch: "main",
+			NewBranch: "main",
+			Author: &files_service.IdentityOptions{
+				Name:  user2.Name,
+				Email: user2.Email,
+			},
+			Committer: &files_service.IdentityOptions{
+				Name:  user2.Name,
+				Email: user2.Email,
+			},
+			Dates: &files_service.CommitDateOptions{
+				Author:    time.Now(),
+				Committer: time.Now(),
+			},
+		})
+		assert.NoError(t, err)
+		assert.NotEmpty(t, addFileResp)
+
+		// the commit message contains a configured skip-ci string, so there is still only 1 record
+		assert.Equal(t, 1, unittest.GetCount(t, &actions_model.ActionRun{RepoID: repo.ID}))
+	})
+}