Reduce unnecessary DB queries for Actions tasks (#25199)

Close #24544

Changes:

- Create `action_tasks_version` table to store the latest version of
each scope (global, org and repo).
- When a job with the status of `waiting` is created, the tasks version
of the scopes it belongs to will increase.
- When the status of a job already in the database is updated to
`waiting`, the tasks version of the scopes it belongs to will increase.
- On Gitea side, in `FeatchTask()`, will try to query the
`action_tasks_version` record of the scope of the runner that call
`FetchTask()`. If the record does not exist, will insert a row. Then,
Gitea will compare the version passed from runner to Gitea with the
version in database, if inconsistent, try pick task. Gitea always
returns the latest version from database to the runner.

Related:

- Protocol: https://gitea.com/gitea/actions-proto-def/pulls/10
- Runner: https://gitea.com/gitea/act_runner/pulls/219

models/actions/run.go

@@ -195,6 +195,7 @@ func InsertRun(ctx context.Context, run *ActionRun, jobs []*jobparser.SingleWork
 	}
 
 	runJobs := make([]*ActionRunJob, 0, len(jobs))
+	var hasWaiting bool
 	for _, v := range jobs {
 		id, job := v.Job()
 		needs := job.Needs()
@@ -205,6 +206,8 @@ func InsertRun(ctx context.Context, run *ActionRun, jobs []*jobparser.SingleWork
 		status := StatusWaiting
 		if len(needs) > 0 || run.NeedApproval {
 			status = StatusBlocked
+		} else {
+			hasWaiting = true
 		}
 		job.Name, _ = util.SplitStringAtByteN(job.Name, 255)
 		runJobs = append(runJobs, &ActionRunJob{
@@ -225,6 +228,13 @@ func InsertRun(ctx context.Context, run *ActionRun, jobs []*jobparser.SingleWork
 		return err
 	}
 
+	// if there is a job in the waiting status, increase tasks version.
+	if hasWaiting {
+		if err := IncreaseTaskVersion(ctx, run.OwnerID, run.RepoID); err != nil {
+			return err
+		}
+	}
+
 	return commiter.Commit()
 }
 

models/actions/run_job.go

@@ -111,6 +111,13 @@ func UpdateRunJob(ctx context.Context, job *ActionRunJob, cond builder.Cond, col
 		return affected, nil
 	}
 
+	if affected != 0 && util.SliceContains(cols, "status") && job.Status.IsWaiting() {
+		// if the status of job changes to waiting again, increase tasks version.
+		if err := IncreaseTaskVersion(ctx, job.OwnerID, job.RepoID); err != nil {
+			return affected, err
+		}
+	}
+
 	if job.RunID == 0 {
 		var err error
 		if job, err = GetRunJobByID(ctx, job.ID); err != nil {

models/actions/task.go

@@ -215,12 +215,11 @@ func GetRunningTaskByToken(ctx context.Context, token string) (*ActionTask, erro
 }
 
 func CreateTaskForRunner(ctx context.Context, runner *ActionRunner) (*ActionTask, bool, error) {
-	dbCtx, commiter, err := db.TxContext(ctx)
+	ctx, commiter, err := db.TxContext(ctx)
 	if err != nil {
 		return nil, false, err
 	}
 	defer commiter.Close()
-	ctx = dbCtx.WithContext(ctx)
 
 	e := db.GetEngine(ctx)
 

models/actions/tasks_version.go

@@ -0,0 +1,105 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package actions
+
+import (
+	"context"
+
+	"code.gitea.io/gitea/models/db"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/timeutil"
+)
+
+// ActionTasksVersion
+// If both ownerID and repoID is zero, its scope is global.
+// If ownerID is not zero and repoID is zero, its scope is org (there is no user-level runner currrently).
+// If ownerID is zero and repoID is not zero, its scope is repo.
+type ActionTasksVersion struct {
+	ID          int64 `xorm:"pk autoincr"`
+	OwnerID     int64 `xorm:"UNIQUE(owner_repo)"`
+	RepoID      int64 `xorm:"INDEX UNIQUE(owner_repo)"`
+	Version     int64
+	CreatedUnix timeutil.TimeStamp `xorm:"created"`
+	UpdatedUnix timeutil.TimeStamp `xorm:"updated"`
+}
+
+func init() {
+	db.RegisterModel(new(ActionTasksVersion))
+}
+
+func GetTasksVersionByScope(ctx context.Context, ownerID, repoID int64) (int64, error) {
+	var tasksVersion ActionTasksVersion
+	has, err := db.GetEngine(ctx).Where("owner_id = ? AND repo_id = ?", ownerID, repoID).Get(&tasksVersion)
+	if err != nil {
+		return 0, err
+	} else if !has {
+		return 0, nil
+	}
+	return tasksVersion.Version, err
+}
+
+func insertTasksVersion(ctx context.Context, ownerID, repoID int64) (*ActionTasksVersion, error) {
+	tasksVersion := &ActionTasksVersion{
+		OwnerID: ownerID,
+		RepoID:  repoID,
+		Version: 1,
+	}
+	if _, err := db.GetEngine(ctx).Insert(tasksVersion); err != nil {
+		return nil, err
+	}
+	return tasksVersion, nil
+}
+
+func increaseTasksVersionByScope(ctx context.Context, ownerID, repoID int64) error {
+	result, err := db.GetEngine(ctx).Exec("UPDATE action_tasks_version SET version = version + 1 WHERE owner_id = ? AND repo_id = ?", ownerID, repoID)
+	if err != nil {
+		return err
+	}
+	affected, err := result.RowsAffected()
+	if err != nil {
+		return err
+	}
+
+	if affected == 0 {
+		// if update sql does not affect any rows, the database may be broken,
+		// so re-insert the row of version data here.
+		if _, err := insertTasksVersion(ctx, ownerID, repoID); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func IncreaseTaskVersion(ctx context.Context, ownerID, repoID int64) error {
+	ctx, commiter, err := db.TxContext(ctx)
+	if err != nil {
+		return err
+	}
+	defer commiter.Close()
+
+	// 1. increase global
+	if err := increaseTasksVersionByScope(ctx, 0, 0); err != nil {
+		log.Error("IncreaseTasksVersionByScope(Global): %v", err)
+		return err
+	}
+
+	// 2. increase owner
+	if ownerID > 0 {
+		if err := increaseTasksVersionByScope(ctx, ownerID, 0); err != nil {
+			log.Error("IncreaseTasksVersionByScope(Owner): %v", err)
+			return err
+		}
+	}
+
+	// 3. increase repo
+	if repoID > 0 {
+		if err := increaseTasksVersionByScope(ctx, 0, repoID); err != nil {
+			log.Error("IncreaseTasksVersionByScope(Repo): %v", err)
+			return err
+		}
+	}
+
+	return commiter.Commit()
+}

models/migrations/migrations.go

@@ -515,6 +515,8 @@ var migrations = []Migration{
 	NewMigration("Alter Actions Artifact table", v1_21.AlterActionArtifactTable),
 	// v266 -> v267
 	NewMigration("Reduce commit status", v1_21.ReduceCommitStatus),
+	// v267 -> v268
+	NewMigration("Add action_tasks_version table", v1_21.CreateActionTasksVersionTable),
 }
 
 // GetCurrentDBVersion returns the current db version

models/migrations/v1_21/v267.go

@@ -0,0 +1,23 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package v1_21 //nolint
+
+import (
+	"code.gitea.io/gitea/modules/timeutil"
+
+	"xorm.io/xorm"
+)
+
+func CreateActionTasksVersionTable(x *xorm.Engine) error {
+	type ActionTasksVersion struct {
+		ID          int64 `xorm:"pk autoincr"`
+		OwnerID     int64 `xorm:"UNIQUE(owner_repo)"`
+		RepoID      int64 `xorm:"INDEX UNIQUE(owner_repo)"`
+		Version     int64
+		CreatedUnix timeutil.TimeStamp `xorm:"created"`
+		UpdatedUnix timeutil.TimeStamp `xorm:"updated"`
+	}
+
+	return x.Sync(new(ActionTasksVersion))
+}

routers/api/actions/runner/runner.go

@@ -127,20 +127,39 @@ func (s *Service) Declare(
 // FetchTask assigns a task to the runner
 func (s *Service) FetchTask(
 	ctx context.Context,
-	_ *connect.Request[runnerv1.FetchTaskRequest],
+	req *connect.Request[runnerv1.FetchTaskRequest],
 ) (*connect.Response[runnerv1.FetchTaskResponse], error) {
 	runner := GetRunner(ctx)
 
 	var task *runnerv1.Task
-	if t, ok, err := pickTask(ctx, runner); err != nil {
-		log.Error("pick task failed: %v", err)
-		return nil, status.Errorf(codes.Internal, "pick task: %v", err)
-	} else if ok {
-		task = t
+	tasksVersion := req.Msg.TasksVersion // task version from runner
+	latestVersion, err := actions_model.GetTasksVersionByScope(ctx, runner.OwnerID, runner.RepoID)
+	if err != nil {
+		return nil, status.Errorf(codes.Internal, "query tasks version failed: %v", err)
+	} else if latestVersion == 0 {
+		if err := actions_model.IncreaseTaskVersion(ctx, runner.OwnerID, runner.RepoID); err != nil {
+			return nil, status.Errorf(codes.Internal, "fail to increase task version: %v", err)
+		}
+		// if we don't increase the value of `latestVersion` here,
+		// the response of FetchTask will return tasksVersion as zero.
+		// and the runner will treat it as an old version of Gitea.
+		latestVersion++
 	}
 
+	if tasksVersion != latestVersion {
+		// if the task version in request is not equal to the version in db,
+		// it means there may still be some tasks not be assgined.
+		// try to pick a task for the runner that send the request.
+		if t, ok, err := pickTask(ctx, runner); err != nil {
+			log.Error("pick task failed: %v", err)
+			return nil, status.Errorf(codes.Internal, "pick task: %v", err)
+		} else if ok {
+			task = t
+		}
+	}
 	res := connect.NewResponse(&runnerv1.FetchTaskResponse{
-		Task: task,
+		Task:         task,
+		TasksVersion: latestVersion,
 	})
 	return res, nil
 }