Implement actions (#21937)

Close #13539.

Co-authored by: @lunny @appleboy @fuxiaohei and others.

Related projects:
- https://gitea.com/gitea/actions-proto-def
- https://gitea.com/gitea/actions-proto-go
- https://gitea.com/gitea/act
- https://gitea.com/gitea/act_runner

### Summary

The target of this PR is to bring a basic implementation of "Actions",
an internal CI/CD system of Gitea. That means even though it has been
merged, the state of the feature is **EXPERIMENTAL**, and please note
that:

- It is disabled by default;
- It shouldn't be used in a production environment currently;
- It shouldn't be used in a public Gitea instance currently;
- Breaking changes may be made before it's stable.

**Please comment on #13539 if you have any different product design
ideas**, all decisions reached there will be adopted here. But in this
PR, we don't talk about **naming, feature-creep or alternatives**.

### ⚠️ Breaking

`gitea-actions` will become a reserved user name. If a user with the
name already exists in the database, it is recommended to rename it.

### Some important reviews

- What is `DEFAULT_ACTIONS_URL` in `app.ini` for?
  - https://github.com/go-gitea/gitea/pull/21937#discussion_r1055954954
- Why the api for runners is not under the normal `/api/v1` prefix?
  - https://github.com/go-gitea/gitea/pull/21937#discussion_r1061173592
- Why DBFS?
  - https://github.com/go-gitea/gitea/pull/21937#discussion_r1061301178
- Why ignore events triggered by `gitea-actions` bot?
  - https://github.com/go-gitea/gitea/pull/21937#discussion_r1063254103
- Why there's no permission control for actions?
  - https://github.com/go-gitea/gitea/pull/21937#discussion_r1090229868

### What it looks like

<details>

#### Manage runners

<img width="1792" alt="image"
src="https://user-images.githubusercontent.com/9418365/205870657-c72f590e-2e08-4cd4-be7f-2e0abb299bbf.png">

#### List runs

<img width="1792" alt="image"
src="https://user-images.githubusercontent.com/9418365/205872794-50fde990-2b45-48c1-a178-908e4ec5b627.png">


#### View logs

<img width="1792" alt="image"
src="https://user-images.githubusercontent.com/9418365/205872501-9b7b9000-9542-4991-8f55-18ccdada77c3.png">



</details>

### How to try it

<details>

#### 1. Start Gitea

Clone this branch and [install from
source](https://docs.gitea.io/en-us/install-from-source).

Add additional configurations in `app.ini` to enable Actions:

```ini
[actions]
ENABLED = true
```

Start it.

If all is well, you'll see the management page of runners:

<img width="1792" alt="image"
src="https://user-images.githubusercontent.com/9418365/205877365-8e30a780-9b10-4154-b3e8-ee6c3cb35a59.png">


#### 2. Start runner

Clone the [act_runner](https://gitea.com/gitea/act_runner), and follow
the
[README](https://gitea.com/gitea/act_runner/src/branch/main/README.md)
to start it.

If all is well, you'll see a new runner has been added:

<img width="1792" alt="image"
src="https://user-images.githubusercontent.com/9418365/205878000-216f5937-e696-470d-b66c-8473987d91c3.png">

#### 3. Enable actions for a repo

Create a new repo or open an existing one, check the `Actions` checkbox
in settings and submit.

<img width="1792" alt="image"
src="https://user-images.githubusercontent.com/9418365/205879705-53e09208-73c0-4b3e-a123-2dcf9aba4b9c.png">
<img width="1792" alt="image"
src="https://user-images.githubusercontent.com/9418365/205879383-23f3d08f-1a85-41dd-a8b3-54e2ee6453e8.png">

If all is well, you'll see a new tab "Actions":

<img width="1792" alt="image"
src="https://user-images.githubusercontent.com/9418365/205881648-a8072d8c-5803-4d76-b8a8-9b2fb49516c1.png">

#### 4. Upload workflow files

Upload some workflow files to `.gitea/workflows/xxx.yaml`, you can
follow the [quickstart](https://docs.github.com/en/actions/quickstart)
of GitHub Actions. Yes, Gitea Actions is compatible with GitHub Actions
in most cases, you can use the same demo:

```yaml
name: GitHub Actions Demo
run-name: ${{ github.actor }} is testing out GitHub Actions 🚀
on: [push]
jobs:
  Explore-GitHub-Actions:
    runs-on: ubuntu-latest
    steps:
      - run: echo "🎉 The job was automatically triggered by a ${{ github.event_name }} event."
      - run: echo "🐧 This job is now running on a ${{ runner.os }} server hosted by GitHub!"
      - run: echo "🔎 The name of your branch is ${{ github.ref }} and your repository is ${{ github.repository }}."
      - name: Check out repository code
        uses: actions/checkout@v3
      - run: echo "💡 The ${{ github.repository }} repository has been cloned to the runner."
      - run: echo "🖥️ The workflow is now ready to test your code on the runner."
      - name: List files in the repository
        run: |
          ls ${{ github.workspace }}
      - run: echo "🍏 This job's status is ${{ job.status }}."
```

If all is well, you'll see a new run in `Actions` tab:

<img width="1792" alt="image"
src="https://user-images.githubusercontent.com/9418365/205884473-79a874bc-171b-4aaf-acd5-0241a45c3b53.png">

#### 5. Check the logs of jobs

Click a run and you'll see the logs:

<img width="1792" alt="image"
src="https://user-images.githubusercontent.com/9418365/205884800-994b0374-67f7-48ff-be9a-4c53f3141547.png">

#### 6. Go on

You can try more examples in [the
documents](https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions)
of GitHub Actions, then you might find a lot of bugs.

Come on, PRs are welcome.

</details>

See also: [Feature Preview: Gitea
Actions](https://blog.gitea.io/2022/12/feature-preview-gitea-actions/)

---------

Co-authored-by: a1012112796 <1012112796@qq.com>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: delvh <dev.lh@web.de>
Co-authored-by: ChristopherHX <christopher.homberger@web.de>
Co-authored-by: John Olheiser <john.olheiser@gmail.com>

4 files changed, 451 insertions, 0 deletions

diff --git a/modules/actions/log.go b/modules/actions/log.go
new file mode 100644
index 0000000000..3868101992
--- /dev/null
+++ b/modules/actions/log.go
@@ -0,0 +1,163 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package actions
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+	"time"
+
+	"code.gitea.io/gitea/models/dbfs"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/storage"
+
+	runnerv1 "code.gitea.io/actions-proto-go/runner/v1"
+	"google.golang.org/protobuf/types/known/timestamppb"
+)
+
+const (
+	MaxLineSize = 64 * 1024
+	DBFSPrefix  = "actions_log/"
+
+	timeFormat     = "2006-01-02T15:04:05.0000000Z07:00"
+	defaultBufSize = MaxLineSize
+)
+
+func WriteLogs(ctx context.Context, filename string, offset int64, rows []*runnerv1.LogRow) ([]int, error) {
+	name := DBFSPrefix + filename
+	f, err := dbfs.OpenFile(ctx, name, os.O_WRONLY|os.O_CREATE)
+	if err != nil {
+		return nil, fmt.Errorf("dbfs OpenFile %q: %w", name, err)
+	}
+	defer f.Close()
+	if _, err := f.Seek(offset, io.SeekStart); err != nil {
+		return nil, fmt.Errorf("dbfs Seek %q: %w", name, err)
+	}
+
+	writer := bufio.NewWriterSize(f, defaultBufSize)
+
+	ns := make([]int, 0, len(rows))
+	for _, row := range rows {
+		n, err := writer.WriteString(FormatLog(row.Time.AsTime(), row.Content) + "\n")
+		if err != nil {
+			return nil, err
+		}
+		ns = append(ns, n)
+	}
+
+	if err := writer.Flush(); err != nil {
+		return nil, err
+	}
+	return ns, nil
+}
+
+func ReadLogs(ctx context.Context, inStorage bool, filename string, offset, limit int64) ([]*runnerv1.LogRow, error) {
+	f, err := openLogs(ctx, inStorage, filename)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	if _, err := f.Seek(offset, io.SeekStart); err != nil {
+		return nil, fmt.Errorf("file seek: %w", err)
+	}
+
+	scanner := bufio.NewScanner(f)
+	maxLineSize := len(timeFormat) + MaxLineSize + 1
+	scanner.Buffer(make([]byte, maxLineSize), maxLineSize)
+
+	var rows []*runnerv1.LogRow
+	for scanner.Scan() && (int64(len(rows)) < limit || limit < 0) {
+		t, c, err := ParseLog(scanner.Text())
+		if err != nil {
+			return nil, fmt.Errorf("parse log %q: %w", scanner.Text(), err)
+		}
+		rows = append(rows, &runnerv1.LogRow{
+			Time:    timestamppb.New(t),
+			Content: c,
+		})
+	}
+
+	if err := scanner.Err(); err != nil {
+		return nil, fmt.Errorf("scan: %w", err)
+	}
+
+	return rows, nil
+}
+
+func TransferLogs(ctx context.Context, filename string) (func(), error) {
+	name := DBFSPrefix + filename
+	remove := func() {
+		if err := dbfs.Remove(ctx, name); err != nil {
+			log.Warn("dbfs remove %q: %v", name, err)
+		}
+	}
+	f, err := dbfs.Open(ctx, name)
+	if err != nil {
+		return nil, fmt.Errorf("dbfs open %q: %w", name, err)
+	}
+	defer f.Close()
+
+	if _, err := storage.Actions.Save(filename, f, -1); err != nil {
+		return nil, fmt.Errorf("storage save %q: %w", filename, err)
+	}
+	return remove, nil
+}
+
+func RemoveLogs(ctx context.Context, inStorage bool, filename string) error {
+	if !inStorage {
+		name := DBFSPrefix + filename
+		err := dbfs.Remove(ctx, name)
+		if err != nil {
+			return fmt.Errorf("dbfs remove %q: %w", name, err)
+		}
+		return nil
+	}
+	err := storage.Actions.Delete(filename)
+	if err != nil {
+		return fmt.Errorf("storage delete %q: %w", filename, err)
+	}
+	return nil
+}
+
+func openLogs(ctx context.Context, inStorage bool, filename string) (io.ReadSeekCloser, error) {
+	if !inStorage {
+		name := DBFSPrefix + filename
+		f, err := dbfs.Open(ctx, name)
+		if err != nil {
+			return nil, fmt.Errorf("dbfs open %q: %w", name, err)
+		}
+		return f, nil
+	}
+	f, err := storage.Actions.Open(filename)
+	if err != nil {
+		return nil, fmt.Errorf("storage open %q: %w", filename, err)
+	}
+	return f, nil
+}
+
+func FormatLog(timestamp time.Time, content string) string {
+	// Content shouldn't contain new line, it will break log indexes, other control chars are safe.
+	content = strings.ReplaceAll(content, "\n", `\n`)
+	if len(content) > MaxLineSize {
+		content = content[:MaxLineSize]
+	}
+	return fmt.Sprintf("%s %s", timestamp.UTC().Format(timeFormat), content)
+}
+
+func ParseLog(in string) (time.Time, string, error) {
+	index := strings.IndexRune(in, ' ')
+	if index < 0 {
+		return time.Time{}, "", fmt.Errorf("invalid log: %q", in)
+	}
+	timestamp, err := time.Parse(timeFormat, in[:index])
+	if err != nil {
+		return time.Time{}, "", err
+	}
+	return timestamp, in[index+1:], nil
+}
diff --git a/modules/actions/task_state.go b/modules/actions/task_state.go
new file mode 100644
index 0000000000..cbbc0b357d
--- /dev/null
+++ b/modules/actions/task_state.go
@@ -0,0 +1,101 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package actions
+
+import (
+	actions_model "code.gitea.io/gitea/models/actions"
+)
+
+const (
+	preStepName  = "Set up job"
+	postStepName = "Complete job"
+)
+
+// FullSteps returns steps with "Set up job" and "Complete job"
+func FullSteps(task *actions_model.ActionTask) []*actions_model.ActionTaskStep {
+	if len(task.Steps) == 0 {
+		return fullStepsOfEmptySteps(task)
+	}
+
+	firstStep := task.Steps[0]
+	var logIndex int64
+
+	preStep := &actions_model.ActionTaskStep{
+		Name:      preStepName,
+		LogLength: task.LogLength,
+		Started:   task.Started,
+		Status:    actions_model.StatusRunning,
+	}
+
+	if firstStep.Status.HasRun() || firstStep.Status.IsRunning() {
+		preStep.LogLength = firstStep.LogIndex
+		preStep.Stopped = firstStep.Started
+		preStep.Status = actions_model.StatusSuccess
+	} else if task.Status.IsDone() {
+		preStep.Stopped = task.Stopped
+		preStep.Status = actions_model.StatusFailure
+	}
+	logIndex += preStep.LogLength
+
+	var lastHasRunStep *actions_model.ActionTaskStep
+	for _, step := range task.Steps {
+		if step.Status.HasRun() {
+			lastHasRunStep = step
+		}
+		logIndex += step.LogLength
+	}
+	if lastHasRunStep == nil {
+		lastHasRunStep = preStep
+	}
+
+	postStep := &actions_model.ActionTaskStep{
+		Name:   postStepName,
+		Status: actions_model.StatusWaiting,
+	}
+	if task.Status.IsDone() {
+		postStep.LogIndex = logIndex
+		postStep.LogLength = task.LogLength - postStep.LogIndex
+		postStep.Status = task.Status
+		postStep.Started = lastHasRunStep.Stopped
+		postStep.Stopped = task.Stopped
+	}
+	ret := make([]*actions_model.ActionTaskStep, 0, len(task.Steps)+2)
+	ret = append(ret, preStep)
+	ret = append(ret, task.Steps...)
+	ret = append(ret, postStep)
+
+	return ret
+}
+
+func fullStepsOfEmptySteps(task *actions_model.ActionTask) []*actions_model.ActionTaskStep {
+	preStep := &actions_model.ActionTaskStep{
+		Name:      preStepName,
+		LogLength: task.LogLength,
+		Started:   task.Started,
+		Stopped:   task.Stopped,
+		Status:    actions_model.StatusRunning,
+	}
+
+	postStep := &actions_model.ActionTaskStep{
+		Name:     postStepName,
+		LogIndex: task.LogLength,
+		Started:  task.Stopped,
+		Stopped:  task.Stopped,
+		Status:   actions_model.StatusWaiting,
+	}
+
+	if task.Status.IsDone() {
+		preStep.Status = task.Status
+		if preStep.Status.IsSuccess() {
+			postStep.Status = actions_model.StatusSuccess
+		} else {
+			postStep.Status = actions_model.StatusCancelled
+		}
+	}
+
+	return []*actions_model.ActionTaskStep{
+		preStep,
+		postStep,
+	}
+}
diff --git a/modules/actions/task_state_test.go b/modules/actions/task_state_test.go
new file mode 100644
index 0000000000..3a599fbcbd
--- /dev/null
+++ b/modules/actions/task_state_test.go
@@ -0,0 +1,112 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package actions
+
+import (
+	"testing"
+
+	actions_model "code.gitea.io/gitea/models/actions"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestFullSteps(t *testing.T) {
+	tests := []struct {
+		name string
+		task *actions_model.ActionTask
+		want []*actions_model.ActionTaskStep
+	}{
+		{
+			name: "regular",
+			task: &actions_model.ActionTask{
+				Steps: []*actions_model.ActionTaskStep{
+					{Status: actions_model.StatusSuccess, LogIndex: 10, LogLength: 80, Started: 10010, Stopped: 10090},
+				},
+				Status:    actions_model.StatusSuccess,
+				Started:   10000,
+				Stopped:   10100,
+				LogLength: 100,
+			},
+			want: []*actions_model.ActionTaskStep{
+				{Name: preStepName, Status: actions_model.StatusSuccess, LogIndex: 0, LogLength: 10, Started: 10000, Stopped: 10010},
+				{Status: actions_model.StatusSuccess, LogIndex: 10, LogLength: 80, Started: 10010, Stopped: 10090},
+				{Name: postStepName, Status: actions_model.StatusSuccess, LogIndex: 90, LogLength: 10, Started: 10090, Stopped: 10100},
+			},
+		},
+		{
+			name: "failed step",
+			task: &actions_model.ActionTask{
+				Steps: []*actions_model.ActionTaskStep{
+					{Status: actions_model.StatusSuccess, LogIndex: 10, LogLength: 20, Started: 10010, Stopped: 10020},
+					{Status: actions_model.StatusFailure, LogIndex: 30, LogLength: 60, Started: 10020, Stopped: 10090},
+					{Status: actions_model.StatusCancelled, LogIndex: 0, LogLength: 0, Started: 0, Stopped: 0},
+				},
+				Status:    actions_model.StatusFailure,
+				Started:   10000,
+				Stopped:   10100,
+				LogLength: 100,
+			},
+			want: []*actions_model.ActionTaskStep{
+				{Name: preStepName, Status: actions_model.StatusSuccess, LogIndex: 0, LogLength: 10, Started: 10000, Stopped: 10010},
+				{Status: actions_model.StatusSuccess, LogIndex: 10, LogLength: 20, Started: 10010, Stopped: 10020},
+				{Status: actions_model.StatusFailure, LogIndex: 30, LogLength: 60, Started: 10020, Stopped: 10090},
+				{Status: actions_model.StatusCancelled, LogIndex: 0, LogLength: 0, Started: 0, Stopped: 0},
+				{Name: postStepName, Status: actions_model.StatusFailure, LogIndex: 90, LogLength: 10, Started: 10090, Stopped: 10100},
+			},
+		},
+		{
+			name: "first step is running",
+			task: &actions_model.ActionTask{
+				Steps: []*actions_model.ActionTaskStep{
+					{Status: actions_model.StatusRunning, LogIndex: 10, LogLength: 80, Started: 10010, Stopped: 0},
+				},
+				Status:    actions_model.StatusRunning,
+				Started:   10000,
+				Stopped:   10100,
+				LogLength: 100,
+			},
+			want: []*actions_model.ActionTaskStep{
+				{Name: preStepName, Status: actions_model.StatusSuccess, LogIndex: 0, LogLength: 10, Started: 10000, Stopped: 10010},
+				{Status: actions_model.StatusRunning, LogIndex: 10, LogLength: 80, Started: 10010, Stopped: 0},
+				{Name: postStepName, Status: actions_model.StatusWaiting, LogIndex: 0, LogLength: 0, Started: 0, Stopped: 0},
+			},
+		},
+		{
+			name: "first step has canceled",
+			task: &actions_model.ActionTask{
+				Steps: []*actions_model.ActionTaskStep{
+					{Status: actions_model.StatusCancelled, LogIndex: 0, LogLength: 0, Started: 0, Stopped: 0},
+				},
+				Status:    actions_model.StatusFailure,
+				Started:   10000,
+				Stopped:   10100,
+				LogLength: 100,
+			},
+			want: []*actions_model.ActionTaskStep{
+				{Name: preStepName, Status: actions_model.StatusFailure, LogIndex: 0, LogLength: 100, Started: 10000, Stopped: 10100},
+				{Status: actions_model.StatusCancelled, LogIndex: 0, LogLength: 0, Started: 0, Stopped: 0},
+				{Name: postStepName, Status: actions_model.StatusFailure, LogIndex: 100, LogLength: 0, Started: 10100, Stopped: 10100},
+			},
+		},
+		{
+			name: "empty steps",
+			task: &actions_model.ActionTask{
+				Steps:     []*actions_model.ActionTaskStep{},
+				Status:    actions_model.StatusSuccess,
+				Started:   10000,
+				Stopped:   10100,
+				LogLength: 100,
+			},
+			want: []*actions_model.ActionTaskStep{
+				{Name: preStepName, Status: actions_model.StatusSuccess, LogIndex: 0, LogLength: 100, Started: 10000, Stopped: 10100},
+				{Name: postStepName, Status: actions_model.StatusSuccess, LogIndex: 100, LogLength: 0, Started: 10100, Stopped: 10100},
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert.Equalf(t, tt.want, FullSteps(tt.task), "FullSteps(%v)", tt.task)
+		})
+	}
+}
diff --git a/modules/actions/workflows.go b/modules/actions/workflows.go
new file mode 100644
index 0000000000..d340a1aa65
--- /dev/null
+++ b/modules/actions/workflows.go
@@ -0,0 +1,75 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package actions
+
+import (
+	"bytes"
+	"io"
+	"strings"
+
+	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/log"
+	webhook_module "code.gitea.io/gitea/modules/webhook"
+
+	"github.com/nektos/act/pkg/model"
+)
+
+func ListWorkflows(commit *git.Commit) (git.Entries, error) {
+	tree, err := commit.SubTree(".gitea/workflows")
+	if _, ok := err.(git.ErrNotExist); ok {
+		tree, err = commit.SubTree(".github/workflows")
+	}
+	if _, ok := err.(git.ErrNotExist); ok {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	entries, err := tree.ListEntriesRecursiveFast()
+	if err != nil {
+		return nil, err
+	}
+
+	ret := make(git.Entries, 0, len(entries))
+	for _, entry := range entries {
+		if strings.HasSuffix(entry.Name(), ".yml") || strings.HasSuffix(entry.Name(), ".yaml") {
+			ret = append(ret, entry)
+		}
+	}
+	return ret, nil
+}
+
+func DetectWorkflows(commit *git.Commit, event webhook_module.HookEventType) (map[string][]byte, error) {
+	entries, err := ListWorkflows(commit)
+	if err != nil {
+		return nil, err
+	}
+
+	workflows := make(map[string][]byte, len(entries))
+	for _, entry := range entries {
+		f, err := entry.Blob().DataAsync()
+		if err != nil {
+			return nil, err
+		}
+		content, err := io.ReadAll(f)
+		_ = f.Close()
+		if err != nil {
+			return nil, err
+		}
+		workflow, err := model.ReadWorkflow(bytes.NewReader(content))
+		if err != nil {
+			log.Warn("ignore invalid workflow %q: %v", entry.Name(), err)
+			continue
+		}
+		for _, e := range workflow.On() {
+			if e == event.Event() {
+				workflows[entry.Name()] = content
+				break
+			}
+		}
+	}
+
+	return workflows, nil
+}