implement graceful shutdown to webhook mode

ensures all pending tasks are finished before quit.

cmd/listen.go

@@ -70,7 +70,7 @@ is up to you, eg. Nginx, Apache, or even a simple Go server.
 			GitPass: token,
 		}
 
-		s, err := lib.UseWebhook(bind, cfg)
+		s, r, err := lib.UseWebhook(bind, cfg)
 		if err != nil {
 			fmt.Println("cannot create server: ", err)
 			return
@@ -85,7 +85,11 @@ is up to you, eg. Nginx, Apache, or even a simple Go server.
 		defer stop()
 
 		fmt.Println("starting server")
-		httptask.Server(s, task.Timeout(10*time.Second)).Run(ctx)
+		task.Wait(
+			httptask.Server(s, task.Timeout(10*time.Second)),
+			r.Run,
+		).Run(ctx)
+
 	},
 }
 

lib/git.go

@@ -0,0 +1,159 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package lib
+
+import (
+	"context"
+	"fmt"
+	"net/url"
+	"os"
+	"os/exec"
+	"path"
+	"path/filepath"
+	"sync"
+)
+
+type repoSpec struct {
+	user string
+	name string
+}
+
+type GitRunner struct {
+	ch  <-chan repoSpec
+	cfg *WebhookCFG
+}
+
+func (g *GitRunner) Run(ctx context.Context) error {
+	// graceful: exit only if all tasks are done
+	for {
+		select {
+		case repo := <-g.ch:
+			err := g.cfg.download(repo.user, repo.name)
+			if err != nil {
+				fmt.Println("Failed to download repo: ", err)
+			}
+		case <-ctx.Done():
+			return ctx.Err()
+		}
+	}
+}
+
+func (c *WebhookCFG) pageDir(user, repo string) string {
+	return filepath.Join(c.PageDir, user, repo)
+}
+
+func (c *WebhookCFG) gitDir(user, repo string) string {
+	return filepath.Join(c.GitDir, user, repo)
+}
+
+func (c *WebhookCFG) checkout(user, repo string) (err error) {
+	pageDir := c.pageDir(user, repo)
+	gitDir := c.gitDir(user, repo)
+
+	git := exec.Command(
+		"git",
+		"--git-dir", gitDir,
+		"--work-tree", pageDir,
+		"checkout", "origin/"+c.Branch,
+	)
+	output, err := git.CombinedOutput()
+	if err != nil {
+		fmt.Println("git checkout failed: ", err)
+		fmt.Println("=========== Dump output: ============")
+		fmt.Println(string(output))
+		fmt.Println("=====================================")
+	}
+
+	return
+}
+
+func (c *WebhookCFG) fetch(user, repo string) (err error) {
+	gitDir := c.gitDir(user, repo)
+	git := exec.Command(
+		"git",
+		"--git-dir", gitDir,
+		"fetch", "origin", c.Branch,
+	)
+	output, err := git.CombinedOutput()
+	if err != nil {
+		fmt.Println("git fetch failed: ", err)
+		fmt.Println("=========== Dump output: ============")
+		fmt.Println(string(output))
+		fmt.Println("=====================================")
+	}
+
+	return
+}
+
+func (c *WebhookCFG) clone(user, repo string) (err error) {
+	pageDir := c.pageDir(user, repo)
+	err = os.MkdirAll(filepath.Dir(pageDir), 0755)
+	if err != nil {
+		return
+	}
+
+	gitDir := c.gitDir(user, repo)
+	err = os.MkdirAll(filepath.Dir(gitDir), 0700)
+	if err != nil {
+		return
+	}
+
+	uri := c.Server
+	uri.Path = "/" + path.Join(user, repo) + ".git"
+	uri.User = url.UserPassword(c.GitUser, c.GitPass)
+
+	git := exec.Command(
+		"git",
+		"clone",
+		"-b", c.Branch,
+		"--single-branch",
+		"--no-tags",
+		"--separate-git-dir", gitDir,
+		uri.String(),
+		pageDir,
+	)
+	output, err := git.CombinedOutput()
+	if err != nil {
+		fmt.Println("git clone failed: ", err)
+		fmt.Println("=========== Dump output: ============")
+		fmt.Println(string(output))
+		fmt.Println("=====================================")
+	}
+
+	os.Remove(filepath.Join(pageDir, ".git"))
+
+	return
+}
+
+var repoLock = &sync.Map{}
+
+func (c *WebhookCFG) lock(user, repo string) func() {
+	key := user + "/" + repo
+
+	lock, _ := repoLock.LoadOrStore(key, &sync.Mutex{})
+	m := lock.(*sync.Mutex)
+	m.Lock()
+	return m.Unlock
+}
+
+func (c *WebhookCFG) download(user, repo string) (err error) {
+	unlock := c.lock(user, repo)
+	defer unlock()
+	fmt.Println("Pulling ", user, repo)
+
+	gitDir := c.gitDir(user, repo)
+	if _, err = os.Stat(gitDir); os.IsNotExist(err) {
+		err = c.clone(user, repo)
+	} else {
+		err = c.fetch(user, repo)
+	}
+
+	if err != nil {
+		return
+	}
+
+	err = c.checkout(user, repo)
+	return
+}

lib/hook.go

@@ -10,12 +10,7 @@ import (
 	"fmt"
 	"io"
 	"net/http"
-	"net/url"
-	"os"
-	"os/exec"
 	"path"
-	"path/filepath"
-	"sync"
 )
 
 type WebhookCFG struct {
@@ -24,123 +19,7 @@ type WebhookCFG struct {
 	GitDir  string
 	GitUser string
 	GitPass string
-}
+	ch      chan<- repoSpec
-
-func (c *WebhookCFG) pageDir(user, repo string) string {
-	return filepath.Join(c.PageDir, user, repo)
-}
-
-func (c *WebhookCFG) gitDir(user, repo string) string {
-	return filepath.Join(c.GitDir, user, repo)
-}
-
-func (c *WebhookCFG) checkout(user, repo string) (err error) {
-	pageDir := c.pageDir(user, repo)
-	gitDir := c.gitDir(user, repo)
-
-	git := exec.Command(
-		"git",
-		"--git-dir", gitDir,
-		"--work-tree", pageDir,
-		"checkout", "origin/"+c.Branch,
-	)
-	output, err := git.CombinedOutput()
-	if err != nil {
-		fmt.Println("git checkout failed: ", err)
-		fmt.Println("=========== Dump output: ============")
-		fmt.Println(string(output))
-		fmt.Println("=====================================")
-	}
-
-	return
-}
-
-func (c *WebhookCFG) fetch(user, repo string) (err error) {
-	gitDir := c.gitDir(user, repo)
-	git := exec.Command(
-		"git",
-		"--git-dir", gitDir,
-		"fetch", "origin", c.Branch,
-	)
-	output, err := git.CombinedOutput()
-	if err != nil {
-		fmt.Println("git fetch failed: ", err)
-		fmt.Println("=========== Dump output: ============")
-		fmt.Println(string(output))
-		fmt.Println("=====================================")
-	}
-
-	return
-}
-
-func (c *WebhookCFG) clone(user, repo string) (err error) {
-	pageDir := c.pageDir(user, repo)
-	err = os.MkdirAll(filepath.Dir(pageDir), 0755)
-	if err != nil {
-		return
-	}
-
-	gitDir := c.gitDir(user, repo)
-	err = os.MkdirAll(filepath.Dir(gitDir), 0700)
-	if err != nil {
-		return
-	}
-
-	uri := c.Server
-	uri.Path = "/" + path.Join(user, repo) + ".git"
-	uri.User = url.UserPassword(c.GitUser, c.GitPass)
-
-	git := exec.Command(
-		"git",
-		"clone",
-		"-b", c.Branch,
-		"--single-branch",
-		"--no-tags",
-		"--separate-git-dir", gitDir,
-		uri.String(),
-		pageDir,
-	)
-	output, err := git.CombinedOutput()
-	if err != nil {
-		fmt.Println("git clone failed: ", err)
-		fmt.Println("=========== Dump output: ============")
-		fmt.Println(string(output))
-		fmt.Println("=====================================")
-	}
-
-	os.Remove(filepath.Join(pageDir, ".git"))
-
-	return
-}
-
-var repoLock = &sync.Map{}
-
-func (c *WebhookCFG) lock(user, repo string) func() {
-	key := user + "/" + repo
-
-	lock, _ := repoLock.LoadOrStore(key, &sync.Mutex{})
-	m := lock.(*sync.Mutex)
-	m.Lock()
-	return m.Unlock
-}
-
-func (c *WebhookCFG) download(user, repo string) (err error) {
-	unlock := c.lock(user, repo)
-	defer unlock()
-
-	gitDir := c.gitDir(user, repo)
-	if _, err = os.Stat(gitDir); os.IsNotExist(err) {
-		err = c.clone(user, repo)
-	} else {
-		err = c.fetch(user, repo)
-	}
-
-	if err != nil {
-		return
-	}
-
-	err = c.checkout(user, repo)
-	return
 }
 
 type webhookPayload struct {
@@ -185,22 +64,19 @@ func (c *WebhookCFG) handle(w http.ResponseWriter, r *http.Request) {
 	user, repo := path.Split(payload.Repository.FullName)
 	user = user[:len(user)-1]
 	go func() {
-		fmt.Println("Pulling ", user, repo)
+		c.ch <- repoSpec{user: user, name: repo}
-		err = c.download(user, repo)
-		if err != nil {
-			fmt.Println("Failed to download repository: ", err)
-			return
-		}
 	}()
 }
 
-func UseWebhook(bind string, cfg *WebhookCFG) (*http.Server, error) {
+func UseWebhook(bind string, cfg *WebhookCFG) (*http.Server, *GitRunner, error) {
 	if cfg == nil {
-		return nil, errors.New("webhook config is nil")
+		return nil, nil, errors.New("webhook config is nil")
 	}
 	s := &http.Server{
 		Addr:    bind,
 		Handler: http.HandlerFunc(cfg.handle),
 	}
-	return s, nil
+	ch := make(chan repoSpec, 5)
+	cfg.ch = ch
+	return s, &GitRunner{ch: ch, cfg: cfg}, nil
 }