From 0003d5d983c1386a697dab19b77d520354dbc840 Mon Sep 17 00:00:00 2001
From: Johan Euphrosine <proppy@google.com>
Date: Mon, 22 Dec 2014 13:13:47 -0800
Subject: [PATCH 1/8] contrib: add git-sync container

---
 contrib/git-sync/Dockerfile |  4 +++
 contrib/git-sync/README.md  | 16 +++++++++
 contrib/git-sync/main.go    | 72 +++++++++++++++++++++++++++++++++++++
 3 files changed, 92 insertions(+)
 create mode 100644 contrib/git-sync/Dockerfile
 create mode 100644 contrib/git-sync/README.md
 create mode 100644 contrib/git-sync/main.go

diff --git a/contrib/git-sync/Dockerfile b/contrib/git-sync/Dockerfile
new file mode 100644
index 00000000000..2c5596c7b90
--- /dev/null
+++ b/contrib/git-sync/Dockerfile
@@ -0,0 +1,4 @@
+FROM golang:1.4-onbuild
+VOLUME ["/git"]
+CMD ["-dest", "/git"]
+ENTRYPOINT ["/go/bin/git-sync"]
diff --git a/contrib/git-sync/README.md b/contrib/git-sync/README.md
new file mode 100644
index 00000000000..a3059d91cd6
--- /dev/null
+++ b/contrib/git-sync/README.md
@@ -0,0 +1,16 @@
+# git-sync
+
+git-sync is a command that periodically sync a git repository to a local directory.
+
+It can be used to source a container volume with the content of a git repo.
+
+## Usage
+
+```
+# build the container
+docker build -t git-sync .
+# run the git-sync container
+docker run -d -e INTERVAL=1s -e REPO=https://github.com/GoogleCloudPlatform/kubernetes -e BRANCH=gh-pages -v /git-data:/usr/share/nginx/html git-sync
+# run a nginx container to serve sync'ed content
+docker run -d -p 8080:80 -v /git-data:/var/www nginx 
+```
diff --git a/contrib/git-sync/main.go b/contrib/git-sync/main.go
new file mode 100644
index 00000000000..2d53e259dce
--- /dev/null
+++ b/contrib/git-sync/main.go
@@ -0,0 +1,72 @@
+package main // import "github.com/GoogleCloudPlatform/kubernetes/git-sync"
+
+import (
+	"flag"
+	"log"
+	"net/http"
+	"os"
+	"os/exec"
+	"path"
+	"strings"
+	"time"
+)
+
+var interval = flag.String("interval", env("INTERVAL", "60s"), "git pull interval")
+var repo = flag.String("repo", env("REPO", ""), "git repo url")
+var branch = flag.String("branch", env("BRANCH", "master"), "git branch")
+var hook = flag.String("hook", env("HOOK", "/"), "web hook path")
+var dest = flag.String("dest", env("DEST", ""), "destination path")
+
+func env(key, def string) string {
+	if env := os.Getenv(key); env != "" {
+		return env
+	}
+	return def
+}
+
+const usage = "usage: REPO= DEST= [INTERVAL= BRANCH= HOOK=] git-sync -repo GIT_REPO_URL -dest PATH [-interval -branch -hook]"
+
+func main() {
+	flag.Parse()
+	if *repo == "" || *dest == "" {
+		flag.Usage()
+		log.Fatal(usage)
+	}
+	pullInterval, err := time.ParseDuration(*interval)
+	if err != nil {
+		log.Fatalf("error parsing time duration %q: %v", *interval, err)
+	}
+	if _, err := exec.LookPath("git"); err != nil {
+		log.Fatalf("required git executable not found: %v", err)
+	}
+	go func() {
+		for _ = range time.Tick(pullInterval) {
+			gitSync()
+		}
+	}()
+	http.HandleFunc(*hook, func(w http.ResponseWriter, r *http.Request) {
+		gitSync()
+	})
+	log.Fatal(http.ListenAndServe(":8080", nil))
+}
+
+func gitSync() {
+	if _, err := os.Stat(path.Join(*dest, ".git")); os.IsNotExist(err) {
+		cmd := exec.Command("git", "clone", "-b", *branch, *repo, *dest)
+		output, err := cmd.CombinedOutput()
+		if err != nil {
+			log.Printf("command %q : %v", strings.Join(cmd.Args, " "), err)
+			return
+		}
+		log.Println(string(output))
+		return
+	}
+	cmd := exec.Command("git", "pull", "origin", *branch)
+	cmd.Dir = *dest
+	output, err := cmd.CombinedOutput()
+	if err != nil {
+		log.Printf("command %q : %v", strings.Join(cmd.Args, " "), err)
+		return
+	}
+	log.Println(string(output))
+}

From d67db4ecfa6f5648909fdddf719af42368208480 Mon Sep 17 00:00:00 2001
From: Johan Euphrosine <proppy@google.com>
Date: Mon, 22 Dec 2014 17:34:56 -0800
Subject: [PATCH 2/8] config/git-sync: add envvar prefix, fix README

---
 contrib/git-sync/Dockerfile |  2 +-
 contrib/git-sync/README.md  |  4 ++--
 contrib/git-sync/main.go    | 14 +++++++-------
 3 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/contrib/git-sync/Dockerfile b/contrib/git-sync/Dockerfile
index 2c5596c7b90..6929d15b454 100644
--- a/contrib/git-sync/Dockerfile
+++ b/contrib/git-sync/Dockerfile
@@ -1,4 +1,4 @@
 FROM golang:1.4-onbuild
 VOLUME ["/git"]
-CMD ["-dest", "/git"]
+ENV GIT_SYNC_DEST /git
 ENTRYPOINT ["/go/bin/git-sync"]
diff --git a/contrib/git-sync/README.md b/contrib/git-sync/README.md
index a3059d91cd6..1ec2d997066 100644
--- a/contrib/git-sync/README.md
+++ b/contrib/git-sync/README.md
@@ -10,7 +10,7 @@ It can be used to source a container volume with the content of a git repo.
 # build the container
 docker build -t git-sync .
 # run the git-sync container
-docker run -d -e INTERVAL=1s -e REPO=https://github.com/GoogleCloudPlatform/kubernetes -e BRANCH=gh-pages -v /git-data:/usr/share/nginx/html git-sync
+docker run -d -e GIT_SYNC_INTERVAL=1s -e GIT_SYNC_REPO=https://github.com/GoogleCloudPlatform/kubernetes -e GIT_SYNC_BRANCH=gh-pages -v /git-data:/git git-sync
 # run a nginx container to serve sync'ed content
-docker run -d -p 8080:80 -v /git-data:/var/www nginx 
+docker run -d -p 8080:80 -v /git-data:/usr/share/nginx/html nginx 
 ```
diff --git a/contrib/git-sync/main.go b/contrib/git-sync/main.go
index 2d53e259dce..4b7cbf2f1be 100644
--- a/contrib/git-sync/main.go
+++ b/contrib/git-sync/main.go
@@ -11,11 +11,11 @@ import (
 	"time"
 )
 
-var interval = flag.String("interval", env("INTERVAL", "60s"), "git pull interval")
-var repo = flag.String("repo", env("REPO", ""), "git repo url")
-var branch = flag.String("branch", env("BRANCH", "master"), "git branch")
-var hook = flag.String("hook", env("HOOK", "/"), "web hook path")
-var dest = flag.String("dest", env("DEST", ""), "destination path")
+var interval = flag.String("interval", env("GIT_SYNC_INTERVAL", "60s"), "git pull interval")
+var repo = flag.String("repo", env("GIT_SYNC_REPO", ""), "git repo url")
+var branch = flag.String("branch", env("GIT_SYNC_BRANCH", "master"), "git branch")
+var handler = flag.String("handler", env("GIT_SYNC_HANDLER", "/"), "web hook handler")
+var dest = flag.String("dest", env("GIT_SYNC_DEST", ""), "destination path")
 
 func env(key, def string) string {
 	if env := os.Getenv(key); env != "" {
@@ -24,7 +24,7 @@ func env(key, def string) string {
 	return def
 }
 
-const usage = "usage: REPO= DEST= [INTERVAL= BRANCH= HOOK=] git-sync -repo GIT_REPO_URL -dest PATH [-interval -branch -hook]"
+const usage = "usage: GIT_SYNC_REPO= GIT_SYNC_DEST= [GIT_SYNC_INTERVAL= GIT_SYNC_BRANCH= GIT_SYNC_HANDLER=] git-sync -repo GIT_REPO_URL -dest PATH [-interval -branch -handler]"
 
 func main() {
 	flag.Parse()
@@ -44,7 +44,7 @@ func main() {
 			gitSync()
 		}
 	}()
-	http.HandleFunc(*hook, func(w http.ResponseWriter, r *http.Request) {
+	http.HandleFunc(*handler, func(w http.ResponseWriter, r *http.Request) {
 		gitSync()
 	})
 	log.Fatal(http.ListenAndServe(":8080", nil))

From 9f37c9d4112a0311f725137b6cd0fba5db4c394d Mon Sep 17 00:00:00 2001
From: Johan Euphrosine <proppy@google.com>
Date: Tue, 23 Dec 2014 13:54:29 -0800
Subject: [PATCH 3/8] contrib/git-sync: add atomic checkout

---
 contrib/git-sync/README.md |   2 +-
 contrib/git-sync/main.go   | 107 +++++++++++++++++++++++++++++++------
 2 files changed, 91 insertions(+), 18 deletions(-)

diff --git a/contrib/git-sync/README.md b/contrib/git-sync/README.md
index 1ec2d997066..52bf2c655d9 100644
--- a/contrib/git-sync/README.md
+++ b/contrib/git-sync/README.md
@@ -12,5 +12,5 @@ docker build -t git-sync .
 # run the git-sync container
 docker run -d -e GIT_SYNC_INTERVAL=1s -e GIT_SYNC_REPO=https://github.com/GoogleCloudPlatform/kubernetes -e GIT_SYNC_BRANCH=gh-pages -v /git-data:/git git-sync
 # run a nginx container to serve sync'ed content
-docker run -d -p 8080:80 -v /git-data:/usr/share/nginx/html nginx 
+docker run -d -p 8080:80 -v /git-data/HEAD:/usr/share/nginx/html nginx 
 ```
diff --git a/contrib/git-sync/main.go b/contrib/git-sync/main.go
index 4b7cbf2f1be..3060fb71e03 100644
--- a/contrib/git-sync/main.go
+++ b/contrib/git-sync/main.go
@@ -2,6 +2,7 @@ package main // import "github.com/GoogleCloudPlatform/kubernetes/git-sync"
 
 import (
 	"flag"
+	"fmt"
 	"log"
 	"net/http"
 	"os"
@@ -39,34 +40,106 @@ func main() {
 	if _, err := exec.LookPath("git"); err != nil {
 		log.Fatalf("required git executable not found: %v", err)
 	}
+	repo, err := NewRepo()
+	if err != nil {
+		log.Fatalf("error creating repo: %v", err)
+	}
+	syncc := make(chan struct{})
+	tick := time.Tick(pullInterval)
 	go func() {
-		for _ = range time.Tick(pullInterval) {
-			gitSync()
+		for {
+			repo.Sync()
+			select {
+			case <-tick:
+			case <-syncc:
+			}
 		}
 	}()
 	http.HandleFunc(*handler, func(w http.ResponseWriter, r *http.Request) {
-		gitSync()
+		syncc <- struct{}{}
 	})
 	log.Fatal(http.ListenAndServe(":8080", nil))
 }
 
-func gitSync() {
-	if _, err := os.Stat(path.Join(*dest, ".git")); os.IsNotExist(err) {
-		cmd := exec.Command("git", "clone", "-b", *branch, *repo, *dest)
-		output, err := cmd.CombinedOutput()
-		if err != nil {
-			log.Printf("command %q : %v", strings.Join(cmd.Args, " "), err)
-			return
-		}
-		log.Println(string(output))
-		return
+type Repo struct {
+	basePath   string
+	mirrorPath string
+	lastRev    string
+}
+
+func NewRepo() (*Repo, error) {
+	mirrorRepoPath := path.Join(*dest, ".git")
+	_, err := os.Stat(mirrorRepoPath)
+	if err == nil {
+		log.Printf("found existing mirror repo %q", mirrorRepoPath)
+		return &Repo{
+			basePath:   *dest,
+			mirrorPath: mirrorRepoPath,
+		}, nil
 	}
-	cmd := exec.Command("git", "pull", "origin", *branch)
-	cmd.Dir = *dest
+	if !os.IsNotExist(err) {
+		return nil, fmt.Errorf("error checking repo %q: %v", mirrorRepoPath, err)
+	}
+	cmd := exec.Command("git", "clone", "--mirror", "-b", *branch, *repo, mirrorRepoPath)
 	output, err := cmd.CombinedOutput()
 	if err != nil {
-		log.Printf("command %q : %v", strings.Join(cmd.Args, " "), err)
+		return nil, fmt.Errorf("error cloning repo %q: %v:", strings.Join(cmd.Args, " "), err)
+	}
+	log.Printf("clone %q: %s", *repo, string(output))
+	return &Repo{
+		basePath:   *dest,
+		mirrorPath: mirrorRepoPath,
+	}, nil
+}
+
+func (r *Repo) Sync() {
+	cmd := exec.Command("git", "fetch", "origin", *branch)
+	cmd.Dir = r.mirrorPath
+	output, err := cmd.CombinedOutput()
+	if err != nil {
+		log.Printf("error running command %q: %v", strings.Join(cmd.Args, " "), err)
+		return
+	}
+	log.Printf("fetch: %s", string(output))
+	cmd = exec.Command("git", "rev-parse", "HEAD")
+	cmd.Dir = r.mirrorPath
+	output, err = cmd.CombinedOutput()
+	if err != nil {
+		log.Printf("error running command %q: %v", strings.Join(cmd.Args, " "), err)
+		return
+	}
+	rev := strings.TrimSpace(string(output))
+	if rev == r.lastRev {
+		log.Printf("no new rev since last check %q", rev)
+		return
+	}
+	r.lastRev = rev
+	log.Printf("HEAD is: %q", rev)
+	repoPath := path.Join(r.basePath, rev)
+	_, err = os.Stat(repoPath)
+	if err == nil {
+		log.Printf("found existing repo: %q", repoPath)
+		return
+	}
+	if !os.IsNotExist(err) {
+		log.Printf("error stating repo %q: %v", repoPath, err)
+		return
+	}
+	cmd = exec.Command("git", "clone", r.mirrorPath, repoPath)
+	output, err = cmd.CombinedOutput()
+	if err != nil {
+		log.Printf("error running command %q : %v", strings.Join(cmd.Args, " "), err)
+		return
+	}
+	log.Printf("clone %q: %v", repoPath, string(output))
+	tempPath := path.Join(r.basePath, "HEAD."+rev)
+	if err := os.Symlink(rev, tempPath); err != nil {
+		log.Printf("error creating temporary symlink %q: %v", tempPath, err)
+		return
+	}
+	linkPath := path.Join(r.basePath, "HEAD")
+	if err := os.Rename(tempPath, linkPath); err != nil {
+		log.Printf("error moving symlink %q: %v", linkPath, err)
 		return
 	}
-	log.Println(string(output))
 }

From 79dd775d72110df443630a2ae1a79b5d350382de Mon Sep 17 00:00:00 2001
From: Johan Euphrosine <proppy@google.com>
Date: Tue, 23 Dec 2014 15:21:51 -0800
Subject: [PATCH 4/8] contrib/git-sync: add comment

---
 contrib/git-sync/main.go | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/contrib/git-sync/main.go b/contrib/git-sync/main.go
index 3060fb71e03..b0aff6179b5 100644
--- a/contrib/git-sync/main.go
+++ b/contrib/git-sync/main.go
@@ -1,3 +1,21 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// git-sync is a command that periodically sync a git repository to a local directory.
+
 package main // import "github.com/GoogleCloudPlatform/kubernetes/git-sync"
 
 import (
@@ -67,6 +85,7 @@ type Repo struct {
 	lastRev    string
 }
 
+// NewRepo initalize a local bare repository mirror.
 func NewRepo() (*Repo, error) {
 	mirrorRepoPath := path.Join(*dest, ".git")
 	_, err := os.Stat(mirrorRepoPath)
@@ -92,6 +111,9 @@ func NewRepo() (*Repo, error) {
 	}, nil
 }
 
+// Sync fetch new revision from the origin remote in the bare repository
+//      create a new checkout named after the revision
+//	update HEAD symlink to point to the new revision
 func (r *Repo) Sync() {
 	cmd := exec.Command("git", "fetch", "origin", *branch)
 	cmd.Dir = r.mirrorPath

From 0415b63ab49310a23b9296e65447fbb297cbb099 Mon Sep 17 00:00:00 2001
From: Johan Euphrosine <proppy@google.com>
Date: Thu, 29 Jan 2015 15:39:51 -0800
Subject: [PATCH 5/8] contrib/git-sync: remove sync loop, simplify logic

---
 contrib/git-sync/README.md |   6 +-
 contrib/git-sync/main.go   | 149 ++++++++++---------------------------
 2 files changed, 41 insertions(+), 114 deletions(-)

diff --git a/contrib/git-sync/README.md b/contrib/git-sync/README.md
index 52bf2c655d9..f8faa4a0cd1 100644
--- a/contrib/git-sync/README.md
+++ b/contrib/git-sync/README.md
@@ -1,6 +1,6 @@
 # git-sync
 
-git-sync is a command that periodically sync a git repository to a local directory.
+git-sync is a command that pull a git repository to a local directory.
 
 It can be used to source a container volume with the content of a git repo.
 
@@ -10,7 +10,7 @@ It can be used to source a container volume with the content of a git repo.
 # build the container
 docker build -t git-sync .
 # run the git-sync container
-docker run -d -e GIT_SYNC_INTERVAL=1s -e GIT_SYNC_REPO=https://github.com/GoogleCloudPlatform/kubernetes -e GIT_SYNC_BRANCH=gh-pages -v /git-data:/git git-sync
+docker run -d GIT_SYNC_REPO=https://github.com/GoogleCloudPlatform/kubernetes -e GIT_SYNC_BRANCH=gh-pages -r HEAD -v /git-data:/git git-sync
 # run a nginx container to serve sync'ed content
-docker run -d -p 8080:80 -v /git-data/HEAD:/usr/share/nginx/html nginx 
+docker run -d -p 8080:80 -v /git-data:/usr/share/nginx/html nginx 
 ```
diff --git a/contrib/git-sync/main.go b/contrib/git-sync/main.go
index b0aff6179b5..355c0e1bc7e 100644
--- a/contrib/git-sync/main.go
+++ b/contrib/git-sync/main.go
@@ -14,27 +14,24 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-// git-sync is a command that periodically sync a git repository to a local directory.
+// git-sync is a command that pull a git repository to a local directory.
 
-package main // import "github.com/GoogleCloudPlatform/kubernetes/git-sync"
+package main // import "github.com/GoogleCloudPlatform/kubernetes/contrib/git-sync"
 
 import (
 	"flag"
 	"fmt"
 	"log"
-	"net/http"
 	"os"
 	"os/exec"
 	"path"
 	"strings"
-	"time"
 )
 
-var interval = flag.String("interval", env("GIT_SYNC_INTERVAL", "60s"), "git pull interval")
-var repo = flag.String("repo", env("GIT_SYNC_REPO", ""), "git repo url")
-var branch = flag.String("branch", env("GIT_SYNC_BRANCH", "master"), "git branch")
-var handler = flag.String("handler", env("GIT_SYNC_HANDLER", "/"), "web hook handler")
-var dest = flag.String("dest", env("GIT_SYNC_DEST", ""), "destination path")
+var flRepo = flag.String("repo", env("GIT_SYNC_REPO", ""), "git repo url")
+var flBranch = flag.String("branch", env("GIT_SYNC_BRANCH", "master"), "git branch")
+var flRev = flag.String("rev", env("GIT_SYNC_BRANCH", "HEAD"), "git rev")
+var flDest = flag.String("dest", env("GIT_SYNC_DEST", ""), "destination path")
 
 func env(key, def string) string {
 	if env := os.Getenv(key); env != "" {
@@ -43,125 +40,55 @@ func env(key, def string) string {
 	return def
 }
 
-const usage = "usage: GIT_SYNC_REPO= GIT_SYNC_DEST= [GIT_SYNC_INTERVAL= GIT_SYNC_BRANCH= GIT_SYNC_HANDLER=] git-sync -repo GIT_REPO_URL -dest PATH [-interval -branch -handler]"
+const usage = "usage: GIT_SYNC_REPO= GIT_SYNC_DEST= [GIT_SYNC_BRANCH=] git-sync -repo GIT_REPO_URL -dest PATH [-branch]"
 
 func main() {
 	flag.Parse()
-	if *repo == "" || *dest == "" {
+	if *flRepo == "" || *flDest == "" {
 		flag.Usage()
 		log.Fatal(usage)
 	}
-	pullInterval, err := time.ParseDuration(*interval)
-	if err != nil {
-		log.Fatalf("error parsing time duration %q: %v", *interval, err)
-	}
 	if _, err := exec.LookPath("git"); err != nil {
 		log.Fatalf("required git executable not found: %v", err)
 	}
-	repo, err := NewRepo()
-	if err != nil {
-		log.Fatalf("error creating repo: %v", err)
+	if err := syncRepo(*flRepo, *flDest, *flBranch, *flRev); err != nil {
+		log.Fatalf("error syncing repo: %v", err)
 	}
-	syncc := make(chan struct{})
-	tick := time.Tick(pullInterval)
-	go func() {
-		for {
-			repo.Sync()
-			select {
-			case <-tick:
-			case <-syncc:
-			}
+}
+
+// syncRepo syncs the branch of a given repository to the destination at the given rev.
+func syncRepo(repo, dest, branch, rev string) error {
+	gitRepoPath := path.Join(dest, ".git")
+	_, err := os.Stat(gitRepoPath)
+	switch {
+	case os.IsNotExist(err):
+		// clone repo
+		cmd := exec.Command("git", "clone", "--no-checkout", "-b", branch, repo, dest)
+		output, err := cmd.CombinedOutput()
+		if err != nil {
+			return fmt.Errorf("error cloning repo %q: %v: %s", strings.Join(cmd.Args, " "), err, string(output))
 		}
-	}()
-	http.HandleFunc(*handler, func(w http.ResponseWriter, r *http.Request) {
-		syncc <- struct{}{}
-	})
-	log.Fatal(http.ListenAndServe(":8080", nil))
-}
-
-type Repo struct {
-	basePath   string
-	mirrorPath string
-	lastRev    string
-}
-
-// NewRepo initalize a local bare repository mirror.
-func NewRepo() (*Repo, error) {
-	mirrorRepoPath := path.Join(*dest, ".git")
-	_, err := os.Stat(mirrorRepoPath)
-	if err == nil {
-		log.Printf("found existing mirror repo %q", mirrorRepoPath)
-		return &Repo{
-			basePath:   *dest,
-			mirrorPath: mirrorRepoPath,
-		}, nil
+		log.Printf("clone %q: %s", repo, string(output))
+	case err != nil:
+		return fmt.Errorf("error checking if repo exist %q: %v", gitRepoPath, err)
 	}
-	if !os.IsNotExist(err) {
-		return nil, fmt.Errorf("error checking repo %q: %v", mirrorRepoPath, err)
-	}
-	cmd := exec.Command("git", "clone", "--mirror", "-b", *branch, *repo, mirrorRepoPath)
+
+	// fetch branch
+	cmd := exec.Command("git", "fetch", "origin", branch)
+	cmd.Dir = dest
 	output, err := cmd.CombinedOutput()
 	if err != nil {
-		return nil, fmt.Errorf("error cloning repo %q: %v:", strings.Join(cmd.Args, " "), err)
+		return fmt.Errorf("error running command %q: %v: %s", strings.Join(cmd.Args, " "), err, string(output))
 	}
-	log.Printf("clone %q: %s", *repo, string(output))
-	return &Repo{
-		basePath:   *dest,
-		mirrorPath: mirrorRepoPath,
-	}, nil
-}
+	log.Printf("fetch %q: %s", branch, string(output))
 
-// Sync fetch new revision from the origin remote in the bare repository
-//      create a new checkout named after the revision
-//	update HEAD symlink to point to the new revision
-func (r *Repo) Sync() {
-	cmd := exec.Command("git", "fetch", "origin", *branch)
-	cmd.Dir = r.mirrorPath
-	output, err := cmd.CombinedOutput()
-	if err != nil {
-		log.Printf("error running command %q: %v", strings.Join(cmd.Args, " "), err)
-		return
-	}
-	log.Printf("fetch: %s", string(output))
-	cmd = exec.Command("git", "rev-parse", "HEAD")
-	cmd.Dir = r.mirrorPath
+	// reset working copy
+	cmd = exec.Command("git", "reset", "--hard", rev)
+	cmd.Dir = dest
 	output, err = cmd.CombinedOutput()
 	if err != nil {
-		log.Printf("error running command %q: %v", strings.Join(cmd.Args, " "), err)
-		return
-	}
-	rev := strings.TrimSpace(string(output))
-	if rev == r.lastRev {
-		log.Printf("no new rev since last check %q", rev)
-		return
-	}
-	r.lastRev = rev
-	log.Printf("HEAD is: %q", rev)
-	repoPath := path.Join(r.basePath, rev)
-	_, err = os.Stat(repoPath)
-	if err == nil {
-		log.Printf("found existing repo: %q", repoPath)
-		return
-	}
-	if !os.IsNotExist(err) {
-		log.Printf("error stating repo %q: %v", repoPath, err)
-		return
-	}
-	cmd = exec.Command("git", "clone", r.mirrorPath, repoPath)
-	output, err = cmd.CombinedOutput()
-	if err != nil {
-		log.Printf("error running command %q : %v", strings.Join(cmd.Args, " "), err)
-		return
-	}
-	log.Printf("clone %q: %v", repoPath, string(output))
-	tempPath := path.Join(r.basePath, "HEAD."+rev)
-	if err := os.Symlink(rev, tempPath); err != nil {
-		log.Printf("error creating temporary symlink %q: %v", tempPath, err)
-		return
-	}
-	linkPath := path.Join(r.basePath, "HEAD")
-	if err := os.Rename(tempPath, linkPath); err != nil {
-		log.Printf("error moving symlink %q: %v", linkPath, err)
-		return
+		return fmt.Errorf("error running command %q : %v: %s", strings.Join(cmd.Args, " "), err, string(output))
 	}
+	log.Printf("reset %q: %v", rev, string(output))
+	return nil
 }

From 5aba5f00c0cf7dbd1b54083d559a49e47f959c53 Mon Sep 17 00:00:00 2001
From: Johan Euphrosine <proppy@google.com>
Date: Thu, 29 Jan 2015 23:21:49 -0800
Subject: [PATCH 6/8] contrib/git-sync: add wait

---
 contrib/git-sync/main.go | 30 ++++++++++++++++++++++++------
 1 file changed, 24 insertions(+), 6 deletions(-)

diff --git a/contrib/git-sync/main.go b/contrib/git-sync/main.go
index 355c0e1bc7e..7667e8df7a5 100644
--- a/contrib/git-sync/main.go
+++ b/contrib/git-sync/main.go
@@ -25,22 +25,37 @@ import (
 	"os"
 	"os/exec"
 	"path"
+	"strconv"
 	"strings"
+	"time"
 )
 
-var flRepo = flag.String("repo", env("GIT_SYNC_REPO", ""), "git repo url")
-var flBranch = flag.String("branch", env("GIT_SYNC_BRANCH", "master"), "git branch")
-var flRev = flag.String("rev", env("GIT_SYNC_BRANCH", "HEAD"), "git rev")
-var flDest = flag.String("dest", env("GIT_SYNC_DEST", ""), "destination path")
+var flRepo = flag.String("repo", envString("GIT_SYNC_REPO", ""), "git repo url")
+var flBranch = flag.String("branch", envString("GIT_SYNC_BRANCH", "master"), "git branch")
+var flRev = flag.String("rev", envString("GIT_SYNC_BRANCH", "HEAD"), "git rev")
+var flDest = flag.String("dest", envString("GIT_SYNC_DEST", ""), "destination path")
+var flWait = flag.Int("wait", envInt("GIT_SYNC_WAIT", 0), "number of seconds to wait before exit")
 
-func env(key, def string) string {
+func envString(key, def string) string {
 	if env := os.Getenv(key); env != "" {
 		return env
 	}
 	return def
 }
 
-const usage = "usage: GIT_SYNC_REPO= GIT_SYNC_DEST= [GIT_SYNC_BRANCH=] git-sync -repo GIT_REPO_URL -dest PATH [-branch]"
+func envInt(key string, def int) int {
+	if env := os.Getenv(key); env != "" {
+		val, err := strconv.Atoi(env)
+		if err != nil {
+			log.Println("invalid value for %q: using default: %q", key, def)
+			return def
+		}
+		return val
+	}
+	return def
+}
+
+const usage = "usage: GIT_SYNC_REPO= GIT_SYNC_DEST= [GIT_SYNC_BRANCH= GIT_SYNC_WAIT=] git-sync -repo GIT_REPO_URL -dest PATH [-branch -wait]"
 
 func main() {
 	flag.Parse()
@@ -54,6 +69,9 @@ func main() {
 	if err := syncRepo(*flRepo, *flDest, *flBranch, *flRev); err != nil {
 		log.Fatalf("error syncing repo: %v", err)
 	}
+	log.Printf("wait %d seconds", *flWait)
+	time.Sleep(time.Duration(*flWait) * time.Second)
+	log.Println("done")
 }
 
 // syncRepo syncs the branch of a given repository to the destination at the given rev.

From 19751abe138b7a92927ab56d39ecd55ea9a77ea7 Mon Sep 17 00:00:00 2001
From: Johan Euphrosine <proppy@google.com>
Date: Mon, 2 Feb 2015 18:02:18 -0800
Subject: [PATCH 7/8] contrib/git-sync: add demo

---
 contrib/git-sync/demo/README.md               | 28 +++++++++++
 contrib/git-sync/demo/blog/archetypes/.keep   |  0
 contrib/git-sync/demo/blog/config.toml        |  3 ++
 contrib/git-sync/demo/blog/content/about.md   |  9 ++++
 .../git-sync/demo/blog/content/post/first.md  |  9 ++++
 contrib/git-sync/demo/blog/layouts/.keep      |  0
 contrib/git-sync/demo/blog/static/.keep       |  0
 contrib/git-sync/demo/config/pod.yaml         | 50 +++++++++++++++++++
 contrib/git-sync/demo/config/service.yaml     |  8 +++
 contrib/git-sync/demo/hugo/Dockerfile         | 13 +++++
 contrib/git-sync/demo/hugo/run-hugo           |  6 +++
 11 files changed, 126 insertions(+)
 create mode 100644 contrib/git-sync/demo/README.md
 create mode 100644 contrib/git-sync/demo/blog/archetypes/.keep
 create mode 100644 contrib/git-sync/demo/blog/config.toml
 create mode 100644 contrib/git-sync/demo/blog/content/about.md
 create mode 100644 contrib/git-sync/demo/blog/content/post/first.md
 create mode 100644 contrib/git-sync/demo/blog/layouts/.keep
 create mode 100644 contrib/git-sync/demo/blog/static/.keep
 create mode 100644 contrib/git-sync/demo/config/pod.yaml
 create mode 100644 contrib/git-sync/demo/config/service.yaml
 create mode 100644 contrib/git-sync/demo/hugo/Dockerfile
 create mode 100755 contrib/git-sync/demo/hugo/run-hugo

diff --git a/contrib/git-sync/demo/README.md b/contrib/git-sync/demo/README.md
new file mode 100644
index 00000000000..b458135bfd9
--- /dev/null
+++ b/contrib/git-sync/demo/README.md
@@ -0,0 +1,28 @@
+# git-blog-demo
+
+This demo shows how to use the `git-sync` sidekick container along side `volumes` and `volumeMounts` to create a markdown powered blog.
+
+## How it works
+
+The pod is composed of 3 containers that share directories using 2 volumes:
+
+- The `git-sync` container clones a git repo into the `markdown` volume
+- The `hugo` container read from the `markdown` volume and render it into the `html` volume.
+- The `nginx` container serve the content from the `html` volume.
+
+## Usage
+
+Build the demo containers, and push them to a registry
+``
+docker build -t <some-registry>/git-sync ..
+docker build -t <some-registry>/hugo hugo/
+docker push <some-registry>/hugo <some-registry>/git-sync
+```
+
+Create the pod and the service for the blog
+```
+kubectl pods create config/pod.html
+kubectl services create config/pod.html
+```
+
+Open the external ip in your browser
diff --git a/contrib/git-sync/demo/blog/archetypes/.keep b/contrib/git-sync/demo/blog/archetypes/.keep
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/contrib/git-sync/demo/blog/config.toml b/contrib/git-sync/demo/blog/config.toml
new file mode 100644
index 00000000000..ab3aa9e446e
--- /dev/null
+++ b/contrib/git-sync/demo/blog/config.toml
@@ -0,0 +1,3 @@
+baseurl = "http://example.com"
+languageCode = "en-us"
+title = "example blog"
diff --git a/contrib/git-sync/demo/blog/content/about.md b/contrib/git-sync/demo/blog/content/about.md
new file mode 100644
index 00000000000..afb2ac0f4bb
--- /dev/null
+++ b/contrib/git-sync/demo/blog/content/about.md
@@ -0,0 +1,9 @@
++++
+date = "2014-12-19T15:29:48-08:00"
+draft = true
+title = "about"
++++
+
+## A headline
+
+Some content about the blog.
diff --git a/contrib/git-sync/demo/blog/content/post/first.md b/contrib/git-sync/demo/blog/content/post/first.md
new file mode 100644
index 00000000000..630bbbd01d3
--- /dev/null
+++ b/contrib/git-sync/demo/blog/content/post/first.md
@@ -0,0 +1,9 @@
++++
+date = "2014-12-19T15:30:18-08:00"
+draft = true
+title = "first"
++++
+
+## first port
+
+This is the first post.
diff --git a/contrib/git-sync/demo/blog/layouts/.keep b/contrib/git-sync/demo/blog/layouts/.keep
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/contrib/git-sync/demo/blog/static/.keep b/contrib/git-sync/demo/blog/static/.keep
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/contrib/git-sync/demo/config/pod.yaml b/contrib/git-sync/demo/config/pod.yaml
new file mode 100644
index 00000000000..75ff074c18b
--- /dev/null
+++ b/contrib/git-sync/demo/config/pod.yaml
@@ -0,0 +1,50 @@
+id: blog-pod
+kind: Pod
+apiVersion: v1beta1
+desiredState:
+  manifest:
+    version: v1beta1
+    containers:
+    - name: git-sync
+      image: proppy/git-sync
+      imagePullPolicy: PullAlways
+      env::
+        - name: GIT_SYNC_REPO
+          value: https://github.com/proppy/blog.git
+        - name: GIT_SYNC_DEST
+          value: /git
+      volumeMounts:
+      - name: markdown
+        mountPath: /git
+    - name: hugo
+      image: proppy/hugo
+      imagePullPolicy: PullAlways
+      env:
+      - name: SRC
+        value: /src
+      - name: BUILD_DRAFT
+        value: 'true'
+      - name: BASE_URL
+        value: kube.proppy.sh
+      volumeMounts:
+      - name: markdown
+        mountPath: /src
+      - name: html
+        mountPath: /dest
+    - name: nginx
+      image: nginx
+      volumeMounts:
+      - name: html
+        mountPath: /usr/share/nginx/html
+      ports:
+      - name: http-server
+        containerPort: 80
+    volumes:
+    - name: markdown
+      source:
+        emptyDir: {}
+    - name: html
+      source:
+        emptyDir: {}
+labels:
+  name: blog
diff --git a/contrib/git-sync/demo/config/service.yaml b/contrib/git-sync/demo/config/service.yaml
new file mode 100644
index 00000000000..646b4c59aa6
--- /dev/null
+++ b/contrib/git-sync/demo/config/service.yaml
@@ -0,0 +1,8 @@
+id: blog-service
+kind: Service
+apiVersion: v1beta1
+port: 80
+containerPort: http-server
+selector:
+  name: blog
+createExternalLoadBalancer: true
diff --git a/contrib/git-sync/demo/hugo/Dockerfile b/contrib/git-sync/demo/hugo/Dockerfile
new file mode 100644
index 00000000000..40af5e67ed8
--- /dev/null
+++ b/contrib/git-sync/demo/hugo/Dockerfile
@@ -0,0 +1,13 @@
+FROM golang
+RUN go get -v github.com/spf13/hugo
+RUN git clone --recursive https://github.com/spf13/hugoThemes.git /themes
+VOLUME ["/src", "/dest"]
+EXPOSE 1313
+ENV SRC /src
+ENV DEST /dest
+ENV THEME hyde
+ENV BUILD_DRAFT false
+ENV BASE_URL ""
+ADD run-hugo /run-hugo
+ENTRYPOINT ["/run-hugo"]
+CMD ["server", "--source=${SRC}", "--theme=${THEME}", "--buildDrafts=${BUILD_DRAFT}", "--baseUrl=${BASE_URL}", "--watch", "--destination=${DEST}", "--appendPort=false"]
diff --git a/contrib/git-sync/demo/hugo/run-hugo b/contrib/git-sync/demo/hugo/run-hugo
new file mode 100755
index 00000000000..c90daa85e25
--- /dev/null
+++ b/contrib/git-sync/demo/hugo/run-hugo
@@ -0,0 +1,6 @@
+#!/bin/bash
+set -ex
+if [ ! -d ${SRC}/themes ]; then
+    ln -s /themes ${SRC}/themes
+fi
+hugo $(eval echo $*) # force default CMD env expansion

From 88734263141b50309f1ec0c4a6122a5c544a299a Mon Sep 17 00:00:00 2001
From: Johan Euphrosine <proppy@google.com>
Date: Mon, 2 Feb 2015 18:05:26 -0800
Subject: [PATCH 8/8] contrib/git-sync/demo: fix README, add license header

---
 contrib/git-sync/demo/README.md     |  6 ++++--
 contrib/git-sync/demo/hugo/run-hugo | 15 +++++++++++++++
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/contrib/git-sync/demo/README.md b/contrib/git-sync/demo/README.md
index b458135bfd9..e2a72465b56 100644
--- a/contrib/git-sync/demo/README.md
+++ b/contrib/git-sync/demo/README.md
@@ -13,16 +13,18 @@ The pod is composed of 3 containers that share directories using 2 volumes:
 ## Usage
 
 Build the demo containers, and push them to a registry
-``
+
+```
 docker build -t <some-registry>/git-sync ..
 docker build -t <some-registry>/hugo hugo/
 docker push <some-registry>/hugo <some-registry>/git-sync
 ```
 
 Create the pod and the service for the blog
+
 ```
 kubectl pods create config/pod.html
 kubectl services create config/pod.html
 ```
 
-Open the external ip in your browser
+Open the service external ip in your browser
diff --git a/contrib/git-sync/demo/hugo/run-hugo b/contrib/git-sync/demo/hugo/run-hugo
index c90daa85e25..37636025523 100755
--- a/contrib/git-sync/demo/hugo/run-hugo
+++ b/contrib/git-sync/demo/hugo/run-hugo
@@ -1,4 +1,19 @@
 #!/bin/bash
+
+# Copyright 2014 Google Inc. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
 set -ex
 if [ ! -d ${SRC}/themes ]; then
     ln -s /themes ${SRC}/themes