NAME
docker-push - Push an image or a repository to the registry
SYNOPSIS
docker push NAME[:TAG]
DESCRIPTION
Push an image or a repository to a registry. The default registry is the Docker Index located at index.docker.io
(https://index.docker.io/v1/). However the image can be pushed to another, perhaps private, registry as demonstrated
in the example below.
本文以私有registry为例
registry地址：127.0.0.1
port：5000
namespace：name
repository：repo
tag：空
docker version:1.0
docker registry:0.9
docker push 127.0.0.1:5000/namespace/repo
代码位置：api/client/command.go:CmdPush
此方法是从docker命令行接收参数，并分析命令行所给的参数，给docker http server发送请求。主要解析的是127.0.0.1:5000/namespace/repo， 从这个参数中解析出registry的地址 127.0.0.1:5000，namespace：namespace，repository：repo，tag：空，另外从HOME命令下的.dockercfg中得到auth和email，其中auth是username和password的加密。两者用于在registry端进行认证，如果找不到.dockercfg文件，docker客户端会使用空间的user和password发送给registry端。
获取命令行参数，其中name=127.0.0.1:5000/namespace/repo
name := cmd.Arg(0)
if name == "" {
cmd.Usage()
return nil
}再从remote中解析出hostname=127.0.0.1:5000，然后从.dockercfg中找到hostname对应的项，.dockercfg这是以key：value方式存储的，key就是registry的hostname，value就是auth和email。根据“/”解析namespace和repository是否合法。
<span style="white-space:pre"> </span>cli.LoadConfigFile()
remote, tag := parsers.ParseRepositoryTag(name)
// Resolve the Repository name from fqn to hostname + name
hostname, _, err := registry.ResolveRepositoryName(remote)
if err != nil {
return err
}
// Resolve the Auth config relevant for this server
authConfig := cli.configFile.ResolveAuthConfig(hostname)
// If we're not using a custom registry, we know the restrictions
// applied to repository names and can warn the user in advance.
// Custom repositories can have different rules, and we must also
// allow pushing by image ID.
if len(strings.SplitN(name, "/", 2)) == 1 {
username := cli.configFile.Configs[registry.IndexServerAddress()].Username
if username == "" {
username = "<user>"
}
return fmt.Errorf("You cannot push a \"root\" repository. Please rename your repository in <user>/<repo> (ex: %s/%s)", username, name)
}
push := func(authConfig registry.AuthConfig) error {
buf, err := json.Marshal(authConfig)
if err != nil {
return err
}
registryAuthHeader := []string{
base64.URLEncoding.EncodeToString(buf),
}
return cli.stream("POST", "/images/"+remote+"/push?"+v.Encode(), nil, cli.out, map[string][]string{
"X-Registry-Auth": ,
})
}如果push请求失败，根据状态码是否是401来决定是否发起login请求。在login请求中同样携带auth认证信息。
if err := push(authConfig); err != nil {
if strings.Contains(err.Error(), "Status 401") {
fmt.Fprintln(cli.out, "\nPlease login prior to push:")
if err := cli.CmdLogin(hostname); err != nil {
return err
}
authConfig := cli.configFile.ResolveAuthConfig(hostname)
return push(authConfig)
}
return err
}
解析X-Rigestry-Auth头信息，如何没有此头，使用空的auth信息。
authConfig := ®istry.AuthConfig{}
authEncoded := r.Header.Get("X-Registry-Auth")
if authEncoded != "" {
// the new format is to handle the authConfig as a header
authJson := base64.NewDecoder(base64.URLEncoding, strings.NewReader(authEncoded))
if err := json.NewDecoder(authJson).Decode(authConfig); err != nil {
// to increase compatibility to existing api it is defaulting to be empty
authConfig = ®istry.AuthConfig{}
}
} else {
// the old format is supported for compatibility if there was no authConfig header
if err := json.NewDecoder(r.Body).Decode(authConfig); err != nil {
return err
}
}
job := eng.Job("push", vars["name"])
job.SetenvJson("metaHeaders", metaHeaders)
job.SetenvJson("authConfig", authConfig)
job.Setenv("tag", r.Form.Get("tag"))
if version.GreaterThan("1.0") {
job.SetenvBool("json", true)
streamJSON(job, w, true)
} else {
job.Stdout.Add(utils.NewWriteFlusher(w))
}
if err := job.Run(); err != nil {
if !job.Stdout.Used() {
return err
}
sf := utils.NewStreamFormatter(version.GreaterThan("1.0"))
w.Write(sf.FormatError(err))
}
</pre><h2><span style="font-family:Courier New">2.3 push job</span></h2>
push job的执行体放在graph/push.go文件中。在docker启动阶段，会注册push job的handler到engine中，关于graph的job处理handler都放在graph中的service.go的install方法中。
job handler的注册，push使用CmdPush handler。
func (s *TagStore) Install(eng *engine.Engine) error {
for name, handler := range map[string]engine.Handler{
"image_set": s.CmdSet,
"image_tag": s.CmdTag,
"tag": s.CmdTagLegacy, // FIXME merge with "image_tag"
"image_get": s.CmdGet,
"image_inspect": s.CmdLookup,
"image_tarlayer": s.CmdTarLayer,
"image_export": s.CmdImageExport,
"history": s.CmdHistory,
"images": s.CmdImages,
"viz": s.CmdViz,
"load": s.CmdLoad,
"import": s.CmdImport,
"pull": s.CmdPull,
"push": s.CmdPush,
} {
if err := eng.Register(name, handler); err != nil {
return fmt.Errorf("Could not register %q: %v", name, err)
}
}
return nil
}
CmdPush handler放在了graph/push.go文件中。这个handler主要完成想registry发起请求的任务。为构建项registry请求解析job环境变量中的参数。
var (
localName = job.Args[0]
sf = utils.NewStreamFormatter(job.GetenvBool("json"))
authConfig = ®istry.AuthConfig{}
metaHeaders map[string][]string
)
tag := job.Getenv("tag")
job.GetenvJson("authConfig", authConfig)
job.GetenvJson("metaHeaders", &metaHeaders)
解析registry的hostname和namespace、repository，hostname为registry的地址"127.0.0.1:5000"， remoteName为"/namespace/repo"
hostname, remoteName, err := registry.ResolveRepositoryName(localName)
检查registry是否可用，将hostname组装成http或https的url，做ping操作，检查是否可用
endpoint, err := registry.ExpandAndVerifyRegistryUrl(hostname)
获取需要push的镜像的graph，graph会单独用一篇文章介绍。
img, err := s.graph.Get(localName)
构建发向registry的请求
r, err2 := registry.NewSession(authConfig, registry.HTTPRequestFactory(metaHeaders), endpoint, false)
if err2 != nil {
return job.Error(err2)
}
如果没有命令行中没有tag，会push所有repository下的镜像，如果有tag，只push tag对应的repository的镜像
if err != nil {
reposLen := 1
if tag == "" {
reposLen = len(s.Repositories[localName])
}
job.Stdout.Write(sf.FormatStatus("", "The push refers to a repository [%s] (len: %d)", localName, reposLen))
// If it fails, try to get the repository
if localRepo, exists := s.Repositories[localName]; exists {
if err := s.pushRepository(r, job.Stdout, localName, remoteName, localRepo, tag, sf); err != nil {
return job.Error(err)
}
return engine.StatusOK
}
return job.Error(err)
}
var token []string
job.Stdout.Write(sf.FormatStatus("", "The push refers to an image: [%s]", localName))
if _, err := s.pushImage(r, job.Stdout, remoteName, img.ID, endpoint, token, sf); err != nil {
return job.Error(err)
}
3.1偷偷的ping
3.2 client上传镜像的lay id和tag信息
3.3 client端registry请求lay id为5111的lay json数据，如果registry有此id的json数据，说明registry有此lay，registry给client返回200 OK
如果没有，registry返回给client 404，client会将此lay的json，lay和checksum上传给registry
对image的所有lay做上述操作。
3.4上传image的tag信息，将tag所在的lay id给registry
3.5client最后做put请求images，但里面什么也没有带，registry发现是空的，就返回给client 204 NO CONTENT，就此push结束（这个地方有点LOW）
