可以从Docker Registry V2获取图像ID吗？

Question

当图像被推送到注册表V2时，图像ID是否会被推送到注册表中？是否有可能从V2注册表获取特定存储库的图像ID？

Answer 1

如果图像用泊坞客户1.10或以上推压，可以从注册表获取图像ID与

GET /v2/<image>/manifests/<tag> 

你的请求必须包括头

Accept: application/vnd.docker.distribution.manifest.v2+json 

在响应中，图像ID将位于Content-Docker-Digest响应标题中。

Answer 2

尽我所知，他们不存储在任何API访问的位置：

bash$ docker run -d -p 5000:5000 --restart=always --name registry registry:2 
Unable to find image 'registry:2' locally 
2: Pulling from library/registry 
... 
bash$ docker tag busybox localhost:5000/busybox 
bash$ docker push localhost:5000/busybox 
The push refers to a repository [localhost:5000/busybox] 
5f70bf18a086: Pushed 
... 
bash$ curl http://localhost:5000/v2/busybox/tags/list 
{"name":"busybox","tags":["latest"]} 
bash$ curl http://localhost:5000/v2/busybox/manifests/latest 
{ 
    "schemaVersion": 1, 
    "name": "busybox", 
    "tag": "latest", 
    "architecture": "amd64", 
    "fsLayers": [ 
     { 
     "blobSum": "sha256:a3ed95caeb02ffe68cdd9fd84406680ae93d633cb16422d00e8a7c22955b46d4" 
     }, 
     { 
     "blobSum": "sha256:385e281300cc6d88bdd155e0931fbdfbb1801c2b0265340a40481ee2b733ae66" 
     } 
    ], 
    "history": [ 
     { 
     "v1Compatibility": "{\"architecture\":\"amd64\",\"config\":{\"Hostname\":\"156e10b83429\",\"Domainname\":\"\",\"User\":\"\",\"AttachStdin\":false,\"AttachStdout\":false,\"AttachStderr\":false,\"Tty\":false,\"OpenStdin\":false,\"StdinOnce\":false,\"Env\":null,\"Cmd\":[\"sh\"],\"Image\":\"56ed16bd6310cca65920c653a9bb22de6b235990dcaa1742ff839867aed730e5\",\"Volumes\":null,\"WorkingDir\":\"\",\"Entrypoint\":null,\"OnBuild\":null,\"Labels\":{}},\"container\":\"5f8098ec29947b5bea80483cd3275008911ce87438fed628e34ec0c522665510\",\"container_config\":{\"Hostname\":\"156e10b83429\",\"Domainname\":\"\",\"User\":\"\",\"AttachStdin\":false,\"AttachStdout\":false,\"AttachStderr\":false,\"Tty\":false,\"OpenStdin\":false,\"StdinOnce\":false,\"Env\":null,\"Cmd\":[\"/bin/sh\",\"-c\",\"#(nop) CMD [\\\"sh\\\"]\"],\"Image\":\"56ed16bd6310cca65920c653a9bb22de6b235990dcaa1742ff839867aed730e5\",\"Volumes\":null,\"WorkingDir\":\"\",\"Entrypoint\":null,\"OnBuild\":null,\"Labels\":{}},\"created\":\"2016-03-18T18:22:48.810791943Z\",\"docker_version\":\"1.9.1\",\"id\":\"437595becdebaaaf3a4fc3db02c59a980f955dee825c153308c670610bb694e1\",\"os\":\"linux\",\"parent\":\"920777304d1d5e337bc59877253e946f224df5aae64c72538672eb74637b3c9e\"}" 
     }, 
     { 
     "v1Compatibility": "{\"id\":\"920777304d1d5e337bc59877253e946f224df5aae64c72538672eb74637b3c9e\",\"created\":\"2016-03-18T18:22:48.262403239Z\",\"container_config\":{\"Cmd\":[\"/bin/sh -C#(nop) ADD file:47ca6e777c36a4cfffe3f918b64a445c8f32300deeb9dfa5cc47261bd7b75d21 in /\"]}}" 
     } 
    ], 
    "signatures": [ 
     { 
     "header": { 
      "jwk": { 
       "crv": "P-256", 
       "kid": "FIFX:SJRD:AQHW:MCFX:M6WC:LXI2:3VO2:4LFW:UHDZ:QUN7:OLX4:6WGD", 
       "kty": "EC", 
       "x": "Xm8wJTzw3nb--rGoD3dxjKffikj7Snb9dHW-qGbqSAM", 
       "y": "GnATS--7lVcA_-jQGuDKTtjhmnGgvBrx8rLdlPOJV3U" 
      }, 
      "alg": "ES256" 
     }, 
     "signature": "f8NVzOF6ujm_0COedniGCGL_q3KsTfKFM9T8ZZDf2MSIMJ3TYoR_s795NqdEy8yWaoLuT2LoI0BCEsuOTZUhCw", 
     "protected": "eyJmb3JtYXRMZW5ndGgiOjE5MTQsImZvcm1hdFRhaWwiOiJDbjAiLCJ0aW1lIjoiMjAxNi0wNi0xMVQwMToxMzoyMVoifQ" 
     } 
    ] 
bash$ curl -I http://localhost:5000/v2/busybox/manifests/latest 
HTTP/1.1 200 OK 
Content-Length: 2561 
Content-Type: application/vnd.docker.distribution.manifest.v1+prettyjws 
Docker-Content-Digest: sha256:e45f25b1760f616e65f106b424f4ef29185fbd80822255d79dabc73b8eb715ad 
Docker-Distribution-Api-Version: registry/2.0 
Etag: "sha256:e45f25b1760f616e65f106b424f4ef29185fbd80822255d79dabc73b8eb715ad" 
X-Content-Type-Options: nosniff 
Date: Sat, 11 Jun 2016 01:21:26 GMT 

无论身在何处的任何这些API调用的我能找到想要的47bcc53 ...图片ID，我看到当地。

bash$ docker inspect busybox:latest 
[ 
    { 
     "Id": "sha256:47bcc53f74dc94b1920f0b34f6036096526296767650f223433fe65c35f149eb", 
     "RepoTags": [ 
      "busybox:latest", 
      "localhost:5000/busybox:latest" 
     ], 
     "RepoDigests": [], 
     "Parent": "", 
     "Comment": "", 
     "Created": "2016-03-18T18:22:48.810791943Z", 
     "Container": "5f8098ec29947b5bea80483cd3275008911ce87438fed628e34ec0c522665510", 
     "ContainerConfig": { 
      "Hostname": "156e10b83429", 
      "Domainname": "", 
      "User": "", 
      "AttachStdin": false, 
      "AttachStdout": false, 
      "AttachStderr": false, 
      "Tty": false, 
      "OpenStdin": false, 
      "StdinOnce": false, 
      "Env": null, 
      "Cmd": [ 
       "/bin/sh", 
       "-c", 
       "#(nop) CMD [\"sh\"]" 
      ], 
      "Image": "56ed16bd6310cca65920c653a9bb22de6b235990dcaa1742ff839867aed730e5", 
      "Volumes": null, 
      "WorkingDir": "", 
      "Entrypoint": null, 
      "OnBuild": null, 
      "Labels": {} 
     }, 
     "DockerVersion": "1.9.1", 
     "Author": "", 
     "Config": { 
      "Hostname": "156e10b83429", 
      "Domainname": "", 
      "User": "", 
      "AttachStdin": false, 
      "AttachStdout": false, 
      "AttachStderr": false, 
      "Tty": false, 
      "OpenStdin": false, 
      "StdinOnce": false, 
      "Env": null, 
      "Cmd": [ 
       "sh" 
      ], 
      "Image": "56ed16bd6310cca65920c653a9bb22de6b235990dcaa1742ff839867aed730e5", 
      "Volumes": null, 
      "WorkingDir": "", 
      "Entrypoint": null, 
      "OnBuild": null, 
      "Labels": {} 
     }, 
     "Architecture": "amd64", 
     "Os": "linux", 
     "Size": 1112820, 
     "VirtualSize": 1112820, 
     "GraphDriver": { 
      "Name": "aufs", 
      "Data": null 
     }, 
     "RootFS": { 
      "Type": "layers", 
      "Layers": [ 
       "sha256:1834950e52ce4d5a88a1bbd131c537f4d0e56d10ff0dd69e66be3b7dfa9df7e6", 
       "sha256:5f70bf18a086007016e948b04aed3b82103a36bea41755b6cddfaf10ace3c6ef" 
      ] 
     } 
    } 
] 

从this image spec的图片ID是一个可重复的哈希值，我的确看到在不同的系统的图片ID相同的值。

图像标识 各图像的ID，通过其配置JSON的SHA256散列给出。它表示为256位的十六进制编码，例如， sha256：a9561eb1b190625c9adb5a9513e72c4dedafc1cb2d4c5236c9a6957ec7dfd5a9。 由于配置JSON在图像中获取散列的每个图层的散列引用哈希值 ，因此ImageID的这个公式使图像 content-addresable。

因此，如果您可以从API调用中重现配置JSON，那么您可以自己生成图像ID。

Answer 3

从我的研究，你可以用

curl -H 'Accept: application/vnd.docker.distribution.manifest.v2+json' http://$server/v2/$repo/manifests/$tag

，并在响应中config.digest字段表示图像标识从注册表获取（2.3.0+）的图像ID，你想要的！

for example

是指： https://duyanghao.github.io/docker-registry-pull-manifest-v2/