问题描述
给出标签 latest，我们想在Docker Hub上找到另一个具有相同映像ID的标签。
Given a tag `latest`, we want to find out another tag with the same image ID on Docker Hub.
以下是查找所有标签的信息使用Docker Hub API v2的仓库：
Here is how to find out all tags for a repo with the Docker Hub API v2:
TOKEN=$(curl -s -H "Content-Type: application/json" -X POST -d '{"username": "'${UNAME}'", "password": "'${UPASS}'"}' https://hub.docker.com/v2/users/login/ | jq -r .token)
curl -s -H "Authorization: JWT ${TOKEN}" https://hub.docker.com/v2/repositories/fluent/fluentd/tags/?page_size=100 | jq
（请参见）
不幸的是，它不包含图片ID，但始终为null。此项的值：
Unfortunately, it doesn't contain the image ID but always a `null` value for this key:
$ curl -s -H "Authorization: JWT ${TOKEN}" https://hub.docker.com/v2/repositories/fluent/fluentd/tags/?page_size=100 | jq
{
"count": 36,
"next": null,
"previous": null,
"results": [
...
{
"name": "v0.14.11",
"full_size": 11964464,
"id": 7084687,
"repository": 219785,
"creator": 2923,
"last_updater": 2923,
"last_updated": "2016-12-27T07:16:41.294807Z",
"image_id": null,
"v2": true,
"platforms": [
5
]
},
...
不幸的是，图像ID与上面JSON中的`id`有所不同。
Unfortunately, the image ID is something different than the `id` in the JSON above.
$ docker images | grep fluent
docker.io/fluent/fluentd v0.14.11 1441d57beff9 3 weeks ago 38.25 MB
从理论上讲，应该可以通过此Docker Registry调用访问Docker清单以及映像ID，但这无济于事：
Theoretically, it should be possible to access the Docker Manifests and along with the the image ID with this Docker Registry call but it doesn't help either:
$ curl -s -H "Authorization: JWT ${TOKEN}" "https://registry.hub.docker.com/v2/fluent/fluentd/manifests/latest"
{"errors":[{"code":"UNAUTHORIZED","message":"authentication required","detail":[{"Type":"repository","Name":"fluent/fluentd","Action":"pull"}]}]}
（请参阅）
这是Docker GitHub存储库中的类似问题，但我仍然找不到解决方案：。
Here is a similar issue in the Docker GitHub repo but I still cannot figure out the solution: https://github.com/docker/distribution/issues/1490 .
PS：这是我尝试推送测试映像的Docker版本：
P.S.: Here is my Docker version with which I tried to push a test image:
$ docker version
Client:
Version: 1.12.6
API version: 1.24
Package version: docker-common-1.12.6-5.git037a2f5.fc25.x86_64
Go version: go1.7.4
Git commit: 037a2f5/1.12.6
Built: Wed Jan 18 12:11:29 2017
OS/Arch: linux/amd64
推荐答案
Docker Registry API v2使用图像摘要而非图像ID来区分图像身份。
Docker Registry API v2 uses image digest instead of image ID to distinguish image identity.
图像摘要可从 Docker-Content-获得。通过进行以下API调用来摘要HTTP响应头中的：
$ REPOSITORY=fluent/fluentd
$ TOKEN=$(curl -s "https://auth.docker.io/token?service=registry.docker.io&scope=repository:$REPOSITORY:pull" | jq -r .token)
$ curl -s -D - -H "Authorization: Bearer $TOKEN" -H "Accept: application/vnd.docker.distribution.manifest.v2+json" https://index.docker.io/v2/$REPOSITORY/manifests/latest
HTTP/1.1 200 OK
Content-Length: 1982
Content-Type: application/vnd.docker.distribution.manifest.v2+json
Docker-Content-Digest: sha256:eaea1edffc34cff3b5e31ee738ea56e46326f90731b4139a19948814a4f0a4db
Docker-Distribution-Api-Version: registry/2.0
Etag: "sha256:eaea1edffc34cff3b5e31ee738ea56e46326f90731b4139a19948814a4f0a4db"
Date: Tue, 24 Jan 2017 13:34:53 GMT
Strict-Transport-Security: max-age=31536000
...
所有标签均可通过以下API调用获得：
All tags can be obtained with the following API call:
$ curl -s -H "Authorization: Bearer $TOKEN" https://index.docker.io/v2/$REPOSITORY/tags/list
{"name":"fluent/fluentd","tags":["edge-onbuild","edge","jemalloc","latest-onbuild","latest","onbuild","stable-onbuild","stable","ubuntu-base","v0.12-latest-onbuild","v0.12-latest","v0.12-onbuild","v0.12.16","v0.12.18","v0.12.19","v0.12.20","v0.12.21","v0.12.23","v0.12.24","v0.12.26-2","v0.12.26-onbuild","v0.12.26","v0.12.27-onbuild","v0.12.27","v0.12.28-onbuild","v0.12.28","v0.12.29-onbuild","v0.12.29","v0.12.30-onbuild","v0.12.30","v0.12.31-onbuild","v0.12.31","v0.12","v0.14-latest-onbuild","v0.14-latest","v0.14-onbuild","v0.14.1","v0.14.10-onbuild","v0.14.10","v0.14.11-onbuild","v0.14.11","v0.14.2","v0.14.6","v0.14.8","v0.14"]}
根据上述内容，找到与特定标签相同的摘要，它将像下面这样的脚本。
Based on the above, to find the same digest as a specific tag, it will be a script like the following.
#!/bin/bash
REPOSITORY=$1
TARGET_TAG=$2
# get authorization token
TOKEN=$(curl -s "https://auth.docker.io/token?service=registry.docker.io&scope=repository:$REPOSITORY:pull" | jq -r .token)
# find all tags
ALL_TAGS=$(curl -s -H "Authorization: Bearer $TOKEN" https://index.docker.io/v2/$REPOSITORY/tags/list | jq -r .tags[])
# get image digest for target
TARGET_DIGEST=$(curl -s -D - -H "Authorization: Bearer $TOKEN" -H "Accept: application/vnd.docker.distribution.manifest.v2+json" https://index.docker.io/v2/$REPOSITORY/manifests/$TARGET_TAG | grep Docker-Content-Digest | cut -d ' ' -f 2)
# for each tags
for tag in ${ALL_TAGS[@]}; do
# get image digest
digest=$(curl -s -D - -H "Authorization: Bearer $TOKEN" -H "Accept: application/vnd.docker.distribution.manifest.v2+json" https://index.docker.io/v2/$REPOSITORY/manifests/$tag | grep Docker-Content-Digest | cut -d ' ' -f 2)
# check digest
if [[ $TARGET_DIGEST = $digest ]]; then
echo "$tag $digest"
fi
done
结果如下：
$ ./find_same_digest.sh fluent/fluentd latest
latest sha256:eaea1edffc34cff3b5e31ee738ea56e46326f90731b4139a19948814a4f0a4db
stable sha256:eaea1edffc34cff3b5e31ee738ea56e46326f90731b4139a19948814a4f0a4db
v0.12.31 sha256:eaea1edffc34cff3b5e31ee738ea56e46326f90731b4139a19948814a4f0a4db
v0.12 sha256:eaea1edffc34cff3b5e31ee738ea56e46326f90731b4139a19948814a4f0a4db
如果要检查本地映像的摘要，可以使用 docker images --digests ：
If you want to check the digest of the local image, you can get it with docker images --digests:
$ docker images --digests | grep fluentd
fluent/fluentd latest sha256:eaea1edffc34cff3b5e31ee738ea56e46326f90731b4139a19948814a4f0a4db 1788ee7dcfcc 14 hours ago 35.41 MB
这篇关于如何通过Docker Hub API确定标签的Docker映像ID？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！