bugfix: add default tag ":latest" when using pouch rmi to remove untagged container images.

[xiechengsheng]

Ⅰ. Describe what this PR did

add default tag ":latest" when using pouch rmi to remove untagged container images.

Ⅱ. Does this pull request fix one issue?

fixes #1104

Ⅲ. Describe how you did it

just use the same way as pouch pull

Ⅳ. Describe how to verify it

frist, pull some images:

pouch pull library/busybox
pouch pull library/hello-world

then, just remove them:

pouch rmi library/busybox library/hello-world

Ⅴ. Special notes for reviews

[pouchrobot]

We found this is your first time to contribute to Pouch, @xiechengsheng
👏 We really appreciate it.
Just remind that you have read the contribution guide: https://github.com/alibaba/pouch/blob/master/CONTRIBUTING.md
If you didn't, you should do that first. If done, welcome again and please enjoy hacking! 🍻

[allencloud]

This is on image side, could you help to review this? @fuweid

And could you squash all three commits into a single one commit and sign off your single commit? @xiechengsheng

[HusterWan]

@xiechengsheng Please execute command blow to fix conflict, thanks a lot

git fetch upstream
git rebase upstream/master 

[xiechengsheng]

@fuweid Could your review this pr? Thanks a lot 😊

[fuweid]

Hi @xiechengsheng ，

sorry for the late reply.

For the pull API, the tag information can be ignored because the latest is default value. But for the inspect/rmi related commands, the name can be one of the following kinds:

• name without tag
• name with tag
• name with digest
• name with tag and digest
• short ID
• image ID

Based on the user cases, I don't think we should separate tag from image name, because we cannot just add the latest at the end if we missing. It is a little different from pull API, right? How do you think?

Please let me know if you have any ideas about this part. Thank you!

Sorry for the late reply again.

[xiechengsheng]

@fuweid Thanks for your apply~

1. emmmm, we could do this just because docker rmi command supports adding default latest tag in image name to remove images...
2. And there still seems to be some bugs in this pr, I will try to fix it ASAP.
3. BTW, does pouch support removing images via name with digest right now? I kown docker rmi supports removing images with name and digest by using docker rmi repository@digest, but there seems to be no repository concept in pouch images.

# pouch images --digest
IMAGE ID       IMAGE NAME                                           DIGEST                                                                    SIZE
e38bc07ac18e   registry.hub.docker.com/library/hello-world:latest   sha256:f5233545e43561214ca4891fd1157e1c3c563316ed8e237750d59bde73361e77   5.95 KB

# pouch rmi registry.hub.docker.com/library@sha256:f5233545e43561214ca4891fd1157e1c3c563316ed8e237750d59bde73361e77
Error: failed to remove image: {"message":"image digest: registry.hub.docker.com/library@sha256:f5233545e43561214ca4891fd1157e1c3c563316ed8e237750d59bde73361e77: not found"}

# pouch rmi registry.hub.docker.com/library/hello-world@sha256:f5233545e43561214ca4891fd1157e1c3c563316ed8e237750d59bde73361e77
Error: failed to remove image: {"message":"failed to remove image: image \"registry.hub.docker.com/library/hello-world@sha256:f5233545e43561214ca4891fd1157e1c3c563316ed8e237750d59bde73361e77\": not found"}

# pouch rmi registry.hub.docker.com/library/hello-world:latest@sha256:f5233545e43561214ca4891fd1157e1c3c563316ed8e237750d59bde73361e77
Error: failed to remove image: {"message":"image digest: registry.hub.docker.com/library/hello-world:latest@sha256:f5233545e43561214ca4891fd1157e1c3c563316ed8e237750d59bde73361e77: not found"}

Looking forward to your apply~

[pouchrobot]

@xiechengsheng Thanks for your contribution. 🍻
Please sign off in each of your commits.

[codecov-io]

Codecov Report

Merging #1191 into master will decrease coverage by <.01%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master    #1191      +/-   ##
==========================================
- Coverage   15.68%   15.68%   -0.01%     
==========================================
  Files         171      171              
  Lines       10408    10411       +3     
==========================================
  Hits         1633     1633              
- Misses       8655     8658       +3     
  Partials      120      120

Impacted Files	Coverage Δ
daemon/mgr/image.go	31.95% <0%> (-0.51%)	⬇️

[fuweid]

Hi @xiechengsheng ，

Thanks for your effort!

The repo name can be composed of name, tag and digest. We have plan to support digest part and tag function. For now, LGTM.

But, could you mind to update the PR title and commit message? thanks

[HusterWan]

LGTM

[HusterWan]

But, could you mind to update the PR title and commit message? thanks

@xiechengsheng Please squash your PR, and rewrite your commit information according to https://github.com/alibaba/pouch/blob/master/CONTRIBUTING.md#commit-message

Then i will merge this PR, thanks a lot again for your work

[fuweid]

LGTM. Thanks @xiechengsheng

[fuweid]

@xiechengsheng , welcome to contribute pouch. Thanks!