Feature request: Add git push option for arbitrary refspec

[aristapimenta]

Hi, in my company we use Gerrit, and there's a special reference which opens the equivalent of merge/pull requests when commits are pushed to this reference:

git push origin HEAD:refs/for/master

It would be really great if we could specify such arbitrary reference, maybe like this:

spec:
  git:
    push:
      refspec: HEAD:refs/for/master

[makkes]

fluxcd/source-controller#1017 might help when implementing this.

The ref would be refs/for/master.

[brovoca]

We heavily use Gerrit in our team and suffer from not being able to create Gerrit changes, as described by @aristapimenta. When I try to configure refs/heads/refs/for/master or refs/for/master, an actual branch is created, which isn't what should happen. Surely, we can push directly to master, but we prefer approving the change first.

[stefanprodan]

I think adding refs would also allow Flux to work with GitLab, but we may need a lis of refs instead of just one item. cc @hiddeco

[hiddeco]

GitLab integrations I was thinking about is different, and called "push options". See:

• https://docs.gitlab.com/ee/user/project/push_options.html
• Allow specifying git push options for image automation controller flux2#3490

[stefanprodan]

@hiddeco then we can add ref name to IAC CRD same as we did with GitRepo and for push options we can have a separate field right?

[aryan9600]

yes we can modify the CRD where the ref name would be specified under spec.git.push.refName or spec.git.push.ref.

[stefanprodan]

I vote for spec.git.push.ref

[thompson-shaun]

GitLab integrations I was thinking about is different, and called "push options". See:

 * https://docs.gitlab.com/ee/user/project/push_options.html

 * [Allow specifying git push options for image automation controller flux2#3490](https://github.com/fluxcd/flux2/discussions/3490)

Found this thread looking for a way to create Merge Requests via GitLab's push options. Very exciting!

[cyclimse]

Looking forward to this feature as well for Gitlab! It looks like gogit supports push_options go-git/go-git#399

[hiddeco]

@hiddeco then we can add ref name to IAC CRD same as we did with GitRepo and for push options we can have a separate field right?

Yes. If we vote for .spec.git.push.ref, I think the counterpart for push options would be .spec.git.push.options. This would take a string list of options.

[aryan9600]

as i pointed out in today's community meeting, the most apt name is .spec.git.push.refspec as a Git Refspec and a Git ref are two different things. (ref: https://git-scm.com/book/en/v2/Git-Internals-The-Refspec, https://git-scm.com/book/en/v2/Git-Internals-Git-References)

[brovoca]

Eagerly waiting for this...

[aryan9600]

Even if we get this feature in, I don't think image-automation-controller will be compatible with Gerrit. Gerrit uses the commit-msg Git hook to insert a identifier called Change-Ids. Atm go-git, the Git library we use does not support Git hooks. Even if it did, the commit-msg Git hook that Gerrit requires is written in bash and shells out to default Git installation in the machine (ref: https://gerrit-review.googlesource.com/Documentation/cmd-hook-commit-msg.html).

That is a big no-no in Flux, and one of the core reasons we use a library and don't shell out ourselves to push, pull, etc.
We can still get this feature in as it might be helpful for other scenarios, but I don't think it solves the Gerrit use case. Please note that my knowledge about Gerrit is extremely limited, so feel free to correct me if I am wrong.

[brovoca]

@aryan9600 I've written my own messageTemplate that generates a Change-Id:

---
apiVersion: image.toolkit.fluxcd.io/v1beta1
kind: ImageUpdateAutomation
metadata:
  name: flux-system-master
  namespace: flux-system
spec:
  interval: 1m0s
  sourceRef:
    kind: GitRepository
    name: flux-system
    namespace: flux-system
  git:
    checkout:
      ref:
        branch: master
    push:
      branch: master
    commit:
      author:
        email: flux@localdomain
        name: flux
      messageTemplate: |
        Perform automatic image update

        Automation name: {{ .AutomationObject }}

        Files:
        {{ range $filename, $_ := .Updated.Files -}}
        - {{ $filename }}
        {{ end }}
        Objects:
        {{ range $resource, $_ := .Updated.Objects -}}
        - {{ $resource.Kind }} {{ $resource.Name }}
        {{ end }}
        Images:
        {{ range .Updated.Images -}}
        - {{ . }}
        {{ end }}
        {{- $ChangeId := .AutomationObject -}}
        {{- $ChangeId = printf "%s%s" $ChangeId ( .Updated.Files | toString ) -}}
        {{- $ChangeId = printf "%s%s" $ChangeId ( .Updated.Objects | toString ) -}}
        {{- $ChangeId = printf "%s%s" $ChangeId ( .Updated.Images | toString ) }}
        Change-Id: {{ printf "I%s" ( sha256sum $ChangeId | trunc 40 ) }}

[aryan9600]

okay, then please follow the instructions provided in #514 (comment) and see if it works for you.

[brovoca]

I will likely do this once back from a long vacation. Thank you for your assistance @aryan9600!

[aryan9600]

@brovoca did you get a chance to try it out?

[brovoca]

Sorry, not yet, just came back from vacation. Not sure when I'll have a moment