Gitlab Merge Request When To Approve - gitlab

So we're having a little bit of a debate where I work as to what point should a reviewer "Approve" a Merge Request.
We have setup some Gitlab Pipelines to run and carry out what I would say are fairly standard stuff (Build, Automated Tests, Sonar etc). Now we're trying to improve best practises across the department and a debate has started as to when the reviewer(s) should actually "Approve" the Merge Request.
We have the 1 argument that says the Pipeline acts as an "Approver" itself and if it fails it basically should prevent the Merge Request from happening, so it doesn't matter when the reviewer(s) hit that "Approve" button, because the reviewer(s) are reviewing the Code and not the pipeline.
And then you have another argument that says the reviewer(s) should not be "Approving" until the Pipeline passes, and they should be dependent on the Pipeline passing as to whether they should be "Approving" the Merge Request or not.
So should the reviewer(s) of a Merge Request wait until the the Gitlab Pipeline finishes and if the pipeline is successful then "Approve" or should they be able to "Approve" once they have reviewed the code, no matter if the pipeline has finished or not?

It's best practice to wait until the pipeline passes, review the code and then do an approval. If the pipeline doesn't pass in the first place, there is an issue and the developer needs to fix his/her PR before someone spends time to review it.

Related

Enabling pre-receive server hook to get PR/MR approval before pushing to dev branch

Use case: I have code on my local machine and If I try to push it to remote server, a pre-receive hook in remote [GitLab] server should get triggered and ask for respective author approval to merge that code onto Gitlab repo.
After [code review] if author approves MR then code from my local repo will be pushed to remote server else push needs to be halted.
I am sure that I was asked to enable pre-receive hook on GitLab server side and not on client side.
I think it is not possible because code exists in developer's local machine and hence approver may not be able to do code review but not sure about pre-receive working.
Can pre-receive hook able to notify approver before code push? If it is possible need to know how?
If not, I want a strong valid point to negotiate😒
MR approval is not requested when one pushed a branch, but only when one makes (once the branch is pushed) a merge request to the target branch.
In your case:
protect the dev branch (nobody can push directly to it, so no need for a pre-receive hook)
make a merge request mandatory for that branch
make sure to configure your merge requests so that they must be approved before they can be merged.
That means any code eventually merged to dev:
will not have been pushed directly to dev (MR required)
will have been reviewed and approved first, before being accepted and merged to dev.
While it is true enforcing the MR approval process, meaning disabling the "Merge" button as long as approval is not met, is not free (premium only), you still have a way to enforce it.
Make sure nobody can push/merge to dev is a "Merge Manager" who is alone responsible to merge or not the MRs. If said merge manager sees there is no approval, they won't merge the MR.

Detect a build requested by pull request and one run by any updates to the PR

I currently have a task that I intend to run only once when a PR is created. Any pipeline runs due to new commits should not trigger the task. I was wondering if there is a way to detect the runs triggered by changes to code in the PR? When I use the predefined variable $(Build.Reason) I get back PullRequest for both builds(One triggered when PR is created and other when updates are made to PR).
This is what I have in my pipeline and I have enabled build validation for my pipeline.
trigger:
- master
pr:
- master
I don't think there's a way to differentiate the "PR is created" and "PR is updated" build reasons based only on the predefined variables.
However, you can choose a different route depending on what this task you should only run once is. If it is something that can be wrapped into a service with a public endpoint, you can try leveraging the Webhooks.
So, if this is an option for you, try the following:
wrap the functionality required to run only on the PR creation into the service with the public endpoint
create a webhook, choose "Pull request created" event type and enter the public URL of your service
As a result, your build logic won't branch depending on the build reason, and that specific action will be run by the webhook.
I understand it all sounds like a hack and unnecessary complexity, but it's up to you to decide whether it fits your case. At least, this is possible technically.

How to run a job after MR is approved, but reject MR, if the job failed?

I would like some automated checks were done after MR is approved, because for those checks pipeline has to access protected variables.
If these checks fail, MR should be rejected.
In other words the desired sequence should be this:
MR created -> build -> run tests -> MR approved (no malicious exposure of protected variables)-> merged to protected branch -> run checks -> rollback on failure.
Is this possible?
You can do this by using the Gitlab API and adding two new jobs at the end of the pipeline.
The when keyword is one of the many ways to control which jobs are executed in a pipeline. Two of the available when options will be useful here. The first job to put at the end of your pipeline will be for the success condition:
approve_merge_request:
stage: approve_merge_request
when: on_success
script:
- # this will call the Gitlab Merge Requests API and approve it. More on this below
This parameter to when is actually the default, so you could leave the when off of this step and it would still work. I added it here for clarity. What it means is that this job will only run if every other job in the pipeline passed. However, if a job fails but has the allow_failure: true attribute, it is still considered a pass and this job will run (there's currently no way to detect that some jobs were allowed to fail in a when condition). In addition, jobs with when: manual that haven't run are considered passed, even though it could later fail. when: manual means the job has to be started by an API call or UI interaction by a user.
The second job will handle our failure condition:
reject_merge_request:
stage: approve_merge_request
when: on_failure
script:
- # this will call the Gitlab Merge Requests API and reject it. More on this below
This parameter to when means that this job will only run if at least one job prior to this has failed, and doesn't have allow_failure: true.
The Merge Requests API can be used to approve, reject, comment on, and merge a Merge Request, among other options. The full documentation is available here: https://docs.gitlab.com/ee/api/merge_requests.html. Unfortunately, the API to use the "approvals" feature of merge requests is available only to paying customers, but you can still get a similar result without the approvals.
You can approve a Merge Request (note, this doesn't merge it, that's "accepting" the merge request. Also, this is a paid feature so is only available to Starter or Bronze customers and above) with the API operation here: https://docs.gitlab.com/ee/api/merge_request_approvals.html#approve-merge-request. After you approve the Merge Request, you probably want to accept it, which will merge the source branch into the target branch. That operation is outlined below.
You can get all of the required ids from the predefined variables Gitlab CI gives you. The project ID can be retrieved from the variable $CI_PROJECT_ID. The Merge Request IID is different from the Merge Request ID. The "ID" version is a unique ID across your entire Gitlab instance, and the "IID" version is specific to the project it's in. For this operation we need the IID. You can get that with the variable $CI_MERGE_REQUEST_IID. You should check that each variable exists before trying to use it as it will cause issues in your API call. It will exist for all pipelines associated with a Merge Request that is open.
There isn't equivalent functionality in Gitlab Merge Requests to "reject" other than commenting and closing, which I outline below.
If you're not a paid customer, or you want to accept and merge the request, you want to use the Accept Merge Request operation here: https://docs.gitlab.com/ee/api/merge_requests.html#accept-mr. This uses the same variables from above.
Finally, if you're not a paid user but still want to "reject" the merge request, you can use the Notes API to add a comment to the Merge Request. The operation to add a comment to a merge request is here: https://docs.gitlab.com/ee/api/merge_requests.html#accept-mr.
After commenting, if you want to close the merge request, you can do so with the Update MR operation and setting the state_event to close: https://docs.gitlab.com/ee/api/merge_requests.html#update-mr

Can I tell who approved merge requests?

I have GitLab Starter which seems to mean that I am unable to restrict code approvers on a directory basis as everyone needs developer level access.
This is causing slight headaches.
Is there a way in GitLab that I can review who approved groups of merge requests? This way I can at least check after the fact that no one has approved code who should not have.
Is there a way to query the backend database or a way of gaining this information in some GUI screen somewhere?
There will be a way, with the upcoming GitLab 13.5 to clearly see the status of the approval process and who has approved a MR.
In the meantime, you still have the GitLab Merge Request approval API and the merge request API, with a call like GET /merge_requests does include paramters like approver_ids
Returns merge requests which have specified all the users with the given ids as individual approvers.
None returns merge requests without approvers.
Any returns merge requests with an approver.
That could help checking who has approved a MR.
Users on GitLab Starter, Bronze, or higher will also see the approvals_before_merge parameter.

Approval step on gitlab CI

I want to discuss and to know more approaches about how to add a approval step on Gitlab CI
Everybody knows that gitlab doesn't has a approval feature on the pipeline
I did a small template to add a kind of approval step in any step
this is the content of the template
.approval_template:
image: node:buster
before_script:
- |
cat <<'EOF' >> approval.js
var users = process.env.USERS.split(',');
if (users.includes(process.env.GITLAB_USER_LOGIN)) {
console.log(process.env.GITLAB_USER_LOGIN + " allowed to run this job")
process.exit(0)
} else {
console.log(process.env.GITLAB_USER_LOGIN + " cannot trigger this job")
console.log("List of users allowed to run this job")
for (user in users)
{
console.log(users[user])
}
process.exit(1)
}
EOF
- node approval.js
- rm approval.js
when: manual
how does it work?
This template checks if the user who triggered the job is inside the USERS variable (array)
The check happens on before_script block and it works in any step (without overwrite the before_script)
It works very well but I want to know if there is a better approach to do it.
Anyone with write access to the repository can change that file and add themselves to the list. But my concern with the scripted approach is a different one, as you may end up confusing your future self or your successor(s) with a block of code to maintain. The person who triggers a job may be a different person than the one who would review the code, also I'm not sure if you want to assume that triggering equals approval.
Let me explain what I've been doing: Imagine having a development and a master branch - only master gets deployed automatically. Nobody can push directly to master when you protect the branch. Everything has to be merged into masterby using merge requests. Permission-wise it still comes down to having write access (developer or a higher role). This keeps the step of approval in the GUI (where you would expect an approval feature to appear once it's added). Additionally, accepting a merge request will trigger a dedicated e-mail notification.
This works very well when you make sure merging into master is a taboo except for the lead developers. Maybe this is not applicable for your situation but a different approach; and even this one needed my successor to be educated on where to click in order to approve a merge request.
If you want to fast-track the deployment of some developers you can assign them a higher role and use my suggested approach to let them push to the master branch directly. That way they skip the step of awaiting approval.

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