Move fast tasks from CircleCI to Cirrus

[strkkk]

Reason: Cirrus CI builds are useless now. They are only run for master and all tasks are duplicated by appveyor build.
On the other hand, CircleCI has too many builds + it has restrictions for developers (e.g. I am not allowed to run builds there)

So, workload can be balanced a bit with some jobs moved to Cirrus.
There is a limitation from Cirrus that does not allow us to run some long-running tasks for each PR. However, there are some very fast tasks, that look like a good candidates to be moved to Cirrus.
Those are:

  git-validation:
    jobs:
      - validate-with-script:
          name: "git-no-merge-commits"
          command: "./.ci/validation.sh git-no-merge-commits"
      - validate-with-script:
          name: "git-check-pull-number"
          command: "./.ci/validation.sh git-check-pull-number"

they together take about 1 minute, so it should be more than enough to run them on every PR and respect the limit.

There are also other good candidates for transfer, such as

but they can be moved later

[strkkk]

@nrmancuso wdyt?)

[nrmancuso]

I am not sure I see any point in doing this until we have some issue with CircleCI. We lean heavily on them since they have been the most reliable CI, and allow us to easily use custom images. Additionally, contributors can view their CI runs in CircleCI, which is not always possible in other CI.

[strkkk]

The point is that at the moment Cirrus is completely useless. Its builds are waste of time (they are duplcates), but we can use this system to move some of the jobs there to increase parallelisation.

[nrmancuso]

increase parallelisation.

Are CircleCI jobs being queued?

[strkkk]

@nrmancuso Yes, they are. This is an example from my PR today, it was even worse before I took a screenshot

[nrmancuso]

These are all GitHub jobs, and they are typically queued. However, I do not see this happen with CircleCI hardly ever.

Additionally, Cirrus was one of the worst for long queues.

[strkkk]

Oh, sorry, it was github.

Anyway, there is queue in Circle too. Most likely, you dont see because you do not open the build itself. All jobs are shown as pending ones.

This is how it looks like if I open Circle. About 10 jobs were waiting for more than a minute (I took a screenshot a bit earlier)

[nrmancuso]

Ok let’s move these two jobs over to cirrus and see how they do :)