Add client for http4s library

[igor-vovk]

Hi! I don't know if there is space for another client, but it seemed appropriate for me to add it, since it's kinda mainstream client in cats-effect ecosystem (http4s/circe/cats-effect). I was kinda surprised not to find it, ended up implementing it, but got tired copying it between my projects where I use elastic4s.

If you think it's a good idea to add it, I will be happy to add tests in this PR as well. Thank you.

[igor-vovk]

It just came to me, @Philippus if you think that elastic4s supports enough clients out of the box (I found that sttp for example already has http4s backend), I can just publish it as a separate library.

[lenguyenthanh]

I would love to use this client! I think currently sttp use future backend (which is backed scala future & akka iiuc). So this is definitely worth adding imho.

Also We probably can have more perform IO backed client if We have this: #2379

[igor-vovk]

@lenguyenthanh I was also thinking about that, addressed in #3119

[lenguyenthanh]

@lenguyenthanh I was also thinking about that, addressed in #3119

this is great, thanks! I was about to do it.

[Philippus]

I think adding a new client is fine, provided someone is using it in production (like you). Maybe we can mark it as experimental, allowing us to make backwards incompatible changes for a certain time.

[igor-vovk]

@Philippus nice! Then I'm going to add tests for it

[igor-vovk]

@Philippus I've added some tests following the pattern from sttp. I think it is ready to be merged, WDYT?

[Philippus]

@igor-vovk now that #3124 is merged, care to get back to this PR and clean it for merging (or create a new one based on the current main branch)?

[igor-vovk]

@Philippus thanks for merging #3124! Yes, cleaned up custom authentication from the implementation, please check

[Philippus]

@lenguyenthanh Do you have time to take a look at the PR to see if this will work for you as well?

[lenguyenthanh]

@lenguyenthanh Do you have time to take a look at the PR to see if this will work for you as well?

of course, I'll take a look tomorrow.

[lenguyenthanh]

I only have few nit comments, otherwise lgtm. And this will be so much better with the other of @igor-vovk's pr: #3119

[igor-vovk]

@lenguyenthanh I've addressed all your comments

[igor-vovk]

@Philippus I also noticed test flakiness, tried to add health check before proceeding on the level of GH actions in #3207, but failing to understand why it fails in GH Actions environment (works locally, probably something with bash options...)

[Philippus]

I think it's because of all the tests running on the same instance. If you change the test to "yellow" or "green" I think it will be fine. Even "red" would be a valid answer for the test I think, because it's about proof of connection.

[igor-vovk]

@Philippus I think what happens is that this status changes from red to yellow and then to green (doc https://www.elastic.co/guide/en/elasticsearch/reference/current/cluster-health.html). And then depending on when the test runs it can receive any of these, thus flakiness of the test. In any case, I've deleted this test. Should I bring it back?

[igor-vovk]

Marked #3207 as ready for review. It now waits elastic to start before continuing, should reduce tests flakiness

[Philippus]

@Philippus I think what happens is that this status changes from red to yellow and then to green (doc https://www.elastic.co/guide/en/elasticsearch/reference/current/cluster-health.html). And then depending on when the test runs it can receive any of these, thus flakiness of the test. In any case, I've deleted this test. Should I bring it back?

If you think it's worth having it as a test I think we can bring it back. We can always remove it again, if it turns out to be flaky again.

[igor-vovk]

Reverted the deletion of the test. After #3207 will be merged, the test should stop being flaky