Add support for /api/v1/format_query API

[siddarth2810]

What this PR does:
The PR enables /api/v1/format_query API endpoint for formatting queries on Query Frontend and Querier

Which issue(s) this PR fixes:
Fixes #6670

Checklist

• [NA] Tests updated
• Documentation added
• CHANGELOG.md updated - the order of entries should be [CHANGE], [FEATURE], [ENHANCEMENT], [BUGFIX]

[SungJin1212]

Thanks for the contribution. Do we have to require the auth?

[siddarth2810]

Thanks for the contribution. Do we have to require the auth?

I ran a simple curl command and it only worked when I added the Auth Header and in documentation I noticed most the API endpoints for query frontend needed authentication so I concluded that, this endpoint too must need authentication.

Let me know if I should be doing some additional checks, would really appreciate it. Thank you so much

[SungJin1212]

This API is for PromQL pretty-formatting, I'm just wondering if the authentication is necessary for it.
@friedrich-at-adobe can you take a look?

[siddarth2810]

This API is for PromQL pretty-formatting, I'm just wondering if the authentication is necessary for it. @friedrich-at-adobe can you take a look?

I see, I went through some documentation and based on Prometheus security what I understand is that a standalone prometheus server dosent need any auth because its presumed that untrusted users have access to the Prometheus HTTP endpoint

but when cortex acts as a prometheus web server it would still look for tenant ID on each request, as mentioned in Cortex Auth, so in the end we need auth ?

Apologies for any confusion I caused

[friedrichg]

@siddarth2810 This looks good, but needs an integration test. Can you add it?

[friedrichg]

Thanks for the contribution. Do we have to require the auth?

I believe auth is handled already. The integration test will prove it.

[siddarth2810]

@siddarth2810 This looks good, but needs an integration test. Can you add it?

Thanks a lot for the review. I have added the test, when testing for both querier and query Frontend is it required to use separate endpoints or testing is done for both when we just add query frontend ? Let me know if querierDirect needs to be removed, and if the test needs more changes.

In my other integration test, I got different results with and without using query frontend so I added both cases in this PR

Really appreaciate for any inputs, thanks ! Btw when -auth.enabled is false the tests work fine

[SungJin1212]

@friedrichg @siddarth2810
I mean, do we need to require the X-Scope-OrgID header to the user? In my understanding, this API is for the pretty-formatting of the promQL query. Both ways I'm fine.

[friedrichg]

I mean, do we need to require the X-Scope-OrgID header to the user? In my understanding, this API is for the pretty-formatting of the promQL query. Both ways I'm fine.

I think I prefer the way it is now. Typically things that do not required the header are things that can be queried by cortex operators, not cortex users. This API path doesn't use any resources, but suppose we impose query limits to this request type, per tenant, or a different format type in the future. We want to do this on a per tenant basis, thus we need the authority header.

it's similar to /api/v1/status/buildinfo.

[friedrichg]

@siddarth2810 Thanks for implementing the test. There is a lint error still:

integration/format_query_api_test.go:106:1: File is not properly formatted (gofmt)
            req.Header.Set("X-Scope-OrgID", "user-1")

[siddarth2810]

@siddarth2810 Thanks for implementing the test. There is a lint error still:

integration/format_query_api_test.go:106:1: File is not properly formatted (gofmt)
            req.Header.Set("X-Scope-OrgID", "user-1")

My bad. Fixed it !

[SungJin1212]

Thanks

[friedrichg]

Great work! Thanks