feat: Performance API: Transaction

[brustolin]

📜 Description

Created a folder with performance API.
Hacked the hell out of the SDK to be able to send a transaction to Sentry.

💡 Motivation and Context

Add performance API to sentry-cocoa SDK.

💚 How did you test it?

This is a draft PR, trying it out from the Sentry iOS app, checking result in Sentry.
Test will came later.

📝 Checklist

• I reviewed the submitted code
• I added tests to verify the changes
• I updated the CHANGELOG
• I updated the docs if needed
• Review from the native team if needed
• No breaking changes

🔮 Next steps

TBD

[bruno-garcia]

We should agree on the next steps. I guess if we can startTransaction on the Hub and then have finish on the transaction itself capture it, that could be a good milestone. So build from here to do that, plus get tests in so we can merge.

Probably best to keep a branch to merge into, and we pull master into that branch from time to time. So that we can continue to release master without having to add the incomplete performance feature.

@philipphofmann @marandaneto wdyt?

[codecov-io]

Codecov Report

Merging #908 (42a9cc2) into feat/performance-monitoring (4e1b2fa) will decrease coverage by 2.81%.
The diff coverage is 0.00%.

@@                       Coverage Diff                       @@
##           feat/performance-monitoring     #908      +/-   ##
===============================================================
- Coverage                        94.73%   91.92%   -2.82%     
===============================================================
  Files                               76       80       +4     
  Lines                             3497     3590      +93     
===============================================================
- Hits                              3313     3300      -13     
- Misses                             184      290     +106     

Impacted Files	Coverage Δ
Sources/Sentry/SentryClient.m	92.00% <0.00%> (-1.41%)	⬇️
Sources/Sentry/SentryEnvelope.m	84.27% <0.00%> (-8.14%)	⬇️
Sources/Sentry/Transactions/SentrySpanContext.m	0.00% <0.00%> (ø)
Sources/Sentry/Transactions/SentrySpanId.m	0.00% <0.00%> (ø)
Sources/Sentry/Transactions/SentryTransaction.m	0.00% <0.00%> (ø)
...ces/Sentry/Transactions/SentryTransactionContext.m	0.00% <0.00%> (ø)
Sources/Sentry/SentrySessionTracker.m	100.00% <0.00%> (ø)
... and 1 more

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[bruno-garcia]

I changed the base branch to feat/performance-monitoring, which can be used for all PRs related to performance. Draft PR for that branch for visibility: #909

[marandaneto]

We should agree on the next steps. I guess if we can startTransaction on the Hub and then have finish on the transaction itself capture it, that could be a good milestone. So build from here to do that, plus get tests in so we can merge.

Probably best to keep a branch to merge into, and we pull master into that branch from time to time. So that we can continue to release master without having to add the incomplete performance feature.

@philipphofmann @marandaneto wdyt?

that would be ideal

[philipphofmann]

Very nice hacking. I'm excited to see some transactions in our SDK. 🥳

I know this is a draft PR, but still, I made lots of comments, so we can get this PR ready for review.

Please move all public headers into the Sources/Public folder see https://github.com/getsentry/sentry-cocoa/blob/master/CONTRIBUTING.md#public-headers. Please also move all .m files to Sources/Sentry.

I'm looking forward to seeing some tests for all of this.

[marandaneto]

@brustolin just to explain the comments prefixes:

l: low, that means, its not important for the reviewer, you could ignore but it'd be nice to be fixed/replied.
m: mid, it's sort of nice that you both agree either on a solution or to ignore it.
h; high, its really important for the reviewer, you definitely should look into it/or reason why not.

context: https://blog.danlew.net/2020/04/15/the-logaf-scale/

[brustolin]

I think I fixed everything you guys commented.

By Bruno request I changed SentryTransaction inheritance to SentryEvent and remove some of the previous SentryTransaction handlers like "sendTransaction" from SentryClient to use "sendEvent", this way the client can prepare the envelope with all required information.

SentryTransaction tests included

[marandaneto]

I think I fixed everything you guys commented.

By Bruno request I changed SentryTransaction inheritance to SentryEvent and remove some of the previous SentryTransaction handlers like "sendTransaction" from SentryClient to use "sendEvent", this way the client can prepare the envelope with all required information.

SentryTransaction tests included

nice, thanks for that.

I've written a few more comments.
btw please resolve the comments that are already addressed, it's easier to review :)

[bruno-garcia]

I see some tests already. Is this still draft?
What's missing to get merged other than address open review comments?

[brustolin]

Well, now I think I have addressed all comments. Still figuring out this way of using GitHub.
A couple of discussion to be solved yet, but I think is ready to be merged, and let's solve these bigger issues in future PRs.

[bruno-garcia]

Lets just address the last open issues pending replies from folks in Vienna but other than those points, LGTM

[bruno-garcia]

@brustolin I believe we agreed on one point, pass nil as scope. Other than that I think we can merge for now. The Transaction/Event discussion we can address later at least, lets not block this PR on that