feat: http client integration

[aldy505]

An effort to implement this: https://develop.sentry.dev/sdk/telemetry/traces/modules/requests/

Since we already have tracing without performance, this should be good to go.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.23%. Comparing base (c243873) to head (4cc9a92).

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #876      +/-   ##
==========================================
+ Coverage   86.07%   86.23%   +0.16%     
==========================================
  Files          62       63       +1     
  Lines        6090     6148      +58     
==========================================
+ Hits         5242     5302      +60     
+ Misses        634      631       -3     
- Partials      214      215       +1     

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[ribice]

@aldy505 We should document this (in _examples, and perhaps sentry-docs?), and also update changelog accordingly.

[aldy505]

A quick note why I prefer this instead of creating a sentry.WithOnlyIfParentExists() (a SpanOption type):

I used the JS SDK a lot at work lately, and I've been wondering the entire week, on their startSpan function, they have this as an option: https://github.com/getsentry/sentry-javascript/blob/216aaeba1ee27cce8a4876e1f9212ba374eb30b3/packages/types/src/startSpanOptions.ts#L14-L15

Should the Go SDK move forward with that, as a SpanOption or not?

We could to the SpanOption thing, but it feels really weird since the way Go SDK handles scopes/hubs with span is to add the span pointer into the scope. See

sentry-go/tracing.go

Lines 196 to 199 in a6acd05

	if clientOptions.EnableTracing {
	hub := hubFromContext(ctx)
	hub.Scope().SetSpan(&span)
	}

Although we could just not call the scope.SetSpan() function, I don't know about the behavior if this span that we're creating will ever have a child span being created manually by the user.

[cleptric]

To support the recently added "Tracing without Performance" feature, we should use hub.GetTraceparent() and hub.GetBaggage()

[aldy505]

@giortzisg @cleptric Is there anything that's blocking this PR to be merged?

[cleptric]

Not sure we actually want to go the route with the round tripper. But we take another look after logs.

[aldy505]

@cleptric @giortzisg any updates?

[giortzisg]

Will have a look after transport refactoring.

[giortzisg]

also we should get a span here.

[aldy505]

@giortzisg updated

[sentry]

Bug: The example _examples/httpclient/main.go uses the non-existent sentryhttpclient.Client variable, leading to a compilation error.
_{Severity: CRITICAL | Confidence: High}

🔍 Detailed Analysis

The example file _examples/httpclient/main.go on line 41 attempts to use sentryhttpclient.Client. However, the sentryhttpclient.Client variable does not exist, as it was intentionally removed from the httpclient package in recent commits. This oversight means the example was not updated, causing a compilation failure and rendering the example non-functional.

💡 Suggested Fix

Update _examples/httpclient/main.go to either remove the section using sentryhttpclient.Client or create a local http.Client with the RoundTripper as shown in lines 31-33.

🤖 Prompt for AI Agent

Review the code at the location below. A potential bug has been identified by an AI
agent.
Verify if this is a real issue. If it is, propose a fix; if not, explain why it's not
valid.

Location: _examples/httpclient/main.go#L41

Potential issue: The example file `_examples/httpclient/main.go` on line 41 attempts to
use `sentryhttpclient.Client`. However, the `sentryhttpclient.Client` variable does not
exist, as it was intentionally removed from the `httpclient` package in recent commits.
This oversight means the example was not updated, causing a compilation failure and
rendering the example non-functional.

_{Did we get this right? 👍 / 👎 to inform future reviews.
Reference ID: 4362237}

[cursor]

Bug: Test cannot detect unwanted spans when expecting none

The test logic for validating the "no span expected" case is broken. When WantSpan is nil, the condition tt.WantSpan == nil && foundMatch at line 308 can never trigger because foundMatch only becomes true when cmp.Diff returns an empty string, but cmp.Diff(nil, gotSpan) always returns a diff when comparing nil to an actual span. This means if the implementation incorrectly creates an http.client span when none is expected (like when a URL doesn't match trace propagation targets), the test will silently pass instead of catching the bug.