Support globalHubMode for OpenTelemetry

[adinauer]

We're planning to release an alpha version from this branch so this PR shouldn't be merged to main yet.

📜 Description

• Always returns a wrapped Context from OpenTelemetry ContextStorage if globalHubMode is enabled
• Returns the last known unfinished root span / transaction from Context.get if there is no (valid) span stored on the context

💡 Motivation and Context

Using Sentry with OpenTelemetry for Java Desktop apps where customers have no control over their scheduling requires globalHubMode to ensure e.g. outgoing HTTP client spans are attached to the root span / transaction that is currently running.

Without this fix, HTTP client spans are recorded as separate Sentry transactions due to OpenTelemetry Context not being propagated e.g. when using new Thread(new Runnable() { ... }).start().

To fix this it's also possible to manually transfer the OpenTelemetry Context but not every customer has control over their scheduling:

    private void fetchTodo() {
        fetchButton.setEnabled(false);

        final Context opentelemetryContext = Context.current(); // <----------------- remember Context ------------------------

        Runnable r = new Runnable() {
            @Override
            public void run() {
                try (Scope scope = opentelemetryContext.makeCurrent()) {   // <------------------ make Context current in thread -----------------------
                    HttpClient client = HttpClient.newHttpClient();
                    HttpRequest request = HttpRequest.newBuilder()
                            .uri(URI.create("https://jsonplaceholder.typicode.com/todos/1"))
                            .build();

                    try {
                        HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
                        String prettyJson = gson.toJson(
                                gson.fromJson(response.body(), Object.class)
                        );
                        resultArea.setText(prettyJson);
                    } catch (Exception e) {
                        resultArea.setText("Error: " + e.getMessage());
                    } finally {
                        fetchButton.setEnabled(true);
                    }
                }
            }
        };
        new Thread(r).start();
    }

💚 How did you test it?

📝 Checklist

• I added tests to verify the changes.
• No new PII added or SDK only sends newly added PII if sendDefaultPII is enabled.
• I updated the docs if needed.
• I updated the wizard if needed.
• Review from the native team if needed.
• No breaking change or entry added to the changelog.
• No breaking change for hybrid SDKs or communicated to hybrid SDKs.

🔮 Next steps

[github-actions]

	Messages
📖	Do not forget to update Sentry-docs with your feature once the pull request gets approved.

Generated by 🚫 dangerJS against be70b9d

[adinauer]

Played around with this too much. It should check whether the key refers to a Span earlier.

[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	421.76 ms	456.98 ms	35.22 ms
Size	1.58 MiB	2.08 MiB	507.93 KiB

Previous results on branch: feat/experimental-otel-global-hub-mode

Startup times

Revision	Plain	With Sentry	Diff
e3d2723	425.58 ms	481.35 ms	55.76 ms
fef532b	444.25 ms	466.31 ms	22.06 ms
d0dccd7	399.63 ms	437.92 ms	38.29 ms
bdc74cc	531.79 ms	677.23 ms	145.44 ms
0eb29b3	431.80 ms	455.50 ms	23.70 ms
0d57111	387.49 ms	414.13 ms	26.64 ms
0f2f4fd	395.67 ms	444.42 ms	48.75 ms
9ab9244	449.06 ms	501.39 ms	52.33 ms
53db701	399.88 ms	423.54 ms	23.66 ms

App size

Revision	Plain	With Sentry	Diff
e3d2723	1.58 MiB	2.08 MiB	507.28 KiB
fef532b	1.58 MiB	2.08 MiB	507.45 KiB
d0dccd7	1.58 MiB	2.08 MiB	507.67 KiB
bdc74cc	1.58 MiB	2.08 MiB	507.34 KiB
0eb29b3	1.58 MiB	2.08 MiB	507.44 KiB
0d57111	1.58 MiB	2.08 MiB	507.45 KiB
0f2f4fd	1.58 MiB	2.08 MiB	507.44 KiB
9ab9244	1.58 MiB	2.08 MiB	507.92 KiB
53db701	1.58 MiB	2.08 MiB	507.28 KiB

[lbloder]

Minor comment about param naming.
Otherwise LGTM 👍

[lbloder]

(l) not sure about the param naming. Would something other than result be more fitting?

[lbloder]

(l) not sure about the param naming. Would something other than result be more fitting?

[github-actions]

• 🚫 The changelog entry seems to be part of an already released section ## 8.11.0.
  Consider moving the entry to the ## Unreleased section, please.

[adinauer]

Closing this for now since it didn't help the customer. If we need this again, we can reopen.

[adinauer]

In case this needs Sentry scopes added to OpenTelemetry Context.root(), we need to be careful since forking Scopes in SentryContextStorage.root() causes a deadlock. See #5226
We might need a lock free scope cloning.