[RUM-7629] New Tracing Headers APIs

[marco-saia-datadog]

What does this PR do?

Introduces new APIs to retrieve the tracing context for different propagator types, and for manually generating Trace IDs and Span IDs.

Tracing Context APIs

A new method has been introduced in this PR, for exposing Tracing Headers and RUM Resource Context attributes:

    /**
     * Gets the tracing context for the given url, tracingSamplingRate and firstPartyHosts.
     * The returned {@link DatadogTracingContext} can be used to retrieve the tracing headers
     * to append to your network request, and the attributes to add to your RUM Resource.
     * @param url the request URL.
     * @param tracingSamplingRate Percentage of tracing integrations for network calls between your app and your backend. Range `0`-`100`.
     * @param firstPartyHosts List of your backends hosts with propagator types.
     */
    getTracingContext(
        url: string,
        tracingSamplingRate: number,
        firstPartyHosts: FirstPartyHost[]
    ): DatadogTracingContext;

(1) Example usage with custom network library (e.g SSL pinning)

// SSL pinning
import {fetch} from 'react-native-ssl-pinning';

const url = "http://example.com/api/getPosts"

const tracingContext = DdRum.getTracingContext(url, samplingRate, firstPartyHosts);

fetch(url, {
	method: "POST" ,
	timeoutInterval: communication_timeout,
	body: body,
	sslPinning: {
		certs: ["cert1","cert2"]
	},
	headers: {
		'Accept': "application/json; charset=utf-8", "Access-Control-Allow-Origin": "*", "e_platform": "mobile",
		...tracingContext.getHeadersForRequest()
	}
});

await DdRum.startResource("My API call", "POST", url, tracingContext.getRumResourceContext());

(2) Example usage with custom network library (e.g SSL pinning) - using injector

// SSL pinning
import {fetch} from 'react-native-ssl-pinning';

const url = "http://example.com/api/getPosts"
const headers = {
     'Accept': "application/json; charset=utf-8", "Access-Control-Allow-Origin": "*", "e_platform": "mobile" 
}

const tracingContext = DdRum.getTracingContext(url, samplingRate, firstPartyHosts);
tracingContext.injectHeadersForRequest((header: string, value: string) => {
    headers[header] = value;
})


fetch(url, {
	method: "POST" ,
	timeoutInterval: communication_timeout,
	body: body,
	sslPinning: {
		certs: ["cert1","cert2"]
	},
	headers: headers
});

const resourceContext = { ...myContext }
tracingContext.injectRumResourceContext((attribute: string, value: string) => {
    resourceContext[attribute] = value;
});

await DdRum.startResource("My API call", "POST", url, resourceContext);

(3) Example utility method with custom network library (e.g SSL pinning)

const fetchWithSslPinning = (
    resourceName: string, 
    resourceContext: any, 
    url: string, 
    body: any, 
    method: string, 
    headers: Record<string, string | number>
) => {
	const tracingContext = DdRum.getTracingContext(url, DD_CONFIGURATION.samplingRate, DD_CONFIGURATION.firstPartyHosts);

	fetch(url, {
		method: method,
		timeoutInterval: communication_timeout,
		body: body,
		sslPinning: {
			certs: ["cert1","cert2"]
		},
		headers: {
			...headers,
			...tracingContext.getHeadersForRequest()
		}
	});

	await DdRum.startResource(resourceName, method, url, {...context, tracingContext.getResourceContext()});
}

---

Trace IDs and Span IDs APIs

/**
 * Generates a unique 128bit Trace ID.
 */
generateTraceId(): DatadogTracingIdentifier;

/**
 * Generates a unique 128bit Span ID.
 */
generateSpanId(): DatadogTracingIdentifier;

Example Usage

const traceId = DdRum.generateTraceId();

// Get the high 64 bit part as padded hex
const traceIdStr = traceId.toString(TracingIdFormat.paddedHighHex)

Additional Notes

This PR is a rework on the original #784 from @jhssilva, by providing a helper class that encapsulates the tracing identifiers and exposes different utility methods to convert it to the desired string representations, and by adding methods to directly retrieve the headers for an easy and out of the box usage.

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests
• Make sure you discussed the feature or bugfix with the maintaining team in an Issue
• Make sure each commit and the PR mention the Issue number (cf the CONTRIBUTING doc)
• If this PR is auto-generated, please make sure also to manually update the code related to the change

[datadog-datadog-prod-us1]

Datadog Report

Branch report: marcosaia/RUM-7629/improve-generate-uuid-api
Commit report: 8436efc
Test service: dd-sdk-reactnative

✅ 0 Failed, 640 Passed, 1 Skipped, 11.89s Total Time

[marco-saia-datadog]

@0xnm I have done a big refactoring and opted for a completely different approach. I have described the changes in the PR notes, let me know if you have any questions :)

Thank you for your feedback and your help with this PR!

[jhssilva]

Hey @marco-saia-datadog . Great work.
I've a few questions regarding this:

• How does a user is aware of the difference between the string required for the resource and for the trace?
• Does the injector will inject as well in the resources? Even if it's a react-native-ssl-pinning library?
• How does a user knows the difference between lowPaddex and highPaddex in the trace context propagation? And how is aware of this in the context of Datadog trace context propagation style?