RUMM-2759 Automatic w3c headers injection

[maciejburda]

What and why?

Adds SDK wide configuration for automatic W3C header support + introduces public API for setting those headers.

How?

Similar approach to OTel. Header part should be straightforward.

Please take extra care when reviewing public API. I decided to add separate model for holding dictionary with header types. Added new sets of APIs that use Dictionary instead of a set and set ones are falling back to dictionary after applying default values.

Review checklist

• Feature or bugfix MUST have appropriate tests (unit, integration)
• Make sure each commit and the PR mention the Issue number or JIRA reference
• Add CHANGELOG entry for user facing changes

Custom CI job configuration (optional)

• Run unit tests
• Run integration tests
• Run smoke tests

[ncreated]

Nice work and great effort to make it consistent given the number of subjects involved in distributed tracing 👌. I like the overall idea and it looks straightforward.

I left few feedbacks - we need to work on public API and its comments before we can merge it.

[maciejburda]

@ncreated @maxep I addressed comments. Please give it another round whenever you're ready :)

[maciejburda]

Bitrise is still timing out with this:

▸ Touching Example\ iOS.app (in target 'Example iOS' from project 'Datadog')
timeout after 5400 seconds

[ncreated]

Good idea to merge sanitizer into FirstPartyHosts 👍

I left few minor comments, but I see a flag on the shape of public API. Now we have a discrepancy and lack of parity between Swift and Objc APIs in this PR:

• Swift API:

// DatadogConfiguration.swift:

public func trackURLSession(firstPartyHostsWithHeaderTypes: FirstPartyHosts) -> Builder


// DDURLSessionDelegate.swift:

public convenience init(additionalFirstPartyHosts: FirstPartyHosts)

• Objc API:

// DatadogConfiguration+objc.swift:

// ⚠️ missing `@objc func trackURLSession(firstPartyHostsWithHeaderTypes:)`


// DDURLSessionDelegate+objc.swift:

public init(additionalFirstPartyHostsWithHeaderTypes: [String: Set<DDTracingHeaderType>]) 

Objc-builder doesn't expose new API variant and the Swift API uses custom struct (FirstPartyHosts) while the Objc-one is based on native dictionary.

IMO it is better to use dictionary for both: it's a native type and it won't require much documentation nor discoverability efforts. Also, it's available to both Swift and Objc.

[ncreated]

The public API still lacks parity:

• Swift API:

// DatadogConfiguration.swift:

public func trackURLSession(firstPartyHostsWithHeaderTypes: [String: Set<TracingHeaderType>]) -> Builder


// DDURLSessionDelegate.swift:

public convenience init(additionalFirstPartyHosts: FirstPartyHosts)

• Objc API:

// DatadogConfiguration+objc.swift:

// ⚠️ missing `@objc func trackURLSession(firstPartyHostsWithHeaderTypes:)`


// DDURLSessionDelegate+objc.swift:

public init(additionalFirstPartyHostsWithHeaderTypes: [String: Set<DDTracingHeaderType>]) 

---

Like discussed, there's no reason for discrepancy and we can provide the same signatures in both modules:

// configuration (Swift + Objc)
trackURLSession(firstPartyHostsWithHeaderTypes: [String: Set<TracingHeaderType>]) -> Builder

// DDURLSessionDelegate (Swift + Objc)
init(additionalFirstPartyHostsWithHeaderTypes: [String: Set<DDTracingHeaderType>]) 

[ncreated]

Suggested change

	public struct FirstPartyHosts: Equatable {
	internal struct FirstPartyHosts: Equatable {

[datadog-datadog-prod-us1]

Datadog Report

Branch report: maciey/RUMM-2759-w3c-tracing-header
Commit report: d3b5925

❌ dd-sdk-ios 2 Failed (0 Known Flaky), 0 New Flaky, 2170 Passed, 0 Skipped, 23m 21.74s Wall Time

❌ Failed Tests (2)

• testRUMTapActionScenario - RUMTapActionScenarioTests - Details

  Expand for error

   Segmentation fault. Check error.crash_log for the full crash log.
  

• testWebViewEventsScenario - WebViewScenarioTest - Details

  Expand for error

   Segmentation fault. Check error.crash_log for the full crash log.
  

[maciejburda]

Great points @ncreated I pushed a commit that unifies the public APIs.

[ncreated]

Nice 🚀 - huge effort and really well done 💪