RUM + Tracer works only one way

[mswswing]

Version: 2.5.0

Implementation 1

Datadog.initialize(
    with: Datadog.Configuration(
        clientToken: clientToken,
        env: environment,
        site: .us1,
        service: serviceName
    ),
    trackingConsent: .granted
)
Datadog.setUserInfo(id: UIDevice.current.identifierForVendor?.uuidString ?? "")
RUM.enable(
    with: RUM.Configuration(
        applicationID: appID,
        uiKitViewsPredicate: DefaultUIKitRUMViewsPredicate(),
        uiKitActionsPredicate: DefaultUIKitRUMActionsPredicate(),
        urlSessionTracking: RUM.Configuration.URLSessionTracking(firstPartyHostsTracing: .trace(
            hosts: [
                "domain.com"
            ],
            sampleRate: sampleRate
        ))
    )
)
Trace.enable(
    with: Trace.Configuration(
        sampleRate: sampleRate,
        service: serviceName,
        urlSessionTracking: Trace.Configuration.URLSessionTracking(
            firstPartyHostsTracing: .trace(
                hosts: [
                    "domain.com"
                ],
                sampleRate: sampleRate
            )
        ),
        bundleWithRumEnabled: false,
        networkInfoEnabled: false
    )
)
URLSessionInstrumentation.enable(with: .init(
    delegateClass: SessionDelegate.self,
    firstPartyHostsTracing: .trace(hosts: [
        "domain.com"
    ])
))
SessionReplay.enable(
    with: SessionReplay.Configuration(
        replaySampleRate: sampleRate,
        defaultPrivacyLevel: .allow
    )
)

let session = Session(
    configuration: configuration,
    interceptor: DDRequestInterceptor(),
    redirectHandler: redirector,
    eventMonitors: [DDEventMonitor()]
)

• RUM works good (I can see backend trace too)
• APM Service Summary not working

Implementation 2

Datadog.initialize(
    with: Datadog.Configuration(
        clientToken: clientToken,
        env: environment,
        site: .us1,
        service: serviceName
    ),
    trackingConsent: .granted
)
Datadog.setUserInfo(id: UIDevice.current.identifierForVendor?.uuidString ?? "")
RUM.enable(
    with: RUM.Configuration(
        applicationID: appID,
        uiKitViewsPredicate: DefaultUIKitRUMViewsPredicate(),
        uiKitActionsPredicate: DefaultUIKitRUMActionsPredicate(),
    )
)
Trace.enable(
    with: Trace.Configuration(
        sampleRate: sampleRate,
        service: serviceName,
        urlSessionTracking: Trace.Configuration.URLSessionTracking(
            firstPartyHostsTracing: .trace(
                hosts: [
                    "domain.com"
                ],
                sampleRate: sampleRate
            )
        ),
        bundleWithRumEnabled: false,
        networkInfoEnabled: false
    )
)
URLSessionInstrumentation.enable(with: .init(
    delegateClass: SessionDelegate.self,
    firstPartyHostsTracing: .trace(hosts: [
        "domain.com"
    ])
))
SessionReplay.enable(
    with: SessionReplay.Configuration(
        replaySampleRate: sampleRate,
        defaultPrivacyLevel: .allow
    )
)

let session = Session(
    configuration: configuration,
    interceptor: DDRequestInterceptor(),
    redirectHandler: redirector,
    eventMonitors: [DDEventMonitor()]
)

urlSessionTracking configuration removed on RUM

• APM works good
• But RUM does not show backend trace

Problem

• To make APM Service Summery working I have to turn off RUM urlSessionTracking

  [DATADOG SDK] 🐶 → 13:43:36.844 💡 (tracing) No upload. Batch to upload: NO, System conditions: ✅

Inspect

• https://github.com/DataDog/dd-sdk-ios/blob/331faa268f387470bd541cec0717282add79c1d1/DatadogTrace/Sources/Integrations/TracingURLSessionHandler.swift#L80C12-L80C141

• I found that TracingURLSessionHandler ignores interception if origin is "rum"

• https://github.com/DataDog/dd-sdk-ios/blob/331faa268f387470bd541cec0717282add79c1d1/DatadogRUM/Sources/Instrumentation/Resources/URLSessionRUMResourcesHandler.swift#L71

• And URLSessionRUMResourcesHandler sets origin = "rum"

I need help

Thanks

[maxep]

Hi @mswswing ! Thank you for the detailed report, it is super clear.

When using RUM, what we offer is a RUM-to-APM distributing tracing integration. This integration prevents from sending Span events to APM, instead a Trace is created backend side when a RUM Resource is received. That's why the TracingURLSessionHandler is not invoked when using RUM. I will ask internally why the RUM-to-APM does not generate service data in APM.

Thanks again 🙏

[mswswing]

Answer cleared thanks