RUMM-1791 WebEventConsumers added

[buranmert]

What and why?

Datadog browser-sdk integration will send log and RUM events to the native SDK and these events will be decorated with the contextual information of the native app.
That way any app with web view can display its users' session in the same timeline, native + webview.

How?

Once the message is passed from browser-sdk, a JS script will catch it and pass it to either WebLogEventConsumer or WebRUMEventConsumer.
Then they will add information to events and persist them in the filesystem where they wait to be uploaded to Datadog.

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

[ncreated]

Needs answers on tracking consent for webview events and more logs on eventual inconsistency of the solution. Currently we only addresses the happy scenario (both Logs and RUM enabled, tracking consent granted and receiving only known events).

[ncreated]

Because we pass Browser events to Logging / RUM feature storage, in case of Logging or RUM being disabled we will be sending Browser SDK events to void. This will result with losing observability and entire set of telemetry from webviews, depending on native SDK configuration. This requires additional handling - @mariusc83 @buranmert @xgouchet what's our strategy for this?

I see 3 options:

• we can send events to their own storage - independent from Logging / RUM feature;
• we can inform the user on dropping event due to misconfiguration:

if eventType == Constants.eventTypeLog {
   if let logEventConsumer = logEventConsumer {
      try logEventConsumer.consume(event: wrappedEvent, eventType: eventType)
   } else {
      userLogger.warn(/* warn that event will be lost because Logging is disabled in native SDK */)
   }
} else {
   if let rumEventConsumer = rumEventConsumer {
      try rumEventConsumer(event: wrappedEvent, eventType: eventType)
   } else {
      userLogger.warn(/* warn that event will be lost because RUM is disabled in native SDK */)
   }
}

• we can register selectively for receiving only Logs / only RUM / both Logs and RUM events from Browser SDK.

[buranmert]

ℹ️ we decided to go with userLogger.warn option at today's daily

[buranmert]

@ncreated should we warn the user every time a new event is received (that might spam their console)?
or only once when WebEventConsumer is created?

[ncreated]

"Given native RUM session rejected by sampler, when receiving event from WebView, it is sent anyway" seems to be critical (it impacts user billing) and not very obvious behaviour (in case of RUM disabled we drop events, but we send events no matter of RUM sampling). I don't see it covered in unit tests, meaning we can easily overlook it and change unawarely.

[buranmert]

context.sessionID == .nullID when the session is sampled-out