Delay event sending after the SDK is initalized

[balavor]

Problem Statement

👋 Hey folks,

💡 We are curious to learn if there is an existing way or if you would consider providing developers with the ability to pause event sending after the SDK is initialized.

Specifically, we're wondering if we can make sure that the SDK is initialized but doesn't send any crash reports (if any) from previous launches until we allow it.

Please note that we are using it in the app extension, and it is critical for us to delay any additional processing, considering that we also extend the event via beforeSend closure, and if it is triggered too early, we will miss adding extra context to it.

Solution Brainstorm

No response

Are you willing to submit a PR?

No response

[linear]

COCOA-910

[philipphofmann]

@balavor, we don't have a straightforward way of pausing sending events after initializing the SDK. What you could do is to use the SentryOptions.urlSessionDelegate or SentryOptions.urlSession to return nil responses. Then the SentryHttpTransport will assume it's not connected to the internet and will just keep all it's data in the offline cache

sentry-cocoa/Sources/Sentry/SentryHttpTransport.m

Lines 403 to 407 in a7a6331

	if (response == nil) {
	SENTRY_LOG_DEBUG(@"No internet connection.");
	[weakSelf finishedSending];
	return;
	}

Something like this could work

final class OfflineURLProtocol: URLProtocol {
    override class func canInit(with request: URLRequest) -> Bool { true }
    override class func canonicalRequest(for request: URLRequest) -> URLRequest { request }
    override func startLoading() {
        let error = NSError(domain: NSURLErrorDomain,
                            code: NSURLErrorNotConnectedToInternet,
                            userInfo: nil)
        client?.urlProtocol(self, didFailWithError: error)
    }
    override func stopLoading() {}
}

final class SentryOfflineURLSessionDelegate: NSObject, URLSessionDelegate, URLSessionTaskDelegate {
    func urlSession(_ session: URLSession, didCreate task: URLSessionTask) { task.cancel() }
    func urlSession(_ session: URLSession,
                    didReceive challenge: URLAuthenticationChallenge,
                    completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
        completionHandler(.performDefaultHandling, nil)
    }
}

And then

let urlSessionDelegate = SentryOfflineURLSessionDelegate()
let offlineURLSession: URLSession = {
    let configuration = URLSessionConfiguration.ephemeral
    configuration.protocolClasses = [OfflineURLProtocol.self]
    return URLSession(configuration: configuration, delegate: urlSessionDelegate, delegateQueue: nil)
}()

options.urlSession = offlineURLSession

Can you please elaborate on why you must delay additional processing?