Envelopes stuck in __processing until restart

[bitsandfoxes]

When offline, the CachingTransport will leave envelopes stuck in __processing. Even if the client goes online again and starts sending new events, the old ones remain there.
Only during restart will those envelopes get moved back to the cache and then sent by the worker.

[bitsandfoxes]

I might be missing something but how is the retry supposed to work

sentry-dotnet/src/Sentry/Internal/Http/CachingTransport.cs

Lines 162 to 166 in 5bd8c8a

	try
	{
	// Wait a bit before retrying
	await Task.Delay(500, _workerCts.Token).ConfigureAwait(false);
	}

if we're waiting for a signal here before doing any processing?

sentry-dotnet/src/Sentry/Internal/Http/CachingTransport.cs

Lines 147 to 152 in 5bd8c8a

	try
	{
	await _workerSignal.WaitAsync(_workerCts.Token).ConfigureAwait(false);
	_options.LogDebug("CachingTransport worker signal triggered.");
	await ProcessCacheAsync(_workerCts.Token).ConfigureAwait(false);
	}

[jamescrosswell]

Lines 162-170 wait for either 500ms or the cancellation token (so basically just delays 500ms in normal circumstances).

... then back at the start of the loop, lines 149-151 execute.

It looks like the only time the _workerSignal gets released is here:

sentry-dotnet/src/Sentry/Internal/Http/CachingTransport.cs

Line 448 in d64358e

_workerSignal.Release();

Possibly we could call that back on line 166 as well, after delaying. That would try every 500ms when offline though... so some kind of progressive backoff might be good here... 500ms after the first successive failure, 1000ms after the second etc. up to some maximum backoff that gets reset back to 500ms after a successful iteration.