When fetch is used keepalive is the default, and Chrome only allows a POST body <= 65536 bytes in that scenario

[beaugunderson]

What is the current behavior?

raven-js has keepalive: true in its fetchDefaults. Because of this, POSTs to Sentry using fetch will fail with a generic error if they are larger than 65536 bytes. This is smaller than Sentry's 100,000 byte limit (as I understand it). It's also smaller than the onpremise limits (which are set by uWSGI, as I understand it).

I opened this Chrome bug which helps explain further: https://bugs.chromium.org/p/chromium/issues/detail?id=871115&can=4&q=&colspec=ID%20Pri%20M%20Stars%20ReleaseBlock%20Component%20Status%20Owner%20Summary%20OS%20Modified

What is the expected behavior?

I expect raven-js to be able to POST messages >= 65536 without failing.

Secondarily, it would be nice if there was some logging for failed log messages (basically echoing the sentiments of the people in the 413/too large issue comments)!

Versions

raven-js: 3.24.2
macOS Chrome: 68.0.3440.84

[beaugunderson]

If anyone needs a workaround:

Raven.config('<DSN>', {
  fetchParameters: {
    keepalive: false
  }
});

[beaugunderson]

update: the 64kb limit is part of the fetch() spec when keepalive is true, so keepalive: true should probably not be the default, or the docs should be updated.

[kamilogorek]

Thanks for the details. I'll look into this.

https://fetch.spec.whatwg.org/#http-network-or-cache-fetch point 8.5.

If the sum of contentLengthValue and inflightKeepaliveBytes is greater than 64 kibibytes, then return a network error.

The above limit ensures that requests that are allowed to outlive the environment settings object and contain a body, have a bounded size and are not allowed to stay alive indefinitely.

[beaugunderson]

thanks so much @kamilogorek! ✨