Handle context canceled errors + better http proxy error handling #644
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Can I please get someone to take a look in this PR? It would be nice to get it in the next release. |
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@danlsgiga yes, sorry I'll try to find some time to give this a look. |
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My team at Hashicorp would love to see this merged. We have some legitimate 502s we'd like to investigate, but we can't see them through the forest of illegitimate context-canceled 502s. |
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Seems a simple change. Thank you @danlsgiga ... and sorry for the long delay. |
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This PR fixes how fabio is handling the HTTP/HTTPS proxy "context canceled" errors that are caused basically by the client side closing the connection before getting any response and wrongly reporting a 502 status code in the logs. This is specially annoying for systems like Nomad that use long polling API endpoints and whenever you navigate in the UI, you are constantly closing the long polled connection and getting the
context cancelederror in the logs.Along with the fix, we are using the HTTP Status Code 499 which is a non standard status code created by Nginx to represent
Client Closed Requestresponses.Since Fabio also supports HTTP/2, this also solves misleading logs reporting 502 responses when HTTP/2 is used... The HTTP/2 RFC allows a client to close a request connection when the requested resources are already in cache.
I've tested these changes in our internal QA environment and stderr logging is also improved by using the HTTP Proxy ErrorHandler along with
context canceledbeing correctly handled.Closes #264