chewbranca opened a new issue, #4993: URL: https://github.com/apache/couchdb/issues/4993
## Summary As mentioned in https://github.com/apache/couchdb/pull/4990, when using a load balancer or proxy in front of CouchDB, the proxy will not receive the chosen `nonce` value from CouchDB until the response headers are sent, which, in the event of long running `_find` queries that return no data, can be a considerable amount of time longer than typical proxy timeouts. The result is that the Mango reports are logged with the `nonce` value but the proxy timed out the request before getting any response headers so it was never able to retrieve the `nonce` for logging and connecting the proxy logs with the mango report. This is exacerbated by `chttpd:maybe_log` typically being set to false when using a proxy alongside a CouchDB cluster. I was going to suggest modifying `chttpd:maybe_log` to be configurable based on error types, but @rnewson had a much simpler suggestion of allowing the proxy to provide the `nonce`, thereby establishing the connection from the get go. I suggest we stick with the existing naming and allow for a request header named `X-Couch-Request-ID`, following https://github.com/apache/couchdb/blob/main/src/chttpd/src/chttpd.erl#L1368. ## Desired Behaviour A frontend proxy load balancer to a CouchDB cluster may supply an `X-Couch-Request-ID` to utilize as the `nonce` value instead of randomly generating one here: https://github.com/apache/couchdb/blob/main/src/chttpd/src/chttpd.erl#L297-L317 ## Possible Solution ```diff diff --git a/src/chttpd/src/chttpd.erl b/src/chttpd/src/chttpd.erl index ab8e1e9a3..6912115c1 100644 --- a/src/chttpd/src/chttpd.erl +++ b/src/chttpd/src/chttpd.erl @@ -294,7 +294,12 @@ handle_request_int(MochiReq) -> Other -> Other end, - Nonce = couch_util:to_hex(crypto:strong_rand_bytes(5)), + Nonce = case MochiReq:get_header_value("x-couch-request-id") of + undefined -> + couch_util:to_hex(crypto:strong_rand_bytes(5)); + Nonce0 -> + Nonce0 + end, HttpReq0 = #httpd{ mochi_req = MochiReq, ``` ## Additional context https://github.com/apache/couchdb/pull/4990 -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
