504 Gateway Timeout Issue for PATCH method calls in private OPDK 17.01

[mpurwar]

PATCH method calls are getting timed-out intermittently with high failures rates with a error response code of 504 Gateway Timeout Issue.

Following are the logs from the system.logs.

103716:2018-04-22 07:20:47,504 NIOThread@9 WARN c.a.p.h.d.DNSCachedAddress - DNSCachedAddress.addressNotReachable() : The last address has been removed from Address list null refreshing 103717:2018-04-22 07:20:47,504 NIOThread@9 ERROR c.a.p.h.d.DNSCachedAddress - DNSCachedAddress.refresh() : Unable to resolve host : null 103718:2018-04-22 07:20:47,504 NIOThread@9 ERROR c.a.p.h.d.DNSCachedAddress - DNSCachedAddress.refresh() : Unable to resolve host : null

Has anyone seen this error before ? Any pointers will be appreciated.

Thanks.

[mpurwar]

This seems to be an Apigee Edge bug, PATCH method with Target Server Configuration in the Target Endpoint - HTTPTargetConnection fails with a 502 Bad Gateway with HTTP protocol and 504 Gateway Timeout with HTTPS protocol.

As a workaround, hardcoded URL in the HTTPTargetConnection seems to be working fine for the PATCH method.