1 # HTTP to gRPC Status Code Mapping 2 3 Since intermediaries are a common part of HTTP infrastructure some responses to 4 gRPC requests may be received that do not include the grpc-status header. In 5 some cases mapping error codes from an intermediary allows the gRPC client to 6 behave more appropriately to the error situation without overloading the 7 semantics of either error code. 8 9 This table is to be used _only_ for clients that received a response that did 10 not include grpc-status. If grpc-status was provided, it _must_ be used. Servers 11 _must not_ use this table to determine an HTTP status code to use; the mappings 12 are neither symmetric nor 1-to-1. 13 14 | HTTP Status Code | gRPC Status Code | 15 |----------------------------|--------------------| 16 | 400 Bad Request | INTERNAL | 17 | 401 Unauthorized | UNAUTHENTICATED | 18 | 403 Forbidden | PERMISSION\_DENIED | 19 | 404 Not Found | UNIMPLEMENTED | 20 | 429 Too Many Requests | UNAVAILABLE | 21 | 502 Bad Gateway | UNAVAILABLE | 22 | 503 Service Unavailable | UNAVAILABLE | 23 | 504 Gateway Timeout | UNAVAILABLE | 24 | _All other codes_ | UNKNOWN | 25 26 Technically, 1xx should have the entire header skipped and a subsequent header 27 be read. See RFC 7540 8.1. 28 29 200 is UNKNOWN because there should be a grpc-status in case of truly OK 30 response. 31
