# Standard HTTP-to-gRPC status code mappings
# Ref: https://github.com/grpc/grpc/blob/master/doc/http-grpc-status-mapping.md
#
error_page 400 = @grpc_internal;
error_page 401 = @grpc_unauthenticated;
error_page 403 = @grpc_permission_denied;
error_page 404 = @grpc_unimplemented;
error_page 429 = @grpc_unavailable;
error_page 502 = @grpc_unavailable;
error_page 503 = @grpc_unavailable;
error_page 504 = @grpc_unavailable;

# NGINX-to-gRPC status code mappings
# Ref: https://github.com/grpc/grpc/blob/master/doc/statuscodes.md
#
error_page 405 = @grpc_internal; # Method not allowed
error_page 408 = @grpc_deadline_exceeded; # Request timeout
error_page 413 = @grpc_resource_exhausted; # Payload too large
error_page 414 = @grpc_resource_exhausted; # Request URI too large
error_page 415 = @grpc_internal; # Unsupported media type;
error_page 426 = @grpc_internal; # HTTP request was sent to HTTPS port
error_page 495 = @grpc_unauthenticated; # Client certificate authentication error
error_page 496 = @grpc_unauthenticated; # Client certificate not presented
error_page 497 = @grpc_internal; # HTTP request was sent to mutual TLS port
error_page 500 = @grpc_internal; # Server error
error_page 501 = @grpc_internal; # Not implemented

# gRPC error responses
# Ref: https://github.com/grpc/grpc-go/blob/master/codes/codes.go
#
location @grpc_deadline_exceeded {
    add_header grpc-status 4;
    add_header grpc-message 'deadline exceeded';
    return 204;
}

location @grpc_permission_denied {
    add_header grpc-status 7;
    add_header grpc-message 'permission denied';
    return 204;
}

location @grpc_resource_exhausted {
    add_header grpc-status 8;
    add_header grpc-message 'resource exhausted';
    return 204;
}

location @grpc_unimplemented {
    add_header grpc-status 12;
    add_header grpc-message unimplemented;
    return 204;
}

location @grpc_internal {
    add_header grpc-status 13;
    add_header grpc-message 'internal error';
    return 204;
}

location @grpc_unavailable {
    add_header grpc-status 14;
    add_header grpc-message unavailable;
    return 204;
}

location @grpc_unauthenticated {
    add_header grpc-status 16;
    add_header grpc-message unauthenticated;
    return 204;
}

# vim: syntax=nginx