nginx.conf

user nginx;

events {
    worker_connections 2048;
}

http {
    grpc_connect_timeout 75;
    proxy_read_timeout 1d;
    proxy_connect_timeout 1d;
    proxy_send_timeout 1d;

    upstream frontend_hosts {
        server temporal-frontend:7237 max_fails=0;
        server temporal-frontend2:7236 max_fails=0;

        keepalive 64;
        keepalive_time 1d;
        keepalive_timeout 75s;
        keepalive_requests 100000;
    }

    server {
        listen 7233 http2;
        location / {
            grpc_pass grpc://frontend_hosts;
            proxy_set_header Connection "";
            proxy_http_version 1.1;
        }

        # 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;
        }
        default_type application/grpc;   # Ensure gRPC for all error responses
    }
}