HTTP/2 flow control in Node.js (grpc-js)

Question

How is HTTP/2 flow control implemented in the Node.js version of gRPC (grpc-js)?

For the Go implementation (grpc-go), the logic is mainly inhttps://github.com/grpc/grpc-go/blob/master/internal/transport/ (flowcontrol.go, bdp_estimator.go); also, it's described here . However, I couldn't find anything for grpc-js.

I am mainly interested in when does a Node.js receiver send WINDOW_UPDATE frames.

Answer 1

The grpc-js library is implemented using Node's http2 module, which handles the details of the HTTP/2 protocol, including flow control. So, there is no code in grpc-js that explicitly performs flow control operations. The http2 module, in turn, is implemeted using the nghttp2 library, so that code is where you will probably find the flow control logic.