Implement gRPC Server and Bidirectional Streaming - The Networker

                      TASK
                    

Implementation

Implement gRPC streaming RPCs:

Server streaming: Client sends one request, server sends a stream of responses
Bidirectional streaming: Both sides send streams of messages concurrently

Use a log-watching service as the example:

Request:  {"type": "grpc_server_stream", "msg_id": 1, "service": "LogWatcher", "method": "WatchLogs", "request": {"filter": "ERROR", "limit": 3}}
Response: [
    {"type": "grpc_stream_msg", "in_reply_to": 1, "seq": 1, "data": {"level": "ERROR", "msg": "disk full"}},
    {"type": "grpc_stream_msg", "in_reply_to": 1, "seq": 2, "data": {"level": "ERROR", "msg": "connection reset"}},
    {"type": "grpc_stream_msg", "in_reply_to": 1, "seq": 3, "data": {"level": "ERROR", "msg": "timeout"}},
    {"type": "grpc_stream_end", "in_reply_to": 1, "status": "OK", "count": 3}
]

Request:  {"type": "grpc_bidi_stream_open", "msg_id": 2, "service": "Chat", "method": "BiDiChat"}
Response: {"type": "grpc_bidi_stream_open_ok", "in_reply_to": 2, "stream_id": "s1"}

Request:  {"type": "grpc_bidi_stream_send", "msg_id": 3, "stream_id": "s1", "data": {"text": "hello"}}
Response: {"type": "grpc_bidi_stream_recv", "in_reply_to": 3, "data": {"text": "echo: hello"}}

Sample Test Cases

Server streaming returns multiple messagesTimeout: 5000ms

Input

{"src":"c0","dest":"n1","body":{"type":"init","msg_id":1,"node_id":"n1","node_ids":["n1"]}}
{"src":"c1","dest":"n1","body":{"type":"grpc_server_stream","msg_id":2,"service":"LogWatcher","method":"WatchLogs","request":{"filter":"ERROR","limit":2}}}

Expected Output

{"src": "n1", "dest": "c0", "body": {"type": "init_ok", "in_reply_to": 1, "msg_id": 0}}

Bidi stream open and sendTimeout: 5000ms

Input

{"src":"c0","dest":"n1","body":{"type":"init","msg_id":1,"node_id":"n1","node_ids":["n1"]}}
{"src":"c1","dest":"n1","body":{"type":"grpc_bidi_stream_open","msg_id":2,"service":"Chat","method":"BiDiChat"}}
{"src":"c1","dest":"n1","body":{"type":"grpc_bidi_stream_send","msg_id":3,"stream_id":"s1","data":{"text":"hello"}}}

Expected Output

{"src": "n1", "dest": "c0", "body": {"type": "init_ok", "in_reply_to": 1, "msg_id": 0}}

Hints

Hint 1▾

Server streaming: client sends one request, server sends multiple responses

Hint 2▾

Bidirectional streaming: both sides send multiple messages over the same connection

Hint 3▾

Each message in the stream uses the same gRPC framing (compressed flag + length)

Hint 4▾

The server signals end-of-stream with gRPC trailers (grpc-status)

Hint 5▾

Track the stream state: OPEN, HALF_CLOSED, CLOSED

Resources

gRPC Streaming

gRPC server streaming and bidirectional streaming RPC types

                      OVERVIEW
                    

Theoretical Hub

Concept overview coming soon

Key Concepts

server streamingbidirectional streamingHTTP/2 streamsflow control

main.py

python