ws4redis

Websocket for redis

Replacement for django-ws-redis daemon. See implementation if you want to re-implement daemon functionality or it subset

Installation

Build or download binary.

Just copy executable to target machine.

Building

You need installed go compiler and valid $GOPATH environment variable

export $GOPATH=~/go # or any another folder with write access
# just skip it you have already exported GOPATH variable
go get -u github.com/destiny-development/ws4redis
# `go get` will download sources and all deps, then build the binary
./$GOPATH/bin/ws4redis -h
# or add $GOPATH/bin to $PATH and just
ws4redis -h
# sources are in $GOPATH/src/github.com/destiny-development/ws4redis
# to update, just
go get -u github.com/destiny-development/ws4redis

Usage

$ ws4redis -h

Usage of ./ws4redis:
  -default="launcher": Default facility
  -facilities="launcher,launcher-staff": Permitted facilities for strict mode
  -heartbeats=false: Use heartbeats
  -max-size=32: Maximum message size
  -port=9050: Listen port
  -redis-addr="localhost:6379": Redis addr
  -redis-db=0: Redis db
  -redis-network="tcp": Redis network
  -redis-prefix="ws": Redis prefix
  -scale=false: Use all cpus
  -strict=false: Allow only white-listed facilities
  -timeout=10s: Heartbeat timeout

Monitoring

One can launch expvarmon to monitor connections/memory usage:

expvarmon -ports="9050" -i=200ms -vars="mem:memstats.Alloc,mem:memstats.Sys,mem:memstats.HeapAlloc,mem:memstats.HeapInuse,,memstats.NumGC,duration:memstats.PauseTotalNs,Goroutines,Clients,RPS,Version"

Just simply curl /stat or use expvar's /debug/vars

$ curl localhost:9050/stat
ws4redis
Version 1.2-production
Facilities 2
	facility launcher:
		 22505 clients
	facility launcher-staff:
		 1 clients
Clients 22506
CPU 24
Goroutines 45022
Memory
	Alloc 195528640
	TotalAlloc 3720837240
	Heap 195528640
	HeapSys 299450368

Performance

22k clients on 1 core = 453mb

2 goroutines and 30kb per client

Implementation

Server listens for websocket connections on {host}:{port}/{prefix}/{facility}, e.g. ws.host.com/ws/launcher, expects heartbeats every 5s (by default, timeout is 10s) and acts as echo-server.

Timeout

If no heartbeats are sent by client in {timeout}, server closes websocket connection

Broadcasting

For every facility server creates redis connection and starts listening on channel {redis-prefix}:broadcast:{facility} (e.g. ws:broadcast:launcher). Every message published on this channel is sent to all clients of {facility} without any changes.