nsqlookupd

nsqlookup 用于收集nsqd上报的topic和channel

基于此对client的查询返回对应的nsqd node

然后client对响应的nsqd进行sub

本篇主要选取查询topic的片段

入口代码位于github.com/nsqio/nsq/apps/nsqlookupd

func (p *program) Start() error {

                    ...

                daemon := nsqlookupd.New(opts)

                 daemon.Main()

                ...

}

func (l *NSQLookupd) Main() {

                ....

                nsqd通过此server交互

                tcpListener, err := net.Listen("tcp", l.opts.TCPAddress)

                tcpServer := &tcpServer{ctx: ctx}

                protocol.TCPServer(tcpListener, tcpServer, l.logf)

               client通过此server交互

                httpListener, err := net.Listen("tcp", l.opts.HTTPAddress)    

                httpServer := newHTTPServer(ctx)

                http_api.Serve(httpListener, httpServer, "HTTP", l.logf)

                ....

}

func (p *tcpServer) Handle(clientConn net.Conn) {

                ....

                  prot = &LookupProtocolV1{ctx: p.ctx}    

                ....

                err = prot.IOLoop(clientConn)

                ....

}

func (p *LookupProtocolV1) IOLoop(conn net.Conn) error {

                ...

                response, err = p.Exec(client, reader, params)

                ...

}

 func (p *LookupProtocolV1) Exec(client *ClientV1, reader *bufio.Reader, params []string) ([]byte, error) {

                ...
                这个是nsqd同步来的topic

                case "REGISTER":

                       return p.REGISTER(client, reader, params[1:])

                ...

}

func newHTTPServer(ctx *Context) *httpServer {

                ....

                   router.Handle("GET", "/lookup", http_api.Decorate(s.doLookup, log, http_api.V1))

}

func (s *httpServer) doLookup(w http.ResponseWriter, req *http.Request, ps httprouter.Params) (interface{}, error) {

                用于查询topic

                .,..

}