yocto-sumo源码解析（七）: BitBakeServer

1. 创建域套接字，管道以及锁：

        self.configuration = configuration
        self.featureset = featureset
        self.sockname = sockname
        self.bitbake_lock = lock
        self.readypipe, self.readypipein = os.pipe()

        # Create server control socket
        if os.path.exists(sockname):
            os.unlink(sockname)

        self.sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
        # AF_UNIX has path length issues so chdir here to workaround
        cwd = os.getcwd()
        logfile = os.path.join(cwd, "bitbake-cookerdaemon.log")

        try:
            os.chdir(os.path.dirname(sockname))
            self.sock.bind(os.path.basename(sockname))
        finally:
            os.chdir(cwd)
        self.sock.listen(1)

2. 创建后台线程执行_startServer：

        os.set_inheritable(self.sock.fileno(), True)
        startdatetime = datetime.datetime.now()
        bb.daemonize.createDaemon(self._startServer, logfile)
        self.sock.close()
        self.bitbake_lock.close()

3. 读者线程：

        ready = ConnectionReader(self.readypipe)
        r = ready.poll(30)
        if r:
            r = ready.get()
        if not r or r != "ready":
            ready.close()
            bb.error("Unable to start bitbake server")
            if os.path.exists(logfile):
                logstart_re = re.compile(self.start_log_format % ('([0-9]+)', '([0-9-]+ [0-9:.]+)'))
                started = False
                lines = []
                with open(logfile, "r") as f:
                    for line in f:
                        if started:
                            lines.append(line)
                        else:
                            res = logstart_re.match(line.rstrip())
                            if res:
                                ldatetime = datetime.datetime.strptime(res.group(2), self.start_log_datetime_format)
                                if ldatetime >= startdatetime:
                                    started = True
                                    lines.append(line)
                if lines:
                    if len(lines) > 10:
                        bb.error("Last 10 lines of server log for this session (%s):\n%s" % (logfile, "".join(lines[-10:])))
                    else:
                        bb.error("Server log for this session (%s):\n%s" % (logfile, "".join(lines)))
            raise SystemExit(1)
        ready.close()
        os.close(self.readypipein)

4. 写者线程：

    def _startServer(self):
        print(self.start_log_format % (os.getpid(), datetime.datetime.now().strftime(self.start_log_datetime_format)))
        server = ProcessServer(self.bitbake_lock, self.sock, self.sockname)
        self.configuration.setServerRegIdleCallback(server.register_idle_function)
        writer = ConnectionWriter(self.readypipein)
        try:
            self.cooker = bb.cooker.BBCooker(self.configuration, self.featureset)
            writer.send("ready")
        except:
            writer.send("fail")
            raise
        finally:
            os.close(self.readypipein)
        server.cooker = self.cooker
        server.server_timeout = self.configuration.server_timeout
        server.xmlrpcinterface = self.configuration.xmlrpcinterface
        print("Started bitbake server pid %d" % os.getpid())
        server.start()