yocto-sumo源碼解析（九）: ProcessServer.main
阿新 • • 發佈：2018-10-28
running acc error: top delay 域套接字 err ror 列表
前面講到BitbakeServer實際上是一個ProcessServer，因此對ProcessServer進行了一個大略的分析集，這裏著重再介紹一下ProcessServer.main。
1. 初始化
def main(self):
self.cooker.pre_serve() #調用cooker.pre_serve()，進入服務前的一些動作，這個後面繼續分解
bb.utils.set_process_name("Cooker") #設置本進程名稱為“Cooker”
ready = [] #聲明一個列表，這個列表從後文看列應該是一個套接字描述符列表
self.controllersock = False #聲明本服務為非控制器套接字
fds = [self.sock] #將本服務套接字添加進文件描述符列表fds
if self.xmlrpc:
fds.append(self.xmlrpc) #若支持xmlrpc，那麽將xmlrpc同樣放入文件描述符列表
print("Entering server connection loop") #即將進入服務器連接循環
def disconnect_client(self, fds): #定義一個斷開客戶連接的函數，後面會要用到
if not self.haveui:
return
print("Disconnecting Client")
fds.remove(self.controllersock) #從文件描述符列表中刪除控制器套接字描述符
fds.remove(self.command_channel) #從文件描述符列表中刪除命令通道套接字描述符，從這兩處並列的刪除步驟看，服務器接受兩個套接字
bb.event.unregister_UIHhandler(self.event_handle, True) #從事件處理器中刪除本事件處理器
self.command_channel_reply.writer.close() #關閉命令通道寫端
self.event_writer.writer.close() #關閉事件寫端
del self.event_writer #析構事件作者
self.controllersock.close() #控制器套接字關閉
self.controllersock = False
self.haveui = False
self.lastui = time.time()
self.cooker.clientComplete() #調用cooker.clientComplete函數，後面再進行分解
if self.timeout is None:
print("No timeout, exiting.")
self.quit = True
2. 服務器連接循環
while not self.quit:
if self.sock in ready: #假設本套接字在ready列表，那麽從本套接字接受一個控制器套接字連入，初始本套接字並不在ready列表
self.controllersock, address = self.sock.accept()
if self.haveui:
print("Dropping connection attempt as we have a UI %s" % (str(ready)))
self.controllersock.close()
else:
print("Accepting %s" % (str(ready)))
fds.append(self.controllersock) #將控制器套接字添加到文件描述符列表
if self.controllersock in ready: #若控制器套接字就緒，則從控制器套接字接受新的ui文件描述符
try:
print("Connecting Client")
ui_fds = recvfds(self.controllersock, 3) #根據控制器套接字中取3個套接字，分別用於事件作者，命令通道作者，命令通道讀者
# Where to write events to
writer = ConnectionWriter(ui_fds[0]) #新建連接作者，用於事件處理
self.event_handle = bb.event.register_UIHhandler(writer, True) #新建本事件處理器
self.event_writer = writer
# Where to read commands from
reader = ConnectionReader(ui_fds[1]) #新建連接命令通道讀者
fds.append(reader) #將讀者添加進文件描述符列表
self.command_channel = reader
# Where to send command return values to
writer = ConnectionWriter(ui_fds[2]) #新建連接命令通道作者，用於向客戶發出回應
self.command_channel_reply = writer
self.haveui = True
except (EOFError, OSError):
disconnect_client(self, fds) #出現異常則斷開客戶連接
if not self.timeout == -1.0 and not self.haveui and self.lastui and self.timeout and (self.lastui + self.timeout) < time.time():
print("Server timeout, exiting.")
self.quit = True
if self.command_channel in ready: #命令通道就緒，從命令通道中讀取一條命令
try:
command = self.command_channel.get()
except EOFError:
# Client connection shutting down
ready = []
disconnect_client(self, fds) #出現異常則斷開客戶連接
continue
if command[0] == "terminateServer":
self.quit = True
continue
try:個
print("Running command %s" % command)
self.command_channel_reply.send(self.cooker.command.runCommand(command)) #執行接收到的命令並且構造響應
except Exception as e:
logger.exception(‘Exception in server main event loop running command %s (%s)‘ % (command, str(e)))
if self.xmlrpc in ready: #xmlrpc就緒，處理xmlrpc請求。
self.xmlrpc.handle_requests()
ready = self.idle_commands(.1, fds) #從套接字中獲取就緒的套接字
3. 退出清理
print("Exiting")
# Remove the socket file so we don‘t get any more connections to avoid races
os.unlink(self.sockname) #刪除域套接字文件
self.sock.close() #關閉本套接字，這裏順序上存疑
try:
self.cooker.shutdown(True) #關閉cooker
self.cooker.notifier.stop() #停止notify
self.cooker.confignotifier.stop() #停止confignotify
except:
pass
self.cooker.post_serve() #調用cooker.post_serve(),這個在後面進行分解
# Finally release the lockfile but warn about other processes holding it open
lock = self.bitbake_lock
lockfile = lock.name
lock.close() #關閉bitbake_lock
lock = None
while not lock:
with bb.utils.timeout(3):
lock = bb.utils.lockfile(lockfile, shared=False, retry=False, block=True)
if not lock:
# Some systems may not have lsof available
procs = None
try:
procs = subprocess.check_output(["lsof", ‘-w‘, lockfile], stderr=subprocess.STDOUT)
except OSError as e:
if e.errno != errno.ENOENT:
raise
if procs is None:
# Fall back to fuser if lsof is unavailable
try:
procs = subprocess.check_output(["fuser", ‘-v‘, lockfile], stderr=subprocess.STDOUT)
except OSError as e:
if e.errno != errno.ENOENT:
raise
msg = "Delaying shutdown due to active processes which appear to be holding bitbake.lock"
if procs:
msg += ":\n%s" % str(procs)
print(msg)
return
# We hold the lock so we can remove the file (hide stale pid data)
bb.utils.remove(lockfile)
bb.utils.unlockfile(lock)
yocto-sumo源碼解析（九）: ProcessServer.main