我想使用subprocess.popen((执行C程序,然后将其实时输出并将其发送给客户端。但是,输出是缓冲的,并在执行结束时一起发送(阻止性质(。如何实时收到输出,然后立即以扭曲的Autobahn发送。
def onConnect(self, request):
try:
self.cont_name = ''.join(random.choice(string.lowercase) for i in range(5))
self.file_name = self.cont_name
print("Connecting...")
except Exception:
print("Failed"+str(Exception))
def onOpen(self):
try:
print("open")
except Exception:
print("Couldn't create container")
def onMessage(self, payload,isBinary=False):
cmd = "docker exec "+self.cont_name+" /tmp/./"+self.file_name
a = subprocess.Popen([cmd], shell=True, stdout=subprocess.PIPE, bufsize=1)
for line in iter(a.stdout.readline, b''):
line = line.encode('utf8')
self.sendMessage(line)
def onClose(self, wasClean, code, reason):
try:
print("Closed container...")
except Exception:
print(str(Exception))
使用子程序执行Docker命令时,C代码的整个输出将立即返回而不是发生。for ex:
#include <stdio.h>
#include <unistd.h>
int main(){
int i=0;
for(i=0;i<5;i++){
fflush(stdout);
printf("Roundedn");
sleep(3);
}
}
在容器中运行此操作后,该程序应在3秒后返回"四舍五入"到客户端。但是,它最终在执行结束时发送了所有"圆形"。
不当行为来自此方法的循环:
def onMessage(self, payload,isBinary=False):
cmd = "docker exec "+self.cont_name+" /tmp/./"+self.file_name
a = subprocess.Popen([cmd], shell=True, stdout=subprocess.PIPE, bufsize=1)
for line in iter(a.stdout.readline, b''):
line = line.encode('utf8')
self.sendMessage(line)
Twisted是一个合作的多任务系统。默认情况下,所有内容都在单个线程("反应堆线程"(中运行。这意味着所有代码必须定期(通常很快(放弃控制权,以便其他代码(应用程序代码或扭曲实施代码(都有机会运行。此功能中的循环从子过程中读取,并尝试使用Autobahn API发送数据 - 一遍又一遍地,永远不要放弃控制。
阻止从流行对象的读取也可能引起问题。您将不知道读取会阻止多长时间,因此您不知道会阻止其他代码在反应堆线程中运行多长时间。您可以将popen读取到新线程中,它们不会阻止反应堆线程:
def onMessage(self, payload,isBinary=False):
cmd = "docker exec "+self.cont_name+" /tmp/./"+self.file_name
popen_in_thread(
lambda line: reactor.callFromThread(
lambda: self.sendMessage(line.encode("utf-8"))
),
[cmd], shell=True, stdout=subprocess.PIPE, bufsize=1
)
def popen_in_thread(callback, *args, **kwargs):
def threaded():
a = subprocess.Popen(*args, **kwargs)
for line in iter(a.stdout.readline, b''):
callback(line)
reactor.callInThread(threaded)
或更好地使用Twisted自己的过程支持:
def onMessage(self, payload,isBinary=False):
class ProcessLinesToMessages(ProcessProtocol):
def outReceived(self, output):
buf = self.buf + output
lines = buf.splitlines()
self.buf = lines.pop()
for line in lines:
self.sendMessage(line.encode("utf-8"))
while True:
line, self.buf = self.buf.splitline
reactor.spawnProcess(
ProcessLinesToMessages(),
"docker",
[
"docker",
"exec",
self.cont_name,
"/tmp/./ + self.file_name,
],
)
(都没有测试过版本,希望这个想法很清楚(