I have code that prints out the output of adb logcat into a wx.TextArea box, this all works great, click the button and logcat prints out, it prints out more when phone taps are made and everything works fine. toolsDir and pkgName are both strings.
params = [toolsDir + "\\adb.exe", "logcat"]
p = Popen(params, stdout=subprocess.PIPE, bufsize=1)
for line in p.stdout:
self.progressBox.AppendText(line.decode('utf-8'))
However I have adapted this code to only print out the logs that are for a particular app, this is done using the windows 'findstr' function, adb logcat | findstr myApp. The code below initially works, but then stops, and doesn't display anything else whatever happens, button tapped, app closed etc. Its like the buffer has reached the end and doesn't process any further events.
args = [toolsDir + '\\adb.exe', 'logcat']
args2 = ['findstr', pkgName]
process_adb = subprocess.Popen(args, stdout=subprocess.PIPE, shell=False)
process_fs = subprocess.Popen(args2, stdin=process_adb.stdout, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=False)
for line in process_fs.stdout:
self.progressBox.AppendText(line.decode('utf-8'))
How come the bottom code, the one that filters the app name, stops printing out real time logs, but the top doesn't? I'm guessing its something to do with the piping of one command to another.
You can use Python to filter lines:
if pkgName in line:
BTW: it can be problem with two processes because probably second waits for EOF (end of file) or other signal (ie. closed pipe) but its stdin is open all the time waiting for new data from first process..
Check this: python-subprocess-interaction-why-does-my-process-work-with-popen-communicate