I can't install any plugins on a fresh install


I tried several times, even with different methods (manual Octoprint installation and prebuild image even a nightly image) to install any plugins on my Raspberry Pi 3 B+. I allways get an unknown error :sweat:

Here is my log file, hope anyone could help me with this:

Traceback (most recent call last):
  File "/home/pi/OctoPrint/venv/lib/python2.7/site-packages/octoprint/plugins/pluginmanager/__init__.py", line 348, in command_install
    returncode, stdout, stderr = self._call_pip(pip_args)
  File "/home/pi/OctoPrint/venv/lib/python2.7/site-packages/octoprint/plugins/pluginmanager/__init__.py", line 652, in _call_pip
    return self._pip_caller.execute(*args)
  File "/home/pi/OctoPrint/venv/local/lib/python2.7/site-packages/octoprint/util/pip.py", line 172, in execute
    return self.call(command, **kwargs)
  File "/home/pi/OctoPrint/venv/local/lib/python2.7/site-packages/octoprint/util/commandline.py", line 83, in call
    p = sarge.run(command, **kwargs)
  File "/home/pi/OctoPrint/venv/local/lib/python2.7/site-packages/sarge/__init__.py", line 1462, in run
    p.run(input=input, async_=async_)
  File "/home/pi/OctoPrint/venv/local/lib/python2.7/site-packages/sarge/__init__.py", line 1071, in run
    self.run_node(node, input=input, async_=False)
  File "/home/pi/OctoPrint/venv/local/lib/python2.7/site-packages/sarge/__init__.py", line 1187, in run_node
    result = getattr(self, method)(node, input, async_)
  File "/home/pi/OctoPrint/venv/local/lib/python2.7/site-packages/sarge/__init__.py", line 1333, in run_command_node
    node.cmd.run(input=input, async_=async_)
  File "/home/pi/OctoPrint/venv/local/lib/python2.7/site-packages/sarge/__init__.py", line 655, in run
    self.process = p = Popen(self.args, **self.kwargs)
TypeError: __init__() got an unexpected keyword argument 'async'
2018-07-08 07:33:56,830 - tornado.access - ERROR - 500 POST /api/plugin/pluginmanager ( 1124.93ms


The sarge issue has been fixed in OctoPrint 1.3.9, which hasn't been released yet. You can (and should, really) upgrade to 1.3.9rc2 or wait for the full release.