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94 lines
3.0 KiB
94 lines
3.0 KiB
#!/usr/bin/env python |
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# |
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# * Corey Goldberg, 2012, 2013, 2015, 2016 |
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# |
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# * inspired by: PyVirtualDisplay |
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"""wrapper for running display inside X virtual framebuffer (Xvfb)""" |
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import os |
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import fnmatch |
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import subprocess |
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import tempfile |
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import time |
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class Xvfb: |
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def __init__(self, width=800, height=680, colordepth=24, **kwargs): |
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self.width = width |
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self.height = height |
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self.colordepth = colordepth |
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if not self.xvfb_exists(): |
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msg = 'Can not find Xvfb. Please install it and try again.' |
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raise EnvironmentError(msg) |
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self.extra_xvfb_args = ['-screen', '0', '{}x{}x{}'.format( |
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self.width, self.height, self.colordepth)] |
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for key, value in kwargs.items(): |
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self.extra_xvfb_args += ['-{}'.format(key), value] |
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if 'DISPLAY' in os.environ: |
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self.orig_display = os.environ['DISPLAY'].split(':')[1] |
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else: |
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self.orig_display = None |
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self.proc = None |
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def __enter__(self): |
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self.start() |
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return self |
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def __exit__(self, exc_type, exc_val, exc_tb): |
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self.stop() |
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def start(self): |
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self.new_display = self._get_next_unused_display() |
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display_var = ':{}'.format(self.new_display) |
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self.xvfb_cmd = ['Xvfb', display_var] + self.extra_xvfb_args |
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with open(os.devnull, 'w') as fnull: |
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self.proc = subprocess.Popen(self.xvfb_cmd, |
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stdout=fnull, |
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stderr=fnull, |
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close_fds=True) |
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time.sleep(0.1) # give Xvfb time to start |
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ret_code = self.proc.poll() |
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if ret_code is None: |
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self._set_display_var(self.new_display) |
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else: |
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raise RuntimeError('Xvfb did not start') |
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def stop(self): |
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if self.orig_display is None: |
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del os.environ['DISPLAY'] |
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else: |
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self._set_display_var(self.orig_display) |
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# TODO: |
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# fix leaking X displays. |
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# killing Xvfb process doesn't up the lock files (/tmp/.X*-lock) |
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if self.proc is not None: |
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self.proc.terminate() |
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self.proc.wait() |
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self.proc = None |
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def _get_next_unused_display(self): |
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tmpdir = tempfile.gettempdir() |
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pattern = '.X*-lock' |
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lockfile_names = fnmatch.filter(os.listdir(tmpdir), pattern) |
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existing_displays = [int(name.split('X')[1].split('-')[0]) |
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for name in lockfile_names] |
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highest_display = max(existing_displays) if existing_displays else 0 |
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return highest_display + 1 |
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def xvfb_exists(self): |
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"""Check that Xvfb is available on PATH and is executable.""" |
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paths = os.environ['PATH'].split(os.pathsep) |
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return any(os.access(os.path.join(path, 'Xvfb'), os.X_OK) |
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for path in paths) |
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def _set_display_var(self, display): |
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os.environ['DISPLAY'] = ':{}'.format(display)
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