René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Make matplotlib fail more gracefully in headless environments","articleBody":"This is reproducible on any headless environment using matplotlib 1.5.1. On my system, the following script:\n\n``` python\nfrom matplotlib import pyplot as plt\nplt.plot([1, 2], [1, 2])\n```\n\nWill produce the following traceback:\n\n```\n---------------------------------------------------------------------------\nTclError                                  Traceback (most recent call last)\n\u003cipython-input-2-8dd816f9ddc7\u003e in \u003cmodule\u003e()\n----\u003e 1 plt.plot([1, 2], [1, 2])\n\n/home/goldbaum/.virtualenvs/yt-dev/local/lib/python2.7/site-packages/matplotlib/pyplot.pyc in plot(*args, **kwargs)\n   3145 @_autogen_docstring(Axes.plot)\n   3146 def plot(*args, **kwargs):\n-\u003e 3147     ax = gca()\n   3148     # allow callers to override the hold state by passing hold=True|False\n   3149     washold = ax.ishold()\n\n/home/goldbaum/.virtualenvs/yt-dev/local/lib/python2.7/site-packages/matplotlib/pyplot.pyc in gca(**kwargs)\n    926     matplotlib.figure.Figure.gca : The figure's gca method.\n    927     \"\"\"\n--\u003e 928     return gcf().gca(**kwargs)\n    929\n    930 # More ways of creating axes:\n\n/home/goldbaum/.virtualenvs/yt-dev/local/lib/python2.7/site-packages/matplotlib/pyplot.pyc in gcf()\n    576         return figManager.canvas.figure\n    577     else:\n--\u003e 578         return figure()\n    579\n    580\n\n/home/goldbaum/.virtualenvs/yt-dev/local/lib/python2.7/site-packages/matplotlib/pyplot.pyc in figure(num, figsize, dpi, facecolor, edgecolor, frameon, FigureClass, **kwargs)\n    525                                         frameon=frameon,\n    526                                         FigureClass=FigureClass,\n--\u003e 527                                         **kwargs)\n    528\n    529         if figLabel:\n\n/home/goldbaum/.virtualenvs/yt-dev/local/lib/python2.7/site-packages/matplotlib/backends/backend_tkagg.pyc in new_figure_manager(num, *args, **kwargs)\n     82     FigureClass = kwargs.pop('FigureClass', Figure)\n     83     figure = FigureClass(*args, **kwargs)\n---\u003e 84     return new_figure_manager_given_figure(num, figure)\n     85\n     86\n\n/home/goldbaum/.virtualenvs/yt-dev/local/lib/python2.7/site-packages/matplotlib/backends/backend_tkagg.pyc in new_figure_manager_given_figure(num, figure)\n     90     \"\"\"\n     91     _focus = windowing.FocusManager()\n---\u003e 92     window = Tk.Tk()\n     93     window.withdraw()\n     94\n\n/usr/lib/python2.7/lib-tk/Tkinter.pyc in __init__(self, screenName, baseName, className, useTk, sync, use)\n   1765                 baseName = baseName + ext\n   1766         interactive = 0\n-\u003e 1767         self.tk = _tkinter.create(screenName, baseName, className, interactive, wantobjects, useTk, sync, use)\n   1768         if useTk:\n   1769             self._loadtk()\n\nTclError: no display name and no $DISPLAY environment variable\n```\n\nI think it would be much nicer if backends somehow detected these sorts of errors, fell back to the Agg backend (probably with a warning) and then goes ahead and makes the plot.\n","author":{"url":"https://github.com/ngoldbaum","@type":"Person","name":"ngoldbaum"},"datePublished":"2016-07-14T18:34:50.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":5},"url":"https://github.com/6739/matplotlib/issues/6739"}