WebAgg: raise WebAggApplication.started flag before blocking #2865
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👍 - seems reasonable to me. |
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Does the started flag ever get unset? |
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Nope. It is used solely in WebAggApplication.start(). Anyway, as seen from the code, the only way to escape from Tornado is hitting ctrl-c, killing the whole application. cls.started looks like an internal protection against running the loop several times. If we had running() in newer Tornado-s, cls.started would be just redundant. In my opinion, WebAgg should not run the darn loop itself at all. Instead, there should be a user callback called. But unfortunately it would break the whole matplotlib abstraction. |
| try: | ||
| tornado.ioloop.IOLoop.instance().start() | ||
| except KeyboardInterrupt: | ||
| print("Server stopped") |
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I think that we should add cls.started = False here. It may not do any good now but it makes sure that the function never returns with the class in an inconsistent state.
Since Tornado's IOLoop start() blocks until the loop is closed, cls.started used to be set to True *after* an application actually stops working. Revert running() check since it no longer exists in newer versions of Tornado and will never return back.
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Done |
WebAgg: raise WebAggApplication.started flag before blocking
You can also just not call show and interface with the WebAgg canvas on the figure directly, if you'd rather start an event loop yourself. This is true of all of the backends. |
Since Tornado's IOLoop start() blocks until the loop is closed,
cls.started used to be set to True after an application actually
stops working.
Revert running() check since it no longer exists in newer versions
of Tornado and will never return back.