I've been getting frequent but not constant errors using Altair saver to save .png files via selenium and chromedriver. First I get a "headless chrome" error:
WebDriverException: Message: unknown error: session deleted because of page crash from unknown error: cannot determine loading status from tab crashed (Session info: headless chrome=90.0.4430.212)
Followed by a "invalid session" error when I try to save it again:
InvalidSessionIdException: Message: invalid session id
Based on my read of StackOverflow and elsewhere, the initial error leaves a chromedriver session open and that causes the second error. It will resolve itself if I close out of everything and reopen but that's not really a workable solution. Any advice on making saving Altair charts more reliable?
Versions are up to date and compatible as far as I know: altair 4.1.0, altair-saver 0.5.0, selenium 3.141.0, Chrome 90.0.4430.212, ChromeDriver 90.0.4430.24, chromedriver-binary 90.0.4430.24.0
Full trackback of headless chrome error:
---------------------------------------------------------------------------
WebDriverException Traceback (most recent call last)
<ipython-input-37-cf20dd94d732> in <module>
---> 30 chart.save('chart.png', scale_factor=3)
c:\programdata\anaconda3\envs\[...]\lib\site-packages\altair\vegalite\v4\api.py in save(self, fp, format, override_data_transformer, scale_factor, vegalite_version, vega_version, vegaembed_version, **kwargs)
474 if override_data_transformer:
475 with data_transformers.disable_max_rows():
--> 476 result = save(**kwds)
477 else:
478 result = save(**kwds)
c:\programdata\anaconda3\envs\[...]\lib\site-packages\altair\utils\save.py in save(chart, fp, vega_version, vegaembed_version, format, mode, vegalite_version, embed_options, json_kwds, webdriver, scale_factor, **kwargs)
119 webdriver=webdriver,
120 scale_factor=scale_factor,
--> 121 **kwargs,
122 )
123 if format == "png":
c:\programdata\anaconda3\envs\[...]\lib\site-packages\altair\utils\mimebundle.py in spec_to_mimebundle(spec, format, mode, vega_version, vegaembed_version, vegalite_version, **kwargs)
58 "see http://github.com/altair-viz/altair_saver/".format(fmt=format)
59 )
---> 60 return altair_saver.render(spec, format, mode=mode, **kwargs)
61 if format == "html":
62 html = spec_to_html(
c:\programdata\anaconda3\envs\[...]\lib\site-packages\altair_saver\_core.py in render(chart, fmts, mode, embed_options, method, **kwargs)
255 Saver = _select_saver(method, mode=mode, fmt=fmt)
256 saver = Saver(spec, mode=mode, embed_options=embed_options, **kwargs)
--> 257 mimebundle.update(saver.mimebundle(fmt))
258
259 return mimebundle
c:\programdata\anaconda3\envs\[...]\lib\site-packages\altair_saver\savers\_saver.py in mimebundle(self, fmts)
88 vegalite_version=self._package_versions["vega-lite"],
89 )
---> 90 bundle[mimetype] = self._serialize(fmt, "mimebundle")
91 return bundle
92
c:\programdata\anaconda3\envs\[...]\lib\site-packages\altair_saver\savers\_selenium.py in _serialize(self, fmt, content_type)
282
283 def _serialize(self, fmt: str, content_type: str) -> MimebundleContent:
--> 284 out = self._extract(fmt)
285 if fmt == "png":
286 assert isinstance(out, str)
c:\programdata\anaconda3\envs\[...]\lib\site-packages\altair_saver\savers\_selenium.py in _extract(self, fmt)
262
263 url = self._serve(html, js_resources)
--> 264 driver.get("about:blank")
265 driver.get(url)
266 try:
c:\programdata\anaconda3\envs\[...]\lib\site-packages\selenium\webdriver\remote\webdriver.py in get(self, url)
331 Loads a web page in the current browser session.
332 """
--> 333 self.execute(Command.GET, {'url': url})
334
335 @property
c:\programdata\anaconda3\envs\[...]\lib\site-packages\selenium\webdriver\remote\webdriver.py in execute(self, driver_command, params)
319 response = self.command_executor.execute(driver_command, params)
320 if response:
--> 321 self.error_handler.check_response(response)
322 response['value'] = self._unwrap_value(
323 response.get('value', None))
c:\programdata\anaconda3\envs\[...]\lib\site-packages\selenium\webdriver\remote\errorhandler.py in check_response(self, response)
240 alert_text = value['alert'].get('text')
241 raise exception_class(message, screen, stacktrace, alert_text)
--> 242 raise exception_class(message, screen, stacktrace)
243
244 def _value_or_default(self, obj, key, default):
WebDriverException: Message: unknown error: session deleted because of page crash
from unknown error: cannot determine loading status
from tab crashed
(Session info: headless chrome=90.0.4430.212)
And invalid session error:
---------------------------------------------------------------------------
InvalidSessionIdException Traceback (most recent call last)
<ipython-input-38-cf20dd94d732> in <module>
29
---> 30 chart.save('chart.png' scale_factor=3)
c:\programdata\anaconda3\envs\[...]\lib\site-packages\altair\vegalite\v4\api.py in save(self, fp, format, override_data_transformer, scale_factor, vegalite_version, vega_version, vegaembed_version, **kwargs)
474 if override_data_transformer:
475 with data_transformers.disable_max_rows():
--> 476 result = save(**kwds)
477 else:
478 result = save(**kwds)
c:\programdata\anaconda3\envs\[...]\lib\site-packages\altair\utils\save.py in save(chart, fp, vega_version, vegaembed_version, format, mode, vegalite_version, embed_options, json_kwds, webdriver, scale_factor, **kwargs)
119 webdriver=webdriver,
120 scale_factor=scale_factor,
--> 121 **kwargs,
122 )
123 if format == "png":
c:\programdata\anaconda3\envs\[...]\lib\site-packages\altair\utils\mimebundle.py in spec_to_mimebundle(spec, format, mode, vega_version, vegaembed_version, vegalite_version, **kwargs)
58 "see http://github.com/altair-viz/altair_saver/".format(fmt=format)
59 )
---> 60 return altair_saver.render(spec, format, mode=mode, **kwargs)
61 if format == "html":
62 html = spec_to_html(
c:\programdata\anaconda3\envs\[...]\lib\site-packages\altair_saver\_core.py in render(chart, fmts, mode, embed_options, method, **kwargs)
255 Saver = _select_saver(method, mode=mode, fmt=fmt)
256 saver = Saver(spec, mode=mode, embed_options=embed_options, **kwargs)
--> 257 mimebundle.update(saver.mimebundle(fmt))
258
259 return mimebundle
c:\programdata\anaconda3\envs\[...]\lib\site-packages\altair_saver\savers\_saver.py in mimebundle(self, fmts)
88 vegalite_version=self._package_versions["vega-lite"],
89 )
---> 90 bundle[mimetype] = self._serialize(fmt, "mimebundle")
91 return bundle
92
c:\programdata\anaconda3\envs\[...]\lib\site-packages\altair_saver\savers\_selenium.py in _serialize(self, fmt, content_type)
282
283 def _serialize(self, fmt: str, content_type: str) -> MimebundleContent:
--> 284 out = self._extract(fmt)
285 if fmt == "png":
286 assert isinstance(out, str)
c:\programdata\anaconda3\envs\[...]\lib\site-packages\altair_saver\savers\_selenium.py in _extract(self, fmt)
262
263 url = self._serve(html, js_resources)
--> 264 driver.get("about:blank")
265 driver.get(url)
266 try:
c:\programdata\anaconda3\envs\[...]\lib\site-packages\selenium\webdriver\remote\webdriver.py in get(self, url)
331 Loads a web page in the current browser session.
332 """
--> 333 self.execute(Command.GET, {'url': url})
334
335 @property
c:\programdata\anaconda3\envs\[...]\lib\site-packages\selenium\webdriver\remote\webdriver.py in execute(self, driver_command, params)
319 response = self.command_executor.execute(driver_command, params)
320 if response:
--> 321 self.error_handler.check_response(response)
322 response['value'] = self._unwrap_value(
323 response.get('value', None))
c:\programdata\anaconda3\envs\[...]\lib\site-packages\selenium\webdriver\remote\errorhandler.py in check_response(self, response)
240 alert_text = value['alert'].get('text')
241 raise exception_class(message, screen, stacktrace, alert_text)
--> 242 raise exception_class(message, screen, stacktrace)
243
244 def _value_or_default(self, obj, key, default):
InvalidSessionIdException: Message: invalid session id