2017-02-09 12:00:03,940 INFO    [mediagoblin.app] GNU MediaGoblin 0.9.0 main server starting
0:00:00.000209241 32335 0x8110be20 INFO                GST_INIT gst.c:510:init_pre: Initializing GStreamer Core Library version 1.10.2                                    
0:00:00.000364217 32335 0x8110be20 INFO                GST_INIT gst.c:511:init_pre: Using library installed in /usr/lib/i386-linux-gnu                                    
0:00:00.000406750 32335 0x8110be20 INFO                GST_INIT gst.c:522:init_pre: Linux gybs 4.5.0-2-686-pae #1 SMP Debian 4.5.5-1 (2016-05-29) i686                    
0:00:00.000882921 32335 0x8110be20 INFO                GST_INIT gstmessage.c:126:_priv_gst_message_initialize: init messages                                              
0:00:00.001508200 32335 0x8110be20 INFO                GST_INIT gstcontext.c:83:_priv_gst_context_initialize: init contexts                                               
0:00:00.001947705 32335 0x8110be20 INFO      GST_PLUGIN_LOADING gstplugin.c:316:_priv_gst_plugin_initialize: registering 0 static plugins                                 
0:00:00.002317789 32335 0x8110be20 INFO      GST_PLUGIN_LOADING gstplugin.c:224:gst_plugin_register_static: registered static plugin "staticelements"                     
0:00:00.002355433 32335 0x8110be20 INFO      GST_PLUGIN_LOADING gstplugin.c:226:gst_plugin_register_static: added static plugin "staticelements", result: 1               
0:00:00.002409699 32335 0x8110be20 INFO            GST_REGISTRY gstregistry.c:1738:ensure_current_registry: reading registry cache: /var/lib/mediagoblin/.cache/gstreamer-
1.0/registry.i686.bin
0:00:00.095080673 32335 0x8110be20 INFO            GST_REGISTRY gstregistrybinary.c:619:priv_gst_registry_binary_read_cache: loaded /var/lib/mediagoblin/.cache/gstreamer-
1.0/registry.i686.bin in 0.092629 seconds
0:00:00.095355425 32335 0x8110be20 INFO            GST_REGISTRY gstregistry.c:1594:scan_and_update_registry: Validating plugins from registry cache: /var/lib/mediagoblin/
.cache/gstreamer-1.0/registry.i686.bin
0:00:00.100099534 32335 0x8110be20 INFO            GST_REGISTRY gstregistry.c:1696:scan_and_update_registry: Registry cache has not changed                               
0:00:00.100208555 32335 0x8110be20 INFO            GST_REGISTRY gstregistry.c:1773:ensure_current_registry: registry reading and updating done, result = 1                
0:00:00.100290687 32335 0x8110be20 INFO                GST_INIT gst.c:720:init_post:GLib runtime version: 2.50.2                                                          
0:00:00.100372330 32335 0x8110be20 INFO                GST_INIT gst.c:722:init_post:GLib headers version: 2.50.2                                                          
0:00:00.100411441 32335 0x8110be20 INFO                GST_INIT gst.c:723:init_post:initialized GStreamer successfully                                                    
/srv/mediagoblin/mediagoblin/media_types/video/transcoders.py:37: PyGIWarning: GstPbutils was imported without specifying a version first. Use gi.require_version('GstPbutils', '1.0') before import to ensure that the right version gets loaded.
  from gi.repository import GstPbutils
2017-02-09 12:00:04,512 INFO    [mediagoblin.app] Setting up plugins.                                                                                                     
/srv/mediagoblin/mediagoblin/media_types/video/transcoders.pyc changed; reloading...
-------------------- Restarting --------------------
2017-02-09 12:08:09,263 INFO    [mediagoblin.app] GNU MediaGoblin 0.9.0 main server starting
0:00:00.000216085  1662 0x82728e20 INFO                GST_INIT gst.c:510:init_pre: Initializing GStreamer Core Library version 1.10.2
0:00:00.000342705  1662 0x82728e20 INFO                GST_INIT gst.c:511:init_pre: Using library installed in /usr/lib/i386-linux-gnu
0:00:00.000462970  1662 0x82728e20 INFO                GST_INIT gst.c:522:init_pre: Linux gybs 4.5.0-2-686-pae #1 SMP Debian 4.5.5-1 (2016-05-29) i686
0:00:00.000963094  1662 0x82728e20 INFO                GST_INIT gstmessage.c:126:_priv_gst_message_initialize: init messages
0:00:00.001626016  1662 0x82728e20 INFO                GST_INIT gstcontext.c:83:_priv_gst_context_initialize: init contexts
0:00:00.002102186  1662 0x82728e20 INFO      GST_PLUGIN_LOADING gstplugin.c:316:_priv_gst_plugin_initialize: registering 0 static plugins
0:00:00.002502090  1662 0x82728e20 INFO      GST_PLUGIN_LOADING gstplugin.c:224:gst_plugin_register_static: registered static plugin "staticelements"
0:00:00.002603288  1662 0x82728e20 INFO      GST_PLUGIN_LOADING gstplugin.c:226:gst_plugin_register_static: added static plugin "staticelements", result: 1
0:00:00.002720131  1662 0x82728e20 INFO            GST_REGISTRY gstregistry.c:1738:ensure_current_registry: reading registry cache: /var/lib/mediagoblin/.cache/gstreamer-
1.0/registry.i686.bin
0:00:00.094591523  1662 0x82728e20 INFO            GST_REGISTRY gstregistrybinary.c:619:priv_gst_registry_binary_read_cache: loaded /var/lib/mediagoblin/.cache/gstreamer-
1.0/registry.i686.bin in 0.091770 seconds
0:00:00.094833519  1662 0x82728e20 INFO            GST_REGISTRY gstregistry.c:1594:scan_and_update_registry: Validating plugins from registry cache: /var/lib/mediagoblin/
.cache/gstreamer-1.0/registry.i686.bin
0:00:00.099793211  1662 0x82728e20 INFO            GST_REGISTRY gstregistry.c:1696:scan_and_update_registry: Registry cache has not changed
0:00:00.099899298  1662 0x82728e20 INFO            GST_REGISTRY gstregistry.c:1773:ensure_current_registry: registry reading and updating done, result = 1
0:00:00.099939876  1662 0x82728e20 INFO                GST_INIT gst.c:720:init_post:GLib runtime version: 2.50.2
0:00:00.100021519  1662 0x82728e20 INFO                GST_INIT gst.c:722:init_post:GLib headers version: 2.50.2
0:00:00.100061118  1662 0x82728e20 INFO                GST_INIT gst.c:723:init_post:initialized GStreamer successfully
2017-02-09 12:08:09,826 INFO    [mediagoblin.app] Setting up plugins.

mediagoblin 0.9, media-type video enabled

Steps to reproduce

1. Start a local ./lazyserver.sh .
2. Access an uploaded video file.

The page is shown correctly, it is possible to watch the video, but the log reads:

2017-02-09 09:12:15,067 ERROR   [waitress] Exception when serving /mgoblin_media/media_entries/13/....webm           
Traceback (most recent call last):
  File "/srv/mediagoblin.latest/lib/python2.7/site-packages/waitress-1.0.2-py2.7.egg/waitress/channel.py", line 338, in service                                           
    task.service()
  File "/srv/mediagoblin.latest/lib/python2.7/site-packages/waitress-1.0.2-py2.7.egg/waitress/task.py", line 169, in service                                              
    self.execute()
  File "/srv/mediagoblin.latest/lib/python2.7/site-packages/waitress-1.0.2-py2.7.egg/waitress/task.py", line 437, in execute                                              
    self.write(chunk)
  File "/srv/mediagoblin.latest/lib/python2.7/site-packages/waitress-1.0.2-py2.7.egg/waitress/task.py", line 303, in write                                                
    channel.write_soon(towrite)
  File "/srv/mediagoblin.latest/lib/python2.7/site-packages/waitress-1.0.2-py2.7.egg/waitress/channel.py", line 320, in write_soon                                        
    self.outbufs[-1].append(data)
  File "/srv/mediagoblin.latest/lib/python2.7/site-packages/waitress-1.0.2-py2.7.egg/waitress/buffers.py", line 242, in append
    buf.append(s)
  File "/srv/mediagoblin.latest/lib/python2.7/site-packages/waitress-1.0.2-py2.7.egg/waitress/buffers.py", line 53, in append
    read_pos = file.tell()
ValueError: I/O operation on closed file

The error was solved by running ./bin/gmg dbupdate

"bug tracker" and "devel mailing list" should be direct links that the reader can follow since the sentences are call to action. Patch will follow.