The flup maintainer has dropped the ball and release a version that isn't actually python3-compatible, while also breaking python2-compatibility (see #5373). When trying to run v0.9.0 with latest flup, users report the below error.

File "/path/to/mediagoblin/lib/python3.4/site-packages/flup-1.0.3.dev20151210-py3.4.egg/flup/server/paste_factory.py", line 7, in asbool
NameError: name 'unicode' is not defined

There are alternative flup packages, such as ​https://pypi.python.org/pypi/flup6. We should try to find one that actually works and update the documentation. Until then, users can't run fcgi with python3.

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.

In the scenario where the user (me) wants to run Mediagoblin under, for example, example.com/mg/, mediagoblin makes this very difficult.

I was able to route /mgoblin_static to /mg/mgoblin_static, and was able to serve the main page under /mg, but was unable to use the site as other actions (like submitting new media) brought me back to / rooted URLs.

Official support for prefixes would be quite nice for people who want to have small setups, or don't want to have a subdomain for this program.