There is some non-obvious issue with external dependency in modules, which I want to say.

Case

Let you need to use some python lib, which is not available in system by default and should be installed manually.

So you just make import: 

from pandas import DataFrame

And maybe you mention required dependence in module's description. Very simple, right? But…

Issue

The case could crash odoo completely.

This is scenario when it could happen:

  • User is not going to use your module with external dependency, but your module available in Local Modules. E.g. if have a lot of modules in your git repository and user just makes git clone and add path to repo to addons-path.
  • User's system doesn't have required dependency
  • Your module has static/ folder, e.g. to place icon.png file.

Then right after restarting server, user would get error: 

2015-07-05 04:57:15,078 5760 ERROR ? werkzeug: Error on request:
Traceback (most recent call last):
  File "/usr/share/pyshared/werkzeug/serving.py", line 159, in run_wsgi
    execute(app)
  File "/usr/share/pyshared/werkzeug/serving.py", line 146, in execute
    application_iter = app(environ, start_response)
  File "/mnt/files/src/odoo/openerp/service/server.py", line 281, in app
    return self.app(e, s)
  File "/mnt/files/src/odoo/openerp/service/wsgi_server.py", line 216, in application
    return application_unproxied(environ, start_response)
  File "/mnt/files/src/odoo/openerp/service/wsgi_server.py", line 202, in application_unproxied
    result = handler(environ, start_response)
  File "/mnt/files/src/odoo/openerp/http.py", line 1244, in __call__
    self.load_addons()
  File "/mnt/files/src/odoo/openerp/http.py", line 1263, in load_addons
    m = __import__('openerp.addons.' + module)
  File "/mnt/files/src/odoo/openerp/modules/module.py", line 77, in load_module
    mod = imp.load_module('openerp.addons.' + module_part, f, path, descr)
  File "/mnt/files/git/addons-yelizariev/import_custom/__init__.py", line 1, in <module>
    import wizard
  File "/mnt/files/git/addons-yelizariev/import_custom/wizard/__init__.py", line 1, in <module>
    import upload
  File "/mnt/files/git/addons-yelizariev/import_custom/wizard/upload.py", line 14, in <module>
    from pandas import DataFrame
ImportError: No module named pandas

Suggestion

Whenever you use external dependency, put your import code in try block 

try:
    from pandas import DataFrame
except ImportError:
    pass

and add external_dependencies to module's manifest: 

"external_dependencies": {
    'python': ['pandas']
},

It will check dependencies before installing and will not raise ImportError if user doesn't use module.

links