pyzmq missing when running ipython notebook

Question

I can run iPython, but when I try to initiate a notebook I get the following error:

~  ipython notebook                   
Traceback (most recent call last):
  File "/usr/local/bin/ipython", line 8, in <module>
    load_entry_point('ipython==2.1.0', 'console_scripts', 'ipython')()
  File "/Library/Python/2.7/site-packages/ipython-2.1.0-py2.7.egg/IPython/__init__.py", line 120, in start_ipython
    return launch_new_instance(argv=argv, **kwargs)
  File "/Library/Python/2.7/site-packages/ipython-2.1.0-py2.7.egg/IPython/config/application.py", line 563, in launch_instance
    app.initialize(argv)
  File "<string>", line 2, in initialize
  File "/Library/Python/2.7/site-packages/ipython-2.1.0-py2.7.egg/IPython/config/application.py", line 92, in catch_config_error
    return method(app, *args, **kwargs)
  File "/Library/Python/2.7/site-packages/ipython-2.1.0-py2.7.egg/IPython/terminal/ipapp.py", line 321, in initialize
    super(TerminalIPythonApp, self).initialize(argv)
  File "<string>", line 2, in initialize
  File "/Library/Python/2.7/site-packages/ipython-2.1.0-py2.7.egg/IPython/config/application.py", line 92, in catch_config_error
    return method(app, *args, **kwargs)
  File "/Library/Python/2.7/site-packages/ipython-2.1.0-py2.7.egg/IPython/core/application.py", line 381, in initialize
    self.parse_command_line(argv)
  File "/Library/Python/2.7/site-packages/ipython-2.1.0-py2.7.egg/IPython/terminal/ipapp.py", line 316, in parse_command_line
    return super(TerminalIPythonApp, self).parse_command_line(argv)
  File "<string>", line 2, in parse_command_line
  File "/Library/Python/2.7/site-packages/ipython-2.1.0-py2.7.egg/IPython/config/application.py", line 92, in catch_config_error
    return method(app, *args, **kwargs)
  File "/Library/Python/2.7/site-packages/ipython-2.1.0-py2.7.egg/IPython/config/application.py", line 475, in parse_command_line
    return self.initialize_subcommand(subc, subargv)
  File "<string>", line 2, in initialize_subcommand
  File "/Library/Python/2.7/site-packages/ipython-2.1.0-py2.7.egg/IPython/config/application.py", line 92, in catch_config_error
    return method(app, *args, **kwargs)
  File "/Library/Python/2.7/site-packages/ipython-2.1.0-py2.7.egg/IPython/config/application.py", line 406, in initialize_subcommand
    subapp = import_item(subapp)
  File "/Library/Python/2.7/site-packages/ipython-2.1.0-py2.7.egg/IPython/utils/importstring.py", line 42, in import_item
    module = __import__(package, fromlist=[obj])
  File "/Library/Python/2.7/site-packages/ipython-2.1.0-py2.7.egg/IPython/html/notebookapp.py", line 39, in <module>
    check_for_zmq('2.1.11', 'IPython.html')
  File "/Library/Python/2.7/site-packages/ipython-2.1.0-py2.7.egg/IPython/utils/zmqrelated.py", line 37, in check_for_zmq
    raise ImportError("%s requires pyzmq >= %s"%(required_by, minimum_version))
ImportError: IPython.html requires pyzmq >= 2.1.11

But as far as I can see, I already have the pyzmq package installed.

~ pip install pyzmq            
Requirement already satisfied (use --upgrade to upgrade): pyzmq in /Library/Python/2.7/site-packages/pyzmq-14.3.1-py2.7-macosx-10.6-intel.egg
Cleaning up...

Answer 1

Arg. The ipython install is a little idiosyncratic. Here's what I had to do to resolve this:

$ pip uninstall ipython
$ pip install "ipython[all]"

The issue is that notebooks have their own set of dependencies, which aren't installed with pip install ipython. However, having installed ipython, pip doesn't see the need to add anything if you then try the [all] form.

As mentioned in comments for some shells (e.g. zsh) it's necessary to escape or quote the square brackets (pip install ipython\[all\] would also work).