Calibre is a very nice e-book organizer, however development documentation is, quite laconic.

Installing it for the first time turned out to be a major pain, when I installed it for the first time, as I had to do some experimentation.

I have installed calibre to a virtual environment, which also is a pain. Nevertheless here is what to do.

1. Download calibre source

   git clone https://github.com/kovidgoyal/calibre
   

2. Install all system dependencies (there quite many of them). For systems not based on Debian install them by hand.

   sudo aptitude build-dep calibre
   

3. Create a virtual environment. You'll have to pass --system-site-packages switch that allows virtualenv to use system python packages.

   cd calibre
   virtualenv -p python2 --system-site-packages venv
   source venv/bin/activate
   

4. Try to launch setup.py

   python setup.py
   Traceback (most recent call last):
     (...)
     File "/tmp/calibre2/setup/build_environment.py", line 103, in get_sip_dir
     (...)
   EnvironmentError: Failed to find the location of the PyQt5 .sip files
   

   Calibre can't find system SIP files for PyQt5, you'll need to edit setup/build_environment.py find a line that contains:

   pyqt['pyqt_sip_dir'] = get_sip_dir(sys.prefix if iswindows else os.path.join(sys.prefix, 'share', 'sip'))
   

   and replace it with:

   pyqt['pyqt_sip_dir'] = get_sip_dir(sys.prefix if iswindows else os.path.join('/usr/', 'share', 'sip'))
   

   Just replace sys.prefix to /usr, if you installed PyQt and other dependencies for calibre setup.py should work now

5. Launch python setup.py  bootstrap. This command does some stuff I don't really understand, but it is necessary to build calibre.

6. Install Calibre in development mode: python setup.py develop.

7. Now to debug Calibre you'll just need to launch venv/bin/calibre in debug mode in your favorite IDE.