fabric Import Error: cannot import name 'isMappingType'

Question

I came across this "ImportError: cannot import name 'isMappingType' " in the middle of process to deploy fabfile for a Django Project.

1.Here is the structure of my fabfile.py

from __future__ import with_statement from fabric.api import * from fabric.contrib.console import confirm from fabric.contrib.files import append, exists, sed  env.hosts = ["127.0.0.1"]  env.user = raw_input('Please enter user:')  def deploy():       sudo("apt-get update -y") sudo("apt-get install git -y") sudo("apt-get install postgresql libpq-dev python-dev python-pip -y")  code_dir = 'backend-directory'  if exists(code_dir):    run('cd %s && git pull' % (code_dir,))  else:    run("git clone git://serveraddress/projects/backend-directory")   with cd(code_dir):   sudo("pip install virtualenv")   run("virtualenv -p /usr/bin/python3.4 venv")   run("source venv/bin/activate")   #sudo("pip install -r requirements/dev.txt")   sudo("pip install -r requirements/production.txt")    with settings(warn_only=True):     with settings(sudo_user = 'postgres'):         sudo("psql -c " + '"CREATE USER new_user WITH PASSWORD ' + "'new_password';" + '"')         sudo("psql -c 'ALTER USER new_user CREATEDB;'")         sudo("psql -c 'CREATE DATABASE newdb;'")         sudo("psql -c 'GRANT ALL PRIVILEGES ON DATABASE 'newdb' to new_user;'")      if run("nginx -v").failed:         sudo(" apt-get install nginx -y")  code_dir = 'frontend-directory'   if exists(code_dir):    run('cd %s && git pull' % (code_dir,))  else:    run("git clone git://serveraddress/frontend-directory")   code_dir = 'backend-directory/project_site'  with cd(code_dir):      run("python manage.py makemigrations --settings=project.settings.development")     run("python manage.py migrate --settings=project.settings.development")     sudo("/etc/init.d/nginx start")      with settings(warn_only=True):       if run("find /etc/uwsgi").failed:           sudo("mkdir /etc/uwsgi")       if run("find /etc/uwsgi/vassals").failed:           sudo("mkdir /etc/uwsgi/vassals")       if run("find /etc/uwsgi/vassals/pam_uwsgi.ini").failed:           sudo("ln -s ~/backend-direcoty/project_site/pam_uwsgi.ini /etc/uwsgi/vassals/")       run("uwsgi --emperor /etc/uwsgi/vassals --uid www-data --gid www-data") 

Next, I have executed the below command in virtual env

(venv)praneeth@praneeth-Latitude-E6400 ~/wru-pam $ fab deploy 

I got the following traceback:-

Traceback (most recent call last):   File "/home/praneeth/wru-pam/venv/bin/fab", line 9, in <module>     load_entry_point('Fabric==1.10.1', 'console_scripts', 'fab')()   File "/home/praneeth/wru-pam/venv/lib/python3.4/site-packages/pkg_resources/__init__.py", line 474, in load_entry_point     return get_distribution(dist).load_entry_point(group, name)   File "/home/praneeth/wru-pam/venv/lib/python3.4/site-packages/pkg_resources/__init__.py", line 2582, in load_entry_point     return ep.load()   File "/home/praneeth/wru-pam/venv/lib/python3.4/site-packages/pkg_resources/__init__.py", line 2265, in load     return self._load()   File "/home/praneeth/wru-pam/venv/lib/python3.4/site-packages/pkg_resources/__init__.py", line 2268, in _load     module = __import__(self.module_name, fromlist=['__name__'], level=0)   File "/home/praneeth/wru-pam/venv/lib/python3.4/site-packages/fabric/main.py", line 12, in <module>     from operator import isMappingType ImportError: cannot import name 'isMappingType' 

What might be the reason for this import error ?

Answer 1

fabric doesn't support Python 3:

Fabric is a Python (2.5-2.7) library and command-line tool for streamlining the use of SSH for application deployment or systems administration tasks.

See also other points and workarounds at:

• Python 3 support for fabric
• python3 compatibility?

From what I understand, migrating to invoke is the first thing to consider.

---

Quick test demonstrating the problem:

$ python2.7 >>> from operator import isMappingType >>>  $ python3.4 >>> from operator import isMappingType Traceback (most recent call last):   File "<stdin>", line 1, in <module> ImportError: cannot import name 'isMappingType' 

Answer 2

Until Python 3 implementation of fabric is released, you can also use any of the available forks.

One of them is available in fabric3 pip package, which is compatible with Python 3:

Install it with pip install fabric3 or pip3 install fabric3

• Fabric3 on GitHub

• Fabric3 in Python Package Index

This is also mentioned in one of the answers in the following question: Python 3 support for fabric

I personally use it in a Pelican blog that uses fabric to build or serve the site. It works flawlessly for now.