pip install flask not working

Question

• Raspberry Pi 3
• OS - Noobs
• Default Python Version - 2.7.9. I have also installed Python 3.6

I want to use the Flask Web Framework for a project on my RasPi 3. I have installed the latest version of pip. I am trying to use pip install flask. But it doesn't seem to work & gives the following error:

 Collecting flask
  Using cached Flask-0.12.2-py2.py3-none-any.whl
Collecting Jinja2>=2.4 (from flask)
  Using cached Jinja2-2.9.6-py2.py3-none-any.whl
Collecting Werkzeug>=0.7 (from flask)
  Using cached Werkzeug-0.12.2-py2.py3-none-any.whl
Collecting click>=2.0 (from flask)
  Using cached click-6.7-py2.py3-none-any.whl
Collecting itsdangerous>=0.21 (from flask)
Collecting MarkupSafe>=0.23 (from Jinja2>=2.4->flask)
Installing collected packages: MarkupSafe, Jinja2, Werkzeug, click, itsdangerous, flask
Exception:
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/pip/basecommand.py", line 215, in main
    status = self.run(options, args)
  File "/usr/local/lib/python2.7/dist-packages/pip/commands/install.py", line 342, in run
    prefix=options.prefix_path,
  File "/usr/local/lib/python2.7/dist-packages/pip/req/req_set.py", line 784, in install
    **kwargs
  File "/usr/local/lib/python2.7/dist-packages/pip/req/req_install.py", line 851, in install
    self.move_wheel_files(self.source_dir, root=root, prefix=prefix)
  File "/usr/local/lib/python2.7/dist-packages/pip/req/req_install.py", line 1064, in move_wheel_files
    isolated=self.isolated,
  File "/usr/local/lib/python2.7/dist-packages/pip/wheel.py", line 345, in move_wheel_files
    clobber(source, lib_dir, True)
  File "/usr/local/lib/python2.7/dist-packages/pip/wheel.py", line 316, in clobber
    ensure_dir(destdir)
  File "/usr/local/lib/python2.7/dist-packages/pip/utils/__init__.py", line 83, in ensure_dir
    os.makedirs(path)
  File "/usr/lib/python2.7/os.py", line 157, in makedirs
    mkdir(name, mode)
OSError: [Errno 13] Permission denied: '/usr/local/lib/python2.7/dist-packages/MarkupSafe-1.0.dist-info'

Answer 1

Looks like you are running pip as an unprivileged user. You can either do

sudo pip install flask

to install it as root for everyone, or

pip install --user flask

to install it just for the current user.