shell module: < with ansible

Question

I want to run a command:

- name: install pip
  shell: "python <(curl https://bootstrap.pypa.io/get-pip.py)"

But achieve an error

failed: [default] => {"changed": true, "cmd": "python <(curl https://bootstrap.pypa.io/get-pip.py)", "delta": "0:00:00.002073", "end": "2014-12-03 15:52:01.780837", "rc": 2, "start": "2014-12-03 15:52:01.778764", "warnings": []}
stderr: /bin/sh: 1: Syntax error: "(" unexpected

I tried to change it to something like:

python <$(curl https://bootstrap.pypa.io/get-pip.py)

but it doesn't work. Any thoughts?

NB: this question about using < operator in shell module and I know that better to use apt for install something

Answer 1

Use command module if you actually do not need shell.

Also you will be better off using get_url module for downloading the file instead of relying on curl being installed on remote server. Recent versions of Ansible will display a warning when you try to use curl instead of get_url module also:

"warnings": ["Consider using get_url module rather than running curl"]

Here is how I would do this:

- name: Download pip installer
  get_url:
    url=https://bootstrap.pypa.io/get-pip.py
    dest=/tmp/get-pip.py
    mode=0440

- name: Install pip
  command: /usr/bin/python /tmp/get-pip.py

For extra options to get_url module visit: http://docs.ansible.com/get_url_module.html

Answer 2

EDIT: though this answers this the question I think mgsk's answer is a better answer since I agree that it's not the right way to go about it with Ansible.

This should fix your issue:

- name: install pip
  shell: "python <(curl https://bootstrap.pypa.io/get-pip.py)" executable=/bin/bash

If you are wondering the difference between these two commands:

python <(curl https://bootstrap.pypa.io/get-pip.py)
python <$(curl https://bootstrap.pypa.io/get-pip.py)

The first one uses process substitution which is a bash feature which is why you cannot use it with /bin/sh as your shell. What it's doing is taking the output of the curl command (which is a python script), writing it to a temporary file and using that file as an argument to python which takes a python script as its first argument.

The second one is an ambiguous redirect because the python script that is generated from the curl is not a file