title: Virtualenv specific pip config files
body: <p>I need to use different pip config files depending on which project I'm currently working on. Each project pulls from a separate pypi repo and needs its own block in my .pip/pip.conf file</p>
  
  <pre><code>[global]
      timeout = 60
      index-url = &lt;my_custom_pypi_repo&gt;
  </code></pre>
  
  <p>Is there a way to provide a pip.conf file on a virtualenv specific basis?</p>
  
  <p>Ideally when I run</p>
  
  <pre><code> workon env1
   pip install env1_package
  </code></pre>
  
  <p>It would only try and download from the env1 config file</p>
  
  <p>And similar for env2
  Ideally when I run</p>
  
  <pre><code> workon env2
   pip install env2_package
  </code></pre>
  
  <p>I would like it to not request this package from the env1 pypi server.</p>