title: psycopg2 installation for python:2.7-alpine in Docker
body: <p>To use PostgreSql in python I need to  </p>
  
  <pre><code>pip install psycopg2   
  </code></pre>
  
  <p>However, it has dependency on libpq-dev and python-dev. I wonder how can I install the dependencies in alpine? Thanks.</p>
  
  <p>Here is a Dockerfile:</p>
  
  <pre><code>FROM python:2.7-alpine
  
  RUN apk add python-dev libpq-dev
  RUN pip install psycopg2
  </code></pre>
  
  <p>and the output is:</p>
  
  <blockquote>
    <p>Step 3 : RUN apk add python-dev libpq-dev  ---> Running in
    3223b1bf7cde WARNING: Ignoring APKINDEX.167438ca.tar.gz: No such file
    or directory WARNING: Ignoring APKINDEX.a2e6dac0.tar.gz: No such file
    or directory ERROR: unsatisfiable constraints:   libpq-dev (missing):
        required by: world[libpq-dev]   python-dev (missing):
        required by: world[python-dev] ERROR: Service 'service' failed to build: The command '/bin/sh -c apk add python-dev libpq-dev' returned
    a non-zero code: 2</p>
  </blockquote>