Install psycopg2-binary need external libraries error.

[qulc]

on docker image: python:3.7-alpine

Collecting psycopg2-binary (from -r requirements.txt (line 6))
  Downloading https://files.pythonhosted.org/packages/17/dc/3f6bfae668594013cb9ef0cba4f4863451220944650868ad67332ca9069c/psycopg2-binary-2.7.5.tar.gz (427kB)
    Complete output from command python setup.py egg_info:
    running egg_info
    creating pip-egg-info/psycopg2_binary.egg-info
    writing pip-egg-info/psycopg2_binary.egg-info/PKG-INFO
    writing dependency_links to pip-egg-info/psycopg2_binary.egg-info/dependency_links.txt
    writing top-level names to pip-egg-info/psycopg2_binary.egg-info/top_level.txt
    writing manifest file 'pip-egg-info/psycopg2_binary.egg-info/SOURCES.txt'

    Error: pg_config executable not found.

    pg_config is required to build psycopg2 from source.  Please add the directory
    containing pg_config to the $PATH or specify the full executable path with the
    option:

        python setup.py build_ext --pg-config /path/to/pg_config build ...

    or with the pg_config option in 'setup.cfg'.

    If you prefer to avoid building psycopg2 from source, please install the PyPI
    'psycopg2-binary' package instead.

    For further information please check the 'doc/src/install.rst' file (also at
    <http://initd.org/psycopg/docs/install.html>).


    ----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-install-_c1mkb45/psycopg2-binary/

[dvarrazzo]

Wheels package are not supported by Linux Alpine. Or Linux Alpine is not supported by wheels packages. One way or the other. See #684.