Installing psycopg2 into virtualenv when PostgreSQ

Question

Is it possible to install psycopg2 into a virtualenv when PostgreSQL isn't installed on my development system—MacBook Pro with OS X 10.6?

When I run pip install psycopg2 from within my virtualenv, I received the error shown below.

I'm trying to connect to a legacy database on a server using Django, and I'd prefer not to install PostgreSQL on my development system if possible.

Why not install PostgreSQL?

I received an error when installing PostgreSQL using homebrew. I have Xcode4—and only Xcode4—installed on my MacBook Pro and am thinking it's related to missing gcc 4.0. However, this is a problem for another StackOverflow question.

Update 8:37 AM on April 12, 2011: I'd still like to know if this is possible without installing PostgreSQL on my MacBook Pro. However, I ran brew update and forced a reinstallation of ossp-uuid with brew install --force ossp-uuid and now brew install postgresql works. With PostgreSQL successfully installed, I was able to pip install psycopg2 from within my virtualenv.

Error from pip install psycopg2

$ pip install psycopg2
Downloading/unpacking psycopg2
  Running setup.py egg_info for package psycopg2

    Error: pg_config executable not found.

    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'.
    Complete output from command python setup.py egg_info:
    running egg_info

writing pip-egg-info/psycopg2.egg-info/PKG-INFO
writing top-level names to pip-egg-info/psycopg2.egg-info/top_level.txt
writing dependency_links to pip-egg-info/psycopg2.egg-info/dependency_links.txt
warning: manifest_maker: standard file '-c' not found

Error: pg_config executable not found.

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'.

----------------------------------------
Command python setup.py egg_info failed with error code 1
Storing complete log in /Users/matthew/.pip/pip.log

Preliminary Research

Below are the articles I read as preliminary research:

• Installing psycopg2 to use Django with PostgreSQL on OS X
• Installing psycopg2 on OS X
• Using psycopg2 with virtualenv on Ubuntu JauntyLucid
• Postgres, psycopg2, virtualenv install hints

Answer 1

Using the method you described in your April 12th update, I was able to install PostgreSQL(+1). Note that I originally was running Python 2.7.1 (32bit) and homebrew threw several errors and warnings regarding using a 32bit version of Python. I have since switched the 64/32 bit version of 2.7.1 and it works like a champ.

Regarding the pyscopg2, I was able to install it into my virtual environment from source by editing setup.cfg. I set pg_config to correct path inside homebrew's Cellar (pg_config=/usr/local/Cellar/postgresql/9.0.4/bin/pg_config). After saving the changes, I ran python setup.py install with zero issues. It's worth noting that I did not set the Mac's default python setting to 32 bit. I used the new 64 bit from start to finish.

After looking over some of the documentation, I think if I added homebrew's postgresql path to the system path I could have used pip to install it.

Reference:
http://favosdream.blogspot.com/2009/09/make-psycopg2-and-readline-work-in-snow.html

Update 6-8-2011:
While porting a project written on OS X to Windows 7, I found out that I had to install PostgreSQL on Windows as well. This ended up creating another user on my start up screen and other things that I just didn't like. While doing some digging I found Windows drivers for PostgreSQL here. I have since uninstalled the full PostgreSQL and installed the ODBC drivers which, thus far, work great.

To address the original question, after doing a bit more digging I think I found the equivalent ODBC for OS X here. I have not had a chance to try them out, but the concept works very well on Windows 7. I will update this when I get a chance to try them out. Until then, I hope this helps.

Answer 2

psycopg depends on pg_config command, and if you don't have it, you can't install psycopg.

If system installation is a problem to you, why don't you try compiling PostgreSQL and including generated bin files in your $PATH? Like:

export PATH=/path/to/compiled/postgresql/bin:"$PATH"
pip install psycopg2

Answer 3

You need to install the python-dev package in order to make use of python extensions such as psycopg2. I don't know how to install packages in mac but I run the following commands to install a python package on my Ubuntu machine.

sudo apt-get install python-dev 

Or

sudo apt-get install python3-dev

if you are using Python3.x.

Once the installation is finished run the following command within your virtual environment.

pip install psycopg2

Answer 4

As I never needed to install postgresql database on this server I installed the following libraries on Ubuntu 14_04 version before running pip install psycopg2 on the same server

apt-get install libpq-dev python-dev and then executed pip install psycopg2 within virtual env.

Output Collecting psycopg2 Using cached psycopg2-2.6.1.tar.gz Building wheels for collected packages: psycopg2 Running setup.py bdist_wheel for psycopg2 Stored in directory: /root/.cache/pip/wheels/e2/9a/5e/7b620848bbc7cfb9084aafea077be11618c2b5067bd532f329 Successfully built psycopg2 Installing collected packages: psycopg2 Successfully installed psycopg2-2.6.1

Answer 5

You don't need the complete PostgreSQL installed: you only need the client side libraries.

Answer 6

apt-get install libpq-dev

helped me in debian squeeze too . After that do pip install psycopg2. I faced problem of pg_config not found problem when i was setting up my environment on heroku , now its working fine .