“Failed building wheel for psycopg2” - MacOSX using virtualenv and pip

Question

I\'m attempting to make a website with a few others for the first time, and have run into a weird error when trying to use Django/Python/VirtualEnv. I\'ve found solutions to

Answer 1

For MacOS users, this question has the correct solution:

install command line tools if necessary:

xcode-select --install

then

env LDFLAGS="-I/usr/local/opt/openssl/include -L/usr/local/opt/openssl/lib" pip install psycopg2

Answer 2

I was also getting same error. Using Python 3.7.3 and pip 19.1.1.

I used following command.

pip install psycopg2-binary==2.8.3

Answer 3

For MacOS users

After trying all the above methods (which did not work for me on MacOS 10.14), that one worked :

• Install openssl with brew install openssl if you don't have it already.
• add openssl path to LIBRARY_PATH :

export LIBRARY_PATH=$LIBRARY_PATH:/usr/local/opt/openssl/lib/

• install psycopg2 with pip pip3 install psycopg2

Answer 4

For Mac OS X users:

1. First check your postgresql path by running this command in terminal:

pg_config

If this fails lookup how to add pg_config to your path.

2. Next install Xcode Tools by running this command in terminal:

xcode-select --install

If you have both those sorted out now try to install psycopg2 again

Answer 5

Is your error message complete? the most encountered reason for failing to install psycopg2 on mac from pip is pg_config is not in path. by the way, using macports or fink to install psycopg2 is more recommended way, so you don't have to worry about pg_config, libpq-dev and python-dev.

plus, are using Python 3.5? then upgrage your wheel to > 0.25.0 using pip.

Answer 6

TDLR

If you aren't used to installing Python C-extensions, and psycopg2 isn't a core part of your work, try

pip install psycopg2-binary

Building Locally

psycopg2 is a C-extension, so it requires compilation when being installed by pip. The Build Prerequisites section of the docs explain what must be done to make installation via pip possible. In summary (for psycopg 2.8.5):

• a C compiler must be installed on the machine
• the Python header files must be installed
• the libpq header files must be installed
• the pg_config program must be installed (it usually comes with the libpq headers) and on $PATH.

With these prerequisites satisfied, pip install psycopg2 ought to succeed.

Installing pre-compiled wheels

Alternatively, pip can install pre-compiled binaries so that compilation (and the associated setup) is not required. They can be installed like this:

pip install psycopg2-binary

The docs note that

The psycopg2-binary package is meant for beginners to start playing with Python and PostgreSQL without the need to meet the build requirements.

but I would suggest that psycopg2-binary is often good enough for local development work if you are not using psycopg2 directly, but just as a dependency.

Concluding advice

Read the informative installation documentation, not only to overcome installation issues but also the impact of using the pre-compiled binaries in some scenarios.