I run

sudo pip install psycopg2

and I get a bunch of output that looks like:

cc -DNDEBUG -g -fwrapv -Os .....
.....
cc -DNDEBUG -g -fwrapv -Os .....
.....

And at the end it says:

ld: library not found for -lssl

clang: error: linker command failed with exit code 1 (use -v to see invocation)

error: command 'cc' failed with exit status 1

----------------------------------------
Cleaning up...
Command /usr/bin/python -c "import setuptools, tokenize;__file__='/private/var/folders/bz/pvj1g9xj16d10pjjgbrfl3fw0000gn/T/pip_build_root/psycopg2/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /var/folders/bz/pvj1g9xj16d10pjjgbrfl3fw0000gn/T/pip-uE3thn-record/install-record.txt --single-version-externally-managed --compile failed with error code 1 in /private/var/folders/bz/pvj1g9xj16d10pjjgbrfl3fw0000gn/T/pip_build_root/psycopg2
Storing debug log for failure in /Users/Tyler/Library/Logs/pip.log

Running easy_install or doing it from source both give me the same error at the end (the part about library not found for -lssl).

Running brew install (or upgrade) openssl yields the below

$ brew upgrade openssl
Error: openssl-1.0.1h already installed

Can anyone help me out?

For anyone looking for a solution for this on macOS Sierra 10.12 (or later, most likely): I fixed this by installing the command line tools:

xcode-select --install

After that, pip install psycopg2 should work.

If it doesn’t, you could also try to link against brew’s openssl:

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

with openssl installed via brew. Note that the brew link openssl --force does not work anymore:

$ brew link openssl --force                                                                                 17.5s
Warning: Refusing to link: openssl
Linking keg-only openssl means you may end up linking against the insecure,
deprecated system OpenSSL while using the headers from Homebrew's openssl.
Instead, pass the full include/library paths to your compiler e.g.:
  -I/usr/local/opt/openssl/include -L/usr/local/opt/openssl/lib

As @macho points out below if this still does not work, you might need to use the --no-cache option of pip, e.g.

env LDFLAGS="-I/usr/local/opt/openssl/include -L/usr/local/opt/openssl/lib" pip --no-cache install psycopg2

I had OpenSSL installed from brew (brew install openssl)

The following worked for me:

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

When running brew link openssl I get the following message:

$ brew link openssl
Warning: Refusing to link: openssl
Linking keg-only openssl means you may end up linking against the insecure,
deprecated system OpenSSL while using the headers from Homebrew's openssl.
Instead, pass the full include/library paths to your compiler e.g.:
  -I/usr/local/opt/openssl/include -L/usr/local/opt/openssl/lib

Following this advice here’s the pip command you need to use:

$ pip install -r requirements.txt --global-option=build_ext --global-option="-I/usr/local/opt/openssl/include" --global-option="-L/usr/local/opt/openssl/lib"

What worked for me was the hint provided in the command to link openssl,

$ brew link openssl
Warning: Refusing to link macOS-provided software: openssl
If you need to have openssl first in your PATH run:
  echo 'export PATH="/usr/local/opt/openssl/bin:$PATH"' >> ~/.zshrc

For compilers to find openssl you may need to set:
  export LDFLAGS="-L/usr/local/opt/openssl/lib"
  export CPPFLAGS="-I/usr/local/opt/openssl/include"

$ export LDFLAGS="-L/usr/local/opt/openssl/lib"
$ export CPPFLAGS="-I/usr/local/opt/openssl/include"

$ pip install psycopg2
Collecting psycopg2
  Using cached https://files.pythonhosted.org/packages/23/7e/93c325482c328619870b6cd09370f6dbe1148283daca65115cd63642e60f/psycopg2-2.8.2.tar.gz
Installing collected packages: psycopg2
  Running setup.py install for psycopg2 ... done
Successfully installed psycopg2-2.8.2

On mojave I added these to the .bash_profile

export PATH="/usr/local/opt/openssl/bin:$PATH"
export LDFLAGS="-L/usr/local/opt/curl/lib -L/usr/local/opt/openssl/lib"
export CPPFLAGS="-I/usr/local/opt/curl/include -I/user/local/opt/openssl/include"

was then able to install psycopg 2.8.3 in a python 3.7.4 virtualenv.

This after reinstalling xcode and the command line tools.

All the answers above helped!

With MacOS Catalina 10.15.4, the following was the only command that worked for me:

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

This’s the problem of new macOs version, where pip cannot install cryptography. What fixed my problem is to provide the env to the install command:

brew install openssl
env LDFLAGS="-L$(brew --prefix openssl)/lib" CFLAGS="-I$(brew --prefix openssl)/include" <YOUR COMMAND HERE>

You can replace <YOUR COMMAND HERE> with pip install cryptography, or pip install <SOMETHING THAT REQUIRES cryptography> for example.

Credit to this article: Fixing macOS Sierra fatal error: ‘openssl/opensslv.h’ or ‘openssl/aes.h’ file not found

Using Fish, the following two commands solved this issue for me after installing OpenSSL with Homebrew.

set -gx LDFLAGS "-L/usr/local/opt/openssl/lib"
set -gx CPPFLAGS "-I/usr/local/opt/openssl/include"

Use brew info openssl to get up-to-date info.

Recently had this problem in High Sierra, having just installed Python 3.7 in a virtualenv.

The solution is to use a later version of psycopg2. Version 2.7.7 worked, where 2.7.1 did not.

Instead of installing psycopg2, install psycopg2-binary, from the same authors:

pip install psycopg2-binary

This is what the documentation says about this PyPI package:

You can […] obtain a stand-alone package, not requiring a compiler or external libraries, by installing the psycopg2-binary package from PyPI:

$ pip install psycopg2-binary

The binary package is a practical choice for development and testing but in production it is advised to use the package built from sources.

I was having this issue on Mojave. Mojave does not create a /usr/include directory, which psycopg2 needs to install. This was not obvious. I found the solution here: How to update Xcode from command line, which references: https://forums.developer.apple.com/thread/104296

I had this same error and got it to resolve after I pip installed cython

Running PyCharm from conda environment, solved my issue using:

--> conda install psycopg2
The following packages will be UPDATED: ...

...
Proceed ([y]/n)? 
--> y
--> pip3 install psycopg2
Installing collected packages: psycopg2
Running setup.py install for psycopg2 ... done
Successfully installed psycopg2-2.8.4

'''

I installed OpenSSL using MacPorts therefore directories are not like those of Brew.

sudo port install openssl

I found the directories by doing:

port contents openssl | grep lib
port contents openssl | grep include

Then I exported the variables:

export LDFLAGS="-L/opt/local/lib"
export CPPFLAGS="-I/opt/local/include/openssl"

You might also have to:

xcode-select --install

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

worked for me

I’ve managed to fix it by using:

brew unlink openssl && brew link openssl --force

I am not sure how this differs from the brew uninstall/upgrades that I did on OpenSSL in prior attempts I’ve made. My assumption is that these operations left some of the “faulty” shared libraries which were preventing this from working. Note that this also fixed issues with installing python cryptography module.