pip install produces the following error on mac: error: command 'gcc' failed with exit status 1

Question

So I tried to install a package from PyPI with the following command:

sudo pip3 install switcheo

But it fails to install the package in the end.

Error checking for conflicts.
Traceback (most recent call last):
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pip/_vendor/pkg_resources/__init__.py", line 2584, in version
return self._version
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pip/_vendor/pkg_resources/__init__.py", line 2691, in __getattr__
raise AttributeError(attr)
AttributeError: _version

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pip/_internal/commands/install.py", line 503, in _warn_about_conflicts
package_set, _dep_info = check_install_conflicts(to_install)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pip/_internal/operations/check.py", line 108, in check_install_conflicts
package_set, _ = create_package_set_from_installed()
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pip/_internal/operations/check.py", line 47, in create_package_set_from_installed
package_set[name] = PackageDetails(dist.version, dist.requires())
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pip/_vendor/pkg_resources/__init__.py", line 2589, in version
raise ValueError(tmpl % self.PKG_INFO, self)
ValueError: ("Missing 'Version:' header and/or METADATA file", Unknown [unknown version] (/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages))
Installing collected packages: scrypt, neocore, switcheo

scrypt-1.2.1/libcperciva/crypto/crypto_aes.c:6:10: fatal error: 'openssl/aes.h' file not found
#include <openssl/aes.h>
         ^~~~~~~~~~~~~~~
1 error generated.
error: command 'gcc' failed with exit status 1

----------------------------------------
Command "/Library/Frameworks/Python.framework/Versions/3.7/bin/python3.7 -u -c "import setuptools, tokenize;__file__='/private/tmp/pip-install-b6w97vc0/scrypt/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" install --record /private/tmp/pip-record-qvammwag/install-record.txt --single-version-externally-managed --compile" failed with error code 1 in /private/tmp/pip-install-b6w97vc0/scrypt/

This is the full output in the terminal after running the pip install line. I found some solutions for linux, but there are not a lot of posts here for mac users.

Answer 1

I dealt with this problem for a while while trying to install another library that relies on openssl in a MacOS virtual env.

Mac has deprecated openssl in favor of their own SSL. So what you need to do is:

    brew install openssl

or if it is already installed,

    brew reinstall openssl

Now you need to to change the LD and CPP Flags. Refer to the openssl reinstall dialog. Should tell you where the commands!

openssl is keg-only, which means it was not symlinked into /usr/local, because Apple has deprecated use of OpenSSL in favor of its own TLS and crypto libraries.

If you need to have openssl first in your PATH run:

    echo 'export PATH="/usr/local/opt/openssl/bin:$PATH"' >> ~/.bash_profile

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"

For pkg-config to find openssl you may need to set:

    export PKG_CONFIG_PATH="/usr/local/opt/openssl/lib/pkgconfig"