`pip install flask_mysqldb` fails due to clang: error: linker command failed with exit code 1

Question

I'm trying to connect my flask app with a mysql db.

Python Version: Python 2.7.11

I'm trying to install flask_mysqldb by pip install flask_mysqldb, but I get this error:

Collecting flask_mysqldb
Requirement already satisfied: Flask>=0.10 in /Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages (from flask_mysqldb) (1.0.2)
Collecting mysqlclient (from flask_mysqldb)
  Using cached https://files.pythonhosted.org/packages/ec/fd/83329b9d3e14f7344d1cb31f128e6dbba70c5975c9e57896815dbb1988ad/mysqlclient-1.3.13.tar.gz
Requirement already satisfied: itsdangerous>=0.24 in /Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages (from Flask>=0.10->flask_mysqldb) (0.24)
Requirement already satisfied: Jinja2>=2.10 in /Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages (from Flask>=0.10->flask_mysqldb) (2.10)
Requirement already satisfied: Werkzeug>=0.14 in /Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages (from Flask>=0.10->flask_mysqldb) (0.14.1)
Requirement already satisfied: click>=5.1 in /Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages (from Flask>=0.10->flask_mysqldb) (6.7)
Requirement already satisfied: MarkupSafe>=0.23 in /Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages (from Jinja2>=2.10->Flask>=0.10->flask_mysqldb) (1.0)
Building wheels for collected packages: mysqlclient
  Running setup.py bdist_wheel for mysqlclient ... error
  Complete output from command /Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python -u -c "import setuptools, tokenize;__file__='/private/var/folders/k0/j8c755m50dndbzkv7fdtj5hh0000gn/T/pip-install-lffPsc/mysqlclient/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" bdist_wheel -d /private/var/folders/k0/j8c755m50dndbzkv7fdtj5hh0000gn/T/pip-wheel-XdyDLe --python-tag cp27:
  /Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/distutils/dist.py:267: UserWarning: Unknown distribution option: 'long_description_content_type'
    warnings.warn(msg)
  running bdist_wheel
  running build
  running build_py
  creating build
  creating build/lib.macosx-10.6-intel-2.7
  copying _mysql_exceptions.py -> build/lib.macosx-10.6-intel-2.7
  creating build/lib.macosx-10.6-intel-2.7/MySQLdb
  copying MySQLdb/__init__.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb
  copying MySQLdb/compat.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb
  copying MySQLdb/connections.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb
  copying MySQLdb/converters.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb
  copying MySQLdb/cursors.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb
  copying MySQLdb/release.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb
  copying MySQLdb/times.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb
  creating build/lib.macosx-10.6-intel-2.7/MySQLdb/constants
  copying MySQLdb/constants/__init__.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb/constants
  copying MySQLdb/constants/CLIENT.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb/constants
  copying MySQLdb/constants/CR.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb/constants
  copying MySQLdb/constants/ER.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb/constants
  copying MySQLdb/constants/FIELD_TYPE.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb/constants
  copying MySQLdb/constants/FLAG.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb/constants
  copying MySQLdb/constants/REFRESH.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb/constants
  running build_ext
  building '_mysql' extension
  creating build/temp.macosx-10.6-intel-2.7
  /usr/bin/clang -fno-strict-aliasing -fno-common -dynamic -arch i386 -arch x86_64 -g -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -Dversion_info=(1,3,13,'final',0) -D__version__=1.3.13 -I/usr/local/Cellar/mysql/8.0.11/include/mysql -I/Library/Frameworks/Python.framework/Versions/2.7/include/python2.7 -c _mysql.c -o build/temp.macosx-10.6-intel-2.7/_mysql.o
  /usr/bin/clang -bundle -undefined dynamic_lookup -arch i386 -arch x86_64 -g build/temp.macosx-10.6-intel-2.7/_mysql.o -L/usr/local/Cellar/mysql/8.0.11/lib -lmysqlclient -lssl -lcrypto -o build/lib.macosx-10.6-intel-2.7/_mysql.so
  ld: library not found for -lssl
  clang: error: linker command failed with exit code 1 (use -v to see invocation)
  error: command '/usr/bin/clang' failed with exit status 1

  ----------------------------------------
  Failed building wheel for mysqlclient
  Running setup.py clean for mysqlclient
Failed to build mysqlclient
matplotlib 1.3.1 requires nose, which is not installed.
matplotlib 1.3.1 requires tornado, which is not installed.
Installing collected packages: mysqlclient, flask-mysqldb
  Running setup.py install for mysqlclient ... error
    Complete output from command /Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python -u -c "import setuptools, tokenize;__file__='/private/var/folders/k0/j8c755m50dndbzkv7fdtj5hh0000gn/T/pip-install-lffPsc/mysqlclient/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/var/folders/k0/j8c755m50dndbzkv7fdtj5hh0000gn/T/pip-record-fvSl2V/install-record.txt --single-version-externally-managed --compile:
    /Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/distutils/dist.py:267: UserWarning: Unknown distribution option: 'long_description_content_type'
      warnings.warn(msg)
    running install
    running build
    running build_py
    creating build
    creating build/lib.macosx-10.6-intel-2.7
    copying _mysql_exceptions.py -> build/lib.macosx-10.6-intel-2.7
    creating build/lib.macosx-10.6-intel-2.7/MySQLdb
    copying MySQLdb/__init__.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb
    copying MySQLdb/compat.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb
    copying MySQLdb/connections.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb
    copying MySQLdb/converters.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb
    copying MySQLdb/cursors.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb
    copying MySQLdb/release.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb
    copying MySQLdb/times.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb
    creating build/lib.macosx-10.6-intel-2.7/MySQLdb/constants
    copying MySQLdb/constants/__init__.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb/constants
    copying MySQLdb/constants/CLIENT.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb/constants
    copying MySQLdb/constants/CR.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb/constants
    copying MySQLdb/constants/ER.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb/constants
    copying MySQLdb/constants/FIELD_TYPE.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb/constants
    copying MySQLdb/constants/FLAG.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb/constants
    copying MySQLdb/constants/REFRESH.py -> build/lib.macosx-10.6-intel-2.7/MySQLdb/constants
    running build_ext
    building '_mysql' extension
    creating build/temp.macosx-10.6-intel-2.7
    /usr/bin/clang -fno-strict-aliasing -fno-common -dynamic -arch i386 -arch x86_64 -g -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -Dversion_info=(1,3,13,'final',0) -D__version__=1.3.13 -I/usr/local/Cellar/mysql/8.0.11/include/mysql -I/Library/Frameworks/Python.framework/Versions/2.7/include/python2.7 -c _mysql.c -o build/temp.macosx-10.6-intel-2.7/_mysql.o
    /usr/bin/clang -bundle -undefined dynamic_lookup -arch i386 -arch x86_64 -g build/temp.macosx-10.6-intel-2.7/_mysql.o -L/usr/local/Cellar/mysql/8.0.11/lib -lmysqlclient -lssl -lcrypto -o build/lib.macosx-10.6-intel-2.7/_mysql.so
    ld: library not found for -lssl
    clang: error: linker command failed with exit code 1 (use -v to see invocation)
    error: command '/usr/bin/clang' failed with exit status 1

    ----------------------------------------
Command "/Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python -u -c "import setuptools, tokenize;__file__='/private/var/folders/k0/j8c755m50dndbzkv7fdtj5hh0000gn/T/pip-install-lffPsc/mysqlclient/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/var/folders/k0/j8c755m50dndbzkv7fdtj5hh0000gn/T/pip-record-fvSl2V/install-record.txt --single-version-externally-managed --compile" failed with error code 1 in /private/var/folders/k0/j8c755m50dndbzkv7fdtj5hh0000gn/T/pip-install-lffPsc/mysqlclient/

Anyone might know what might be the issue?

Answer 1

If using macOS, try xcode-select --install to install the command-line tools. If this does not work:

1.

brew install openssl

2.

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