libpq native extension crashed on ruby on rails

Question

i'm trying to install pg ( postgreSQL gem ) on my Mac and got this error

  Installing pg 0.18.1 with native extensions

  Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

  current directory: /private/var/folders/h5/slvxw4xd0d30dxzxf8vg5c600000gp/T/bundler20160302-7420-1orffo8pg-0.18.1/gems/pg-0.18.1/ext
  /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/bin/ruby -r ./siteconf20160302-7420-h4zq8h.rb extconf.rb
  checking for pg_config... yes
  Using config values from /usr/local/bin/pg_config
    checking for libpq-fe.h... yes
    checking for libpq/libpq-fs.h... yes
    checking for pg_config_manual.h... yes
    checking for PQconnectdb() in -lpq... no
    checking for PQconnectdb() in -llibpq... no
    checking for PQconnectdb() in -lms/libpq... no
    Can't find the PostgreSQL client library (libpq)
  *** extconf.rb failed ***
  Could not create Makefile due to some reason, probably lack of necessary
  libraries and/or headers.  Check the mkmf.log file for more details.  You may
  need configuration options.

  Provided configuration options:
    --with-opt-dir
    --without-opt-dir
    --with-opt-include
    --without-opt-include=${opt-dir}/include
    --with-opt-lib
    --without-opt-lib=${opt-dir}/lib
    --with-make-prog
    --without-make-prog
    --srcdir=.
    --curdir
    --ruby=/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/bin/ruby
    --with-pg
    --without-pg
    --enable-windows-cross
    --disable-windows-cross
    --with-pg-config
    --without-pg-config
    --with-pg_config
    --without-pg_config
    --with-pg-dir
    --without-pg-dir
    --with-pg-include
    --without-pg-include=${pg-dir}/include
    --with-pg-lib
    --without-pg-lib=${pg-dir}/
    --with-pqlib
    --without-pqlib
    --with-libpqlib
    --without-libpqlib
    --with-ms/libpqlib
    --without-ms/libpqlib

  To see why this extension failed to compile, please check the mkmf.log which can be found here:

    /var/folders/h5/slvxw4xd0d30dxzxf8vg5c600000gp/T/bundler20160302-7420-1orffo8pg-0.18.1/extensions/universal-darwin-15/2.0.0/pg-0.18.1/mkmf.log

  extconf failed, exit code 1

  Gem files will remain installed in /var/folders/h5/slvxw4xd0d30dxzxf8vg5c600000gp/T/bundler20160302-7420-1orffo8pg-0.18.1/gems/pg-0.18.1 for inspection.
  Results logged to /var/folders/h5/slvxw4xd0d30dxzxf8vg5c600000gp/T/bundler20160302-7420-1orffo8pg-0.18.1/extensions/universal-darwin-15/2.0.0/pg-0.18.1/gem_make.out

So i check all my packages installed :

Mac OS X El Capitan v10.11.3

$ruby -v
-> ruby 2.0.0p645 (2015-04-13 revision 50299) [universal.x86_64-darwin15]
$rails -v    
-> Rails 4.2.5.1
$brew -v
-> Homebrew 0.9.5 (git revision c9aee; last commit 2016-02-15)
$benv -v
-> rbenv 0.4.0
$postgres -V    
-> postgres (PostgreSQL) 9.4.5
$xcode-select -p
/Applications/Xcode.app/Contents/Developer
$gcc --version
-> Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
    Apple LLVM version 7.0.2 (clang-700.1.81)
    Target: x86_64-apple-darwin15.3.0
    Thread model: posix

I don't want to have installed postgre via browser app download, i want it via brew package, so there is a way to install the annoying libpq ?

Answer 1

You shouldn't need libpq for postgres to work with ruby on Mac OSX.

If you installed postgres with Postgres.app, you sould be able to remove it by simply moving postgres.app to the trash can and deleting the data directory from ~/Library/Application Support/Postgres (only if you want to delete all existing postgres databases on your machine)

Then, with homebrew, install postgres via brew install postgresql. The pg gem should work directly with the postgres Homebrew install.