Failing installing pg gem, "mkmf.rb can't find header files for ruby" (Mac OSX 10.6.5)

I just upgraded to Rails 3 and had a bit of a mess with MacPorts, gems and databases to sort out. I threw out all the gems and installed them fresh. Everything seems to be OK except for the requirement of the pg gem.

After creating a new Rails 3 project, prepared for PostgreSQL, the server would not start, complaining about the missing pg gem. Doing bundle install, it chugged along for a while and, of course, fails on the pg gem.

Installing pg (0.10.0) with native extensions /Library/Ruby/Site/1.8/rubygems/installer.rb:483:in `build_extensions': ERROR: Failed to build gem native extension. (Gem::Installer::ExtensionBuildError)

/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby extconf.rb 
mkmf.rb can't find header files for ruby at /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/ruby.h


Gem files will remain installed in /Library/Ruby/Gems/1.8/gems/pg-0.10.0 for inspection.
Results logged to /Library/Ruby/Gems/1.8/gems/pg-0.10.0/ext/gem_make.out
    from /Library/Ruby/Site/1.8/rubygems/installer.rb:446:in `each'
    from /Library/Ruby/Site/1.8/rubygems/installer.rb:446:in `build_extensions'
    from /Library/Ruby/Site/1.8/rubygems/installer.rb:198:in `install'
    from /Library/Ruby/Gems/1.8/gems/bundler-1.0.7/lib/bundler/source.rb:95:in `install'
    from /Library/Ruby/Gems/1.8/gems/bundler-1.0.7/lib/bundler/installer.rb:55:in `run'
    from /Library/Ruby/Gems/1.8/gems/bundler-1.0.7/lib/bundler/spec_set.rb:12:in `each'
    from /Library/Ruby/Gems/1.8/gems/bundler-1.0.7/lib/bundler/spec_set.rb:12:in `each'
    from /Library/Ruby/Gems/1.8/gems/bundler-1.0.7/lib/bundler/installer.rb:44:in `run'
    from /Library/Ruby/Gems/1.8/gems/bundler-1.0.7/lib/bundler/installer.rb:8:in `install'
    from /Library/Ruby/Gems/1.8/gems/bundler-1.0.7/lib/bundler/cli.rb:225:in `install'
    from /Library/Ruby/Gems/1.8/gems/bundler-1.0.7/lib/bundler/vendor/thor/ta开发者_Python百科sk.rb:22:in `send'
    from /Library/Ruby/Gems/1.8/gems/bundler-1.0.7/lib/bundler/vendor/thor/task.rb:22:in `run'
    from /Library/Ruby/Gems/1.8/gems/bundler-1.0.7/lib/bundler/vendor/thor/invocation.rb:118:in `invoke_task'
    from /Library/Ruby/Gems/1.8/gems/bundler-1.0.7/lib/bundler/vendor/thor.rb:246:in `dispatch'
    from /Library/Ruby/Gems/1.8/gems/bundler-1.0.7/lib/bundler/vendor/thor/base.rb:389:in `start'
    from /Library/Ruby/Gems/1.8/gems/bundler-1.0.7/bin/bundle:13
    from /usr/bin/bundle:19:in `load'
    from /usr/bin/bundle:19

The most common suggestion I have found on forums and blogs is to (re)install the XCode developer tools. They were already there, but I reinstalled them anyway, with no better outcome than the above.

which ruby says /usr/bin/ruby, and ruby -v says ruby 1.8.7 (2009-06-12 patchlevel 174) [universal-darwin10.0], if there's any clue there.

Pointers are welcome. Any missing information that would help figuring this out, I'll gladly and promptly provide!

---

I downloaded XCode since the DVD version is said to be broken and things went better for a while. bundle install started talking about "archflags" instead, so I did:

sudo env ARCHFLAGS="-arch i386" bundle install

and things seemed to go fine, until starting Rails barfed, saying:

/Library/Ruby/Gems/1.8/gems/pg-0.10.0/lib/pg_ext.bundle: dlopen(/Library/Ruby/Gems/1.8/gems/pg-0.10.0/lib/pg_ext.bundle, 9): no suitable image found.  Did find: (LoadError)
    /Library/Ruby/Gems/1.8/gems/pg-0.10.0/lib/pg_ext.bundle: mach-o, but wrong architecture - /Library/Ruby/Gems/1.8/gems/pg-0.10.0/lib/pg_ext.bundle

Grappling for anything, I tried bundle install with archflags set to -arch x86_64, but it didn't go well:

*** Your PostgreSQL installation doesn't seem to have an architecture in common with the running ruby interpreter ([] vs. ["x86_64"])
I'll continue anyway, but if it fails, try setting ARCHFLAGS.
[...]
Can't find the PostgreSQL client library (libpq)
*** extconf.rb failed ***

Is libpq something I now have to supply a path to via some flags? Or am I completely out to lunch?

---

I encountered this error when I tried to install rails by gem on CentOS 6.3.

After googling a bit, I found a quick fix: installing the ruby-devel package.

sudo yum install ruby-devel

After that, everything worked fine.

---

Generally the gem bundles for Postgres want to know where pg_config is hiding so they can ask about the Postgres installation.

Use locate pg_config to see if your Mac knows where it's hiding.

I installed a copy of Postgres using mappstack, so my Mac says there's a copy at:

/Applications/mappstack-1.2-3/postgresql/bin/pg_config

and another at:

/Library/PostgreSQL/9.0/bin/pg_config

I don't remember installing the one at /Library/PostgreSQL/9.0, so it might have been preinstalled by Snow Leopard, or I did it when under the influence of too much work, possibly using the Postgres installer from EnterpriseDB.

Once you've found the location of pg_config try adding that directory to the start of your PATH and then rerun the gem install. Or use:

export SQL_PATH=/Library/PostgreSQL/9.0
gem install pg -- --with-pg-config=$SQL_PATH/bin/pg_config

and try installing. If either of those work you're done. Otherwise...

The next thing the installers might want are access to the Postgres headers, so you look in the parent of the bin directories, and see if you can find an include directory.

After that, look in that directory for a lib directory. Once you know those locations you should have all you need to set your environment variables to let the installer complete. You'll need to read the README or INSTALL file of the installer and see what needs to be set up. You'll be configuring:

export include_dir=$SQL_PATH/include/
export     lib_dir=$SQL_PATH/lib/
gem install pg -- --with-pgsql-include-dir=$include_dir --with-pgsql-lib-dir=$lib_dir

Hopefully that'll all help. I have Rails 3 and my Postgres running fine, using the mappstack Postgres and the EnterpriseDB versions, so the above info should get you there.

---

This worked for me on OS X 10.6.6, with PostgreSQL 9.0.1 installed from the source code:

export PATH=/usr/local/psql/bin:$PATH
export ARCHFLAGS='-arch x86_64'
gem install pg

You'll likely need to edit that PATH to match your postgres install location.

---

I've got postgres 1.9.0 installed via macports. OS X 10.5 PPC

This worked for me:

gem install pg -- --with-pg-lib=/opt/local/lib/postgresql90 --with-pg-include=/opt/local/include/postgresql90

Good luck!

---

Generally the gem bundles for Postgres want to know where pg_config is hiding . . .

Right - this could be the trick. If you just installed PostgreSQL and added it to your path, and did "bundle install" in an old shell, it won't be able to find pg_config. If that's the case, just get a new shell and try again. Otherwise, follow the steps above to find it and get it seen by bundler.

The macports install for postgresql83 works fine and plays nicely with rails right out of the box - that's another way to do it.

---

I just spent a good deal of time getting this to work tonight. I saw a similar error to this:

Can't find the PostgreSQL client library (libpq)
*** extconf.rb failed ***

I tried different gem install variations:

gem install pg -- --with-pg-config=/Library/PostgreSQL/9.1/bin/ --with-pg-lib=/Library/PostgreSQL/9.1/lib/ --with-pg-include=/Library/PostgreSQL/9.1/include/

But finally what worked for me was:

gem install pg -- --with-pg-dir=/Library/PostgreSQL/9.1/

Also, before that I updated rvm (rvm get head) and reinstalled ruby (rvm --force install 1.9.2). Not sure if this helped or not, but it might be worth trying if you still hit issues

---

You might want to try going with homebrew for installing postgres (brew install postgres) and Ruby Version Manager for installing and maintaining ruby and ruby gems.

It'll leave your default versions (installed with OSX) untouched and give you more flexibility. For example, you could have different rails apps using rails 2 or 3 with ruby 1.8.7 and 1.9.2 all installed on the same system without problems.

---

This worked for me:

sudo env ARCHFLAGS="-arch x86_64" gem install pg

---

All the suggestions here and around the Web were incomplete for me, until I run the following on CentOS 6.6:

wget -c ftp://mirror.switch.ch/pool/4/mirror/scientificlinux/6.3/x86_64/updates/security/kernel-devel-2.6.32-504.1.3.el6.x86_64.rpm && sudo yum install kernel-devel-2.6.32-504.1.3.el6.x86_64.rpm
wget -c ftp://mirror.switch.ch/pool/4/mirror/scientificlinux/6.6/x86_64/updates/security/kernel-headers-2.6.32-504.30.3.el6.x86_64.rpm && sudo yum install kernel-headers-2.6.32-504.30.3.el6.x86_64.rpm
sudo yum groupinstall "Development Tools" "Development Libraries" 
sudo yum -y install gcc gcc-c++ git ruby ruby-devel rubygems libvirt-devel mysql-devel postgresql-devel openssl-devel libxml2-devel sqlite-devel libxslt-devel zlib-devel readline-devel tar make automake autoconf curl-devel openssl-devel zlib-devel httpd-devel apr-devel apr-util-devel sqlite-devel ruby193-ruby-doc ruby193-ruby-devel ruby193-build
curl -L get.rvm.io | bash -s stable && source $HOME/.rvm/scripts/rvm && rvm requirements

---

Install Postgres.app:

http://postgresapp.com/

Verify what version was installed:

$ ls /Library/PostgreSQL/
# 9.4

Export the SQL_PATH:

export SQL_PATH=/Library/PostgreSQL/9.4

Install pg:

gem install pg -- --with-pg-config=$SQL_PATH/bin/pg_config