Forum: Ruby on Rails Unable to install pg gem file on CENT OS

please help me in this... I am unable to install pg gem file


[root@vdimc04 ~]# gem install pg -v '0.12.0'
/usr/local/lib/ruby/1.9.1/yaml.rb:56:in `<top (required)>':
It seems your ruby installation is missing psych (for YAML output).
To eliminate this warning, please install libyaml and reinstall your 
ruby.
Fetching: rake-compiler-0.8.1.gem (100%)
Fetching: pg-0.12.0.gem (100%)
Building native extensions.  This could take a while...
ERROR:  Error installing pg:
    ERROR: Failed to build gem native extension.

        /usr/local/bin/ruby extconf.rb
checking for pg_config... no
No pg_config... trying anyway. If building fails, please try again with
 --with-pg-config=/path/to/pg_config
checking for libpq-fe.h... no
Can't find the 'libpq-fe.h header
*** 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=/usr/local/bin/ruby
    --with-pg
    --without-pg
    --with-pg-dir
    --without-pg-dir
    --with-pg-include
    --without-pg-include=${pg-dir}/include
    --with-pg-lib
    --without-pg-lib=${pg-dir}/lib
    --with-pg-config
    --without-pg-config
    --with-pg_config
    --without-pg_config


Gem files will remain installed in
/usr/local/lib/ruby/gems/1.9.1/gems/pg-0.12.0 for inspection.
Results logged to
/usr/local/lib/ruby/gems/1.9.1/gems/pg-0.12.0/ext/gem_make.out

Install postgresql-libs and also recompile your Ruby after install 
libyaml.

On Tue, Dec 4, 2012 at 6:50 AM, PavanKumar Chamarthi

You will need to install libyaml-devel from the epel repositories (which
you will also need to add).

PavanKumar Chamarthi wrote in post #1087845:
> please help me in this... I am unable to install pg gem file
>
>
> [root@vdimc04 ~]# gem install pg -v '0.12.0'
> /usr/local/lib/ruby/1.9.1/yaml.rb:56:in `<top (required)>':
> It seems your ruby installation is missing psych (for YAML output).
> To eliminate this warning, please install libyaml and reinstall your
> ruby.
> Fetching: rake-compiler-0.8.1.gem (100%)
> Fetching: pg-0.12.0.gem (100%)
> Building native extensions.  This could take a while...
> ERROR:  Error installing pg:
>     ERROR: Failed to build gem native extension.
>
>         /usr/local/bin/ruby extconf.rb
> checking for pg_config... no
> No pg_config... trying anyway. If building fails, please try again with
>  --with-pg-config=/path/to/pg_config


> checking for libpq-fe.h... no
> Can't find the 'libpq-fe.h header
> *** extconf.rb failed ***

It is in your own interest to provide more detail respecting your 
installation when reporting a problem and asking for help.  For example, 
are you running CentOS-6 or 5?  What point release?  Are you using the 
stock PostgreSQl install, have you installed a different version from 
another respoitory,  or have you built PostgreSQl yourself?  In any case 
what version of Postgres?

Providing that you are running CentOS-6.x; and assuming that you are 
evidently not using the Postgres provided with that distribution; and 
guessing that you are likely using the pgdg-91-centos.repo; and also 
guessing that you are using either rvm or rbenv then you likely need to 
do something akin to the following

yum install postgresql91-devel libyaml
gem install pg --with-pg-config=/usr/pgsql-9.1/bin/pg_config

HTH