Rails 3 - can't install pg gem

问题

When I try to run bundle (bundle install), I all the time get

Installing pg (0.13.2) with native extensions 
Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.

        /Users/ryan/.rvm/rubies/ruby-1.9.2-p290/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=/Users/ryan/.rvm/rubies/ruby-1.9.2-p290/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 /Users/ryan/.rvm/gems/ruby-1.9.2-p290/gems/pg-0.13.2 for inspection.
Results logged to /Users/ryan/.rvm/gems/ruby-1.9.2-p290/gems/pg-0.13.2/ext/gem_make.out
An error occured while installing pg (0.13.2), and Bundler cannot continue.
Make sure that `gem install pg -v \'0.13.2\'` succeeds before bundling.

I use Mac OS X 10.6, the version of installed PostgreSQL is 9.1. I found the problem is in the libpq-dev, how could I install/fix that?

回答1:

As stated in your error log you need to pass in the path to the pg_config. Try to install the gem using:

gem install pg -- --with-pg-config= 'PATH_TO_YOUR_PG_CONFIG'

If you are not sure where your pg_config is, and assuming you are on Linux or Mac, you can run the following command:

which pg_config

Your pg-config can be in different locations depending on how you installed postgres.

回答2:

if you are running on Linux you may be interested in what worked for me:

sudo apt-get install postgresql
sudo apt-get install libpq-dev

Then

gem install pg

then

bundle install

src: http://wikimatze.de/installing-postgresql-gem-under-ubuntu-and-mac

回答3:

If you're using Postgress.app then youll want access to its command-line tools. Enter the following line in your terminal or your PATH profile:

 PATH="/Applications/Postgres.app/Contents/MacOS/bin:$PATH"

gem install pg should now work. (This is what worked for me.)

Note New versions path looks like:

/Applications/Postgres.app/Contents/Versions/<version>/bin

回答4:

If you have homebrew, just type:

$ brew install postgresql

If you dont have it, download typing this in your terminal:

ruby -e "$(curl -fsSL https://raw.github.com/Homebrew/homebrew/go/install)"

回答5:

Search for libpq:

brew search libpq

Should output libpqxx

Then try install it:

brew install libpqxx

回答6:

You only need to install libpq-dev:

sudo apt-get install libpq-dev

Then the gem should install just fine.

回答7:

Follow the post-installation instructions: http://postgresapp.com/documentation/configuration-ruby.html

To install the pg gem, make sure you have set up your $PATH correctly (as specified in http://postgresapp.com/documentation/cli-tools.html), then run

sudo ARCHFLAGS="-arch x86_64" gem install pg

I strongly recommend reading both pages. Just skimmed them and lost 1 hour of my life. Read them, problem solved.

回答8:

The problem I had was that for some reason it was trying to compile with /usr/bin/gcc-4.2. I found that out by changing try_cpp in mkmf.rb (which I saw in the stack trace) to raise an exception with the compile line that was failing.

I soft-linked gcc to gcc-4.2 and it worked:

sudo ln -s /usr/bin/gcc /usr/bin/gcc-4.2

Why was it trying to use gcc-4.2? No idea.

The actual compile line:

/usr/bin/gcc-4.2 -E -I/Users/dfrankow/.rvm/rubies/ruby-1.9.3-p125/include/ruby-1.9.1/x86_64-darwin11.4.0 -I/Users/dfrankow/.rvm/rubies/ruby-1.9.3-p125/include/ruby-1.9.1/ruby/backward -I/Users/dfrankow/.rvm/rubies/ruby-1.9.3-p125/include/ruby-1.9.1 -I. -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE   -I/usr/local/Cellar/postgresql/9.1.4/include  -O3 -ggdb -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Wpointer-arith -Wwrite-strings -Wdeclaration-after-statement -Wshorten-64-to-32 -Wimplicit-function-declaration  -fno-common -pipe  conftest.c -o conftest.i (RuntimeError)

回答9:

I got the same issue but my Postgres was install in

/Library/PostgreSQL/9.3

Updated the ~/.bash_profile by adding:

export PATH=/Library/PostgreSQL/9.3/bin:$PATH

Open a new terminal, run bundle update and also it worked for me. Thanks Ari.

回答10:

You can set a build config option bundle config build.pg --with-pg-config=/Applications/Postgres.app/Contents/Versions/9.3/bin/pg_config and use gem install pg without any options (the path to pg_config may be different for you, this one is for the Postgresapp 9.3.5.0)

回答11:

I had the same problem in my openSUSE13.1 KDE machine. Before that issue I encountered I had installed only the packages postgresql and postgresql-server using zypper command. Then installed again 2 more packages :

[arup@to_do_app]$ sudo zypper in postgresql-devel postgresql-contrib
root's password:
Loading repository data...
Reading installed packages...
Resolving package dependencies...
#....

Then, I ran again bundle install, and success!!!

回答12:

For a working OSX solution see this guide http://krugerdavid.com/journal/how-to-install-xcode-homebrew-git-rvm-postgresql-ruby-1-9-3-on-snow-leopard/

It will walk you through installing PostgreSQL using homebrew. Tested and working for me on OSX 10.8.3, PostgreSQL 9.2.3, and Ruby 2.0.0-p0

回答13:

First, uninstall any Homebrew versions. The --force option makes it uninstall all versions.

brew rm postgresql --force

Change paths accordingly for your version.

sudo /sbin/SystemStarter stop postgresql-8.4
sudo rm -rf /Applications/PostgreSQL\ 8.4
sudo rm -rf /etc/postgres-reg.ini
sudo rm -rf /Library/StartupItems/postgresql-8.4
sudo rm -rf /Library/PostgreSQL/8.4
sudo dscl . delete /users/postgres

Edit /etc/profile and delete any lines that reference "postgres".

nano /etc/profile

Install PostgresSQL

brew update
brew install postgresql

Install de PG GEM

gem install pg

That's it. Regards.

回答14:

You can first check to see if you have a postrgresql file in your terminal by going to lib file. going cd ~/opt/local/lib/ and then type ls and the enter button. This will show you a list of all the files that are located in the lib directory.

1.if you dont have postreseql you can download through macports. sudo port install postgresql93 @9.3.2_1

Now cd back into your folder which you are trying to bundle install

1. getting your pg to work with your postgesql file you have or just downloaded gem install pg -- --with-pg-config=/opt/local/lib/postgresql93/bin/pg_config

now run bundle install

回答15:

On Fedora:

dnf install postgresql-devel

回答16:

What worked for me on El Capitan was upgrading ruby from the system default to 2.3.1 seemed to find the correct libraries that the pg gem needed.

来源：https://stackoverflow.com/questions/9668753/rails-3-cant-install-pg-gem