Install postgresql gem `pg` on macOS

install_pg_gem.md

Installing pg gem on macOS

If you're trying to install the postgresql gem pg and it is failing with the following error message:

Installing pg 1.2.3 with native extensions
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

    current directory: ~/.rbenv/versions/3.0.0/lib/ruby/gems/3.0.0/gems/pg-1.2.3/ext
~/.rbenv/versions/3.0.0/bin/ruby -I ~/.rbenv/versions/3.0.0/lib/ruby/3.0.0 -r ./siteconf20210125-97201-pycpo.rb 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

The following helped me resolve the issue without having to install the entire postgresql as recommended in the stop Stack Overflow post (already using it in a Docker container):

1. brew install libpq
2. gem install pg -- --with-pg-config=/usr/local/opt/libpq/bin/pg_config

bundle config build.pg --with-pg-config="$(brew --prefix)/opt/libpq/bin/pg_config"

Amazing, many other solutions didn't work (from fresh Ventura OS install).

On Apple Silicon, after installing the libpq, running gem install pg -- --with-pg-config=/opt/homebrew/opt/libpq/bin/pg_config

should do the trick.

@isheebo you just saved me 10000 hours I owe you everything

What worked for me was the suggestion by @oamado:

gem install pg -v '0.18.4' -- --with-cflags="-Wno-error=implicit-function-declaration"

I am on an older Mac (MacBook Pro 2018) running macOS 12.5.1 (Monterey).

To use with bundler / apple silicon:

brew install libpq
bundle config build.pg --with-pg-config=/opt/homebrew/opt/libpq/bin/pg_config
bundle

This worked for m1, Postgres.app. Thank you
But after that, psql may not work. The following helped me:
brew link --force libpq

gem install pg -- --with-pg-config=/opt/homebrew/opt/libpq/bin/pg_config

Works for me. Thanks!

To use with bundler / apple silicon:

brew install libpq
bundle config build.pg --with-pg-config=/opt/homebrew/opt/libpq/bin/pg_config
bundle

Thanks! It works!

To use with bundler / apple silicon:

brew install libpq
bundle config build.pg --with-pg-config=/opt/homebrew/opt/libpq/bin/pg_config
bundle

Worked for me. I'm using Apple M1 Sonoma.

gem install pg -- --with-pg-config=/opt/homebrew/opt/libpq/bin/pg_config

You may need to do a user-level install depending on permissions.

 gem install pg --user-install -- --with-pg-config=/opt/homebrew/opt/libpq/bin/pg_config

works for me.

Switching the ruby version worked for me
rbenv global 3.2.2
sudo chown -R $(whoami) ~/.rbenv
gem install pg

Merci!!