我使用的是Ruby on Rails 3.1预版本。我喜欢使用PostgreSQL,但问题是安装pg gem。它给了我以下错误:

$ gem install pg
Building native extensions.  This could take a while...
ERROR:  Error installing pg:
    ERROR: Failed to build gem native extension.

        /home/u/.rvm/rubies/ruby-1.9.2-p0/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=/home/u/.rvm/rubies/ruby-1.9.2-p0/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 /home/u/.rvm/gems/ruby-1.9.2-p0/gems/pg-0.11.0 for inspection.
    Results logged to /home/u/.rvm/gems/ruby-1.9.2-p0/gems/pg-0.11.0/ext/gem_make.out

我怎么解决这个问题?


当前回答

在Ubuntu 20.04上,我已经有libpq5:amd64 version 13.2-1.pgdg20.04+1。现在,当我试图从apt存储库安装libpq-dev时,我正在接收

The following packages have unmet dependencies:
libpq-dev : Depends: libpq5 (= 12.6-0ubuntu0.20.04.1) but 13.2-1.pgdg20.04+1 is to be installed

我从http://ftp.us.debian.org/debian/pool/main/p/postgresql-13/libpq-dev_13.2-1_amd64.deb上获取了deb,并做了以下工作:

mkdir -p /tmp/libpq-dev
dpkg-deb -R libpq-dev_13.2-1_amd64.deb /tmp/libpq-dev
sed -i 's|= 13.2-1|= 13.2-1.pgdg20.04+1|' /tmp/libpq-dev/DEBIAN/control
dpkg-deb -b /tmp/libpq-dev /tmp/libpq-dev-new.deb
sudo dpkg -i /tmp/libpq-dev-new.deb

从那以后,我一直在愉快地使用宝石。没有额外的安装或任何东西。

其他回答

我在通过asdf安装postgres时遇到了同样的错误。pg-config解决方案对我不起作用。相反,我必须找到包含该文件的postgres include文件夹,并运行带有——with-pg-include标志的命令

gem install pg -- --with-pg-include=/<path>/.asdf/installs/postgres/<version>/include

我通过rvm重新安装Ruby修复了同样的错误:

rvm reinstall 1.9.3

在CentOS上,我使用下面的命令安装libpq-dev包

yum install postgresql-devel

执行gem install pg返回与“No pg_config…”不管怎样。如果构建失败,请使用——with-pg-config=/path/to/pg_config"再试一次。

安装宝石如下解决了我的问题

gem install pg -- --with-pg-config=/usr/pgsql-x.x/bin/pg_config

在Debian 7.0, 64位(Wheezy)上,只需运行:

sudo apt-get install libpq-dev

成功安装libpq-dev后,运行:

bundle install

我可以用另一种方法解决这个问题。我在系统里找不到图书馆。因此,我使用PostgreSQL主网站上的应用程序安装了它。在我的情况下(OS X),我发现文件在/Library/PostgreSQL/9.1/include/安装结束后。如果你已经安装了PostgreSQL,你也可以在其他地方安装这个文件,这取决于你的系统。

多亏了这个关于如何为gem安装添加额外路径的链接,我可以用下面的命令将gem指向lib:

export CONFIGURE_ARGS="with-pg-include=/Library/PostgreSQL/9.1/include/"
gem install pg

在那之后,它就工作了,因为它现在知道在哪里找到丢失的库。只需将路径替换为libpq-fe.h的正确位置