Ruby on Rails / PostgreSQL - 启动服务器时库未加载错误

Question

嘿嘿。 如果这个问题已经在另一个线程中得到回答，我提前道歉。 我已经搜索了该网站，但没有找到答案。 但是，最接近的相关问题是Ruby on Rails / PostgreSQL - Library not Loaded error when started server- libq.5.dylib ，但从未解决，答案对我没有帮助。

我试图让 PostgreSQL 在我的 Mac OSX 10.6.8 上运行。 我已经安装了 Ruby 1.9.3p392 和 Rails 3.2.13。

由于我有 10.6.8，而 PostGresApp 需要 10.7+，我尝试使用此处提供的手动安装程序 (v9.2.3) 安装 PG： http://www.enterprisedb.com/products-services-training/pgdownload

我首先将它安装到默认路径：/Library/PostgreSQL/9.2/。 然后我安装了 pg gem（ PATH=$PATH:/Library/PostgreSQL/9.2/bin sudo gem install pg ）。 当我尝试使用rails s启动我的 localhost 时，出现以下错误。

经过一番阅读，我猜测可能是路径错误，所以我删除了 pg gem，然后使用了 postgresql 卸载程序。 然后我在 /users/stewartmccoy/Library/PostgreSQL/9.2/... 中重新安装了 pg，然后重新安装了 pg gem。 但我仍然得到同样的错误。

关于如何正确安装 PostgreSQL 并让我的 rails 服务器运行的任何想法？

stewart-mccoys-macbook:footy_subs stewartmccoy$ rails s
/Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392/gems/pg-0.14.1/lib/pg.rb:4:in `require': dlopen(/Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392/gems/pg-0.14.1/lib/pg_ext.bundle, 9): Library not loaded: libpq.5.dylib (LoadError)
  Referenced from: /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392/gems/pg-0.14.1/lib/pg_ext.bundle
  Reason: image not found - /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392/gems/pg-0.14.1/lib/pg_ext.bundle
    from /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392/gems/pg-0.14.1/lib/pg.rb:4:in `<top (required)>'
    from /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392@global/gems/bundler-1.3.4/lib/bundler/runtime.rb:72:in `require'
    from /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392@global/gems/bundler-1.3.4/lib/bundler/runtime.rb:72:in `block (2 levels) in require'
    from /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392@global/gems/bundler-1.3.4/lib/bundler/runtime.rb:70:in `each'
    from /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392@global/gems/bundler-1.3.4/lib/bundler/runtime.rb:70:in `block in require'
    from /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392@global/gems/bundler-1.3.4/lib/bundler/runtime.rb:59:in `each'
    from /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392@global/gems/bundler-1.3.4/lib/bundler/runtime.rb:59:in `require'
    from /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392@global/gems/bundler-1.3.4/lib/bundler.rb:132:in `require'
    from /Users/stewartmccoy/Code/footy_subs/config/application.rb:13:in `<top (required)>'
    from /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392/gems/railties-3.2.13/lib/rails/commands.rb:53:in `require'
    from /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392/gems/railties-3.2.13/lib/rails/commands.rb:53:in `block in <top (required)>'
    from /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392/gems/railties-3.2.13/lib/rails/commands.rb:50:in `tap'
    from /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392/gems/railties-3.2.13/lib/rails/commands.rb:50:in `<top (required)>'
    from script/rails:6:in `require'
    from script/rails:6:in `<main>'
stewart-mccoys-macbook:footy_subs stewartmccoy$ gem uninstall pgSuccessfully uninstalled pg-0.14.1
stewart-mccoys-macbook:footy_subs stewartmccoy$ PATH=$PATH:/users/stewartmccoy/Library/PostgreSQL/9.2/bin sudo gem install pg
Password:
Fetching: pg-0.14.1.gem (100%)
Building native extensions.  This could take a while...
Successfully installed pg-0.14.1
1 gem installed
Installing ri documentation for pg-0.14.1...
Installing RDoc documentation for pg-0.14.1...
stewart-mccoys-macbook:footy_subs stewartmccoy$ rails s
/Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392/gems/pg-0.14.1/lib/pg.rb:4:in `require': dlopen(/Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392/gems/pg-0.14.1/lib/pg_ext.bundle, 9): Library not loaded: libpq.5.dylib (LoadError)
  Referenced from: /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392/gems/pg-0.14.1/lib/pg_ext.bundle
  Reason: image not found - /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392/gems/pg-0.14.1/lib/pg_ext.bundle
    from /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392/gems/pg-0.14.1/lib/pg.rb:4:in `<top (required)>'
    from /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392@global/gems/bundler-1.3.4/lib/bundler/runtime.rb:72:in `require'
    from /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392@global/gems/bundler-1.3.4/lib/bundler/runtime.rb:72:in `block (2 levels) in require'
    from /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392@global/gems/bundler-1.3.4/lib/bundler/runtime.rb:70:in `each'
    from /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392@global/gems/bundler-1.3.4/lib/bundler/runtime.rb:70:in `block in require'
    from /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392@global/gems/bundler-1.3.4/lib/bundler/runtime.rb:59:in `each'
    from /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392@global/gems/bundler-1.3.4/lib/bundler/runtime.rb:59:in `require'
    from /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392@global/gems/bundler-1.3.4/lib/bundler.rb:132:in `require'
    from /Users/stewartmccoy/Code/footy_subs/config/application.rb:13:in `<top (required)>'
    from /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392/gems/railties-3.2.13/lib/rails/commands.rb:53:in `require'
    from /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392/gems/railties-3.2.13/lib/rails/commands.rb:53:in `block in <top (required)>'
    from /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392/gems/railties-3.2.13/lib/rails/commands.rb:50:in `tap'
    from /Users/stewartmccoy/.rvm/gems/ruby-1.9.3-p392/gems/railties-3.2.13/lib/rails/commands.rb:50:in `<top (required)>'
    from script/rails:6:in `require'
    from script/rails:6:in `<main>'

Answer 1

错误的关键部分是：

Library not loaded: libpq.5.dylib (LoadError)

这表明ruby在运行时找不到libpq 。 为了解决这个问题，您应该将DYLD_LIBRARY_PATH环境变量设置为指向PostgreSQL安装的lib目录，无论是全局还是用于启动Rails的包装脚本。 有关更多信息，请参阅此超级用户问题 。

Pg gem可以在编译和安装期间找到库，因为pg_config可执行文件位于PATH ，并使用它来查找libpq 。 它似乎不存储在运行时使用的路径，因此您必须自己设置运行时动态链接器。

一个简单的包装脚本（如果你不想修改你的全局环境）是这样的：

#!/bin/bash
export DYLD_LIBRARY_PATH=/path/to/pg/lib 
exec rails "$@"

“$ @”基本上意味着“将所有参数传递给此脚本，就好像它们是直接传递给这里一样”。 它保留了正确的引用，实质上意味着rails命令无法告诉你没有直接运行它。

Answer 2

类似的stackoverflow答案建议从你的PATH中删除Postgres.app，卸载pg gem，然后再次安装pg gem。

（我没有花时间仔细检查这是否适用于这个问题，但它解决了我遇到的问题，因为我无法找到它，所以我想传播解决方案。）

Answer 3

我想把我的两分钱放在上面的答案上。

有时只需重新安装pg gem 就足够了。

gem uninstall pg && gem install pg

就我而言，我将 postgresql 服务器从9.6升级到14.x ，并且更改了 dylib 路径。

/opt/local/lib/postgresql96/libpq.5.dylib -> /opt/local/lib/postgresql14/libpq.5.dylib

gem 使用pg_config来确定/opt/local/lib/postgresql[version]文件夹（名为PKGLIBDIR ）的路径。 要为 gem rake 构建本机库，通过在 compile 中从pg_config中获取动态库来设置动态库的路径。 编译pg gem 后，路径将永远链接。 因此，重新安装会重新编译并将路径重新链接到新库。