Windows下Rails用rpush启动报错：uninitialized constant Process::RLIMIT_NOFILE

Hey there! I’ve dealt with this exact problem when setting up rpush on Windows, so I know how annoying that error can be. Let’s walk through the fixes step by step.

The Root Cause #

As you noted, the Process::RLIMIT_NOFILE constant is Unix-only—Windows doesn’t expose this system API, which is why the DEFAULT_POOL_SIZE definition in persistent.rb breaks when you run rpush start.

Solution 1: Modify the rpush Gem’s Source Code (Quick Fix) #

• Locate the persistent.rb file:
  First, find where the rpush gem is installed on your system. Run this command in your terminal:

  bundle show rpush
  

  This will output the full path to the gem. Navigate to the daemon directory inside it—usually something like [gem_path]/lib/rpush/daemon/.

• Edit the DEFAULT_POOL_SIZE definition:
  Open persistent.rb in a text editor. Look for the line that sets DEFAULT_POOL_SIZE (it probably looks like this):

  DEFAULT_POOL_SIZE = Process.getrlimit(Process::RLIMIT_NOFILE)[0] / 4
  

  Replace it with a Windows-compatible check:

  if RbConfig::CONFIG['host_os'] =~ /mswin|mingw|cygwin/
    # Set a reasonable fixed pool size for Windows
    DEFAULT_POOL_SIZE = 512
  else
    # Keep the original Unix logic
    DEFAULT_POOL_SIZE = Process.getrlimit(Process::RLIMIT_NOFILE)[0] / 4
  end
  

• Save and test:
  Save the file, then run rpush start again. The error should be gone.

Solution 2: Use a Monkey Patch (Permanent, Gem-Safe Fix) #

If you don’t want to modify the gem directly (since gem updates will overwrite your changes), use a monkey patch in your Rails project:

• Create an initializer file:
  In your Rails app, create a new file at config/initializers/rpush_windows_fix.rb.

• Add the patch code:
  Paste this into the file:

  module Rpush
    module Daemon
      module Persistent
        # Override DEFAULT_POOL_SIZE for Windows systems
        if RbConfig::CONFIG['host_os'] =~ /mswin|mingw|cygwin/
          DEFAULT_POOL_SIZE = 512
        end
      end
    end
  end
  

• Restart your Rails server (if running):
  The initializer will load when your app starts, overriding the problematic constant for Windows. Now run rpush start—it should work without errors.

Why This Works #

By checking the host OS first, we avoid referencing the Unix-only Process::RLIMIT_NOFILE constant on Windows. The fixed pool size of 512 is a reasonable default that works for most rpush use cases on Windows.

内容的提问来源于stack exchange，提问作者Pinki