From f9baab18705218dae4c37c2c92d1ceea151bba8e Mon Sep 17 00:00:00 2001 From: Eric Wong Date: Thu, 10 Jun 2010 17:57:08 -0700 Subject: docs: hopefully clarify preload_app=false behavior While we're at it, inform people of why they might use a symlink --- SIGNALS | 7 ++++++- lib/unicorn/configurator.rb | 21 ++++++++++++++++++--- 2 files changed, 24 insertions(+), 4 deletions(-) diff --git a/SIGNALS b/SIGNALS index be96892..8851775 100644 --- a/SIGNALS +++ b/SIGNALS @@ -14,7 +14,12 @@ Unicorn and nginx. will also pick up any application code changes when restarted. If "preload_app" is true, then application code changes will have no effect; USR2 + QUIT (see below) must be used to load newer code in - this case. + this case. When reloading the application, +Gem.refresh+ will + be called so updated code for your application can pick up newly + installed RubyGems. It is not recommended that you uninstall + libraries your application depends on while Unicorn is running, + as respawned workers may enter a spawn loop when they fail to + load an uninstalled dependency. * INT/TERM - quick shutdown, kills all workers immediately diff --git a/lib/unicorn/configurator.rb b/lib/unicorn/configurator.rb index 71c7a8a..533e0ed 100644 --- a/lib/unicorn/configurator.rb +++ b/lib/unicorn/configurator.rb @@ -311,7 +311,22 @@ module Unicorn # # In addition to reloading the unicorn-specific config settings, # SIGHUP will reload application code in the working - # directory/symlink when workers are gracefully restarted. + # directory/symlink when workers are gracefully restarted when + # preload_app=false (the default). As reloading the application + # sometimes requires RubyGems updates, +Gem.refresh+ is always + # called before the application is loaded (for RubyGems users). + # + # During deployments, care should _always_ be taken to ensure your + # applications are properly deployed and running. Using + # preload_app=false (the default) means you _must_ check if + # your application is responding properly after a deployment. + # Improperly deployed applications can go into a spawn loop + # if the application fails to load. While your children are + # in a spawn loop, it is is possible to fix an application + # by properly deploying all required code and dependencies. + # Using preload_app=true means any application load error will + # cause the master process to exit with an error. + def preload_app(bool) case bool when TrueClass, FalseClass @@ -344,9 +359,9 @@ module Unicorn set_path(:stdout_path, path) end - # sets the working directory for Unicorn. This ensures USR2 will + # sets the working directory for Unicorn. This ensures SIGUSR2 will # start a new instance of Unicorn in this directory. This may be - # a symlink. + # a symlink, a common scenario for Capistrano users. def working_directory(path) # just let chdir raise errors path = File.expand_path(path) -- cgit v1.2.3-24-ge0c7