Rework application configuration

Use a preinitializer to load the settings from application.yml so
that they are available as early as possible. All settings can also
be overridden using environment variables.

The ad-hoc settins in environment.rb are then moved to this new
system so we have one consistent location for settings.

config/initializers/load_configs.rb

@@ -1,4 +0,0 @@
-# This file loads various yml configuration files
-
-# Load application config
-APP_CONFIG = YAML.load(File.read(RAILS_ROOT + "/config/application.yml"))[RAILS_ENV]

config/initializers/memory_limits.rb

@@ -1,11 +1,11 @@
 # Setup any specified hard limit on the virtual size of the process
-if APP_CONFIG.include?('hard_memory_limit') and Process.const_defined?(:RLIMIT_AS)
-  Process.setrlimit Process::RLIMIT_AS, APP_CONFIG['hard_memory_limit']*1024*1024, Process::RLIM_INFINITY
+if defined?(HARD_MEMORY_LIMIT) and Process.const_defined?(:RLIMIT_AS)
+  Process.setrlimit Process::RLIMIT_AS, HARD_MEMORY_LIMIT*1024*1024, Process::RLIM_INFINITY
 end
 
 # If we're running under passenger and a soft memory limit is
 # configured then setup some rack middleware to police the limit
-if APP_CONFIG.include?('soft_memory_limit') and defined?(PhusionPassenger)
+if defined?(SOFT_MEMORY_LIMIT) and defined?(PhusionPassenger)
   # Define some rack middleware to police the soft memory limit
   class MemoryLimit
     def initialize(app)
@@ -17,7 +17,7 @@ if APP_CONFIG.include?('soft_memory_limit') and defined?(PhusionPassenger)
       status, headers, body = @app.call(env)
       
       # Restart if we've hit our memory limit
-      if resident_size > APP_CONFIG['soft_memory_limit']
+      if resident_size > SOFT_MEMORY_LIMIT
         Process.kill("USR1", 0)
       end
       

config/initializers/session_store.rb

@@ -12,6 +12,6 @@ ActionController::Base.session = {
 # Use the database for sessions instead of the cookie-based default,
 # which shouldn't be used to store highly confidential information
 # (create the session table with "rake db:sessions:create")
-unless OSM_STATUS == :database_offline or OSM_STATUS == :database_readonly
+unless STATUS == :database_offline or STATUS == :database_readonly
   ActionController::Base.session_store = :sql_session_store
 end

config/initializers/sql_session_store.rb

@@ -4,6 +4,6 @@ adapter = Rails.configuration.database_configuration[environment]["adapter"]
 session_class = adapter + "_session"
 
 # Configure SqlSessionStore
-unless  OSM_STATUS == :database_offline
+unless  STATUS == :database_offline
   SqlSessionStore.session_class = session_class.camelize.constantize
 end