Class: ActiveRecord::ConnectionAdapters::ConnectionHandler

Inherits:
Object
  • Object
show all
Defined in:
lib/active_record/connection_adapters/abstract/connection_pool.rb

Overview

ConnectionHandler is a collection of ConnectionPool objects. It is used for keeping separate connection pools for Active Record models that connect to different databases.

For example, suppose that you have 5 models, with the following hierarchy:

|
+-- Book
|    |
|    +-- ScaryBook
|    +-- GoodBook
+-- Author
+-- BankAccount

Suppose that Book is to connect to a separate database (i.e. one other than the default database). Then Book, ScaryBook and GoodBook will all use the same connection pool. Likewise, Author and BankAccount will use the same connection pool. However, the connection pool used by Author/BankAccount is not the same as the one used by Book/ScaryBook/GoodBook.

Normally there is only a single ConnectionHandler instance, accessible via ActiveRecord::Base.connection_handler. Active Record models use this to determine that connection pool that they should use.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(pools = {}) ⇒ ConnectionHandler

Returns a new instance of ConnectionHandler.



281
282
283
 
# File 'lib/active_record/connection_adapters/abstract/connection_pool.rb', line 281

def initialize(pools = {})
  @connection_pools = pools
end

Instance Attribute Details

#connection_pools ⇒ Object (readonly)

Returns the value of attribute connection_pools.



279
280
281
 
# File 'lib/active_record/connection_adapters/abstract/connection_pool.rb', line 279

def connection_pools
  @connection_pools
end

Instance Method Details

#clear_active_connections! ⇒ Object

Returns any connections in use by the current thread back to the pool, and also returns connections to the pool cached by threads that are no longer alive.



292
293
294
 
# File 'lib/active_record/connection_adapters/abstract/connection_pool.rb', line 292

def clear_active_connections!
  @connection_pools.each_value {|pool| pool.release_connection }
end

#clear_all_connections! ⇒ Object 



301
302
303
 
# File 'lib/active_record/connection_adapters/abstract/connection_pool.rb', line 301

def clear_all_connections!
  @connection_pools.each_value {|pool| pool.disconnect! }
end

#clear_reloadable_connections! ⇒ Object

Clears the cache which maps classes



297
298
299
 
# File 'lib/active_record/connection_adapters/abstract/connection_pool.rb', line 297

def clear_reloadable_connections!
  @connection_pools.each_value {|pool| pool.clear_reloadable_connections! }
end

#connected?(klass) ⇒ Boolean

Returns true if a connection that’s accessible to this class has already been opened.

Returns:

  • (Boolean) 


321
322
323
324
 
# File 'lib/active_record/connection_adapters/abstract/connection_pool.rb', line 321

def connected?(klass)
  conn = retrieve_connection_pool(klass)
  conn && conn.connected?
end

#establish_connection(name, spec) ⇒ Object 



285
286
287
 
# File 'lib/active_record/connection_adapters/abstract/connection_pool.rb', line 285

def establish_connection(name, spec)
  @connection_pools[name] = ConnectionAdapters::ConnectionPool.new(spec)
end

#remove_connection(klass) ⇒ Object

Remove the connection for this class. This will close the active connection and the defined connection (if they exist). The result can be used as an argument for establish_connection, for easily re-establishing the connection.



330
331
332
333
334
335
336
337
 
# File 'lib/active_record/connection_adapters/abstract/connection_pool.rb', line 330

def remove_connection(klass)
  pool = @connection_pools[klass.name]
  return nil unless pool

  @connection_pools.delete_if { |key, value| value == pool }
  pool.disconnect!
  pool.spec.config
end

#retrieve_connection(klass) ⇒ Object

Locate the connection of the nearest super class. This can be an active or defined connection: if it is the latter, it will be opened and set as the active connection for the class it was defined for (not necessarily the current class).



314
315
316
317
 
# File 'lib/active_record/connection_adapters/abstract/connection_pool.rb', line 314

def retrieve_connection(klass) #:nodoc:
  pool = retrieve_connection_pool(klass)
  (pool && pool.connection) or raise ConnectionNotEstablished
end

#retrieve_connection_pool(klass) ⇒ Object 



339
340
341
342
343
344
 
# File 'lib/active_record/connection_adapters/abstract/connection_pool.rb', line 339

def retrieve_connection_pool(klass)
  pool = @connection_pools[klass.name]
  return pool if pool
  return nil if ActiveRecord::Base == klass
  retrieve_connection_pool klass.superclass
end

#verify_active_connections! ⇒ Object

Verify active connections.



306
307
308
 
# File 'lib/active_record/connection_adapters/abstract/connection_pool.rb', line 306

def verify_active_connections! #:nodoc:
  @connection_pools.each_value {|pool| pool.verify_active_connections! }
end