Class: ActiveRecord::ConnectionAdapters::ConnectionHandler

Inherits:
Object
  • Object
show all
Defined in:
activerecord/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

- (ConnectionHandler) initialize(pools = {})

A new instance of ConnectionHandler



283
284
285
 
# File 'activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb', line 283

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

Instance Attribute Details

- (Object) connection_pools (readonly)

Returns the value of attribute connection_pools



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

def connection_pools
  @connection_pools
end

Instance Method Details

- (Object) clear_active_connections!

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.



294
295
296
 
# File 'activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb', line 294

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

- (Object) clear_all_connections! 



303
304
305
 
# File 'activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb', line 303

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

- (Object) clear_reloadable_connections!

Clears the cache which maps classes



299
300
301
 
# File 'activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb', line 299

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

- (Boolean) connected?(klass)

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

Returns:

  • (Boolean) 


323
324
325
326
 
# File 'activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb', line 323

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

- (Object) establish_connection(name, spec) 



287
288
289
 
# File 'activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb', line 287

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

- (Object) remove_connection(klass)

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.



332
333
334
335
336
337
338
339
 
# File 'activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb', line 332

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

- (Object) retrieve_connection(klass)

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).



316
317
318
319
 
# File 'activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb', line 316

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

- (Object) retrieve_connection_pool(klass) 



341
342
343
344
345
346
 
# File 'activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb', line 341

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

- (Object) verify_active_connections!

Verify active connections.



308
309
310
 
# File 'activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb', line 308

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