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.


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# File 'lib/active_record/connection_adapters/abstract/connection_pool.rb', line 369

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

Instance Attribute Details

#connection_poolsObject (readonly)

Returns the value of attribute connection_pools


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# File 'lib/active_record/connection_adapters/abstract/connection_pool.rb', line 367

def connection_pools
  @connection_pools
end

Instance Method Details

#active_connections?Boolean

Returns true if there are any active connections among the connection pools that the ConnectionHandler is managing.

Returns:

  • (Boolean)

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# File 'lib/active_record/connection_adapters/abstract/connection_pool.rb', line 381

def active_connections?
  connection_pools.values.any? { |pool| pool.active_connection? }
end

#clear_active_connections!Object

Returns any connections in use by the current thread back to the pool.


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# File 'lib/active_record/connection_adapters/abstract/connection_pool.rb', line 386

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

#clear_all_connections!Object


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# File 'lib/active_record/connection_adapters/abstract/connection_pool.rb', line 395

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

#clear_reloadable_connections!Object

Clears the cache which maps classes.


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# File 'lib/active_record/connection_adapters/abstract/connection_pool.rb', line 391

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)

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# File 'lib/active_record/connection_adapters/abstract/connection_pool.rb', line 415

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

#establish_connection(name, spec) ⇒ Object


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# File 'lib/active_record/connection_adapters/abstract/connection_pool.rb', line 374

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


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# File 'lib/active_record/connection_adapters/abstract/connection_pool.rb', line 424

def remove_connection(klass)
  pool = @class_to_pool.delete(klass.name)
  return nil unless pool

  @connection_pools.delete pool.spec
  pool.automatic_reconnect = false
  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).


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# File 'lib/active_record/connection_adapters/abstract/connection_pool.rb', line 408

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

#retrieve_connection_pool(klass) ⇒ Object


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# File 'lib/active_record/connection_adapters/abstract/connection_pool.rb', line 434

def retrieve_connection_pool(klass)
  pool = @class_to_pool[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.


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# File 'lib/active_record/connection_adapters/abstract/connection_pool.rb', line 400

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