Module: ActiveRecordShards::ConnectionSwitcher
- Defined in:
- lib/active_record_shards/connection_switcher.rb,
lib/active_record_shards/connection_switcher-4-0.rb,
lib/active_record_shards/connection_switcher-5-0.rb,
lib/active_record_shards/connection_switcher-5-1.rb
Defined Under Namespace
Classes: MasterSlaveProxy
Constant Summary
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- SHARD_NAMES_CONFIG_KEY =
'shard_names'.freeze
Class Method Summary
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Instance Method Summary
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Class Method Details
.extended(base) ⇒ Object
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# File 'lib/active_record_shards/connection_switcher.rb', line 8
def self.extended(base)
base.singleton_class.send(:alias_method, :columns_without_default_shard, :columns)
base.singleton_class.send(:alias_method, :columns, :columns_with_default_shard)
base.singleton_class.send(:alias_method, :table_exists_without_default_shard?, :table_exists?)
base.singleton_class.send(:alias_method, :table_exists?, :table_exists_with_default_shard?)
end
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Instance Method Details
#connection_pool_name ⇒ Object
Name of the connection pool. Used by ConnectionHandler to retrieve the current connection pool.
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# File 'lib/active_record_shards/connection_switcher-4-0.rb', line 4
def connection_pool_name name = current_shard_selection.shard_name(self)
if configurations[name].nil? && on_slave?
current_shard_selection.shard_name(self, false)
else
name
end
end
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#connection_specification_name ⇒ Object
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# File 'lib/active_record_shards/connection_switcher-5-0.rb', line 3
def connection_specification_name
name = current_shard_selection.resolve_connection_name(sharded: is_sharded?, configurations: configurations)
unless configurations[name] || name == "primary"
raise ActiveRecord::AdapterNotSpecified, "No database defined by #{name} in database.yml"
end
name
end
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#current_shard_id ⇒ Object
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# File 'lib/active_record_shards/connection_switcher.rb', line 130
def current_shard_id
current_shard_selection.shard
end
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#current_shard_selection ⇒ Object
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# File 'lib/active_record_shards/connection_switcher.rb', line 126
def current_shard_selection
Thread.current[:shard_selection] ||= ShardSelection.new
end
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#default_shard=(new_default_shard) ⇒ Object
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# File 'lib/active_record_shards/connection_switcher.rb', line 16
def default_shard=(new_default_shard)
ActiveRecordShards::ShardSelection.default_shard = new_default_shard
switch_connection(shard: new_default_shard)
end
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#on_all_shards ⇒ Object
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# File 'lib/active_record_shards/connection_switcher.rb', line 38
def on_all_shards
old_options = current_shard_selection.options
if supports_sharding?
shard_names.map do |shard|
switch_connection(shard: shard)
yield(shard)
end
else
[yield]
end
ensure
switch_connection(old_options)
end
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#on_cx_switch_block(which, options = {}, &block) ⇒ Object
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# File 'lib/active_record_shards/connection_switcher.rb', line 98
def on_cx_switch_block(which, options = {}, &block)
@disallow_slave ||= 0
old_options = current_shard_selection.options
switch_to_slave = (which == :slave && @disallow_slave.zero?)
switch_connection(slave: switch_to_slave)
@disallow_slave += 1 if which == :master
if self == ActiveRecord::Base || !switch_to_slave || options[:construct_ro_scope] == false
yield
else
readonly.scoping(&block)
end
ensure
@disallow_slave -= 1 if which == :master
switch_connection(old_options)
end
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#on_first_shard ⇒ Object
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# File 'lib/active_record_shards/connection_switcher.rb', line 29
def on_first_shard
shard_name = shard_names.first
on_shard(shard_name) { yield }
end
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#on_master(&block) ⇒ Object
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# File 'lib/active_record_shards/connection_switcher.rb', line 89
def on_master(&block)
on_master_or_slave(:master, &block)
end
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#on_master_if(condition, &block) ⇒ Object
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# File 'lib/active_record_shards/connection_switcher.rb', line 60
def on_master_if(condition, &block)
condition ? on_master(&block) : yield
end
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#on_master_or_slave(which, &block) ⇒ Object
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# File 'lib/active_record_shards/connection_switcher.rb', line 68
def on_master_or_slave(which, &block)
if block_given?
on_cx_switch_block(which, &block)
else
MasterSlaveProxy.new(self, which)
end
end
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#on_master_unless(condition, &block) ⇒ Object
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# File 'lib/active_record_shards/connection_switcher.rb', line 64
def on_master_unless(condition, &block)
on_master_if(!condition, &block)
end
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#on_shard(shard) ⇒ Object
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# File 'lib/active_record_shards/connection_switcher.rb', line 21
def on_shard(shard)
old_options = current_shard_selection.options
switch_connection(shard: shard) if supports_sharding?
yield
ensure
switch_connection(old_options)
end
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#on_slave(&block) ⇒ Object
Also known as:
with_slave
Executes queries using the slave database. Fails over to master if no slave is found. if you want to execute a block of code on the slave you can go:
Account.on_slave do
Account.first
end
the first account will be found on the slave DB
For one-liners you can simply do
Account.on_slave.first
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# File 'lib/active_record_shards/connection_switcher.rb', line 85
def on_slave(&block)
on_master_or_slave(:slave, &block)
end
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#on_slave? ⇒ Boolean
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# File 'lib/active_record_shards/connection_switcher.rb', line 122
def on_slave?
current_shard_selection.on_slave?
end
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#on_slave_if(condition, &block) ⇒ Object
Also known as:
with_slave_if
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# File 'lib/active_record_shards/connection_switcher.rb', line 52
def on_slave_if(condition, &block)
condition ? on_slave(&block) : yield
end
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#on_slave_unless(condition, &block) ⇒ Object
Also known as:
with_slave_unless
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# File 'lib/active_record_shards/connection_switcher.rb', line 56
def on_slave_unless(condition, &block)
on_slave_if(!condition, &block)
end
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#shard_names ⇒ Object
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# File 'lib/active_record_shards/connection_switcher.rb', line 134
def shard_names
unless config = configurations[shard_env]
raise "Did not find #{shard_env} in configurations, did you forget to add it to your database.yml ? (configurations: #{configurations.inspect})"
end
config[SHARD_NAMES_CONFIG_KEY] || []
end
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#shards ⇒ Object
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# File 'lib/active_record_shards/connection_switcher.rb', line 34
def shards
ShardSupport.new(self == ActiveRecord::Base ? nil : where(nil))
end
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#supports_sharding? ⇒ Boolean
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# File 'lib/active_record_shards/connection_switcher.rb', line 118
def supports_sharding?
shard_names.any?
end
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