Class: Rails::Sharding::Core

Inherits:
Object
  • Object
show all
Defined in:
lib/rails/sharding/core.rb

Class Method Summary collapse

Class Method Details

.configurations(environment = Rails.env) ⇒ Object 



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# File 'lib/rails/sharding/core.rb', line 30

def self.configurations(environment=Rails.env)
  @@db_configs ||= YAML.load_file(Config.shards_config_file)
  environment_config = @@db_configs[environment]
  return environment_config if environment_config

  raise Errors::ConfigNotFoundError, 'Found no shard configurations for enviroment "' + environment + '" in ' + Config.shards_config_file.to_s + ' file was not found'
rescue Errno::ENOENT
  raise Errors::ConfigNotFoundError, Config.shards_config_file.to_s + ' file was not found'
end

.for_each_shard(shard_group_filter = nil, shard_name_filter = nil) ⇒ Object

yields a block for each shard in each shard group, with its configurations shard_group_filter: if passed yields only shards of this group shard_name_filter: if passed yields only shards with this name



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# File 'lib/rails/sharding/core.rb', line 59

def self.for_each_shard(shard_group_filter=nil, shard_name_filter=nil)
  shard_group_filter.to_s if shard_group_filter
  shard_name_filter.to_s if shard_name_filter

  configurations.each do |shard_group, shards_configurations|
    next if shard_group_filter && shard_group_filter != shard_group.to_s

    shards_configurations.each do |shard, configuration|
      next if shard_name_filter && shard_name_filter != shard.to_s
      yield shard_group, shard, configuration
    end
  end
end

.reset_configurations_cache ⇒ Object 



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# File 'lib/rails/sharding/core.rb', line 40

def self.reset_configurations_cache
  @@db_configs = nil
end

.setup ⇒ Object

Method that should be called on a rails initializer



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# File 'lib/rails/sharding/core.rb', line 74

def self.setup
  if block_given?
    yield Config
  end

  if Config.establish_all_connections_on_setup
    # Establishes connections with all shards specified in config/shards.yml
    ConnectionHandler.establish_all_connections
  end

  if Config.extend_active_record_scope
    # includes the #using_shard method to all AR scopes
    ActiveRecordExtensions.extend_active_record_scope
  end
end

.shard_groups ⇒ Object 



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# File 'lib/rails/sharding/core.rb', line 48

def self.shard_groups
  self.configurations.keys
end

.shard_names(shard_group) ⇒ Object 



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# File 'lib/rails/sharding/core.rb', line 52

def self.shard_names(shard_group)
  self.configurations[shard_group.to_s].keys
end

.test_configurations ⇒ Object 



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# File 'lib/rails/sharding/core.rb', line 44

def self.test_configurations
  self.configurations('test')
end

.using_shard(shard_group, shard_name) ⇒ Object

Opens a block where all queries will be directed to the selected shard



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# File 'lib/rails/sharding/core.rb', line 12

def self.using_shard(shard_group, shard_name)
  ShardThreadRegistry.push_current_shard(shard_group, shard_name)
  yield
ensure
  shard_group, shard_name, connection_used = ShardThreadRegistry.pop_current_shard

  # shows warning to user
  if Config.no_connection_retrieved_warning && !connection_used
    puts "Warning: no connection to shard '#{shard_group}:#{shard_name}' was retrieved inside the using_shard block. Make sure you don't forget to include Rails::Sharding::ShardableModel to the models you want to be sharded. Disable this warning with Rails::Sharding::Config.no_connection_retrieved_warning = false."
  end

  # Releases connections in case user left some connection in the reserved state
  # (by calling retrieve_connection instead of with_connection). Also, using
  # normal activerecord queries leaves a connection in the reserved state
  # Obs: don't do this with a master database connection
  ConnectionHandler.connection_pool(shard_group, shard_name).release_connection if shard_group && shard_name
end