class Rails::Sharding::Core

Public Class Methods

configurations(environment=Rails.env) click to toggle source
# File lib/rails/sharding/core.rb, line 31
def self.configurations(environment=Rails.env)
  @@db_configs ||= YAML.load(ERB.new(File.read(Config.shards_config_file)).result)
  environment_config = @@db_configs[environment]
  return environment_config if environment_config

  raise Errors::ConfigNotFoundError, 'Found no shard configurations for environment "' + 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(environment:Rails.env, shard_group_filter:nil, shard_name_filter:nil) { |shard_group, shard, configuration| ... } click to toggle source

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

# File lib/rails/sharding/core.rb, line 60
def self.for_each_shard(environment:Rails.env, 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(environment).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() click to toggle source
# File lib/rails/sharding/core.rb, line 41
def self.reset_configurations_cache
  @@db_configs = nil
end
setup() { |Config| ... } click to toggle source

Method that should be called on a rails initializer

# File lib/rails/sharding/core.rb, line 75
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() click to toggle source
# File lib/rails/sharding/core.rb, line 49
def self.shard_groups
  self.configurations.keys
end
shard_names(shard_group) click to toggle source
# File lib/rails/sharding/core.rb, line 53
def self.shard_names(shard_group)
  self.configurations[shard_group.to_s].keys
end
test_configurations() click to toggle source
# File lib/rails/sharding/core.rb, line 45
def self.test_configurations
  self.configurations('test')
end
using_shard(shard_group, shard_name) { || ... } click to toggle source

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

# 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
  was_connected_to_master = ShardThreadRegistry.connecting_to_master?
  shard_group, shard_name, connection_used = ShardThreadRegistry.pop_current_shard

  # shows warning to user (except when connected to master database)
  if Config.no_connection_retrieved_warning && !connection_used && !was_connected_to_master
    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