Class | Sequel::ShardedSingleConnectionPool |
In: |
lib/sequel/connection_pool/sharded_single.rb
|
Parent: | Sequel::ConnectionPool |
A ShardedSingleConnectionPool is a single threaded connection pool that works with multiple shards/servers.
The single threaded pool takes the following options:
:servers : | A hash of servers to use. Keys should be symbols. If not present, will use a single :default server. |
:servers_hash : | The base hash to use for the servers. By default, Sequel uses Hash.new(:default). You can use a hash with a default proc that raises an error if you want to catch all cases where a nonexistent server is used. |
# File lib/sequel/connection_pool/sharded_single.rb, line 14 14: def initialize(db, opts=OPTS) 15: super 16: @conns = {} 17: @servers = opts.fetch(:servers_hash, Hash.new(:default)) 18: add_servers([:default]) 19: add_servers(opts[:servers].keys) if opts[:servers] 20: end
Adds new servers to the connection pool. Primarily used in conjunction with master/slave or shard configurations. Allows for dynamic expansion of the potential slaves/shards at runtime. servers argument should be an array of symbols.
# File lib/sequel/connection_pool/sharded_single.rb, line 25 25: def add_servers(servers) 26: servers.each{|s| @servers[s] = s} 27: end
Yield all of the currently established connections
# File lib/sequel/connection_pool/sharded_single.rb, line 30 30: def all_connections 31: @conns.values.each{|c| yield c} 32: end
The connection for the given server.
# File lib/sequel/connection_pool/sharded_single.rb, line 35 35: def conn(server=:default) 36: @conns[@servers[server]] 37: end
Disconnects from the database. Once a connection is requested using hold, the connection is reestablished. Options:
:server : | Should be a symbol specifing the server to disconnect from, or an array of symbols to specify multiple servers. |
# File lib/sequel/connection_pool/sharded_single.rb, line 43 43: def disconnect(opts=OPTS) 44: (opts[:server] ? Array(opts[:server]) : servers).each{|s| disconnect_server(s)} 45: end
# File lib/sequel/connection_pool/sharded_single.rb, line 47 47: def freeze 48: @servers.freeze 49: super 50: end
Yields the connection to the supplied block for the given server. This method simulates the ConnectionPool#hold API.
# File lib/sequel/connection_pool/sharded_single.rb, line 54 54: def hold(server=:default) 55: begin 56: server = pick_server(server) 57: yield(@conns[server] ||= make_new(server)) 58: rescue Sequel::DatabaseDisconnectError, *@error_classes => e 59: disconnect_server(server) if disconnect_error?(e) 60: raise 61: end 62: end
The ShardedSingleConnectionPool always has a maximum size of 1.
# File lib/sequel/connection_pool/sharded_single.rb, line 65 65: def max_size 66: 1 67: end
# File lib/sequel/connection_pool/sharded_single.rb, line 90 90: def pool_type 91: :sharded_single 92: end
Remove servers from the connection pool. Similar to disconnecting from all given servers, except that after it is used, future requests for the server will use the :default server instead.
# File lib/sequel/connection_pool/sharded_single.rb, line 72 72: def remove_servers(servers) 73: raise(Sequel::Error, "cannot remove default server") if servers.include?(:default) 74: servers.each do |server| 75: disconnect_server(server) 76: @servers.delete(server) 77: end 78: end