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# frozen-string-literal: true
# The base connection pool class, which all other connection pools are based
# on. This class is not instantiated directly, but subclasses should at
# the very least implement the following API:
#
# initialize(Database, Hash) :: Initialize using the passed Sequel::Database
# object and options hash.
# hold(Symbol, &block) :: Yield a connection object (obtained from calling
# the block passed to +initialize+) to the current block. For sharded
# connection pools, the Symbol passed is the shard/server to use.
# disconnect(Symbol) :: Disconnect the connection object. For sharded
# connection pools, the Symbol passed is the shard/server to use.
# servers :: An array of shard/server symbols for all shards/servers that this
# connection pool recognizes.
# size :: an integer representing the total number of connections in the pool,
# or for the given shard/server if sharding is supported.
# max_size :: an integer representing the maximum size of the connection pool,
# or the maximum size per shard/server if sharding is supported.
#
# For sharded connection pools, the sharded API adds the following methods:
#
# add_servers(Array of Symbols) :: start recognizing all shards/servers specified
# by the array of symbols.
# remove_servers(Array of Symbols) :: no longer recognize all shards/servers
# specified by the array of symbols.
class Sequel::ConnectionPool
OPTS = Sequel::OPTS
POOL_CLASS_MAP = {
:threaded => :ThreadedConnectionPool,
:single => :SingleConnectionPool,
:sharded_threaded => :ShardedThreadedConnectionPool,
:sharded_single => :ShardedSingleConnectionPool
}.freeze
# Class methods used to return an appropriate pool subclass, separated
# into a module for easier overridding by extensions.
module ClassMethods
# Return a pool subclass instance based on the given options. If a <tt>:pool_class</tt>
# option is provided is provided, use that pool class, otherwise
# use a new instance of an appropriate pool subclass based on the
# <tt>:single_threaded</tt> and <tt>:servers</tt> options.
def get_pool(db, opts = OPTS)
connection_pool_class(opts).new(db, opts)
end
private
# Return a connection pool class based on the given options.
def connection_pool_class(opts)
if pc = opts[:pool_class]
unless pc.is_a?(Class)
unless name = POOL_CLASS_MAP[pc]
raise Sequel::Error, "unsupported connection pool type, please pass appropriate class as the :pool_class option"
end
require_relative "connection_pool/#{pc}"
pc = Sequel.const_get(name)
end
pc
else
pc = if opts[:single_threaded]
opts[:servers] ? :sharded_single : :single
else
opts[:servers] ? :sharded_threaded : :threaded
end
connection_pool_class(:pool_class=>pc)
end
end
end
extend ClassMethods
# The after_connect proc used for this pool. This is called with each new
# connection made, and is usually used to set custom per-connection settings.
attr_accessor :after_connect
# An array of sql strings to execute on each new connection.
attr_accessor :connect_sqls
# The Sequel::Database object tied to this connection pool.
attr_accessor :db
# Instantiates a connection pool with the given options. The block is called
# with a single symbol (specifying the server/shard to use) every time a new
# connection is needed. The following options are respected for all connection
# pools:
# :after_connect :: A callable object called after each new connection is made, with the
# connection object (and server argument if the callable accepts 2 arguments),
# useful for customizations that you want to apply to all connections.
# :connect_sqls :: An array of sql strings to execute on each new connection, after :after_connect runs.
def initialize(db, opts=OPTS)
@db = db
@after_connect = opts[:after_connect]
@connect_sqls = opts[:connect_sqls]
@error_classes = db.send(:database_error_classes).dup.freeze
end
# An array of symbols for all shards/servers, which is a single <tt>:default</tt> by default.
def servers
[:default]
end
private
# Remove the connection from the pool. For threaded connections, this should be
# called without the mutex, because the disconnection may block.
def disconnect_connection(conn)
db.disconnect_connection(conn)
end
# Whether the given exception is a disconnect exception.
def disconnect_error?(exception)
exception.is_a?(Sequel::DatabaseDisconnectError) || db.send(:disconnect_error?, exception, OPTS)
end
# Return a new connection by calling the connection proc with the given server name,
# and checking for connection errors.
def make_new(server)
begin
conn = @db.connect(server)
if ac = @after_connect
if ac.arity == 2
ac.call(conn, server)
else
ac.call(conn)
end
end
if cs = @connect_sqls
cs.each do |sql|
db.send(:log_connection_execute, conn, sql)
end
end
rescue Exception=>exception
raise Sequel.convert_exception_class(exception, Sequel::DatabaseConnectionError)
end
raise(Sequel::DatabaseConnectionError, "Connection parameters not valid") unless conn
conn
end
end
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