Class: EventMachine::Hiredis::BaseClient

Inherits:
Object
  • Object
show all
Includes:
EM::Deferrable, EventEmitter
Defined in:
lib/em-hiredis/base_client.rb

Overview

Emits the following events

  • :connected - on successful connection or reconnection

  • :reconnected - on successful reconnection

  • :disconnected - no longer connected, when previously in connected state

  • :reconnect_failed(failure_number) - a reconnect attempt failed

    This event is passed number of failures so far (1,2,3...)

  • :monitor

Direct Known Subclasses

Client, PubsubClient

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from EventEmitter

#emit, #listeners, #on, #remove_all_listeners, #remove_listener

Constructor Details

#initialize(host = 'localhost', port = 6379, password = nil, db = nil) ⇒ BaseClient

Returns a new instance of BaseClient.



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# File 'lib/em-hiredis/base_client.rb', line 19

def initialize(host = 'localhost', port = 6379, password = nil, db = nil)
  @host, @port, @password, @db = host, port, password, db
  @defs = []
  @command_queue = []

  @reconnect_failed_count = 0
  @reconnect_timer = nil
  @failed = false

  self.on(:failed) {
    @failed = true
    @command_queue.each do |df, _, _|
      df.fail(Error.new("Redis connection in failed state"))
    end
    @command_queue = []
  }
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(sym, *args) ⇒ Object (private) 



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# File 'lib/em-hiredis/base_client.rb', line 186

def method_missing(sym, *args)
  deferred = EM::DefaultDeferrable.new
  # Shortcut for defining the callback case with just a block
  deferred.callback { |result| yield(result) } if block_given?

  if @connected
    @connection.send_command(sym, args)
    @defs.push(deferred)
  elsif @failed
    deferred.fail(Error.new("Redis connection in failed state"))
  else
    @command_queue << [deferred, sym, args]
  end

  deferred
end

Instance Attribute Details

#db ⇒ Object (readonly)

Returns the value of attribute db.



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# File 'lib/em-hiredis/base_client.rb', line 17

def db
  @db
end

#host ⇒ Object (readonly)

Returns the value of attribute host.



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# File 'lib/em-hiredis/base_client.rb', line 17

def host
  @host
end

#password ⇒ Object (readonly)

Returns the value of attribute password.



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# File 'lib/em-hiredis/base_client.rb', line 17

def password
  @password
end

#port ⇒ Object (readonly)

Returns the value of attribute port.



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# File 'lib/em-hiredis/base_client.rb', line 17

def port
  @port
end

Instance Method Details

#auth(password, &blk) ⇒ Object 



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# File 'lib/em-hiredis/base_client.rb', line 165

def auth(password, &blk)
  @password = password
  method_missing(:auth, password, &blk)
end

#close_connection ⇒ Object 



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# File 'lib/em-hiredis/base_client.rb', line 170

def close_connection
  EM.cancel_timer(@reconnect_timer) if @reconnect_timer
  @auto_reconnect = false
  @connection.close_connection_after_writing
end

#configure(uri_string) ⇒ Object

Configure the redis connection to use

In usual operation, the uri should be passed to initialize. This method is useful for example when failing over to a slave connection at runtime



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# File 'lib/em-hiredis/base_client.rb', line 42

def configure(uri_string)
  uri = URI(uri_string)

  if uri.scheme == "unix"
    @host = uri.path
    @port = nil
  else
    @host = uri.host
    @port = uri.port
    @password = uri.password
    path = uri.path[1..-1]
    @db = path.to_i # Empty path => 0
  end
end

#connect ⇒ Object 



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# File 'lib/em-hiredis/base_client.rb', line 70

def connect
  @auto_reconnect = true
  @connection = EM.connect(@host, @port, Connection, @host, @port)

  @connection.on(:closed) do
    if @connected
      @defs.each { |d| d.fail(Error.new("Redis disconnected")) }
      @defs = []
      @deferred_status = nil
      @connected = false
      if @auto_reconnect
        # Next tick avoids reconnecting after for example EM.stop
        EM.next_tick { reconnect }
      end
      emit(:disconnected)
      EM::Hiredis.logger.info("#{@connection} Disconnected")
    else
      if @auto_reconnect
        @reconnect_failed_count += 1
        @reconnect_timer = EM.add_timer(EM::Hiredis.reconnect_timeout) {
          @reconnect_timer = nil
          reconnect
        }
        emit(:reconnect_failed, @reconnect_failed_count)
        EM::Hiredis.logger.info("#{@connection} Reconnect failed")

        if @reconnect_failed_count >= 4
          emit(:failed)
          self.fail(Error.new("Could not connect after 4 attempts"))
        end
      end
    end
  end

  @connection.on(:connected) do
    @connected = true
    @reconnect_failed_count = 0
    @failed = false

    select(@db) unless @db == 0
    auth(@password) if @password

    @command_queue.each do |df, command, args|
      @connection.send_command(command, args)
      @defs.push(df)
    end
    @command_queue = []

    emit(:connected)
    EM::Hiredis.logger.info("#{@connection} Connected")
    succeed

    if @reconnecting
      @reconnecting = false
      emit(:reconnected)
    end
  end

  @connection.on(:message) do |reply|
    if RuntimeError === reply
      raise "Replies out of sync: #{reply.inspect}" if @defs.empty?
      deferred = @defs.shift
      error = RedisError.new(reply.message)
      error.redis_error = reply
      deferred.fail(error) if deferred
    else
      handle_reply(reply)
    end
  end

  @connected = false
  @reconnecting = false

  return self
end

#connected? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/em-hiredis/base_client.rb', line 156

def connected?
  @connected
end

#pending_commands? ⇒ Boolean

Indicates that commands have been sent to redis but a reply has not yet been received

This can be useful for example to avoid stopping the eventmachine reactor while there are outstanding commands

Returns:

  • (Boolean) 


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# File 'lib/em-hiredis/base_client.rb', line 152

def pending_commands?
  @connected && @defs.size > 0
end

#reconnect!(new_uri = nil) ⇒ Object

Disconnect then reconnect the redis connection.

Pass optional uri - e.g. to connect to a different redis server. Any pending redis commands will be failed, but during the reconnection new commands will be queued and sent after connected.



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# File 'lib/em-hiredis/base_client.rb', line 63

def reconnect!(new_uri = nil)
  @connection.close_connection
  configure(new_uri) if new_uri
  @auto_reconnect = true
  EM.next_tick { reconnect_connection }
end

#reconnect_connection ⇒ Object

Note: This method doesn’t disconnect if already connected. You probably want to use ‘reconnect!`



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# File 'lib/em-hiredis/base_client.rb', line 178

def reconnect_connection
  @auto_reconnect = true
  EM.cancel_timer(@reconnect_timer) if @reconnect_timer
  reconnect
end

#select(db, &blk) ⇒ Object 



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# File 'lib/em-hiredis/base_client.rb', line 160

def select(db, &blk)
  @db = db
  method_missing(:select, db, &blk)
end