Class: Shoryuken::Polling::BaseStrategy Abstract

Inherits:
Object
  • Object
show all
Includes:
Util
Defined in:
lib/shoryuken/polling/base_strategy.rb

Overview

This class is abstract.

Subclass and override #next_queue, #messages_found, and #active_queues to implement a custom polling strategy.

Abstract base class for queue polling strategies.

This class defines the interface that all polling strategies must implement to manage queue selection and message flow control in Shoryuken workers. Polling strategies determine which queue to fetch messages from next and how to handle scenarios where queues have no messages available.

Examples:

Implementing a custom polling strategy

class CustomStrategy < BaseStrategy
  def initialize(queues)
    @queues = queues
  end

  def next_queue
    # Return next queue to poll
    @queues.sample
  end

  def messages_found(queue, count)
    # Handle result of polling
    logger.info "Found #{count} messages in #{queue}"
  end

  def active_queues
    # Return list of active queues
    @queues
  end
end

See Also:

Direct Known Subclasses

StrictPriority, WeightedRoundRobin

Instance Method Summary collapse

Methods included from Util

#elapsed, #fire_event, #logger, #unparse_queues, #worker_name

Instance Method Details

#==(other) ⇒ Boolean

Compares this strategy with another object for equality.

Two strategies are considered equal if they have the same active queues. This method also supports comparison with Array objects for backward compatibility.

Parameters:

  • other (Object) —

    Object to compare with

Returns:

  • (Boolean) —

    true if strategies are equivalent



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# File 'lib/shoryuken/polling/base_strategy.rb', line 101

def ==(other)
  case other
  when Array
    @queues == other
  else
    if other.respond_to?(:active_queues)
      active_queues == other.active_queues
    else
      false
    end
  end
end

#active_queues ⇒ Array

This method is abstract.

Subclasses must implement this method

Returns the list of currently active queues.

This method should return an array representing the queues that are currently active and available for polling. The format may vary by strategy implementation.

Returns:

  • (Array) —

    List of active queues

Raises:

  • (NotImplementedError) —

    if not implemented by subclass



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# File 'lib/shoryuken/polling/base_strategy.rb', line 89

def active_queues
  fail NotImplementedError
end

#delay ⇒ Float

Returns the delay time for pausing empty queues.

This method returns the amount of time (in seconds) that empty queues should be paused before being polled again. The delay can be set at the strategy level or falls back to the global Shoryuken delay setting.

Returns:

  • (Float) —

    Delay time in seconds



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# File 'lib/shoryuken/polling/base_strategy.rb', line 121

def delay
  @delay || Shoryuken.options[:delay].to_f
end

#message_processed(_queue) ⇒ void

This method returns an undefined value.

Called when a message from a queue has been processed.

This optional callback is invoked after a message has been successfully processed by a worker. Strategies can use this information for cleanup or to adjust their polling behavior.

Parameters:

  • _queue (String) —

    The name of the queue whose message was processed



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# File 'lib/shoryuken/polling/base_strategy.rb', line 78

def message_processed(_queue); end

#messages_found(_queue, _messages_found) ⇒ Object

This method is abstract.

Subclasses must implement this method

Called when messages are found (or not found) in a queue.

This method is invoked after polling a queue to inform the strategy about the number of messages that were retrieved. Strategies can use this information to make decisions about future polling behavior, such as pausing empty queues or adjusting queue weights.

Parameters:

  • _queue (String) —

    The name of the queue that was polled

  • _messages_found (Integer) —

    The number of messages retrieved

Raises:

  • (NotImplementedError) —

    if not implemented by subclass



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# File 'lib/shoryuken/polling/base_strategy.rb', line 66

def messages_found(_queue, _messages_found)
  fail NotImplementedError
end

#next_queue ⇒ QueueConfiguration?

This method is abstract.

Subclasses must implement this method

Returns the next queue to poll for messages.

This method should return a QueueConfiguration object representing the next queue that should be polled for messages, or nil if no queues are currently available for polling.

Returns:

Raises:

  • (NotImplementedError) —

    if not implemented by subclass



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# File 'lib/shoryuken/polling/base_strategy.rb', line 51

def next_queue
  fail NotImplementedError
end