class JoobQ::Timeout::TimeoutError

• JoobQ::Timeout::TimeoutError
• Exception
• Reference
• Object

Overview

The Timeout class in the JoobQ module provides a mechanism to execute a block of code with a specified timeout. If the block takes longer than the specified timeout to complete, it raises a Timeout::TimeoutError.

Properties

• TimeoutError < Exception - Custom exception raised when a block exceeds the specified timeout.

Methods

run

def self.run(timeout : Time::Span, &block : ->)

Executes the given block with a timeout. If the block takes longer than the specified timeout (in seconds) to complete, it raises a Timeout::TimeoutError.

• Parameters:
  • timeout (Time::Span): The maximum duration that the block is allowed to run.
  • block (->): The block of code to execute with a timeout.
• Raises:
  • Timeout::TimeoutError if the block exceeds the specified timeout.

Usage

Executing a Block with a Timeout

To execute a block of code with a timeout, use the run method:

begin
  JoobQ::Timeout.run(5.seconds) do
    # Your code here
    sleep 10 # Simulate a long-running task
  end
rescue JoobQ::Timeout::TimeoutError
  puts "The block exceeded the timeout!"
end

Workflow

1. Initialization:

• The run method is called with a specified timeout and a block of code.
• A timeout_channel is created to signal the completion or timeout of the block.

2. Executing the Block:

• A fiber (task_fiber) is spawned to execute the block.
• The block is called, and upon completion, a signal is sent through the timeout_channel.
• If an exception occurs within the block, the signal is still sent, and the exception is re-raised.

3. Enforcing the Timeout:

• Another fiber is spawned to enforce the timeout.
• The fiber sleeps for the specified timeout duration and then closes the timeout_channel.

4. Checking Completion:

• The method waits on the timeout_channel to check if the block completed within the timeout.
• If the block completes within the timeout, the method returns true.
• If the block exceeds the timeout, a Timeout::TimeoutError is raised, and the task_fiber is terminated.

Example

Here is a complete example demonstrating how to use the Timeout class:

require "joobq"

begin
  JoobQ::Timeout.run(5.seconds) do
    puts "Starting a task..."
    sleep 10 # Simulate a long-running task
    puts "Task completed!"
  end
rescue JoobQ::Timeout::TimeoutError
  puts "The block exceeded the timeout!"
end

This example attempts to execute a block that sleeps for 10 seconds with a timeout of 5 seconds. Since the block exceeds the timeout, a Timeout::TimeoutError is raised, and the message "The block exceeded the timeout!" is printed.

Defined in:

joobq/timeout.cr