We need a system Orchestrator to implement the robot behaviorRobot Behaviors This Coordinator or Task Planner is also the highest level of abstraction of our system, where we focus on WHAT the robot

used when we created them.” - Albert EinsteinSo what is there to Rethink?Rethinking: Task Queues Problem #1 - Task Queues Do Not Scale Well: ● Contention: ○ Even the most meticulously designed lock-free problems: ○ Task starvation ○ Load balancing ○ Forfeits strict FIFO behaviour ○ Increases memory footprint (or requires allocations) ○ Terrible task selection “fairness” Task Thread Thread Thread Task Task Task Task Task Task Task Task Back Front Task Queue Execute Task() Thread Thread PoolRethinking: Task Queues Problem #2 - No Inherent Support For Prioritization: ● Priority queues address this but

in a top-down task graph What is Task Graph-based Programming System (TGPS) Code 4• TGPS encapsulates function calls and their dependencies in a top-down task graph What is Task Graph-based Programming top-down task graph What is Task Graph-based Programming System (TGPS) Code A B C D B A C D 6• TGPS encapsulates function calls and their dependencies in a top-down task graph What is Task Graph-based sched; 2 task_a = sched.emplace([](&){ 3 // Code block A; 4 }); 5 task_b = sched.emplace([](&){ 6 // Code block B; 7 }); 8 task_c = sched.emplace([](&){ 9 // Code block C; 10 }); 11 task_d = sched

older version of Celery (2.1). For the latest stable version please go here. Celery - Distributed Task Queue Contents: Getting Started Introduction Broker Installation First steps with Celery Resources Reference Task Decorators - celery.decorators Defining Tasks - celery.task.base Task Sets, Subtasks and Callbacks - celery.task.sets Executing Tasks - celery.execute Task Result - celery.result Task Information Information and Utilities - celery.task Configuration - celery.conf Remote Management of Workers - celery.task.control HTTP Callback Tasks - celery.task.http Periodic Task Schedule Behaviors - celery.schedules

112 9 API Reference 113 9.1 Task Decorators - celery.decorators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 9.2 Defining Tasks - celery.task.base . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114 9.3 Task Sets, Subtasks and Callbacks - celery.task.sets . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 9.4 Executing Tasks - celery . . . . . 122 9.5 Task Result - celery.result . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123 9.6 Task Information and Utilities - celery.task . . . . . . . . . .

http://github.com/ask/celery/ Keywords task queue, job queue, asynchronous, rabbitmq, amqp, redis, python, webhooks, queue, dis- tributed – Celery is an open source asynchronous task queue/job queue based on distributed of the task can be stored for later retrieval (called its “tombstone”). 1.1.2 Example You probably want to see some code by now, so here’s an example task adding two numbers: from celery.task import import task @task def add(x, y): return x + y You can execute the task in the background, or wait for it to finish: >>> result = add.delay(4, 4) >>> result.wait() # wait for and return the result 8 Simple

documentation » This document describes Celery 2.3. For development docs, go here. Celery - Distributed Task Queue Contents: Getting Started Introduction Broker Installation First steps with Celery Resources Installing RabbitMQ on OS X First steps with Celery Creating a simple task Configuration Running the celery worker server Executing the task Where to go from here Resources Getting Help Bug tracker Wiki Contributing http://github.com/ask/celery/ Keywords: task queue, job queue, asynchronous, rabbitmq, amqp, redis, python, webhooks, queue, distributed – Celery is an open source asynchronous task queue/job queue based on distributed

operations with the tools required to maintain such a system. It’s a task queue with focus on real-time processing, while also supporting task scheduling. Celery has a large and diverse community of users and Release 4.1.0 • What’s a Task Queue? • What do I need? • Get Started • Celery is... • Features • Framework Integration • Quick Jump • Installation What’s a Task Queue? Task queues are used as a mechanism to distribute work across threads or machines. A task queue’s input is a unit of work called a task. Dedicated worker processes constantly monitor task queues for new work to perform. Celery communicates

describes the current stable version of Celery (4.1). For development docs, go here. Celery - Distributed Task Queue Celery is a simple, flexible, and reliable distributed system to process vast amounts of messages operations with the tools required to maintain such a system. It’s a task queue with focus on real-time processing, while also supporting task scheduling. Celery has a large and diverse community of users and docs, go here. Getting Started Release: 4.1 Date: Jul 24, 2017 Introduction to Celery What’s a Task Queue? What do I need? Get Started Celery is… Features Framework Integration Quick Jump Installation

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219 10.2 celery.app.task . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222 10 . . . . . . . . . . . 231 10.5 celery.task . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232 10.6 celery.task.base . . . . . . . . . . . . . . . . . . . . . . . . . . . 233 10.7 celery.task.sets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240 10.8 celery.task.chords . . . . . . . . . . . . . . . .