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

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

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

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 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 . . . . . . . . . . . . . . . .

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 4.0.2 • 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

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 4.0.2 • 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

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 4.0.1 • 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