gocelery

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 Go to latest Published: Dec 12, 2018 License: MIT Imports: 11 Imported by: 0

README

gocelery

Go Client/Server for Celery Distributed Task Queue

Build Status Coverage Status Go Report Card GoDoc License motivation

Why?

Having being involved in a number of projects migrating server from python to go, I have realized Go can help improve performance of existing python web applications. Celery distributed tasks are used heavily in many python web applications and this library allows you to implement celery workers in Go as well as being able to submit celery tasks in Go.

You can also use this library as pure go distributed task queue.

Go Celery Worker in Action

demo

Supported Brokers/Backends

Now supporting both Redis and AMQP!!

  • Redis (broker/backend)
  • AMQP (broker/backend) - does not allow concurrent use of channels

Celery Configuration

Celery must be configured to use json instead of default pickle encoding. This is because Go currently has no stable support for decoding pickle objects. Pass below configuration parameters to use json.

CELERY_TASK_SERIALIZER='json',
CELERY_ACCEPT_CONTENT=['json'],  # Ignore other content
CELERY_RESULT_SERIALIZER='json',
CELERY_ENABLE_UTC=True,

Celery Worker Example

Run Celery Worker implemented in Go

// example/worker/main.go

// Celery Task
func add(a int, b int) int {
	return a + b
}

func main() {
    // create broker and backend
	celeryBroker := gocelery.NewRedisCeleryBroker("localhost:6379", 0, "pass", gocelery.BrokerQueueName("queue-busy"))
    celeryBackend := gocelery.NewRedisCeleryBackend("localhost:6379", 0,  "pass")

    // use AMQP instead
    // celeryBroker := gocelery.NewAMQPCeleryBroker("amqp://")
    // celeryBackend := gocelery.NewAMQPCeleryBackend("amqp://")

	// Configure with 2 celery workers
	celeryClient, _ := gocelery.NewCeleryClient(celeryBroker, celeryBackend, 2)

	// worker.add name reflects "add" task method found in "worker.py"
	celeryClient.Register("worker.add", add)

    // Start Worker - blocking method
	go celeryClient.StartWorker()

    // Wait 30 seconds and stop all workers
	time.Sleep(30 * time.Second)
	celeryClient.StopWorker()
}

go run example/worker/main.go

You can use custom struct instead to hold shared structures.


type MyStruct struct {
	MyInt int
}

func (so *MyStruct) add(a int, b int) int {
	return a + b + so.MyInt
}

// code omitted ...

ms := &MyStruct{10}
celeryClient.Register("worker.add", ms.add)

// code omitted ...

Submit Task from Python Client

# example/test.py

from celery import Celery

app = Celery('tasks',
    broker='redis://localhost:6379',
    backend='redis://localhost:6379'
)

@app.task
def add(x, y):
    return x + y

if __name__ == '__main__':
    # submit celery task to be executed in Go workers
    ar = add.apply_async((5456, 2878), serializer='json')
    print(ar.get())

python example/test.py

Celery Client Example

Run Celery Worker implemented in Python

# example/worker.py

from celery import Celery

app = Celery('tasks',
    broker='redis://localhost:6379',
    backend='redis://localhost:6379'
)

@app.task
def add(x, y):
    return x + y

cd example
celery -A worker worker --loglevel=debug --without-heartbeat --without-mingle

Submit Task from Go Client

func main() {
    // create broker and backend
	celeryBroker := gocelery.NewRedisCeleryBroker("localhost:6379", "")
    celeryBackend := gocelery.NewRedisCeleryBackend("localhost:6379", "")

    // use AMQP instead
    // celeryBroker := gocelery.NewAMQPCeleryBroker("amqp://")
    // celeryBackend := gocelery.NewAMQPCeleryBackend("amqp://")

    // create client
	celeryClient, _ := gocelery.NewCeleryClient(celeryBroker, celeryBackend, 0)

    // send task
	asyncResult, err := celeryClient.Delay("worker.add", 3, 5)
	if err != nil {
		panic(err)
	}

    // check if result is ready
	isReady, _ := asyncResult.Ready()
	fmt.Printf("ready status %v\n", isReady)

    // get result with 5s timeout
	res, err = asyncResult.Get(5 * time.Second)
	if err != nil {
		fmt.Println(err)
	} else {
        fmt.Println(res)
    }
}

go run example/client/main.go

Sample Celery Task Message

{
    "expires": null,
    "utc": true,
    "args": [5456, 2878],
    "chord": null,
    "callbacks": null,
    "errbacks": null,
    "taskset": null,
    "id": "c8535050-68f1-4e18-9f32-f52f1aab6d9b",
    "retries": 0,
    "task": "worker.add",
    "timelimit": [null, null],
    "eta": null,
    "kwargs": {}
}

Contributing

You are more than welcome to make any contributions. Please create Pull Request for any changes.

LICENSE

The gocelery is offered under MIT license.

Documentation

Overview

Package gocelery is Celery Distributed Task Queue in Go

Celery distributed tasks are used heavily in many python web applications and this library allows you to implement celery workers in Go as well as being able to submit celery tasks in Go.

This package can also be used as pure go distributed task queue.

Supported brokers/backends

  • Redis (broker/backend)
  • AMQP (broker/backend)

Celery must be configured to use json instead of default pickle encoding. This is because Go currently has no stable support for decoding pickle objects. Pass below configuration parameters to use json. 

CELERY_TASK_SERIALIZER='json'
CELERY_ACCEPT_CONTENT=['json']  # Ignore other content
CELERY_RESULT_SERIALIZER='json'
CELERY_ENABLE_UTC=True

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func GetRealValue 

func GetRealValue(val *reflect.Value) interface{}

GetRealValue returns real value of reflect.Value Required for JSON Marshalling

func NewAMQPConnection 

func NewAMQPConnection(host string) (*amqp.Connection, *amqp.Channel)

NewAMQPConnection creates new AMQP channel

func NewRedisPool 

func NewRedisPool(host string, db int, pass string) *redis.Pool

NewRedisPool creates pool of redis connections

Types

type AMQPCeleryBackend 

type AMQPCeleryBackend struct {
	*amqp.Channel
	// contains filtered or unexported fields
}

AMQPCeleryBackend CeleryBackend for AMQP

func NewAMQPCeleryBackend 

func NewAMQPCeleryBackend(host string) *AMQPCeleryBackend

NewAMQPCeleryBackend creates new AMQPCeleryBackend

func (*AMQPCeleryBackend) GetResult 

func (b *AMQPCeleryBackend) GetResult(taskID string) (*ResultMessage, error)

GetResult retrieves result from AMQP queue

func (*AMQPCeleryBackend) Reconnect 

func (b *AMQPCeleryBackend) Reconnect()

Reconnect reconnects to AMQP server

func (*AMQPCeleryBackend) SetResult 

func (b *AMQPCeleryBackend) SetResult(taskID string, result *ResultMessage) error

SetResult sets result back to AMQP queue

type AMQPCeleryBroker 

type AMQPCeleryBroker struct {
	*amqp.Channel
	// contains filtered or unexported fields
}

AMQPCeleryBroker is RedisBroker for AMQP

func NewAMQPCeleryBroker 

func NewAMQPCeleryBroker(host string) *AMQPCeleryBroker

NewAMQPCeleryBroker creates new AMQPCeleryBroker

func (*AMQPCeleryBroker) CreateExchange 

func (b *AMQPCeleryBroker) CreateExchange() error

CreateExchange declares AMQP exchange with stored configuration

func (*AMQPCeleryBroker) CreateQueue 

func (b *AMQPCeleryBroker) CreateQueue() error

CreateQueue declares AMQP Queue with stored configuration

func (*AMQPCeleryBroker) GetTaskMessage 

func (b *AMQPCeleryBroker) GetTaskMessage() (*TaskMessage, error)

GetTaskMessage retrieves task message from AMQP queue

func (*AMQPCeleryBroker) SendCeleryMessage 

func (b *AMQPCeleryBroker) SendCeleryMessage(message *CeleryMessage) error

SendCeleryMessage sends CeleryMessage to broker

func (*AMQPCeleryBroker) StartConsumingChannel 

func (b *AMQPCeleryBroker) StartConsumingChannel() error

StartConsumingChannel spawns receiving channel on AMQP queue

type AMQPExchange 

type AMQPExchange struct {
	Name       string
	Type       string
	Durable    bool
	AutoDelete bool
}

AMQPExchange stores AMQP Exchange configuration

func NewAMQPExchange 

func NewAMQPExchange(name string) *AMQPExchange

NewAMQPExchange creates new AMQPExchange

type AMQPQueue 

type AMQPQueue struct {
	Name       string
	Durable    bool
	AutoDelete bool
}

AMQPQueue stores AMQP Queue configuration

func NewAMQPQueue 

func NewAMQPQueue(name string) *AMQPQueue

NewAMQPQueue creates new AMQPQueue

type AsyncResult 

type AsyncResult struct {
	// contains filtered or unexported fields
}

AsyncResult is pending result

func (*AsyncResult) AsyncGet 

func (ar *AsyncResult) AsyncGet() (interface{}, error)

AsyncGet gets actual result from redis and returns nil if not available

func (*AsyncResult) Get 

func (ar *AsyncResult) Get(timeout time.Duration) (interface{}, error)

Get gets actual result from redis It blocks for period of time set by timeout and return error if unavailable

func (*AsyncResult) Ready 

func (ar *AsyncResult) Ready() (bool, error)

Ready checks if actual result is ready

type BrokerOptions 

type BrokerOptions struct {
	// contains filtered or unexported fields
}

func BrokerQueueName 

func BrokerQueueName(queueName string) BrokerOptions

type CeleryBackend 

type CeleryBackend interface {
	GetResult(string) (*ResultMessage, error) // must be non-blocking
	SetResult(taskID string, result *ResultMessage) error
}

CeleryBackend is interface for celery backend database

type CeleryBroker 

type CeleryBroker interface {
	SendCeleryMessage(*CeleryMessage) error
	GetTaskMessage() (*TaskMessage, error) // must be non-blocking
}

CeleryBroker is interface for celery broker database

type CeleryClient 

type CeleryClient struct {
	// contains filtered or unexported fields
}

CeleryClient provides API for sending celery tasks

func NewCeleryClient 

func NewCeleryClient(broker CeleryBroker, backend CeleryBackend, numWorkers int) (*CeleryClient, error)

NewCeleryClient creates new celery client

func (*CeleryClient) Delay 

func (cc *CeleryClient) Delay(task string, args ...interface{}) (*AsyncResult, error)

Delay gets asynchronous result

func (*CeleryClient) DelayKwargs 

func (cc *CeleryClient) DelayKwargs(task string, args map[string]interface{}) (*AsyncResult, error)

DelayKwargs gets asynchronous results with argument map

func (*CeleryClient) Register 

func (cc *CeleryClient) Register(name string, task interface{})

Register task

func (*CeleryClient) StartWorker 

func (cc *CeleryClient) StartWorker()

StartWorker starts celery workers

func (*CeleryClient) StopWorker 

func (cc *CeleryClient) StopWorker()

StopWorker stops celery workers

type CeleryDeliveryInfo 

type CeleryDeliveryInfo struct {
	Priority   int    `json:"priority"`
	RoutingKey string `json:"routing_key"`
	Exchange   string `json:"exchange"`
}

CeleryDeliveryInfo represents deliveryinfo json

type CeleryMessage 

type CeleryMessage struct {
	Body            string                 `json:"body"`
	Headers         map[string]interface{} `json:"headers"`
	ContentType     string                 `json:"content-type"`
	Properties      CeleryProperties       `json:"properties"`
	ContentEncoding string                 `json:"content-encoding"`
}

CeleryMessage is actual message to be sent to Redis

func (*CeleryMessage) GetTaskMessage 

func (cm *CeleryMessage) GetTaskMessage() *TaskMessage

GetTaskMessage retrieve and decode task messages from broker

type CeleryProperties 

type CeleryProperties struct {
	BodyEncoding  string             `json:"body_encoding"`
	CorrelationID string             `json:"correlation_id"`
	ReplyTo       string             `json:"replay_to"`
	DeliveryInfo  CeleryDeliveryInfo `json:"delivery_info"`
	DeliveryMode  int                `json:"delivery_mode"`
	DeliveryTag   string             `json:"delivery_tag"`
}

CeleryProperties represents properties json

type CeleryTask 

type CeleryTask interface {

	// ParseKwargs - define a method to parse kwargs
	ParseKwargs(map[string]interface{}) error

	// RunTask - define a method to run
	RunTask() (interface{}, error)
}

CeleryTask is an interface that represents actual task Passing CeleryTask interface instead of function pointer avoids reflection and may have performance gain. ResultMessage must be obtained using GetResultMessage()

type CeleryWorker 

type CeleryWorker struct {
	// contains filtered or unexported fields
}

CeleryWorker represents distributed task worker

func NewCeleryWorker 

func NewCeleryWorker(broker CeleryBroker, backend CeleryBackend, numWorkers int) *CeleryWorker

NewCeleryWorker returns new celery worker

func (*CeleryWorker) GetNumWorkers 

func (w *CeleryWorker) GetNumWorkers() int

GetNumWorkers returns number of currently running workers

func (*CeleryWorker) GetTask 

func (w *CeleryWorker) GetTask(name string) interface{}

GetTask retrieves registered task

func (*CeleryWorker) Register 

func (w *CeleryWorker) Register(name string, task interface{})

Register registers tasks (functions)

func (*CeleryWorker) RunTask 

func (w *CeleryWorker) RunTask(message *TaskMessage) (*ResultMessage, error)

RunTask runs celery task

func (*CeleryWorker) StartWorker 

func (w *CeleryWorker) StartWorker()

StartWorker starts celery worker

func (*CeleryWorker) StopWorker 

func (w *CeleryWorker) StopWorker()

StopWorker stops celery workers

type RedisCeleryBackend 

type RedisCeleryBackend struct {
	*redis.Pool
}

RedisCeleryBackend is CeleryBackend for Redis

func NewRedisCeleryBackend 

func NewRedisCeleryBackend(host string, db int, pass string) *RedisCeleryBackend

NewRedisCeleryBackend creates new RedisCeleryBackend

func (*RedisCeleryBackend) GetResult 

func (cb *RedisCeleryBackend) GetResult(taskID string) (*ResultMessage, error)

GetResult calls API to get asynchronous result Should be called by AsyncResult

func (*RedisCeleryBackend) SetResult 

func (cb *RedisCeleryBackend) SetResult(taskID string, result *ResultMessage) error

SetResult pushes result back into backend

type RedisCeleryBroker 

type RedisCeleryBroker struct {
	*redis.Pool
	QueueName string
	// contains filtered or unexported fields
}

RedisCeleryBroker is CeleryBroker for Redis

func NewRedisCeleryBroker 

func NewRedisCeleryBroker(host string, db int, pass string, options ...BrokerOptions) *RedisCeleryBroker

NewRedisCeleryBroker creates new RedisCeleryBroker

func (*RedisCeleryBroker) GetCeleryMessage 

func (cb *RedisCeleryBroker) GetCeleryMessage() (*CeleryMessage, error)

GetCeleryMessage retrieves celery message from redis queue

func (*RedisCeleryBroker) GetTaskMessage 

func (cb *RedisCeleryBroker) GetTaskMessage() (*TaskMessage, error)

GetTaskMessage retrieves task message from redis queue

func (*RedisCeleryBroker) SendCeleryMessage 

func (cb *RedisCeleryBroker) SendCeleryMessage(message *CeleryMessage) error

SendCeleryMessage sends CeleryMessage to redis queue

type ResultMessage 

type ResultMessage struct {
	ID        string        `json:"task_id"`
	Status    string        `json:"status"`
	Traceback interface{}   `json:"traceback"`
	Result    interface{}   `json:"result"`
	Children  []interface{} `json:"children"`
}

ResultMessage is return message received from broker

type TaskMessage 

type TaskMessage struct {
	ID      string                 `json:"id"`
	Task    string                 `json:"task"`
	Args    []interface{}          `json:"args"`
	Kwargs  map[string]interface{} `json:"kwargs"`
	Retries int                    `json:"retries"`
	ETA     string                 `json:"eta"`
}

TaskMessage is celery-compatible message

func DecodeTaskMessage 

func DecodeTaskMessage(encodedBody string) (*TaskMessage, error)

DecodeTaskMessage decodes base64 encrypted body and return TaskMessage object

func (*TaskMessage) Encode 

func (tm *TaskMessage) Encode() (string, error)

Encode returns base64 json encoded string

Source Files

View all Source files

Directories

Path Synopsis
example
client
worker

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