Machinery is an asynchronous task queue/job queue based on distributed message passing.

Overview

Machinery

Machinery is an asynchronous task queue/job queue based on distributed message passing.

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V2 Experiment

Please be advised that V2 is work in progress and breaking changes can and will happen until it is ready.

You can use the current V2 in order to avoid having to import all dependencies for brokers and backends you are not using.

Instead of factory, you will need to inject broker and backend objects to the server constructor:

import (
  "github.com/RichardKnop/machinery/v2"
  backendsiface "github.com/RichardKnop/machinery/v1/backends/iface"
  brokersiface "github.com/RichardKnop/machinery/v1/brokers/iface"
)

var broker brokersiface.Broker
var backend backendsiface.Backend
server, err := machinery.NewServer(cnf, broker, backend)
if err != nil {
  // do something with the error
}

First Steps

Add the Machinery library to your $GOPATH/src:

go get github.com/RichardKnop/machinery/v1

First, you will need to define some tasks. Look at sample tasks in example/tasks/tasks.go to see a few examples.

Second, you will need to launch a worker process with one of these commands (v2 is recommended since it doesn't import dependencies for all brokers / backends, only those you actually need):

go run example/v2/amqp/main.go worker
go run example/v2/redigo/main.go worker // Redis with redigo driver
go run example/v2/go-redis/main.go worker // Redis with Go Redis driver

go run example/v1/amqp/main.go worker
go run example/v1/redis/main.go worker

Example worker

Finally, once you have a worker running and waiting for tasks to consume, send some tasks with one of these commands (v2 is recommended since it doesn't import dependencies for all brokers / backends, only those you actually need):

go run example/v2/amqp/main.go send
go run example/v2/redigo/main.go send // Redis with redigo driver
go run example/v2/go-redis/main.go send // Redis with Go Redis driver

go run example/v1/amqp/main.go send
go run example/v1/redis/main.go send

You will be able to see the tasks being processed asynchronously by the worker:

Example worker receives tasks

Configuration

The config package has convenience methods for loading configuration from environment variables or a YAML file. For example, load configuration from environment variables:

cnf, err := config.NewFromEnvironment()

Or load from YAML file:

cnf, err := config.NewFromYaml("config.yml", true)

Second boolean flag enables live reloading of configuration every 10 seconds. Use false to disable live reloading.

Machinery configuration is encapsulated by a Config struct and injected as a dependency to objects that need it.

Lock

Redis

Use Redis URL in one of these formats:

redis://[[email protected]]host[port][/db_num]

For example:

  1. redis://localhost:6379, or with password redis://[email protected]:6379

Broker

A message broker. Currently supported brokers are:

AMQP

Use AMQP URL in the format:

amqp://[username:[email protected]]@host[:port]

For example:

  1. amqp://guest:[email protected]:5672

AMQP also supports multiples brokers urls. You need to specify the URL separator in the MultipleBrokerSeparator field.

Redis

Use Redis URL in one of these formats:

redis://[[email protected]]host[port][/db_num]
redis+socket://[[email protected]]/path/to/file.sock[:/db_num]

For example:

  1. redis://localhost:6379, or with password redis://[email protected]:6379
  2. redis+socket://[email protected]/path/to/file.sock:/0
AWS SQS

Use AWS SQS URL in the format:

https://sqs.us-east-2.amazonaws.com/123456789012

See AWS SQS docs for more information. Also, configuring AWS_REGION is required, or an error would be thrown.

To use a manually configured SQS Client:

var sqsClient = sqs.New(session.Must(session.NewSession(&aws.Config{
  Region:         aws.String("YOUR_AWS_REGION"),
  Credentials:    credentials.NewStaticCredentials("YOUR_AWS_ACCESS_KEY", "YOUR_AWS_ACCESS_SECRET", ""),
  HTTPClient:     &http.Client{
    Timeout: time.Second * 120,
  },
})))
var visibilityTimeout = 20
var cnf = &config.Config{
  Broker:          "YOUR_SQS_URL"
  DefaultQueue:    "machinery_tasks",
  ResultBackend:   "YOUR_BACKEND_URL",
  SQS: &config.SQSConfig{
    Client: sqsClient,
    // if VisibilityTimeout is nil default to the overall visibility timeout setting for the queue
    // https://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/sqs-visibility-timeout.html
    VisibilityTimeout: &visibilityTimeout,
    WaitTimeSeconds: 30,
  },
}
GCP Pub/Sub

Use GCP Pub/Sub URL in the format:

gcppubsub://YOUR_GCP_PROJECT_ID/YOUR_PUBSUB_SUBSCRIPTION_NAME

To use a manually configured Pub/Sub Client:

pubsubClient, err := pubsub.NewClient(
    context.Background(),
    "YOUR_GCP_PROJECT_ID",
    option.WithServiceAccountFile("YOUR_GCP_SERVICE_ACCOUNT_FILE"),
)

cnf := &config.Config{
  Broker:          "gcppubsub://YOUR_GCP_PROJECT_ID/YOUR_PUBSUB_SUBSCRIPTION_NAME"
  DefaultQueue:    "YOUR_PUBSUB_TOPIC_NAME",
  ResultBackend:   "YOUR_BACKEND_URL",
  GCPPubSub: config.GCPPubSubConfig{
    Client: pubsubClient,
  },
}

DefaultQueue

Default queue name, e.g. machinery_tasks.

ResultBackend

Result backend to use for keeping task states and results.

Currently supported backends are:

Redis

Use Redis URL in one of these formats:

redis://[[email protected]]host[port][/db_num]
redis+socket://[[email protected]]/path/to/file.sock[:/db_num]

For example:

  1. redis://localhost:6379, or with password redis://[email protected]:6379
  2. redis+socket://[email protected]/path/to/file.sock:/0
  3. cluster redis://host1:port1,host2:port2,host3:port3
  4. cluster with password redis://[email protected]:port1,host2:port2,host3:port3
Memcache

Use Memcache URL in the format:

memcache://host1[:port1][,host2[:port2],...[,hostN[:portN]]]

For example:

  1. memcache://localhost:11211 for a single instance, or
  2. memcache://10.0.0.1:11211,10.0.0.2:11211 for a cluster
AMQP

Use AMQP URL in the format:

amqp://[username:[email protected]]@host[:port]

For example:

  1. amqp://guest:[email protected]:5672

Keep in mind AMQP is not recommended as a result backend. See Keeping Results

MongoDB

Use Mongodb URL in the format:

mongodb://[username:[email protected]]host1[:port1][,host2[:port2],...[,hostN[:portN]]][/[database][?options]]

For example:

  1. mongodb://localhost:27017/taskresults

See MongoDB docs for more information.

ResultsExpireIn

How long to store task results for in seconds. Defaults to 3600 (1 hour).

AMQP

RabbitMQ related configuration. Not necessary if you are using other broker/backend.

  • Exchange: exchange name, e.g. machinery_exchange
  • ExchangeType: exchange type, e.g. direct
  • QueueBindingArguments: an optional map of additional arguments used when binding to an AMQP queue
  • BindingKey: The queue is bind to the exchange with this key, e.g. machinery_task
  • PrefetchCount: How many tasks to prefetch (set to 1 if you have long running tasks)

DynamoDB

DynamoDB related configuration. Not necessary if you are using other backend.

  • TaskStatesTable: Custom table name for saving task states. Default one is task_states, and make sure to create this table in your AWS admin first, using TaskUUID as table's primary key.
  • GroupMetasTable: Custom table name for saving group metas. Default one is group_metas, and make sure to create this table in your AWS admin first, using GroupUUID as table's primary key. For example:
dynamodb:
  task_states_table: 'task_states'
  group_metas_table: 'group_metas'

If these tables are not found, an fatal error would be thrown.

If you wish to expire the records, you can configure the TTL field in AWS admin for these tables. The TTL field is set based on the ResultsExpireIn value in the Server's config. See https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/howitworks-ttl.html for more information.

Redis

Redis related configuration. Not necessary if you are using other backend.

See: config (TODO)

GCPPubSub

GCPPubSub related configuration. Not necessary if you are using other backend.

See: config (TODO)

Custom Logger

You can define a custom logger by implementing the following interface:

type Interface interface {
  Print(...interface{})
  Printf(string, ...interface{})
  Println(...interface{})

  Fatal(...interface{})
  Fatalf(string, ...interface{})
  Fatalln(...interface{})

  Panic(...interface{})
  Panicf(string, ...interface{})
  Panicln(...interface{})
}

Then just set the logger in your setup code by calling Set function exported by github.com/RichardKnop/machinery/v1/log package:

log.Set(myCustomLogger)

Server

A Machinery library must be instantiated before use. The way this is done is by creating a Server instance. Server is a base object which stores Machinery configuration and registered tasks. E.g.:

import (
  "github.com/RichardKnop/machinery/v1/config"
  "github.com/RichardKnop/machinery/v1"
)

var cnf = &config.Config{
  Broker:        "amqp://guest:[email protected]:5672/",
  DefaultQueue:  "machinery_tasks",
  ResultBackend: "amqp://guest:[email protected]:5672/",
  AMQP: &config.AMQPConfig{
    Exchange:     "machinery_exchange",
    ExchangeType: "direct",
    BindingKey:   "machinery_task",
  },
}

server, err := machinery.NewServer(cnf)
if err != nil {
  // do something with the error
}

Workers

In order to consume tasks, you need to have one or more workers running. All you need to run a worker is a Server instance with registered tasks. E.g.:

worker := server.NewWorker("worker_name", 10)
err := worker.Launch()
if err != nil {
  // do something with the error
}

Each worker will only consume registered tasks. For each task on the queue the Worker.Process() method will be run in a goroutine. Use the second parameter of server.NewWorker to limit the number of concurrently running Worker.Process() calls (per worker). Example: 1 will serialize task execution while 0 makes the number of concurrently executed tasks unlimited (default).

Tasks

Tasks are a building block of Machinery applications. A task is a function which defines what happens when a worker receives a message.

Each task needs to return an error as a last return value. In addition to error tasks can now return any number of arguments.

Examples of valid tasks:

func Add(args ...int64) (int64, error) {
  sum := int64(0)
  for _, arg := range args {
    sum += arg
  }
  return sum, nil
}

func Multiply(args ...int64) (int64, error) {
  sum := int64(1)
  for _, arg := range args {
    sum *= arg
  }
  return sum, nil
}

// You can use context.Context as first argument to tasks, useful for open tracing
func TaskWithContext(ctx context.Context, arg Arg) error {
  // ... use ctx ...
  return nil
}

// Tasks need to return at least error as a minimal requirement
func DummyTask(arg string) error {
  return errors.New(arg)
}

// You can also return multiple results from the task
func DummyTask2(arg1, arg2 string) (string, string, error) {
  return arg1, arg2, nil
}

Registering Tasks

Before your workers can consume a task, you need to register it with the server. This is done by assigning a task a unique name:

server.RegisterTasks(map[string]interface{}{
  "add":      Add,
  "multiply": Multiply,
})

Tasks can also be registered one by one:

server.RegisterTask("add", Add)
server.RegisterTask("multiply", Multiply)

Simply put, when a worker receives a message like this:

{
  "UUID": "48760a1a-8576-4536-973b-da09048c2ac5",
  "Name": "add",
  "RoutingKey": "",
  "ETA": null,
  "GroupUUID": "",
  "GroupTaskCount": 0,
  "Args": [
    {
      "Type": "int64",
      "Value": 1,
    },
    {
      "Type": "int64",
      "Value": 1,
    }
  ],
  "Immutable": false,
  "RetryCount": 0,
  "RetryTimeout": 0,
  "OnSuccess": null,
  "OnError": null,
  "ChordCallback": null
}

It will call Add(1, 1). Each task should return an error as well so we can handle failures.

Ideally, tasks should be idempotent which means there will be no unintended consequences when a task is called multiple times with the same arguments.

Signatures

A signature wraps calling arguments, execution options (such as immutability) and success/error callbacks of a task so it can be sent across the wire to workers. Task signatures implement a simple interface:

// Arg represents a single argument passed to invocation fo a task
type Arg struct {
  Type  string
  Value interface{}
}

// Headers represents the headers which should be used to direct the task
type Headers map[string]interface{}

// Signature represents a single task invocation
type Signature struct {
  UUID           string
  Name           string
  RoutingKey     string
  ETA            *time.Time
  GroupUUID      string
  GroupTaskCount int
  Args           []Arg
  Headers        Headers
  Immutable      bool
  RetryCount     int
  RetryTimeout   int
  OnSuccess      []*Signature
  OnError        []*Signature
  ChordCallback  *Signature
}

UUID is a unique ID of a task. You can either set it yourself or it will be automatically generated.

Name is the unique task name by which it is registered against a Server instance.

RoutingKey is used for routing a task to correct queue. If you leave it empty, the default behaviour will be to set it to the default queue's binding key for direct exchange type and to the default queue name for other exchange types.

ETA is a timestamp used for delaying a task. if it's nil, the task will be published for workers to consume immediately. If it is set, the task will be delayed until the ETA timestamp.

GroupUUID, GroupTaskCount are useful for creating groups of tasks.

Args is a list of arguments that will be passed to the task when it is executed by a worker.

Headers is a list of headers that will be used when publishing the task to AMQP queue.

Immutable is a flag which defines whether a result of the executed task can be modified or not. This is important with OnSuccess callbacks. Immutable task will not pass its result to its success callbacks while a mutable task will prepend its result to args sent to callback tasks. Long story short, set Immutable to false if you want to pass result of the first task in a chain to the second task.

RetryCount specifies how many times a failed task should be retried (defaults to 0). Retry attempts will be spaced out in time, after each failure another attempt will be scheduled further to the future.

RetryTimeout specifies how long to wait before resending task to the queue for retry attempt. Default behaviour is to use fibonacci sequence to increase the timeout after each failed retry attempt.

OnSuccess defines tasks which will be called after the task has executed successfully. It is a slice of task signature structs.

OnError defines tasks which will be called after the task execution fails. The first argument passed to error callbacks will be the error string returned from the failed task.

ChordCallback is used to create a callback to a group of tasks.

Supported Types

Machinery encodes tasks to JSON before sending them to the broker. Task results are also stored in the backend as JSON encoded strings. Therefor only types with native JSON representation can be supported. Currently supported types are:

  • bool
  • int
  • int8
  • int16
  • int32
  • int64
  • uint
  • uint8
  • uint16
  • uint32
  • uint64
  • float32
  • float64
  • string
  • []bool
  • []int
  • []int8
  • []int16
  • []int32
  • []int64
  • []uint
  • []uint8
  • []uint16
  • []uint32
  • []uint64
  • []float32
  • []float64
  • []string

Sending Tasks

Tasks can be called by passing an instance of Signature to an Server instance. E.g:

import (
  "github.com/RichardKnop/machinery/v1/tasks"
)

signature := &tasks.Signature{
  Name: "add",
  Args: []tasks.Arg{
    {
      Type:  "int64",
      Value: 1,
    },
    {
      Type:  "int64",
      Value: 1,
    },
  },
}

asyncResult, err := server.SendTask(signature)
if err != nil {
  // failed to send the task
  // do something with the error
}

Delayed Tasks

You can delay a task by setting the ETA timestamp field on the task signature.

// Delay the task by 5 seconds
eta := time.Now().UTC().Add(time.Second * 5)
signature.ETA = &eta

Retry Tasks

You can set a number of retry attempts before declaring task as failed. Fibonacci sequence will be used to space out retry requests over time. (See RetryTimeout for details.)

// If the task fails, retry it up to 3 times
signature.RetryCount = 3

Alternatively, you can return tasks.ErrRetryTaskLater from your task and specify duration after which the task should be retried, e.g.:

return tasks.NewErrRetryTaskLater("some error", 4 * time.Hour)

Get Pending Tasks

Tasks currently waiting in the queue to be consumed by workers can be inspected, e.g.:

server.GetBroker().GetPendingTasks("some_queue")

Currently only supported by Redis broker.

Keeping Results

If you configure a result backend, the task states and results will be persisted. Possible states:

const (
	// StatePending - initial state of a task
	StatePending = "PENDING"
	// StateReceived - when task is received by a worker
	StateReceived = "RECEIVED"
	// StateStarted - when the worker starts processing the task
	StateStarted = "STARTED"
	// StateRetry - when failed task has been scheduled for retry
	StateRetry = "RETRY"
	// StateSuccess - when the task is processed successfully
	StateSuccess = "SUCCESS"
	// StateFailure - when processing of the task fails
	StateFailure = "FAILURE"
)

When using AMQP as a result backend, task states will be persisted in separate queues for each task. Although RabbitMQ can scale up to thousands of queues, it is strongly advised to use a better suited result backend (e.g. Memcache) when you are expecting to run a large number of parallel tasks.

// TaskResult represents an actual return value of a processed task
type TaskResult struct {
  Type  string      `bson:"type"`
  Value interface{} `bson:"value"`
}

// TaskState represents a state of a task
type TaskState struct {
  TaskUUID  string        `bson:"_id"`
  State     string        `bson:"state"`
  Results   []*TaskResult `bson:"results"`
  Error     string        `bson:"error"`
}

// GroupMeta stores useful metadata about tasks within the same group
// E.g. UUIDs of all tasks which are used in order to check if all tasks
// completed successfully or not and thus whether to trigger chord callback
type GroupMeta struct {
  GroupUUID      string   `bson:"_id"`
  TaskUUIDs      []string `bson:"task_uuids"`
  ChordTriggered bool     `bson:"chord_triggered"`
  Lock           bool     `bson:"lock"`
}

TaskResult represents a slice of return values of a processed task.

TaskState struct will be serialized and stored every time a task state changes.

GroupMeta stores useful metadata about tasks within the same group. E.g. UUIDs of all tasks which are used in order to check if all tasks completed successfully or not and thus whether to trigger chord callback.

AsyncResult object allows you to check for the state of a task:

taskState := asyncResult.GetState()
fmt.Printf("Current state of %v task is:\n", taskState.TaskUUID)
fmt.Println(taskState.State)

There are couple of convenient methods to inspect the task status:

asyncResult.GetState().IsCompleted()
asyncResult.GetState().IsSuccess()
asyncResult.GetState().IsFailure()

You can also do a synchronous blocking call to wait for a task result:

results, err := asyncResult.Get(time.Duration(time.Millisecond * 5))
if err != nil {
  // getting result of a task failed
  // do something with the error
}
for _, result := range results {
  fmt.Println(result.Interface())
}

Error Handling

When a task returns with an error, the default behavior is to first attempty to retry the task if it's retriable, otherwise log the error and then eventually call any error callbacks.

To customize this, you can set a custom error handler on the worker which can do more than just logging after retries fail and error callbacks are trigerred:

worker.SetErrorHandler(func (err error) {
  customHandler(err)
})

Workflows

Running a single asynchronous task is fine but often you will want to design a workflow of tasks to be executed in an orchestrated way. There are couple of useful functions to help you design workflows.

Groups

Group is a set of tasks which will be executed in parallel, independent of each other. E.g.:

import (
  "github.com/RichardKnop/machinery/v1/tasks"
  "github.com/RichardKnop/machinery/v1"
)

signature1 := tasks.Signature{
  Name: "add",
  Args: []tasks.Arg{
    {
      Type:  "int64",
      Value: 1,
    },
    {
      Type:  "int64",
      Value: 1,
    },
  },
}

signature2 := tasks.Signature{
  Name: "add",
  Args: []tasks.Arg{
    {
      Type:  "int64",
      Value: 5,
    },
    {
      Type:  "int64",
      Value: 5,
    },
  },
}

group, _ := tasks.NewGroup(&signature1, &signature2)
asyncResults, err := server.SendGroup(group, 0) //The second parameter specifies the number of concurrent sending tasks. 0 means unlimited.
if err != nil {
  // failed to send the group
  // do something with the error
}

SendGroup returns a slice of AsyncResult objects. So you can do a blocking call and wait for the result of groups tasks:

for _, asyncResult := range asyncResults {
  results, err := asyncResult.Get(time.Duration(time.Millisecond * 5))
  if err != nil {
    // getting result of a task failed
    // do something with the error
  }
  for _, result := range results {
    fmt.Println(result.Interface())
  }
}

Chords

Chord allows you to define a callback to be executed after all tasks in a group finished processing, e.g.:

import (
  "github.com/RichardKnop/machinery/v1/tasks"
  "github.com/RichardKnop/machinery/v1"
)

signature1 := tasks.Signature{
  Name: "add",
  Args: []tasks.Arg{
    {
      Type:  "int64",
      Value: 1,
    },
    {
      Type:  "int64",
      Value: 1,
    },
  },
}

signature2 := tasks.Signature{
  Name: "add",
  Args: []tasks.Arg{
    {
      Type:  "int64",
      Value: 5,
    },
    {
      Type:  "int64",
      Value: 5,
    },
  },
}

signature3 := tasks.Signature{
  Name: "multiply",
}

group := tasks.NewGroup(&signature1, &signature2)
chord, _ := tasks.NewChord(group, &signature3)
chordAsyncResult, err := server.SendChord(chord, 0) //The second parameter specifies the number of concurrent sending tasks. 0 means unlimited.
if err != nil {
  // failed to send the chord
  // do something with the error
}

The above example executes task1 and task2 in parallel, aggregates their results and passes them to task3. Therefore what would end up happening is:

multiply(add(1, 1), add(5, 5))

More explicitly:

(1 + 1) * (5 + 5) = 2 * 10 = 20

SendChord returns ChordAsyncResult which follows AsyncResult's interface. So you can do a blocking call and wait for the result of the callback:

results, err := chordAsyncResult.Get(time.Duration(time.Millisecond * 5))
if err != nil {
  // getting result of a chord failed
  // do something with the error
}
for _, result := range results {
  fmt.Println(result.Interface())
}

Chains

Chain is simply a set of tasks which will be executed one by one, each successful task triggering the next task in the chain. E.g.:

import (
  "github.com/RichardKnop/machinery/v1/tasks"
  "github.com/RichardKnop/machinery/v1"
)

signature1 := tasks.Signature{
  Name: "add",
  Args: []tasks.Arg{
    {
      Type:  "int64",
      Value: 1,
    },
    {
      Type:  "int64",
      Value: 1,
    },
  },
}

signature2 := tasks.Signature{
  Name: "add",
  Args: []tasks.Arg{
    {
      Type:  "int64",
      Value: 5,
    },
    {
      Type:  "int64",
      Value: 5,
    },
  },
}

signature3 := tasks.Signature{
  Name: "multiply",
  Args: []tasks.Arg{
    {
      Type:  "int64",
      Value: 4,
    },
  },
}

chain, _ := tasks.NewChain(&signature1, &signature2, &signature3)
chainAsyncResult, err := server.SendChain(chain)
if err != nil {
  // failed to send the chain
  // do something with the error
}

The above example executes task1, then task2 and then task3. When a task is completed successfully, the result is appended to the end of list of arguments for the next task in the chain. Therefore what would end up happening is:

multiply(4, add(5, 5, add(1, 1)))

More explicitly:

  4 * (5 + 5 + (1 + 1))   # task1: add(1, 1)        returns 2
= 4 * (5 + 5 + 2)         # task2: add(5, 5, 2)     returns 12
= 4 * (12)                # task3: multiply(4, 12)  returns 48
= 48

SendChain returns ChainAsyncResult which follows AsyncResult's interface. So you can do a blocking call and wait for the result of the whole chain:

results, err := chainAsyncResult.Get(time.Duration(time.Millisecond * 5))
if err != nil {
  // getting result of a chain failed
  // do something with the error
}
for _, result := range results {
  fmt.Println(result.Interface())
}

Periodic Tasks & Workflows

Machinery now supports scheduling periodic tasks and workflows. See examples bellow.

Periodic Tasks

import (
  "github.com/RichardKnop/machinery/v1/tasks"
)

signature := &tasks.Signature{
  Name: "add",
  Args: []tasks.Arg{
    {
      Type:  "int64",
      Value: 1,
    },
    {
      Type:  "int64",
      Value: 1,
    },
  },
}

err := server.RegisterPeriodTask("0 6 * * ?", "periodic-task", signature)
if err != nil {
  // failed to register periodic task
}

Periodic Groups

import (
  "github.com/RichardKnop/machinery/v1/tasks"
  "github.com/RichardKnop/machinery/v1"
)

signature1 := tasks.Signature{
  Name: "add",
  Args: []tasks.Arg{
    {
      Type:  "int64",
      Value: 1,
    },
    {
      Type:  "int64",
      Value: 1,
    },
  },
}

signature2 := tasks.Signature{
  Name: "add",
  Args: []tasks.Arg{
    {
      Type:  "int64",
      Value: 5,
    },
    {
      Type:  "int64",
      Value: 5,
    },
  },
}

group, _ := tasks.NewGroup(&signature1, &signature2)
err := server.RegisterPeriodGroup("0 6 * * ?", "periodic-group", group)
if err != nil {
  // failed to register periodic group
}

Periodic Chains

import (
  "github.com/RichardKnop/machinery/v1/tasks"
  "github.com/RichardKnop/machinery/v1"
)

signature1 := tasks.Signature{
  Name: "add",
  Args: []tasks.Arg{
    {
      Type:  "int64",
      Value: 1,
    },
    {
      Type:  "int64",
      Value: 1,
    },
  },
}

signature2 := tasks.Signature{
  Name: "add",
  Args: []tasks.Arg{
    {
      Type:  "int64",
      Value: 5,
    },
    {
      Type:  "int64",
      Value: 5,
    },
  },
}

signature3 := tasks.Signature{
  Name: "multiply",
  Args: []tasks.Arg{
    {
      Type:  "int64",
      Value: 4,
    },
  },
}

chain, _ := tasks.NewChain(&signature1, &signature2, &signature3)
err := server.RegisterPeriodChain("0 6 * * ?", "periodic-chain", chain)
if err != nil {
  // failed to register periodic chain
}

Chord

import (
  "github.com/RichardKnop/machinery/v1/tasks"
  "github.com/RichardKnop/machinery/v1"
)

signature1 := tasks.Signature{
  Name: "add",
  Args: []tasks.Arg{
    {
      Type:  "int64",
      Value: 1,
    },
    {
      Type:  "int64",
      Value: 1,
    },
  },
}

signature2 := tasks.Signature{
  Name: "add",
  Args: []tasks.Arg{
    {
      Type:  "int64",
      Value: 5,
    },
    {
      Type:  "int64",
      Value: 5,
    },
  },
}

signature3 := tasks.Signature{
  Name: "multiply",
}

group := tasks.NewGroup(&signature1, &signature2)
chord, _ := tasks.NewChord(group, &signature3)
err := server.RegisterPeriodChord("0 6 * * ?", "periodic-chord", chord)
if err != nil {
  // failed to register periodic chord
}

Development

Requirements

  • Go
  • RabbitMQ (optional)
  • Redis
  • Memcached (optional)
  • MongoDB (optional)

On OS X systems, you can install requirements using Homebrew:

brew install go
brew install rabbitmq
brew install redis
brew install memcached
brew install mongodb

Or optionally use the corresponding Docker containers:

docker run -d -p 5672:5672 rabbitmq
docker run -d -p 6379:6379 redis
docker run -d -p 11211:11211 memcached
docker run -d -p 27017:27017 mongo
docker run -d -p 6831:6831/udp -p 16686:16686 jaegertracing/all-in-one:latest

Dependencies

Since Go 1.11, a new recommended dependency management system is via modules.

This is one of slight weaknesses of Go as dependency management is not a solved problem. Previously Go was officially recommending to use the dep tool but that has been abandoned now in favor of modules.

Testing

Easiest (and platform agnostic) way to run tests is via docker-compose:

make ci

This will basically run docker-compose command:

(docker-compose -f docker-compose.test.yml -p machinery_ci up --build -d) && (docker logs -f machinery_sut &) && (docker wait machinery_sut)

Alternative approach is to setup a development environment on your machine.

In order to enable integration tests, you will need to install all required services (RabbitMQ, Redis, Memcache, MongoDB) and export these environment variables:

export AMQP_URL=amqp://guest:[email protected]:5672/
export REDIS_URL=localhost:6379
export MEMCACHE_URL=localhost:11211
export MONGODB_URL=localhost:27017

To run integration tests against an SQS instance, you will need to create a "test_queue" in SQS and export these environment variables:

export SQS_URL=https://YOUR_SQS_URL
export AWS_ACCESS_KEY_ID=YOUR_AWS_ACCESS_KEY_ID
export AWS_SECRET_ACCESS_KEY=YOUR_AWS_SECRET_ACCESS_KEY
export AWS_DEFAULT_REGION=YOUR_AWS_DEFAULT_REGION

Then just run:

make test

If the environment variables are not exported, make test will only run unit tests.

Issues
  • Redis type issue still persists in v1.9.9

    Redis type issue still persists in v1.9.9

    Upgraded to new version v1.9.9 and got the same error as previous issue #625

    # github.com/RichardKnop/machinery/v1/backends/redis
    ../../../go-code/pkg/mod/github.com/!richard!knop/[email protected]/v1/backends/redis/goredis.go:57:43: cannot use b.rclient (type "github.com/go-redis/redis/v8".UniversalClient) as type *"github.com/go-redis/redis/v8".Client in argument to goredis.NewPool: need type assertion
    

    From Code: Screen Shot 2020-11-23 at 4 50 37 PM

    Mods:

    module github.com/...
    
    go 1.15
    
    require (
    	github.com/RichardKnop/machinery v1.9.9
    	github.com/go-redis/redis/v8 v8.4.0 // indirect
    	github.com/gomodule/redigo v2.0.0+incompatible
    )
    
    opened by mrz1836 17
  • Feature Request: Delay task

    Feature Request: Delay task

    Ability to delay the tasks for processing e.g run task in 5 Min.

    Could be implemented by adding a Execute Time to the task signature, and by user a helper method e.g

    func (t *TaskSignature) Delay(d time.Duration) 
    

    When the worker gets the task, it holds onto it until the execution time and then runs it.

    You want a store a time to execute and not just the delay as you want to guarantee that the task is run as close as possible to it, If the worker crashes the delay would start again otherwise.

    enhancement 
    opened by owenhaynes 15
  • Implements AWS SQS Broker Support

    Implements AWS SQS Broker Support

    This adds an AWS SQS broker implementation.

    opened by mjetpax 11
  • Insanely high CPU usage on the Redis adapter.

    Insanely high CPU usage on the Redis adapter.

    Seems like the Redis adaptor is using LPOP instead of BLPOP which leads to super busy polling.

    opened by rvera 10
  •  backend mongo json changes

    backend mongo json changes

    @RichardKnop This changes is required to get the backend result into json format. i tested the integration test with go test command and i am getting success .if you have found anything please let me know.

    opened by surendratiwari3 9
  • Backend mongo json changes

    Backend mongo json changes

    mongodb changes travis ci build with added support for mongodb result value to be in json.now we can have json in the result set of result.

    opened by surendratiwari3 9
  • feat(tracing): implement trace context propagation using the Opentracing api

    feat(tracing): implement trace context propagation using the Opentracing api

    This PR enables context propagation using newly introduced functions while maintaining backwards compatibility:

    • SendTaskWithContext
    • SendGroupWithContext
    • SendChordWithContext
    • SendChainWithContext

    Essentially what happens is that if one of these functions is called it will try to inject the trace context found in context.Context into the signature's headers before calling the original non-WithContext function. On the worker side an attempt is made to extract that context again and add it to the tasks context. All these actions will simply start a new span if no trace context is found. As an extra the trace span will be available in the called function's context if the registered function has context.Context as a first argument so the trace can travel on. To get a good view of what a user should enable to get the benefits of tracing check example/machinery.go and uncomment the jaeger code in example/tracers/jaeger.go. Below is a screenshot of the jaeger's ui after a run of the example. Note that I've disabled the long running task so the graph is prettier. There are also some screen shots of the tags captured by the spans.

    What is missing is a bit more documentation in the readme and some tests that verify the traces are actually propagating.

    screenshot from 2018-02-25 16-21-04 screenshot from 2018-02-25 16-22-05 screenshot from 2018-02-25 16-22-58

    opened by rio 8
  • Error when pulling from Github (mongo client)

    Error when pulling from Github (mongo client)

    We've been using Machinery for some time - suddenly this morning all attempts to pull from github (go get -u) are resulting in:

    ../../../github.com/RichardKnop/machinery/v1/backends/mongo/mongodb.go:302:32: cannot use uri (type string) as type *options.ClientOptions in argument to mongo.NewClient

    It's happening during download from Github, not during the Go build.

    Can't see any changes recently in the repo (we successfully deployed yesterday).

    Any ideas?

    opened by seonixx 8
  • Lost periodic task

    Lost periodic task

    Hi

    I have periodic task, but sometime it has been lost. Server use redis.

    Task registration. this is one of the attempts: err = machineryServer.RegisterPeriodicGroup("*/5 * * * *", "fiveMinutesGroup", 0, fiveMinutesGroup.Tasks...)

    example of data: lost

    If I change time description to err = machineryServer.RegisterPeriodicGroup("@every 5m", "fiveMinutesGroup", 0, fiveMinutesGroup.Tasks...) it working fine, but not precision

    how do I figure out what the problem is? Time on the server synced by chronyd(for testing I try disable chroned, and enable ntpd, but result is some)

    Thanks

    opened by agvol 8
  • redis:// lock URI does not support username:password or /db in the URI

    redis:// lock URI does not support username:password or /db in the URI

    Hi!

    URIs such as redis://user1:[email protected]/0 do not work as lock property in the machinery server config. Specifically the existing code does not handle well the username:password tuple nor the database number in the path [1]

    Other factories https://github.com/RichardKnop/machinery/issues/214 have been modified to ignore the username and correctly parse the DB number and although that's not ideal since usernames are supported in Redis since v6.0 we should at least level up the behavior.

    Thanks for your work on this, it's very useful!

    [1]

    dial tcp: address tcp/6379/0: unknown port  
    
    or
    
    WRONGPASS invalid username-password pair or user is disabled.  
    
    opened by migmartri 0
  •  Task not registered with this worker.

    Task not registered with this worker.

    if task is not registered in worker ,the worker will keep print msgs like below even restart worker , the only sollution is restart redis when worker is printing msgs down there, what caused this problem?

    Requeuing message: {"UUID":"task_f9ef7434-6e93-451a-9902-d9a34d41e10f","Name":"pmapDecode","RoutingKey":"machinery_tasks","ETA":null,"GroupUUID":"","GroupTaskCount":0,"Args":[{"Name":"","Type":"[]string","Value":["1111","222222222","33333333"]}],"Headers":{},"Priority":0,"Immutable":false,"RetryCount":0,"RetryTimeout":0,"OnSuccess":null,"OnError":null,"ChordCallback":null,"BrokerMessageGroupId":"","SQSReceiptHandle":"","StopTaskDeletion
    
    opened by FirYuen 0
  • v2_unused_function_delete

    v2_unused_function_delete

    1. v2-->suite_test.go-->testSetup The initialization service has been placed in the specific test.
    2. v2-->server.go-->NewServerWithBrokerBackendLock has been replaced by NewServer
    opened by xiaozuo7 0
  • add PublishToLocal for health check

    add PublishToLocal for health check

    I need a health check function to check if the local worker can still run properly (e.g. if all the goroutines are stuck and can't start new ones due to concurrency).

    One way to do this is to check if the local worker can run and complete a new task in the expected time. So I need a PublishToLocal method.


    A health check example:

    var healthCheckCompleteChan = make(chan string, 1)
    
    ...
    	server.RegisterTask(healthCheckTaskName, func(healthCheckUUID string) error {
    		select {
    		case healthCheckCompleteChan <- healthCheckUUID: // success and send uuid
    			return nil
    		case <-time.After(5 * time.Second):
    			return fmt.Errorf("send health check result error: %v", healthCheckUUID)
    		}
    	})
    ...
    
    func checkHealth(consumerTag string, taskExecutionTimeout time.Duration) error {
    	// clear channel
    	select {
    	case <-healthCheckCompleteChan:
    	default:
    	}
    
    	broker := server.GetBroker()
    	healthCheckUUID, err := uuid.NewUUID()
    	if err != nil {
    		return err
    	}
    	if err := broker.PublishToLocal(consumerTag, &tasks.Signature{
    		UUID: healthCheckUUID.String(),
    		Name: healthCheckTaskName,
    		Args: []tasks.Arg{
    			{Type: "string", Value: healthCheckUUID.String()},
    		},
    	}, 5*time.Second); err != nil {
    		return err
    	}
    
    	// wait for task execution success
    	select {
    	case successUUID := <-healthCheckCompleteChan:
    		if successUUID == healthCheckUUID.String() {
    			return nil
    		}
    	case <-time.After(taskExecutionTimeout):
    	}
    	return fmt.Errorf("health check execution fail: %v", healthCheckUUID.String())
    }
    

    Then I can run checkHealth(consumerTag, TasksShouldBeCompletedIn) method and do the appropriate processing.

    opened by sljeff 1
  • Add Azure service bus as a broker

    Add Azure service bus as a broker

    Hi, I Add Azure Service bus as a new type of broker, hope this helps someone trap in Azure cloud :P Azure Service Bus docs for more information.

    opened by sgrodriguez 0
  • go get failed because v1.10.5 requires v2.0.4

    go get failed because v1.10.5 requires v2.0.4

    I would install machinery/v1 by below command:

    go get github.com/RichardKnop/machinery/v1
    go get: github.com/RichardKnop/[email protected] updating to
    	github.com/RichardKnop/[email protected] requires
    	github.com/RichardKnop/machinery/[email protected]: reading github.com/RichardKnop/machinery/go.mod at revision v2.0.4: unknown revision v2.0.4
    

    The file go.mod at v1.10.5 contains

    require github.com/RichardKnop/machinery/v2 v2.0.4 // indirect
    

    but there is no v2.0.4.

    Is it a wrong require ?

    opened by chowyi 2
  • onsuccess callback function. How to receive parameters? Regarding the callback of success and failure, you can add a demo

    onsuccess callback function. How to receive parameters? Regarding the callback of success and failure, you can add a demo

    onsuccess callback function. How to receive parameters? Regarding the callback of success and failure, you can add a demo

    opened by jiangby123 0
  • RegisterPeriodicTask repeated execute

    RegisterPeriodicTask repeated execute

    The program deploys multiple instances with the RegisterPeriodicTask task registered on each instance. At this point, each machine will execute the tasks simultaneously, resulting in repeated execution. For example, the Python celery celery_once program will execute a timed task only once.

    opened by lxjian01 1
  • In the sender use task not registered with this worker have error

    In the sender use task not registered with this worker have error

    INFO: 2021/04/30 10:43:54 redis.go:321 Task not registered with this worker. Requeuing message: {"UUID":"task_f4daacd0-bad7-4ed6-91b9-2842bc9f06f2","Name":"Minus","RoutingKey":"goms_tasks","ETA":null,"GroupUUID":"","GroupTaskCount":0,"Args":[{"Name":"","Type":"int64","Value":1},{"Name":"","Type":"int64","Value":2}],"Headers":{},"Priority":0,"Immutable":false,"RetryCount":0,"RetryTimeout":0,"OnSuccess":null,"OnError":null,"ChordCallback":null,"BrokerMessageGroupId":"","SQSReceiptHandle":"","StopTaskDeletionOnError":false,"IgnoreWhenTaskNotRegistered":false} INFO: 2021/04/30 10:43:54 redis.go:321 Task not registered with this worker. Requeuing message: {"UUID":"task_f4daacd0-bad7-4ed6-91b9-2842bc9f06f2","Name":"Minus","RoutingKey":"goms_tasks","ETA":null,"GroupUUID":"","GroupTaskCount":0,"Args":[{"Name":"","Type":"int64","Value":1},{"Name":"","Type":"int64","Value":2}],"Headers":{},"Priority":0,"Immutable":false,"RetryCount":0,"RetryTimeout":0,"OnSuccess":null,"OnError":null,"ChordCallback":null,"BrokerMessageGroupId":"","SQSReceiptHandle":"","StopTaskDeletionOnError":false,"IgnoreWhenTaskNotRegistered":false} INFO: 2021/04/30 10:43:54 redis.go:321 Task not registered with this worker. Requeuing message: ..... keep outputting .....

    opened by huanbaogihub 0
Releases(v2.0.11)
Owner
Richard Knop
I'm an experienced software engineer, open source contributor. I have mostly focused on backend programming in Go & Python
Richard Knop
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