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Foundations - Go SDK feature guide

The Foundations section of the Temporal Developer's guide covers the minimum set of concepts and implementation details needed to build and run a Temporal Application—that is, all the relevant steps to start a Workflow Execution that executes an Activity.

In this section you can find the following:

How to install Temporal CLI and run a development server

This section describes how to install the Temporal CLI and run a development Cluster. The local development Cluster comes packaged with the Temporal Web UI.

For information on deploying and running a self-hosted production Cluster, see the Self-hosted guide, or sign up for Temporal Cloud and let us run your production Cluster for you.

Temporal CLI is a tool for interacting with a Temporal Cluster from the command line and it includes a distribution of the Temporal Server and Web UI. This local development Cluster runs as a single process with zero runtime dependencies and it supports persistence to disk and in-memory mode through SQLite.

Install the Temporal CLI

Choose one of the following install methods to install the Temporal CLI.

  • Install the Temporal CLI with Homebrew.

    brew install temporal
  • Install the Temporal CLI with cURL.

    curl -sSf https://temporal.download/cli.sh | sh
  • Install the Temporal CLI from CDN.

    1. Select the platform and architecture needed.
    2. Extract the downloaded archive.
    3. Add the temporal binary to your PATH.

Start the Temporal Development Server

Start the Temporal Development Server by using the server start-dev command.

temporal server start-dev

This command automatically starts the Web UI, creates the default Namespace, and uses an in-memory database.

The Temporal Server should be available on localhost:7233 and the Temporal Web UI should be accessible at http://localhost:8233.

The server's startup configuration can be customized using command line options. For a full list of options, run:

temporal server start-dev --help

How to install a Temporal SDK

A Temporal SDK provides a framework for Temporal Application development.

An SDK provides you with the following:

Build Status Coverage Status Go reference

Add the Temporal Go SDK to your project:

go get go.temporal.io/sdk

Or clone the Go SDK repo to your preferred location:

git clone git@github.com:temporalio/sdk-go.git

How to find the Go SDK API reference

The Temporal Go SDK API reference is published on pkg.go.dev.

Where are SDK-specific code examples?

You can find a complete list of executable code samples in Temporal's GitHub repository.

Additionally, several of the Tutorials are backed by a fully executable template application.

How to connect a Temporal Client to a Temporal Cluster

A Temporal Client enables you to communicate with the Temporal Cluster. Communication with a Temporal Cluster includes, but isn't limited to, the following:

  • Starting Workflow Executions.
  • Sending Signals to Workflow Executions.
  • Sending Queries to Workflow Executions.
  • Getting the results of a Workflow Execution.
  • Providing an Activity Task Token.
caution

A Temporal Client cannot be initialized and used inside a Workflow. However, it is acceptable and common to use a Temporal Client inside an Activity to communicate with a Temporal Cluster.

When you are running a Cluster locally (such as the Temporal CLI), the number of connection options you must provide is minimal. Many SDKs default to the local host or IP address and port that Temporalite and Docker Compose serve (127.0.0.1:7233).

Use the Dial() API available in the go.temporal.io/sdk/client package to create a Client.

If you don't provide HostPort, the Client defaults the address and port number to 127.0.0.1:7233, which is the port of the development Cluster.

If you don't set a custom Namespace name in the Namespace field, the client connects to the default Namespace.

View the source code in the context of the rest of the application code.

package main

import (
"context"
"encoding/json"
"log"
"net/http"

"documentation-samples-go/yourapp"

"go.temporal.io/sdk/client"
)


func main() {
// Create a Temporal Client to communicate with the Temporal Cluster.
// A Temporal Client is a heavyweight object that should be created just once per process.
temporalClient, err := client.Dial(client.Options{
HostPort: client.DefaultHostPort,
})
if err != nil {
log.Fatalln("Unable to create Temporal Client", err)
}
defer temporalClient.Close()
// ...
}

How to connect to Temporal Cloud

When you connect to Temporal Cloud, you need to provide additional connection and client options that include the following:

  • An address that includes your Cloud Namespace Name and a port number: <Namespace>.<ID>.tmprl.cloud:<port>.
  • mTLS CA certificate.
  • mTLS private key.

For more information about managing and generating client certificates for Temporal Cloud, see How to manage certificates in Temporal Cloud.

For more information about configuring TLS to secure inter- and intra-network communication for a Temporal Cluster, see Temporal Customization Samples.

To connect to and run Workflows through Temporal Cloud, you need the following:

For more information about managing and generating client certificates for Temporal Cloud, see How to manage certificates in Temporal Cloud.

For more information about configuring TLS to secure inter- and intra-network communication for a Temporal Cluster, see Temporal Customization Samples.

View the source code in the context of the rest of the application code.

package main

import (
"context"
"crypto/tls"
"encoding/json"
"log"

"documentation-samples-go/cloud"

"go.temporal.io/sdk/client"
)


func main() {
// Get the key and cert from your env or local machine
clientKeyPath := "./secrets/yourkey.key"
clientCertPath := "./secrets/yourcert.pem"
// Specify the host and port of your Temporal Cloud Namespace
// Host and port format: namespace.unique_id.tmprl.cloud:port
hostPort := "<yournamespace>.<id>.tmprl.cloud:7233"
namespace := "<yournamespace>.<id>"
// Use the crypto/tls package to create a cert object
cert, err := tls.LoadX509KeyPair(clientCertPath, clientKeyPath)
if err != nil {
log.Fatalln("Unable to load cert and key pair.", err)
}
// Add the cert to the tls certificates in the ConnectionOptions of the Client
temporalClient, err := client.Dial(client.Options{
HostPort: hostPort,
Namespace: namespace,
ConnectionOptions: client.ConnectionOptions{
TLS: &tls.Config{Certificates: []tls.Certificate{cert}},
},
})
if err != nil {
log.Fatalln("Unable to connect to Temporal Cloud.", err)
}
defer temporalClient.Close()
// ...
}

How to develop a basic Workflow

Workflows are the fundamental unit of a Temporal Application, and it all starts with the development of a Workflow Definition.

In the Temporal Go SDK programming model, a Workflow Definition is an exportable function. Below is an example of a basic Workflow Definition.

View the source code in the context of the rest of the application code.

package yourapp

import (
"time"

"go.temporal.io/sdk/workflow"
)
// ...

// YourSimpleWorkflowDefintiion is the most basic Workflow Defintion.
func YourSimpleWorkflowDefinition(ctx workflow.Context) error {
// ...
return nil
}

How to define Workflow parameters

Temporal Workflows may have any number of custom parameters. However, we strongly recommend that objects are used as parameters, so that the object's individual fields may be altered without breaking the signature of the Workflow. All Workflow Definition parameters must be serializable.

The first parameter of a Go-based Workflow Definition must be of the workflow.Context type. It is used by the Temporal Go SDK to pass around Workflow Execution context, and virtually all the Go SDK APIs that are callable from the Workflow require it. It is acquired from the go.temporal.io/sdk/workflow package.

The workflow.Context entity operates similarly to the standard context.Context entity provided by Go. The only difference between workflow.Context and context.Context is that the Done() function, provided by workflow.Context, returns workflow.Channel instead of the standard Go chan.

Additional parameters can be passed to the Workflow when it is invoked. A Workflow Definition may support multiple custom parameters, or none. These parameters can be regular type variables or safe pointers. However, the best practice is to pass a single parameter that is of a struct type, so there can be some backward compatibility if new parameters are added.

All Workflow Definition parameters must be serializable and can't be channels, functions, variadic, or unsafe pointers.

View the source code in the context of the rest of the application code.

package yourapp

import (
"time"

"go.temporal.io/sdk/workflow"
)


// YourWorkflowParam is the object passed to the Workflow.
type YourWorkflowParam struct {
WorkflowParamX string
WorkflowParamY int
}
// ...
// YourWorkflowDefinition is your custom Workflow Definition.
func YourWorkflowDefinition(ctx workflow.Context, param YourWorkflowParam) (*YourWorkflowResultObject, error) {
// ...
}

How to define Workflow return parameters

Workflow return values must also be serializable. Returning results, returning errors, or throwing exceptions is fairly idiomatic in each language that is supported. However, Temporal APIs that must be used to get the result of a Workflow Execution will only ever receive one of either the result or the error.

A Go-based Workflow Definition can return either just an error or a customValue, error combination. Again, the best practice here is to use a struct type to hold all custom values. A Workflow Definition written in Go can return both a custom value and an error. However, it's not possible to receive both a custom value and an error in the calling process, as is normal in Go. The caller will receive either one or the other. Returning a non-nil error from a Workflow indicates that an error was encountered during its execution and the Workflow Execution should be terminated, and any custom return values will be ignored by the system.

View the source code in the context of the rest of the application code.

package yourapp

import (
"time"

"go.temporal.io/sdk/workflow"
)
// ...

// YourWorkflowResultObject is the object returned by the Workflow.
type YourWorkflowResultObject struct {
WFResultFieldX string
WFResultFieldY int
}
// ...
// YourWorkflowDefinition is your custom Workflow Definition.
func YourWorkflowDefinition(ctx workflow.Context, param YourWorkflowParam) (*YourWorkflowResultObject, error) {
// ...
if err != nil {
return nil, err
}
// Make the results of the Workflow Execution available.
workflowResult := &YourWorkflowResultObject{
WFResultFieldX: activityResult.ResultFieldX,
WFResultFieldY: activityResult.ResultFieldY,
}
return workflowResult, nil
}

How to customize Workflow Type in Go

In Go, by default, the Workflow Type name is the same as the function name.

To customize the Workflow Type, set the Name parameter with RegisterOptions when registering your Workflow with a Worker.

View the source code in the context of the rest of the application code.

package main

import (
"log"

"go.temporal.io/sdk/activity"
"go.temporal.io/sdk/client"
"go.temporal.io/sdk/worker"
"go.temporal.io/sdk/workflow"

"documentation-samples-go/yourapp"
)
// ...
func main() {
// ...
yourWorker := worker.New(temporalClient, "your-custom-task-queue-name", worker.Options{})
// ...
// Use RegisterOptions to set the name of the Workflow Type for example.
registerWFOptions := workflow.RegisterOptions{
Name: "JustAnotherWorkflow",
}
yourWorker.RegisterWorkflowWithOptions(yourapp.YourSimpleWorkflowDefinition, registerWFOptions)
// ...
}

How develop Workflow logic

Workflow logic is constrained by deterministic execution requirements. Therefore, each language is limited to the use of certain idiomatic techniques. However, each Temporal SDK provides a set of APIs that can be used inside your Workflow to interact with external (to the Workflow) application code.

In Go, Workflow Definition code cannot directly do the following:

  • Iterate over maps using range, because with range the order of the map's iteration is randomized. Instead you can collect the keys of the map, sort them, and then iterate over the sorted keys to access the map. This technique provides deterministic results. You can also use a Side Effect or an Activity to process the map instead.
  • Call an external API, conduct a file I/O operation, talk to another service, etc. (Use an Activity for these.)

The Temporal Go SDK has APIs to handle equivalent Go constructs:

  • workflow.Now() This is a replacement for time.Now().
  • workflow.Sleep() This is a replacement for time.Sleep().
  • workflow.GetLogger() This ensures that the provided logger does not duplicate logs during a replay.
  • workflow.Go() This is a replacement for the go statement.
  • workflow.Channel This is a replacement for the native chan type. Temporal provides support for both buffered and unbuffered channels.
  • workflow.Selector This is a replacement for the select statement. Learn more on the Go SDK Selectors page.
  • workflow.Context This is a replacement for context.Context. See Tracing for more information about context propagation.

How to develop an Activity Definition in Go

In the Temporal Go SDK programming model, an Activity Definition is an exportable function or a struct method. Below is an example of both a basic Activity Definition and of an Activity defined as a Struct method. An Activity struct can have more than one method, with each method acting as a separate Activity Type. Activities written as struct methods can use shared struct variables, such as:

  • an application level DB pool
  • client connection to another service
  • reusable utilities
  • any other expensive resources that you only want to initialize once per process

Because this is such a common need, the rest of this guide shows Activities written as struct methods.

View the source code in the context of the rest of the application code.

package yourapp

import (
"context"

"go.temporal.io/sdk/activity"
)
// ...

// YourSimpleActivityDefinition is a basic Activity Definiton.
func YourSimpleActivityDefinition(ctx context.Context) error {
return nil
}

// YourActivityObject is the struct that maintains shared state across Activities.
// If the Worker crashes this Activity object loses its state.
type YourActivityObject struct {
Message *string
Number *int
}

// YourActivityDefinition is your custom Activity Definition.
// An Activity Definiton is an exportable function.
func (a *YourActivityObject) YourActivityDefinition(ctx context.Context, param YourActivityParam) (*YourActivityResultObject, error) {
// ...
}

How to develop Activity Parameters

There is no explicit limit to the total number of parameters that an Activity Definition may support. However, there is a limit to the total size of the data that ends up encoded into a gRPC message Payload.

A single argument is limited to a maximum size of 2 MB. And the total size of a gRPC message, which includes all the arguments, is limited to a maximum of 4 MB.

Also, keep in mind that all Payload data is recorded in the Workflow Execution Event History and large Event Histories can affect Worker performance. This is because the entire Event History could be transferred to a Worker Process with a Workflow Task.

Some SDKs require that you pass context objects, others do not. When it comes to your application data—that is, data that is serialized and encoded into a Payload—we recommend that you use a single object as an argument that wraps the application data passed to Activities. This is so that you can change what data is passed to the Activity without breaking a function or method signature.

The first parameter of an Activity Definition is context.Context. This parameter is optional for an Activity Definition, though it is recommended, especially if the Activity is expected to use other Go SDK APIs.

An Activity Definition can support as many other custom parameters as needed. However, all parameters must be serializable (parameters can’t be channels, functions, variadic, or unsafe pointers), and it is recommended to pass a single struct that can be updated later.

View the source code in the context of the rest of the application code.


// YourActivityParam is the struct passed to your Activity.
// Use a struct so that your function signature remains compatible if fields change.
type YourActivityParam struct {
ActivityParamX string
ActivityParamY int
}
// ...
func (a *YourActivityObject) YourActivityDefinition(ctx context.Context, param YourActivityParam) (*YourActivityResultObject, error) {
// ...
}

How to define Activity return values

All data returned from an Activity must be serializable.

There is no explicit limit to the amount of data that can be returned by an Activity, but keep in mind that all return values are recorded in a Workflow Execution Event History.

A Go-based Activity Definition can return either just an error or a customValue, error combination (same as a Workflow Definition). You may wish to use a struct type to hold all custom values, just keep in mind they must all be serializable.

View the source code in the context of the rest of the application code.


// YourActivityResultObject is the struct returned from your Activity.
// Use a struct so that you can return multiple values of different types.
// Additionally, your function signature remains compatible if the fields change.
type YourActivityResultObject struct {
ResultFieldX string
ResultFieldY int
}
// ...
func (a *YourActivityObject) YourActivityDefinition(ctx context.Context, param YourActivityParam) (*YourActivityResultObject, error) {
// ...
result := &YourActivityResultObject{
ResultFieldX: "Success",
ResultFieldY: 1,
}
// Return the results back to the Workflow Execution.
// The results persist within the Event History of the Workflow Execution.
return result, nil
}

How to customize Activity Type in Go

To customize the Activity Type, set the Name parameter with RegisterOptions when registering your Activity with a Worker.

View the source code in the context of the rest of the application code.

func main() {
// ...
yourWorker := worker.New(temporalClient, "your-custom-task-queue-name", worker.Options{})
// ...
// Use RegisterOptions to change the name of the Activity Type for example.
registerAOptions := activity.RegisterOptions{
Name: "JustAnotherActivity",
}
yourWorker.RegisterActivityWithOptions(yourapp.YourSimpleActivityDefinition, registerAOptions)
// Run the Worker
err = yourWorker.Run(worker.InterruptCh())
// ...
}
// ...

How to start an Activity Execution

Calls to spawn Activity Executions are written within a Workflow Definition. The call to spawn an Activity Execution generates the ScheduleActivityTask Command. This results in the set of three Activity Task related Events (ActivityTaskScheduled, ActivityTaskStarted, and ActivityTask[Closed])in your Workflow Execution Event History.

A single instance of the Activities implementation is shared across multiple simultaneous Activity invocations. Activity implementation code should be idempotent.

The values passed to Activities through invocation parameters or returned through a result value are recorded in the Execution history. The entire Execution history is transferred from the Temporal service to Workflow Workers when a Workflow state needs to recover. A large Execution history can thus adversely impact the performance of your Workflow.

Therefore, be mindful of the amount of data you transfer through Activity invocation parameters or Return Values. Otherwise, no additional limitations exist on Activity implementations.

To spawn an Activity Execution, call ExecuteActivity() inside your Workflow Definition. The API is available from the go.temporal.io/sdk/workflow package. The ExecuteActivity() API call requires an instance of workflow.Context, the Activity function name, and any variables to be passed to the Activity Execution. The Activity function name can be provided as a variable object (no quotations) or as a string. The benefit of passing the actual function object is that the framework can validate the parameters against the Activity Definition. The ExecuteActivity call returns a Future, which can be used to get the result of the Activity Execution.

View the source code in the context of the rest of the application code.

func YourWorkflowDefinition(ctx workflow.Context, param YourWorkflowParam) (*YourWorkflowResultObject, error) {
// Set the options for the Activity Execution.
// Either StartToClose Timeout OR ScheduleToClose is required.
// Not specifying a Task Queue will default to the parent Workflow Task Queue.
activityOptions := workflow.ActivityOptions{
StartToCloseTimeout: 10 * time.Second,
}
ctx = workflow.WithActivityOptions(ctx, activityOptions)
activityParam := YourActivityParam{
ActivityParamX: param.WorkflowParamX,
ActivityParamY: param.WorkflowParamY,
}
// Use a nil struct pointer to call Activities that are part of a struct.
var a *YourActivityObject
// Execute the Activity and wait for the result.
var activityResult YourActivityResultObject
err := workflow.ExecuteActivity(ctx, a.YourActivityDefinition, activityParam).Get(ctx, &activityResult)
if err != nil {
return nil, err
}
// ...
}

How to set the required Activity Timeouts

Activity Execution semantics rely on several parameters. The only required value that needs to be set is either a Schedule-To-Close Timeout or a Start-To-Close Timeout. These values are set in the Activity Options.

To set an Activity Timeout in Go, create an instance of ActivityOptions from the go.temporal.io/sdk/workflow package, set the Activity Timeout field, and then use the WithActivityOptions() API to apply the options to the instance of workflow.Context.

Available timeouts are:

  • StartToCloseTimeout
  • ScheduleToClose
  • ScheduleToStartTimeout
activityoptions := workflow.ActivityOptions{
// Set Activity Timeout duration
ScheduleToCloseTimeout: 10 * time.Second,
// StartToCloseTimeout: 10 * time.Second,
// ScheduleToStartTimeout: 10 * time.Second,
}
ctx = workflow.WithActivityOptions(ctx, activityoptions)
var yourActivityResult YourActivityResult
err = workflow.ExecuteActivity(ctx, YourActivityDefinition, yourActivityParam).Get(ctx, &yourActivityResult)
if err != nil {
// ...
}

Go ActivityOptions reference

Create an instance of ActivityOptions from the go.temporal.io/sdk/workflow package and use WithActivityOptions() to apply it to the instance of workflow.Context.

The instance of workflow.Context is then passed to the ExecuteActivity() call.

FieldRequiredType
ActivityIDNostring
TaskQueueNameNostring
ScheduleToCloseTimeoutYes (or StartToCloseTimeout)time.Duration
ScheduleToStartTimeoutNotime.Duration
StartToCloseTimeoutYes (or ScheduleToCloseTimeout)time.Duration
HeartbeatTimeoutNotime.Duration
WaitForCancellationNobool
OriginalTaskQueueNameNostring
RetryPolicyNoRetryPolicy

ActivityID

  • Type: string
  • Default: None
activityoptions := workflow.ActivityOptions{
ActivityID: "your-activity-id",
}
ctx = workflow.WithActivityOptions(ctx, activityoptions)
var yourActivityResult YourActivityResult
err = workflow.ExecuteActivity(ctx, YourActivityDefinition, yourActivityParam).Get(ctx, &yourActivityResult)
if err != nil {
// ...
}

TaskQueueName

  • Type: string
  • Default: Inherits the TaskQueue name from the Workflow.
activityoptions := workflow.ActivityOptions{
TaskQueueName: "your-task-queue-name",
}
ctx = workflow.WithActivityOptions(ctx, activityoptions)
var yourActivityResult YourActivityResult
err = workflow.ExecuteActivity(ctx, YourActivityDefinition, yourActivityParam).Get(ctx, &yourActivityResult)
if err != nil {
// ...
}

ScheduleToCloseTimeout

To set a Schedule-To-Close Timeout, create an instance of ActivityOptions from the go.temporal.io/sdk/workflow package, set the ScheduleToCloseTimeout field, and then use the WithActivityOptions() API to apply the options to the instance of workflow.Context.

This or StartToCloseTimeout must be set.

  • Type: time.Duration
  • Default: ∞ (infinity - no limit)
activityoptions := workflow.ActivityOptions{
ScheduleToCloseTimeout: 10 * time.Second,
}
ctx = workflow.WithActivityOptions(ctx, activityoptions)
var yourActivityResult YourActivityResult
err = workflow.ExecuteActivity(ctx, YourActivityDefinition, yourActivityParam).Get(ctx, &yourActivityResult)
if err != nil {
// ...
}

ScheduleToStartTimeout

To set a Schedule-To-Start Timeout, create an instance of ActivityOptions from the go.temporal.io/sdk/workflow package, set the ScheduleToStartTimeout field, and then use the WithActivityOptions() API to apply the options to the instance of workflow.Context.

  • Type: time.Duration
  • Default: ∞ (infinity - no limit)
activityoptions := workflow.ActivityOptions{
ScheduleToStartTimeout: 10 * time.Second,
}
ctx = workflow.WithActivityOptions(ctx, activityoptions)
var yourActivityResult YourActivityResult
err = workflow.ExecuteActivity(ctx, YourActivityDefinition, yourActivityParam).Get(ctx, &yourActivityResult)
if err != nil {
// ...
}

StartToCloseTimeout

To set a Start-To-Close Timeout, create an instance of ActivityOptions from the go.temporal.io/sdk/workflow package, set the StartToCloseTimeout field, and then use the WithActivityOptions() API to apply the options to the instance of workflow.Context.

This or ScheduleToCloseTimeout must be set.

  • Type: time.Duration
  • Default: Same as the ScheduleToCloseTimeout
activityoptions := workflow.ActivityOptions{
StartToCloseTimeout: 10 * time.Second,
}
ctx = workflow.WithActivityOptions(ctx, activityoptions)
var yourActivityResult YourActivityResult
err = workflow.ExecuteActivity(ctx, YourActivityDefinition, yourActivityParam).Get(ctx, &yourActivityResult)
if err != nil {
// ...
}

HeartbeatTimeout

To set a Heartbeat Timeout, create an instance of ActivityOptions from the go.temporal.io/sdk/workflow package, set the RetryPolicy field, and then use the WithActivityOptions() API to apply the options to the instance of workflow.Context.

activityoptions := workflow.ActivityOptions{
HeartbeatTimeout: 10 * time.Second,
}
ctx = workflow.WithActivityOptions(ctx, activityoptions)
var yourActivityResult YourActivityResult
err = workflow.ExecuteActivity(ctx, YourActivityDefinition, yourActivityParam).Get(ctx, &yourActivityResult)
if err != nil {
// ...
}

WaitForCancellation

If true the Activity Execution will finish executing should there be a Cancellation request.

  • Type: bool
  • Default: false
activityoptions := workflow.ActivityOptions{
WaitForCancellation: false,
}
ctx = workflow.WithActivityOptions(ctx, activityoptions)
var yourActivityResult YourActivityResult
err = workflow.ExecuteActivity(ctx, YourActivityDefinition, yourActivityParam).Get(ctx, &yourActivityResult)
if err != nil {
// ...
}

OriginalTaskQueueName

activityoptions := workflow.ActivityOptions{
OriginalTaskQueueName: "your-original-task-queue-name",
}
ctx = workflow.WithActivityOptions(ctx, activityoptions)
var yourActivityResult YourActivityResult
err = workflow.ExecuteActivity(ctx, YourActivityDefinition, yourActivityParam).Get(ctx, &yourActivityResult)
if err != nil {
// ...
}

RetryPolicy

To set a RetryPolicy, create an instance of ActivityOptions from the go.temporal.io/sdk/workflow package, set the RetryPolicy field, and then use the WithActivityOptions() API to apply the options to the instance of workflow.Context.

retrypolicy := &temporal.RetryPolicy{
InitialInterval: time.Second,
BackoffCoefficient: 2.0,
MaximumInterval: time.Second * 100, // 100 * InitialInterval
MaximumAttempts: 0, // Unlimited
NonRetryableErrorTypes: []string, // empty
}

Providing a Retry Policy here is a customization that overwrites individual Field defaults.

retrypolicy := &temporal.RetryPolicy{
InitialInterval: time.Second,
BackoffCoefficient: 2.0,
MaximumInterval: time.Second * 100,
}

activityoptions := workflow.ActivityOptions{
RetryPolicy: retrypolicy,
}
ctx = workflow.WithActivityOptions(ctx, activityoptions)
var yourActivityResult YourActivityResult
err = workflow.ExecuteActivity(ctx, YourActivityDefinition, yourActivityParam).Get(ctx, &yourActivityResult)
if err != nil {
// ...
}

How to get the results of an Activity Execution

The call to spawn an Activity Execution generates the ScheduleActivityTask Command and provides the Workflow with an Awaitable. Workflow Executions can either block progress until the result is available through the Awaitable or continue progressing, making use of the result when it becomes available.

The ExecuteActivity API call returns an instance of workflow.Future which has the following two methods:

  • Get(): Takes an instance of the workflow.Context, that was passed to the Activity Execution, and a pointer as parameters. The variable associated with the pointer is populated with the Activity Execution result. This call blocks until the results are available.
  • IsReady(): Returns true when the result of the Activity Execution is ready.

Call the Get() method on the instance of workflow.Future to get the result of the Activity Execution. The type of the result parameter must match the type of the return value declared by the Activity function.

func YourWorkflowDefinition(ctx workflow.Context, param YourWorkflowParam) (YourWorkflowResponse, error) {
// ...
future := workflow.ExecuteActivity(ctx, YourActivityDefinition, yourActivityParam)
var yourActivityResult YourActivityResult
if err := future.Get(ctx, &yourActivityResult); err != nil {
// ...
}
// ...
}

Use the IsReady() method first to make sure the Get() call doesn't cause the Workflow Execution to wait on the result.

func YourWorkflowDefinition(ctx workflow.Context, param YourWorkflowParam) (YourWorkflowResponse, error) {
// ...
future := workflow.ExecuteActivity(ctx, YourActivityDefinition, yourActivityParam)
// ...
if(future.IsReady()) {
var yourActivityResult YourActivityResult
if err := future.Get(ctx, &yourActivityResult); err != nil {
// ...
}
}
// ...
}

It is idiomatic to invoke multiple Activity Executions from within a Workflow. Therefore, it is also idiomatic to either block on the results of the Activity Executions or continue on to execute additional logic, checking for the Activity Execution results at a later time.

How to develop a Worker in Go

Create an instance of Worker by calling worker.New(), available through the go.temporal.io/sdk/worker package, and pass it the following parameters:

  1. An instance of the Temporal Go SDK Client.
  2. The name of the Task Queue that it will poll.
  3. An instance of worker.Options, which can be empty.

Then, register the Workflow Types and the Activity Types that the Worker will be capable of executing.

Lastly, call either the Start() or the Run() method on the instance of the Worker. Run accepts an interrupt channel as a parameter, so that the Worker can be stopped in the terminal. Otherwise, the Stop() method must be called to stop the Worker.

tip

If you have gow installed, the Worker Process automatically "reloads" when you update the Worker file:

go install github.com/mitranim/gow@latest
gow run worker/main.go # automatically reloads when file changes
View the source code in the context of the rest of the application code.

package main

import (
"log"

"go.temporal.io/sdk/activity"
"go.temporal.io/sdk/client"
"go.temporal.io/sdk/worker"
"go.temporal.io/sdk/workflow"

"documentation-samples-go/yourapp"
)


func main() {
// Create a Temporal Client
// A Temporal Client is a heavyweight object that should be created just once per process.
temporalClient, err := client.Dial(client.Options{})
if err != nil {
log.Fatalln("Unable to create client", err)
}
defer temporalClient.Close()
// Create a new Worker.
yourWorker := worker.New(temporalClient, "your-custom-task-queue-name", worker.Options{})
// Register your Workflow Definitions with the Worker.
// Use the ReisterWorkflow or RegisterWorkflowWithOptions method for each Workflow registration.
yourWorker.RegisterWorkflow(yourapp.YourWorkflowDefinition)
// ...
// Register your Activity Definitons with the Worker.
// Use this technique for registering all Activities that are part of a struct and set the shared variable values.
message := "This could be a connection string or endpoint details"
number := 100
activities := &yourapp.YourActivityObject{
Message: &message,
Number: &number,
}
// Use the RegisterActivity or RegisterActivityWithOptions method for each Activity.
yourWorker.RegisterActivity(activities)
// ...
// Run the Worker
err = yourWorker.Run(worker.InterruptCh())
if err != nil {
log.Fatalln("Unable to start Worker", err)
}
}
// ...

How to set WorkerOptions in Go

Create an instance of Options from the go.temporal.io/sdk/worker package, set any of the optional fields, and pass the instance to the New call.

FieldRequiredType
MaxConcurrentActivityExecutionSizeNoint
WorkerActivitiesPerSecondNofloat64
MaxConcurrentLocalActivityExecutionSizeNoint
WorkerLocalActivitiesPerSecondNofloat64
TaskQueueActivitiesPerSecondNofloat64
MaxConcurrentActivityTaskPollersNoint
MaxConcurrentWorkflowTaskExecutionSizeNoint
MaxConcurrentWorkflowTaskPollersNoint
EnableLoggingInReplayNobool
DisableStickyExecutionNobool
StickyScheduleToStartTimeoutNotime.Duration
BackgroundActivityContextNocontext.Context
WorkflowPanicPolicyNoWorkflowPanicPolicy
WorkerStopTimeoutNotime.Duration
EnableSessionWorkerNobool
MaxConcurrentSessionExecutionSizeNoint
WorkflowInterceptorChainFactoriesNo[]WorkflowInterceptor
LocalActivityWorkerOnlyNobool
IdentityNostring
DeadlockDetectionTimeoutNotime.Duration

MaxConcurrentActivityExecutionSize

Sets the maximum concurrent Activity Executions for the Worker.

  • Type: int
  • Default: 1000

A value of 0 sets to the default.

// ...
workerOptions := worker.Options{
MaxConcurrentActivityExecutionSize: 1000,
// ...
}
w := worker.New(c, "your_task_queue_name", workerOptions)
// ...

WorkerActivitiesPerSecond

Rate limits the number of Activity Task Executions started per second for the Worker.

  • Type: float64
  • Default: 100000

A value of 0 sets to the default.

Intended use case is to limit resources used by the Worker.

Notice that the value type is a float so that the value can be less than 1 if needed. For example, if set to 0.1, Activity Task Executions will happen once every ten seconds. This can be used to protect down stream services from flooding with requests.

// ...
workerOptions := worker.Options{
WorkerActivitiesPerSecond: 100000,
// ..
}
w := worker.New(c, "your_task_queue_name", workerOptions)
// ...

MaxConcurrentLocalActivityExecutionSize

Set the maximum concurrent Local Activity Executions for the Worker.

  • Type: int
  • Default: 1000

A value of 0 sets to the default value.

// ...
workerOptions := worker.Options{
MaxConcurrentLocalActivityExecutionSize: 1000,
// ...
}
w := worker.New(c, "your_task_queue_name", workerOptions)
// ...

WorkerLocalActivitiesPerSecond

Rate limits the number of Local Activity Executions per second executed for the Worker.

  • Type: float64
  • Default: 100000

A value of 0 sets to the default value.

Intended use case is to limit resources used by the Worker.

Notice that the value type is a float so that the value can be less than 1 if needed. For example, if set to 0.1, Local Activity Task Executions will happen once every ten seconds. This can be used to protect down stream services from flooding with requests.

// ...
workerOptions := worker.Options{
WorkerLocalActivitiesPerSecond: 100000,
// ...
}
w := worker.New(c, "your_task_queue_name", workerOptions)
// ...

TaskQueueActivitiesPerSecond

Rate limits the number of Activity Executions that can be started per second.

  • Type: float64
  • Default: 100000

A value of 0 sets to the default value.

This rate is managed by the Temporal Cluster and limits the Activity Tasks per second for the entire Task Queue. This is in contrast to WorkerActivityTasksPerSecond controls activities only per Worker.

Notice that the number is represented in float, so that you can set it to less than 1 if needed. For example, set the number to 0.1 means you want your Activity to be executed once for every 10 seconds. This can be used to protect down stream services from flooding.

// ...
workerOptions := worker.Options{
TaskQueueActivitiesPerSecond: 100000,
// ...
}
w := worker.New(c, "your_task_queue_name", workerOptions)
// ...

MaxConcurrentActivityTaskPollers

Sets the maximum number of goroutines to concurrently poll the Task Queue for Activity Tasks.

  • Type: int
  • Default: 2

Changing this value will affect the rate at which the Worker is able to consume Activity Tasks from the Task Queue.

// ...
workerOptions := worker.Options{
MaxConcurrentActivityTaskPollers: 2,
// ...
}
w := worker.New(c, "your_task_queue_name", workerOptions)
// ...

MaxConcurrentWorkflowTaskExecutionSize

Sets the maximum number of concurrent Workflow Task Executions the Worker can have.

  • Type: int
  • Default: 1000

A value of 0 sets to the default value.

// ...
workerOptions := worker.Options{
MaxConcurrentWorkflowTaskExecutionSize: 1000,
// ...
}
w := worker.New(c, "your_task_queue_name", workerOptions)
// ...

MaxConcurrentWorkflowTaskPollers

Sets the maximum number of goroutines that will concurrently poll the Task Queue for Workflow Tasks.

  • Type: int
  • Default: 2

Changing this value will affect the rate at which the Worker is able to consume Workflow Tasks from the Task Queue.

// ...
workerOptions := worker.Options{
MaxConcurrentWorkflowTaskPollers: 2,
// ...
}
w := worker.New(c, "your_task_queue_name", workerOptions)
// ...

EnableLoggingInReplay

Set to enable logging in Workflow Execution replays.

  • type: bool
  • Default: false

In Workflow Definitions you can use workflow.GetLogger(ctx) to write logs. By default, the logger will skip logging during replays, so you do not see duplicate logs.

This is only really useful for debugging purpose.

// ...
workerOptions := worker.Options{
EnableLoggingInReplay: false,
// ...
}
w := worker.New(c, "your_task_queue_name", workerOptions)
// ...

DisableStickyExecution

Deprecated

When DisableStickyExecution is true it can harm performance. It will be removed soon. See SetStickyWorkflowCacheSize instead.

Set to disable Sticky Executions

  • Type: bool
  • Default: false

Sticky Execution runs Workflow Tasks of a Workflow Execution on same host (could be a different Worker, as long as it is on the same host). This is an optimization for Workflow Executions. When sticky execution is enabled, Worker keeps the Workflow state in memory. New Workflow Task contains the new history events will be dispatched to the same Worker. If this Worker crashes, the sticky Workflow Task will timeout after StickyScheduleToStartTimeout, and Temporal Cluster will clear the stickiness for that Workflow Execution and automatically reschedule a new Workflow Task that is available for any Worker to pick up and resume the progress.

// ...
workerOptions := worker.Options{
StickyScheduleToStartTimeout: time.Second(5),
// ...
}
w := worker.New(c, "your_task_queue_name", workerOptions)
// ...

StickyScheduleToStartTimeout

Sets the Sticky Execution Schedule-To-Start Timeout for Workflow Tasks.

The resolution is in seconds.

// ...
workerOptions := worker.Options{
StickyScheduleToStartTimeout: time.Second(5),
// ...
}
w := worker.New(c, "your_task_queue_name", workerOptions)
// ...

BackgroundActivityContext

Not recommended

This method of passing dependencies between Activity Task Executions is not recommended anymore.

Instead, we recommend using a struct with fields that contain dependencies and develop Activity Definitions as struct methods and then pass all the dependencies on the structure initialization.

Sets the background context.Context for all Activity Types registered with the Worker.

The context can be used to pass external dependencies such as database connections to Activity Task Executions.

// ...
ctx := context.WithValue(context.Background(), "your-key", "your-value")
workerOptions := worker.Options{
BackgroundActivityContext: ctx,
// ...
}
w := worker.New(c, "your_task_queue_name", workerOptions)
// ...

WorkflowPanicPolicy

Sets how the Workflow Worker handles a non-deterministic Workflow Execution History Event and other panics from Workflow Definition code.

// ...
workerOptions := worker.Options{
DisableStickyExecution: internal.BlockWorkflow,
// ...
}
w := worker.New(c, "your_task_queue_name", workerOptions)
// ...

WorkerStopTimeout

Sets the Worker's graceful stop timeout

Value resolution is in seconds.

// ...
workerOptions := worker.Options{
WorkerStopTimeout: time.Second(0),
// ...
}
w := worker.New(c, "your_task_queue_name", workerOptions)
// ...

EnableSessionWorker

Enables Sessions for Activity Workers.

  • Type: bool
  • Default: false

When true the Activity Worker creates a Session to sequentially process Activity Tasks for the given Task Queue.

// ...
workerOptions := worker.Options{
EnableSessionWorker: true,
// ...
}
w := worker.New(c, "your_task_queue_name", workerOptions)
// ...

MaxConcurrentSessionExecutionSize

Sets the maximum number of concurrent Sessions that the Worker can support.

  • Type: int
  • Default: 1000
// ...
workerOptions := worker.Options{
MaxConcurrentSessionExecutionSize: 1000,
// ...
}
w := worker.New(c, "your_task_queue_name", workerOptions)
// ...

WorkflowInterceptorChainFactories

Specifies the factories used to instantiate the Workflow interceptor chain.

The chain is instantiated for each replay of a Workflow Execution.

LocalActivityWorkerOnly

Sets the Worker to only handle Workflow Tasks and local Activity Tasks.

  • Type: bool
  • Default: false
// ...
workerOptions := worker.Options{
LocalActivityWorkerOnly: 1000,
// ...
}
w := worker.New(c, "your_task_queue_name", workerOptions)
// ...

Identity

Sets the Temporal Client-level Identity value, overwriting the existing one.

  • Type: string
  • Default: client identity
// ...
workerOptions := worker.Options{
Identity: "your_custom_identity",
// ...
}
w := worker.New(c, "your_task_queue_name", workerOptions)
// ...

DeadlockDetectionTimeout

Sets the maximum time that a Workflow Task can execute for.

Resolution is in seconds.

// ...
workerOptions := worker.Options{
DeadlockDetectionTimeout: time.Second(1),
// ...
}
w := worker.New(c, "your_task_queue_name", workerOptions)
// ...

How to run a Temporal Cloud Worker

To run a Worker that uses Temporal Cloud, you need to provide additional connection and client options that include the following:

  • An address that includes your Cloud Namespace Name and a port number: <Namespace>.<ID>.tmprl.cloud:<port>.
  • mTLS CA certificate.
  • mTLS private key.

For more information about managing and generating client certificates for Temporal Cloud, see How to manage certificates in Temporal Cloud.

For more information about configuring TLS to secure inter- and intra-network communication for a Temporal Cluster, see Temporal Customization Samples.

To run a Worker that talks to Temporal Cloud, you need the following:

For more information about managing and generating client certificates for Temporal Cloud, see How to manage certificates in Temporal Cloud.

For more information about configuring TLS to secure inter- and intra-network communication for a Temporal Cluster, see Temporal Customization Samples.

View the source code in the context of the rest of the application code.

package main

import (
"crypto/tls"
"log"

"go.temporal.io/sdk/client"
"go.temporal.io/sdk/worker"

"documentation-samples-go/cloud"
)


func main() {
// Get the key and cert from your env or local machine
clientKeyPath := "./secrets/yourkey.key"
clientCertPath := "./secrets/yourcert.pem"
// Specify the host and port of your Temporal Cloud Namespace
// Host and port format: namespace.unique_id.tmprl.cloud:port
hostPort := "<yournamespace>.<id>.tmprl.cloud:7233"
namespace := "<yournamespace>.<id>"
// Use the crypto/tls package to create a cert object
cert, err := tls.LoadX509KeyPair(clientCertPath, clientKeyPath)
if err != nil {
log.Fatalln("Unable to load cert and key pair.", err)
}
// Add the cert to the tls certificates in the ConnectionOptions of the Client
temporalClient, err := client.Dial(client.Options{
HostPort: hostPort,
Namespace: namespace,
ConnectionOptions: client.ConnectionOptions{
TLS: &tls.Config{Certificates: []tls.Certificate{cert}},
},
})
if err != nil {
log.Fatalln("Unable to connect to Temporal Cloud.", err)
}
defer temporalClient.Close()
// Create a new Worker.
yourWorker := worker.New(temporalClient, "cloud-connection-example-go-task-queue", worker.Options{})
// ...
}

How to register types

All Workers listening to the same Task Queue name must be registered to handle the exact same Workflows Types and Activity Types.

If a Worker polls a Task for a Workflow Type or Activity Type it does not know about, it fails that Task. However, the failure of the Task does not cause the associated Workflow Execution to fail.

The RegisterWorkflow() and RegisterActivity() calls essentially create an in-memory mapping between the Workflow Types and their implementations, inside the Worker process.

Registering Activity structs

Per Activity Definition best practices, you might have an Activity struct that has multiple methods and fields. When you use RegisterActivity() for an Activity struct, that Worker has access to all exported methods.

Registering multiple Types

To register multiple Activity Types and/or Workflow Types with the Worker Entity, just make multiple Activity registration calls, but make sure each Type name is unique:

w.RegisterActivity(ActivityA)
w.RegisterActivity(ActivityB)
w.RegisterActivity(ActivityC)
w.RegisterWorkflow(WorkflowA)
w.RegisterWorkflow(WorkflowB)
w.RegisterWorkflow(WorkflowC)

How to set RegisterWorkflowOptions in Go

Create an instance of RegisterOptions from the go.temporal.io/sdk/workflow package and pass it to the RegisterWorkflowWithOptions call when registering the Workflow Type with the Worker.

  • Used to set options for registering a Workflow
FieldRequiredType
NameNostring
DisableAlreadyRegisteredCheckNobool

Name

See How to customize a Workflow Type in Go

DisableAlreadyRegisteredCheck

Disables the check to see if the Workflow Type has already been registered.

  • Type: bool
  • Default: false
// ...
w := worker.New(temporalClient, "your_task_queue_name", worker.Options{})
registerOptions := workflow.RegisterOptions{
DisableAlreadyRegisteredCheck: `false`,
// ...
}
w.RegisterWorkflowWithOptions(YourWorkflowDefinition, registerOptions)
// ...

How to set RegisterActivityOptions in Go

Create an instance of RegisterOptions from the go.temporal.io/sdk/activity package and pass it to the RegisterActivityWithOptions call when registering the Activity Type with the Worker.

Options for registering an Activity

FieldRequiredType
NameNostring
DisableAlreadyRegisteredCheckNobool
SkipInvalidStructFunctionsNobool

Name

See How to customize Activity Type in Go.

DisableAlreadyRegisteredCheck

Disables the check to see if the Activity has already been registered.

  • Type: bool
  • Default: false
// ...
w := worker.New(temporalClient, "your_task_queue_name", worker.Options{})
registerOptions := activity.RegisterOptions{
DisableAlreadyRegisteredCheck: false,
// ...
}
w.RegisterActivityWithOptions(a.YourActivityDefinition, registerOptions)
// ...

SkipInvalidStructFunctions

When registering a struct that has Activities, skip functions that are not valid. If false, registration panics.

  • Type: bool
  • Default: false
// ...
w := worker.New(temporalClient, "your_task_queue_name", worker.Options{})
registerOptions := activity.RegisterOptions{
SkipInvalidStructFunctions: false,
// ...
}
w.RegisterActivityWithOptions(a.YourActivityDefinition, registerOptions)
// ...

How to start a Workflow Execution

Workflow Execution semantics rely on several parameters—that is, to start a Workflow Execution you must supply a Task Queue that will be used for the Tasks (one that a Worker is polling), the Workflow Type, language-specific contextual data, and Workflow Function parameters.

In the examples below, all Workflow Executions are started using a Temporal Client. To spawn Workflow Executions from within another Workflow Execution, use either the Child Workflow or External Workflow APIs.

See the Customize Workflow Type section to see how to customize the name of the Workflow Type.

A request to spawn a Workflow Execution causes the Temporal Cluster to create the first Event (WorkflowExecutionStarted) in the Workflow Execution Event History. The Temporal Cluster then creates the first Workflow Task, resulting in the first WorkflowTaskScheduled Event.

To spawn a Workflow Execution, use the ExecuteWorkflow() method on the Go SDK Client.

The ExecuteWorkflow() API call requires an instance of context.Context, an instance of StartWorkflowOptions, a Workflow Type name, and all variables to be passed to the Workflow Execution. The ExecuteWorkflow() call returns a Future, which can be used to get the result of the Workflow Execution.

package main

import (
// ...

"go.temporal.io/sdk/client"
)

func main() {
temporalClient, err := client.Dial(client.Options{})
if err != nil {
// ...
}
defer temporalClient.Close()
// ...
workflowOptions := client.StartWorkflowOptions{
// ...
}
workflowRun, err := temporalClient.ExecuteWorkflow(context.Background(), workflowOptions, YourWorkflowDefinition, param)
if err != nil {
// ...
}
// ...
}

func YourWorkflowDefinition(ctx workflow.Context, param YourWorkflowParam) (YourWorkflowResponse, error) {
// ...
}

If the invocation process has access to the function directly, then the Workflow Type name parameter can be passed as if the function name were a variable, without quotations.

workflowRun, err := temporalClient.ExecuteWorkflow(context.Background(), workflowOptions, YourWorkflowDefinition, param)

If the invocation process does not have direct access to the statically defined Workflow Definition, for example, if the Workflow Definition is in an un-importable package, or it is written in a completely different language, then the Workflow Type can be provided as a string.

workflowRun, err := c.ExecuteWorkflow(context.Background(), workflowOptions, "YourWorkflowDefinition", param)

How to set a Workflow's Task Queue

In most SDKs, the only Workflow Option that must be set is the name of the Task Queue.

For any code to execute, a Worker Process must be running that contains a Worker Entity that is polling the same Task Queue name.

Create an instance of StartWorkflowOptions from the go.temporal.io/sdk/client package, set the TaskQueue field, and pass the instance to the ExecuteWorkflow call.

  • Type: string
  • Default: None, this is a required field to be set by the developer
workflowOptions := client.StartWorkflowOptions{
// ...
TaskQueue: "your-task-queue",
// ...
}
workflowRun, err := c.ExecuteWorkflow(context.Background(), workflowOptions, YourWorkflowDefinition)
if err != nil {
// ...
}

How to set a custom Workflow Id in Go

Although it is not required, we recommend providing your own Workflow Id that maps to a business process or business entity identifier, such as an order identifier or customer identifier.

Create an instance of StartWorkflowOptions from the go.temporal.io/sdk/client package, set the ID field, and pass the instance to the ExecuteWorkflow call.

  • Type: string
  • Default: System generated UUID
workflowOptions := client.StartWorkflowOptions{
// ...
ID: "Your-Custom-Workflow-Id",
// ...
}
workflowRun, err := c.ExecuteWorkflow(context.Background(), workflowOptions, YourWorkflowDefinition)
if err != nil {
// ...
}

Go StartWorkflowOptions reference

Create an instance of StartWorkflowOptions from the go.temporal.io/sdk/client package, and pass the instance to the ExecuteWorkflow call.

The following fields are available:

FieldRequiredType
IDNostring
TaskQueueYesstring
WorkflowExecutionTimeoutNotime.Duration
WorkflowRunTimeoutNotime.Duration
WorkflowTaskTimeoutNotime.Duration
WorkflowIDReusePolicyNoWorkflowIdReusePolicy
WorkflowExecutionErrorWhenAlreadyStartedNobool
RetryPolicyNoRetryPolicy
CronScheduleNostring
MemoNomap[string]interface{}
SearchAttributesNomap[string]interface{}

ID

Although it is not required, we recommend providing your own Workflow Id that maps to a business process or business entity identifier, such as an order identifier or customer identifier.

Create an instance of StartWorkflowOptions from the go.temporal.io/sdk/client package, set the ID field, and pass the instance to the ExecuteWorkflow call.

  • Type: string
  • Default: System generated UUID
workflowOptions := client.StartWorkflowOptions{
// ...
ID: "Your-Custom-Workflow-Id",
// ...
}
workflowRun, err := c.ExecuteWorkflow(context.Background(), workflowOptions, YourWorkflowDefinition)
if err != nil {
// ...
}

TaskQueue

Create an instance of StartWorkflowOptions from the go.temporal.io/sdk/client package, set the TaskQueue field, and pass the instance to the ExecuteWorkflow call.

  • Type: string
  • Default: None; this is a required field to be set by the developer
workflowOptions := client.StartWorkflowOptions{
// ...
TaskQueue: "your-task-queue",
// ...
}
workflowRun, err := c.ExecuteWorkflow(context.Background(), workflowOptions, YourWorkflowDefinition)
if err != nil {
// ...
}

WorkflowExecutionTimeout

Create an instance of StartWorkflowOptions from the go.temporal.io/sdk/client package, set the WorkflowExecutionTimeout field, and pass the instance to the ExecuteWorkflow call.

  • Type: time.Duration
  • Default: Unlimited
workflowOptions := client.StartWorkflowOptions{
// ...
WorkflowExecutionTimeout: time.Hours * 24 * 365 * 10,
// ...
}
workflowRun, err := c.ExecuteWorkflow(context.Background(), workflowOptions, YourWorkflowDefinition)
if err != nil {
// ...
}

WorkflowRunTimeout

Create an instance of StartWorkflowOptions from the go.temporal.io/sdk/client package, set the WorkflowRunTimeout field, and pass the instance to the ExecuteWorkflow call.

workflowOptions := client.StartWorkflowOptions{
WorkflowRunTimeout: time.Hours * 24 * 365 * 10,
// ...
}
workflowRun, err := c.ExecuteWorkflow(context.Background(), workflowOptions, YourWorkflowDefinition)
if err != nil {
// ...
}

WorkflowTaskTimeout

Create an instance of StartWorkflowOptions from the go.temporal.io/sdk/client package, set the WorkflowTaskTimeout field, and pass the instance to the ExecuteWorkflow call.

  • Type: time.Duration
  • Default: time.Seconds * 10
workflowOptions := client.StartWorkflowOptions{
WorkflowTaskTimeout: time.Second * 10,
//...
}
workflowRun, err := c.ExecuteWorkflow(context.Background(), workflowOptions, YourWorkflowDefinition)
if err != nil {
// ...
}

WorkflowIDReusePolicy

Set a value from the go.temporal.io/api/enums/v1 package.

workflowOptions := client.StartWorkflowOptions{
WorkflowIdReusePolicy: enums.WORKFLOW_ID_REUSE_POLICY_ALLOW_DUPLICATE,
// ...
}
workflowRun, err := c.ExecuteWorkflow(context.Background(), workflowOptions, YourWorkflowDefinition)
if err != nil {
// ...
}

WorkflowExecutionErrorWhenAlreadyStarted

  • Type: bool
  • Default: false
workflowOptions := client.StartWorkflowOptions{
WorkflowExecutionErrorWhenAlreadyStarted: false,
// ...
}
workflowRun, err := c.ExecuteWorkflow(context.Background(), workflowOptions, YourWorkflowDefinition)
if err != nil {
// ...
}

RetryPolicy

Create an instance of a RetryPolicy from the go.temporal.io/sdk/temporal package and provide it as the value to the RetryPolicy field of the instance of StartWorkflowOptions.

retrypolicy := &temporal.RetryPolicy{
InitialInterval: time.Second,
BackoffCoefficient: 2.0,
MaximumInterval: time.Second * 100,
}
workflowOptions := client.StartWorkflowOptions{
RetryPolicy: retrypolicy,
// ...
}
workflowRun, err := temporalClient.ExecuteWorkflow(context.Background(), workflowOptions, YourWorkflowDefinition)
if err != nil {
// ...
}

CronSchedule

  • Type: string
  • Default: None
workflowOptions := client.StartWorkflowOptions{
CronSchedule: "15 8 * * *",
// ...
}
workflowRun, err := c.ExecuteWorkflow(context.Background(), workflowOptions, YourWorkflowDefinition)
if err != nil {
// ...
}

Sample

Memo

  • Type: map[string]interface{}
  • Default: Empty
workflowOptions := client.StartWorkflowOptions{
Memo: map[string]interface{}{
"description": "Test search attributes workflow",
},
// ...
}
workflowRun, err := c.ExecuteWorkflow(context.Background(), workflowOptions, YourWorkflowDefinition)
if err != nil {
// ...
}

SearchAttributes

How to set Workflow Execution Search Attributes in Go

  • Type: map[string]interface{}
  • Default: Empty.

These are the corresponding Search Attribute value types in Go:

  • Keyword = string
  • Int = int64
  • Double = float64
  • Bool = bool
  • Datetime = time.Time
  • Text = string
searchAttributes := map[string]interface{}{
"CustomIntField": 1,
"MiscData": "yellow",
}
workflowOptions := client.StartWorkflowOptions{
SearchAttributes: searchAttributes,
// ...
}
workflowRun, err := c.ExecuteWorkflow(context.Background(), workflowOptions, YourWorkflowDefinition)
if err != nil {
// ...
}

How to get the results of a Workflow Execution

If the call to start a Workflow Execution is successful, you will gain access to the Workflow Execution's Run Id.

The Workflow Id, Run Id, and Namespace may be used to uniquely identify a Workflow Execution in the system and get its result.

It's possible to both block progress on the result (synchronous execution) or get the result at some other point in time (asynchronous execution).

In the Temporal Platform, it's also acceptable to use Queries as the preferred method for accessing the state and results of Workflow Executions.

The ExecuteWorkflow call returns an instance of WorkflowRun, which is the workflowRun variable in the following line.

 workflowRun, err := c.ExecuteWorkflow(context.Background(), workflowOptions, app.YourWorkflowDefinition, param)
if err != nil {
// ...
}
// ...
}

The instance of WorkflowRun has the following three methods:

  • GetWorkflowID(): Returns the Workflow Id of the invoked Workflow Execution.
  • GetRunID(): Always returns the Run Id of the initial Run (See Continue As New) in the series of Runs that make up the full Workflow Execution.
  • Get: Takes a pointer as a parameter and populates the associated variable with the Workflow Execution result.

To wait on the result of Workflow Execution in the same process that invoked it, call Get() on the instance of WorkflowRun that is returned by the ExecuteWorkflow() call.

 workflowRun, err := c.ExecuteWorkflow(context.Background(), workflowOptions, YourWorkflowDefinition, param)
if err != nil {
// ...
}
var result YourWorkflowResponse
err = workflowRun.Get(context.Background(), &result)
if err != nil {
// ...
}
// ...
}

However, the result of a Workflow Execution can be obtained from a completely different process. All that is needed is the Workflow Id. (A Run Id is optional if more than one closed Workflow Execution has the same Workflow Id.) The result of the Workflow Execution is available for as long as the Workflow Execution Event History remains in the system.

Call the GetWorkflow() method on an instance of the Go SDK Client and pass it the Workflow Id used to spawn the Workflow Execution. Then call the Get() method on the instance of WorkflowRun that is returned, passing it a pointer to populate the result.

 // ...
workflowID := "Your-Custom-Workflow-Id"
workflowRun := c.GetWorkflow(context.Background, workflowID)

var result YourWorkflowResponse
err = workflowRun.Get(context.Background(), &result)
if err != nil {
// ...
}
// ...

Get last completion result

In the case of a Temporal Cron Job, you might need to get the result of the previous Workflow Run and use it in the current Workflow Run.

To do this, use the HasLastCompletionResult and GetLastCompletionResult APIs, available from the go.temporal.io/sdk/workflow package, directly in your Workflow code.

type CronResult struct {
Count int
}

func YourCronWorkflowDefinition(ctx workflow.Context) (CronResult, error) {
count := 1

if workflow.HasLastCompletionResult(ctx) {
var lastResult CronResult
if err := workflow.GetLastCompletionResult(ctx, &lastResult); err == nil {
count = count + lastResult.Count
}
}

newResult := CronResult {
Count: count,
}
return newResult, nil
}

This will work even if one of the cron Workflow Runs fails. The next Workflow Run gets the result of the last successfully Completed Workflow Run.