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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.

Function

// basic function signature
func YourActivityDefinition(ctx context.Context) error {
 // ...
 return nil
}

// with parameters and return values
func SimpleActivity(ctx context.Context, value string) (string, error)

Struct method

type YourActivityStruct struct {
 ActivityFieldOne string
 ActivityFieldTwo int
}

func(a *YourActivityStruct) YourActivityDefinition(ctx context.Context) error {
 // ...
}

func(a *YourActivityStruct) YourActivityDefinitionTwo(ctx context.Context) error {
 // ...
}

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.