Build a Go Task Worker

Install

go get github.com/swift-conductor/conductor-client-golang

Implementing the Worker

To create a worker, implement the WorkerTaskFunction function:

type WorkerTaskFunction func(t *WorkerTask) (interface{}, error)

Worker returns a struct as the output of the task execution. The struct MUST be serializable to a JSON map. If an error is returned, the task is marked as FAILED

Task worker that returns a struct

// TaskOutput struct that represents the output of the task execution
type TaskOutput struct {
    Keys    []string
    Message string
    Value   float64
}

// SampleWorker function accepts Task as input and returns TaskOutput as result
// If there is a failure, error can be returned and the task will be marked as FAILED
func SampleWorker(t *model.WorkerTask) (interface{}, error) {
    taskResult := model.NewTaskResultFromTask(t)
    taskResult.Status = model.CompletedTask

    taskResult.OutputData = map[string]interface{}{
        "outputKey1":  "value",
        "oddEven": 1,
        "mod": 4,
    }

    return taskResult, nil
}

Upon completion, set the TaskResult with status as one of the following:

1. CompletedTask: If the task has completed successfully.
2. FailedTask or return error: If there are failures - business or system failures. Based on the task's configuration, when a task fails, it may be retried.

Running Workers via WorkerHost

The WorkerHost can be used to register the worker(s) and initialize the polling loop. It manages the task workers thread pool and server communication (poll and task update).

The taskName parameter of the WorkerHost.StartWorker method specifies the name of the task which the worker should handle.

httpSettings := settings.NewHttpSettings("http://localhost:8080/api")
apiClient := client.NewAPIClient(httpSettings)

workerHost := worker.NewWorkerHostWithApiClient(apiClient)

// start polling for a task by name "task_1", with a batch size of 1 and 1 second interval
workerHost.StartWorker("task_1", SampleWorker, 1, 1*time.Second)
workerHost.StartWorker("task_2", SampleWorker, 1, 1*time.Second)

// block
workerHost.WaitWorkers()

See Create and run task workers for additional information.