How to: Manage workflows

Manage and run workflows

Note

Dapr Workflow is currently in beta. See known limitations for 1.14.1.

Now that you’ve authored the workflow and its activities in your application, you can start, terminate, and get information about the workflow using HTTP API calls. For more information, read the workflow API reference.

Python
JavaScript
.NET
Java
Go
HTTP

Manage your workflow within your code. In the workflow example from the Author a workflow guide, the workflow is registered in the code using the following APIs:

start_workflow: Start an instance of a workflow
get_workflow: Get information on the status of the workflow
pause_workflow: Pauses or suspends a workflow instance that can later be resumed
resume_workflow: Resumes a paused workflow instance
raise_workflow_event: Raise an event on a workflow
purge_workflow: Removes all metadata related to a specific workflow instance
terminate_workflow: Terminate or stop a particular instance of a workflow

from dapr.ext.workflow import WorkflowRuntime, DaprWorkflowContext, WorkflowActivityContext
from dapr.clients import DaprClient
# Sane parameters
instanceId = "exampleInstanceID"
workflowComponent = "dapr"
workflowName = "hello_world_wf"
eventName = "event1"
eventData = "eventData"
# Start the workflow
start_resp = d.start_workflow(instance_id=instanceId, workflow_component=workflowComponent,
                        workflow_name=workflowName, input=inputData, workflow_options=workflowOptions)
# Get info on the workflow
getResponse = d.get_workflow(instance_id=instanceId, workflow_component=workflowComponent)
# Pause the workflow
d.pause_workflow(instance_id=instanceId, workflow_component=workflowComponent)
# Resume the workflow
d.resume_workflow(instance_id=instanceId, workflow_component=workflowComponent)
# Raise an event on the workflow. 
 d.raise_workflow_event(instance_id=instanceId, workflow_component=workflowComponent,
                    event_name=eventName, event_data=eventData)
# Purge the workflow
d.purge_workflow(instance_id=instanceId, workflow_component=workflowComponent)
# Terminate the workflow
d.terminate_workflow(instance_id=instanceId, workflow_component=workflowComponent)

Manage your workflow within your code. In the workflow example from the Author a workflow guide, the workflow is registered in the code using the following APIs:

client.workflow.start: Start an instance of a workflow
client.workflow.get: Get information on the status of the workflow
client.workflow.pause: Pauses or suspends a workflow instance that can later be resumed
client.workflow.resume: Resumes a paused workflow instance
client.workflow.purge: Removes all metadata related to a specific workflow instance
client.workflow.terminate: Terminate or stop a particular instance of a workflow

import { DaprClient } from "@dapr/dapr";
async function printWorkflowStatus(client: DaprClient, instanceId: string) {
  const workflow = await client.workflow.get(instanceId);
  console.log(
    `Workflow ${workflow.workflowName}, created at ${workflow.createdAt.toUTCString()}, has status ${
      workflow.runtimeStatus
    }`,
  );
  console.log(`Additional properties: ${JSON.stringify(workflow.properties)}`);
  console.log("--------------------------------------------------\n\n");
}
async function start() {
  const client = new DaprClient();
  // Start a new workflow instance
  const instanceId = await client.workflow.start("OrderProcessingWorkflow", {
    Name: "Paperclips",
    TotalCost: 99.95,
    Quantity: 4,
  });
  console.log(`Started workflow instance ${instanceId}`);
  await printWorkflowStatus(client, instanceId);
  // Pause a workflow instance
  await client.workflow.pause(instanceId);
  console.log(`Paused workflow instance ${instanceId}`);
  await printWorkflowStatus(client, instanceId);
  // Resume a workflow instance
  await client.workflow.resume(instanceId);
  console.log(`Resumed workflow instance ${instanceId}`);
  await printWorkflowStatus(client, instanceId);
  // Terminate a workflow instance
  await client.workflow.terminate(instanceId);
  console.log(`Terminated workflow instance ${instanceId}`);
  await printWorkflowStatus(client, instanceId);
  // Wait for the workflow to complete, 30 seconds!
  await new Promise((resolve) => setTimeout(resolve, 30000));
  await printWorkflowStatus(client, instanceId);
  // Purge a workflow instance
  await client.workflow.purge(instanceId);
  console.log(`Purged workflow instance ${instanceId}`);
  // This will throw an error because the workflow instance no longer exists.
  await printWorkflowStatus(client, instanceId);
}
start().catch((e) => {
  console.error(e);
  process.exit(1);
});

Manage your workflow within your code. In the OrderProcessingWorkflow example from the Author a workflow guide, the workflow is registered in the code. You can now start, terminate, and get information about a running workflow:

string orderId = "exampleOrderId";
string workflowComponent = "dapr";
string workflowName = "OrderProcessingWorkflow";
OrderPayload input = new OrderPayload("Paperclips", 99.95);
Dictionary<string, string> workflowOptions; // This is an optional parameter
// Start the workflow. This returns back a "StartWorkflowResponse" which contains the instance ID for the particular workflow instance.
StartWorkflowResponse startResponse = await daprClient.StartWorkflowAsync(orderId, workflowComponent, workflowName, input, workflowOptions);
// Get information on the workflow. This response contains information such as the status of the workflow, when it started, and more!
GetWorkflowResponse getResponse = await daprClient.GetWorkflowAsync(orderId, workflowComponent, eventName);
// Terminate the workflow
await daprClient.TerminateWorkflowAsync(orderId, workflowComponent);
// Raise an event (an incoming purchase order) that your workflow will wait for. This returns the item waiting to be purchased.
await daprClient.RaiseWorkflowEventAsync(orderId, workflowComponent, workflowName, input);
// Pause
await daprClient.PauseWorkflowAsync(orderId, workflowComponent);
// Resume
await daprClient.ResumeWorkflowAsync(orderId, workflowComponent);
// Purge the workflow, removing all inbox and history information from associated instance
await daprClient.PurgeWorkflowAsync(orderId, workflowComponent);

Manage your workflow within your code. In the workflow example from the Java SDK, the workflow is registered in the code using the following APIs:

scheduleNewWorkflow: Starts a new workflow instance
getInstanceState: Get information on the status of the workflow
waitForInstanceStart: Pauses or suspends a workflow instance that can later be resumed
raiseEvent: Raises events/tasks for the running workflow instance
waitForInstanceCompletion: Waits for the workflow to complete its tasks
purgeInstance: Removes all metadata related to a specific workflow instance
terminateWorkflow: Terminates the workflow
purgeInstance: Removes all metadata related to a specific workflow

package io.dapr.examples.workflows;
import io.dapr.workflows.client.DaprWorkflowClient;
import io.dapr.workflows.client.WorkflowInstanceStatus;
// ...
public class DemoWorkflowClient {
  // ...
  public static void main(String[] args) throws InterruptedException {
    DaprWorkflowClient client = new DaprWorkflowClient();
    try (client) {
      // Start a workflow
      String instanceId = client.scheduleNewWorkflow(DemoWorkflow.class, "input data");
      // Get status information on the workflow
      WorkflowInstanceStatus workflowMetadata = client.getInstanceState(instanceId, true);
      // Wait or pause for the workflow instance start
      try {
        WorkflowInstanceStatus waitForInstanceStartResult =
            client.waitForInstanceStart(instanceId, Duration.ofSeconds(60), true);
      }
      // Raise an event for the workflow; you can raise several events in parallel
      client.raiseEvent(instanceId, "TestEvent", "TestEventPayload");
      client.raiseEvent(instanceId, "event1", "TestEvent 1 Payload");
      client.raiseEvent(instanceId, "event2", "TestEvent 2 Payload");
      client.raiseEvent(instanceId, "event3", "TestEvent 3 Payload");
      // Wait for workflow to complete running through tasks
      try {
        WorkflowInstanceStatus waitForInstanceCompletionResult =
            client.waitForInstanceCompletion(instanceId, Duration.ofSeconds(60), true);
      } 
      // Purge the workflow instance, removing all metadata associated with it
      boolean purgeResult = client.purgeInstance(instanceId);
      // Terminate the workflow instance
      client.terminateWorkflow(instanceToTerminateId, null);
    System.exit(0);
  }
}

Manage your workflow within your code. In the workflow example from the Go SDK, the workflow is registered in the code using the following APIs:

StartWorkflow: Starts a new workflow instance
GetWorkflow: Get information on the status of the workflow
PauseWorkflow: Pauses or suspends a workflow instance that can later be resumed
RaiseEventWorkflow: Raises events/tasks for the running workflow instance
ResumeWorkflow: Waits for the workflow to complete its tasks
PurgeWorkflow: Removes all metadata related to a specific workflow instance
TerminateWorkflow: Terminates the workflow

// Start workflow
type StartWorkflowRequest struct {
    InstanceID        string // Optional instance identifier
    WorkflowComponent string
    WorkflowName      string
    Options           map[string]string // Optional metadata
    Input             any               // Optional input
    SendRawInput      bool              // Set to True in order to disable serialization on the input
}
type StartWorkflowResponse struct {
    InstanceID string
}
// Get the workflow status
type GetWorkflowRequest struct {
    InstanceID        string
    WorkflowComponent string
}
type GetWorkflowResponse struct {
    InstanceID    string
    WorkflowName  string
    CreatedAt     time.Time
    LastUpdatedAt time.Time
    RuntimeStatus string
    Properties    map[string]string
}
// Purge workflow
type PurgeWorkflowRequest struct {
    InstanceID        string
    WorkflowComponent string
}
// Terminate workflow
type TerminateWorkflowRequest struct {
    InstanceID        string
    WorkflowComponent string
}
// Pause workflow
type PauseWorkflowRequest struct {
    InstanceID        string
    WorkflowComponent string
}
// Resume workflow
type ResumeWorkflowRequest struct {
    InstanceID        string
    WorkflowComponent string
}
// Raise an event for the running workflow
type RaiseEventWorkflowRequest struct {
    InstanceID        string
    WorkflowComponent string
    EventName         string
    EventData         any
    SendRawData       bool // Set to True in order to disable serialization on the data
}

Manage your workflow using HTTP calls. The example below plugs in the properties from the Author a workflow example with a random instance ID number.

Start workflow

To start your workflow with an ID 12345678, run:

POST http://localhost:3500/v1.0-beta1/workflows/dapr/OrderProcessingWorkflow/start?instanceID=12345678

Note that workflow instance IDs can only contain alphanumeric characters, underscores, and dashes.

Terminate workflow

To terminate your workflow with an ID 12345678, run:

POST http://localhost:3500/v1.0-beta1/workflows/dapr/12345678/terminate

Raise an event

For workflow components that support subscribing to external events, such as the Dapr Workflow engine, you can use the following “raise event” API to deliver a named event to a specific workflow instance.

POST http://localhost:3500/v1.0-beta1/workflows/<workflowComponentName>/<instanceID>/raiseEvent/<eventName>

An eventName can be any function.

Pause or resume a workflow

To plan for down-time, wait for inputs, and more, you can pause and then resume a workflow. To pause a workflow with an ID 12345678 until triggered to resume, run:

POST http://localhost:3500/v1.0-beta1/workflows/dapr/12345678/pause

To resume a workflow with an ID 12345678, run:

POST http://localhost:3500/v1.0-beta1/workflows/dapr/12345678/resume

Purge a workflow

The purge API can be used to permanently delete workflow metadata from the underlying state store, including any stored inputs, outputs, and workflow history records. This is often useful for implementing data retention policies and for freeing resources.

Only workflow instances in the COMPLETED, FAILED, or TERMINATED state can be purged. If the workflow is in any other state, calling purge returns an error.

POST http://localhost:3500/v1.0-beta1/workflows/dapr/12345678/purge

Get information about a workflow

To fetch workflow information (outputs and inputs) with an ID 12345678, run:

GET http://localhost:3500/v1.0-beta1/workflows/dapr/12345678

Learn more about these HTTP calls in the workflow API reference guide.

Next steps

Last modified October 11, 2024: Fixed typo (#4389) (fe17926)