How to: Manage workflows
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.
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, workflowName); // 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 await daprClient.PurgeWorkflowAsync(orderId, 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:
- 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 using HTTP calls. The example below plugs in the properties from the Author a workflow example with a random instance ID number.
To start your workflow with an ID
Note that workflow instance IDs can only contain alphanumeric characters, underscores, and dashes.
To terminate your workflow with an ID
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.
eventNamecan 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:
To resume a workflow with an ID
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.
Get information about a workflow
To fetch workflow information (outputs and inputs) with an ID
Learn more about these HTTP calls in the workflow API reference guide.
- Try out the Workflow quickstart
- Try out the full SDK examples:
- Workflow API reference
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