Skip to main content

Write Workflows Using Code

Write workflows in code to create dynamic workflows that can't be predefined. Support for defining workflows in code is part of all the supported SDKs.

Use this approach when:

  • The number or type of tasks depends on runtime data (for example, spawning one task per item in a list).
  • Workflow logic is generated by your application rather than defined upfront.

How it works​

The following steps use Java examples. The same concepts apply across all supported SDKs.

1. Define tasks

Each step in a workflow is a task. You define a task by providing two names; the task definition name (what the worker polls for) and a reference name (used to refer to this task's output later in the workflow).

SimpleTask getUserDetails = new SimpleTask("get_user_info", "get_user_info");
//                                          ^ task def name  ^ reference name

2. Wire inputs and outputs

Tasks receive inputs either from the workflow's initial input or from a previous task's output. Use the expression syntax ${source.output.field} to reference values.

// From workflow input
getUserDetails.input("userId", "${workflow.input.userId}");

// From a previous task's output
sendEmail.input("email", "${get_user_info.output.email}");

3. Add control flow

Use a Switch task to branch execution based on a value; similar to a switch/case statement.

Switch emailOrSMS = new Switch("emailorsms", "${workflow.input.notificationPref}")
    .switchCase("EMAIL", sendEmail)
    .switchCase("SMS", sendSMS);

Other operators like Fork/Join, Do-While, and Dynamic Task are available for more complex flows. See the Task Reference for the full list.

4. Register the workflow

Add your tasks to the workflow and register it with the Conductor server. Registration saves the workflow definition as JSON on the server so it can be executed.

workflow.add(getUserDetails);
workflow.add(emailOrSMS);
workflow.registerWorkflow(true); // true = overwrite if already exists

5. Execute

Run the workflow and wait for it to complete.

CompletableFuture<Workflow> future = workflow.executeDynamic(input);
Workflow result = future.get(10, TimeUnit.SECONDS);

Create workflows in code​: User notification workflow​

The following example puts it all together. The workflow retrieves user details, then routes to either an email or SMS task based on the user's notification preference.

The workflow in the following examples performs these steps:

  1. Get user details: Retrieves the user information based on the userId provided as the workflow input.
  2. Determine notification type: Uses a Switch task to check the preferred notification method from the input and determine how to notify the user.
  3. Send email: If the notification preference is email, send a message to the user’s email address.
  4. Send SMS: If the preference is SMS, send a text message to the phone number.

user notification workflow

Select your preferred language and use the code example to define and register the workflow in your Conductor environment.


        ConductorWorkflow<WorkflowInput> workflow = new ConductorWorkflow<>(executor);
        workflow.setName("user_notification");
        workflow.setVersion(1);

        SimpleTask getUserDetails = new SimpleTask("get_user_info", "get_user_info");
        getUserDetails.input("userId", "${workflow.input.userId}");

        SimpleTask sendEmail = new SimpleTask("send_email", "send_email");
        // get user details user info, which contains the email field
        sendEmail.input("email", "${get_user_info.output.email}");

        SimpleTask sendSMS = new SimpleTask("send_sms", "send_sms");
        // get user details user info, which contains the phone Number field
        sendSMS.input("phoneNumber", "${get_user_info.output.phoneNumber}");

        Switch emailOrSMS = new Switch("emailorsms", "${workflow.input.notificationPref}")
                .switchCase(WorkflowInput.NotificationPreference.EMAIL.name(), sendEmail)
                .switchCase(WorkflowInput.NotificationPreference.SMS.name(), sendSMS);

        workflow.add(getUserDetails);
        workflow.add(emailOrSMS);

        //Execute the workflow and get the output
        WorkflowInput input = new WorkflowInput("userA");
        input.setNotificationPref(WorkflowInput.NotificationPreference.EMAIL);
        CompletableFuture<Workflow> workflowExecution = simpleWorkflow.executeDynamic(input);
        Workflow workflowRun = workflowExecution.get(10, TimeUnit.SECONDS);


Once running, go to Executions > Workflow in the Conductor UI to view run status, task outputs, and any failures. See Debugging Workflow Executions.