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feat: Migrate 5 more recipe samples to new_samples with generator pattern
- childworkflow: Parent/child workflow relationships, ContinueAsNew - retryactivity: Retry policies and heartbeat progress tracking - query: Workflow query handlers for state inspection - localactivity: Fast local activities without server round-trips - sleep: Simple workflow.Sleep for delays Signed-off-by: Diana Zawadzki <[email protected]>
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‎new_samples/childworkflow/README.md‎

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<!-- THIS IS A GENERATED FILE -->
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<!-- PLEASE DO NOT EDIT -->
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# Child Workflow Sample
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## Prerequisites
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0. Install Cadence CLI. See instruction [here](https://cadenceworkflow.io/docs/cli/).
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1. Run the Cadence server:
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1. Clone the [Cadence](https://github.com/cadence-workflow/cadence) repository if you haven't done already: `git clone https://github.com/cadence-workflow/cadence.git`
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2. Run `docker compose -f docker/docker-compose.yml up` to start Cadence server
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3. See more details at https://github.com/uber/cadence/blob/master/README.md
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2. Once everything is up and running in Docker, open [localhost:8088](localhost:8088) to view Cadence UI.
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3. Register the `cadence-samples` domain:
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```bash
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cadence --env development --domain cadence-samples domain register
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```
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Refresh the [domains page](http://localhost:8088/domains) from step 2 to verify `cadence-samples` is registered.
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## Steps to run sample
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Inside the folder this sample is defined, run the following command:
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```bash
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go run .
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```
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This will call the main function in main.go which starts the worker, which will be execute the sample workflow code
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## Child Workflow Sample
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This sample demonstrates **parent-child workflow relationships** and the **ContinueAsNew** pattern.
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### Start the Workflow
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```bash
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cadence --env development \
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--domain cadence-samples \
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workflow start \
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--tl cadence-samples-worker \
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--et 60 \
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--workflow_type cadence_samples.ParentWorkflow
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```
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### What Happens
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```
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┌─────────────────────┐
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│ ParentWorkflow │
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└──────────┬──────────┘
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│
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│ ExecuteChildWorkflow
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▼
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┌─────────────────────┐
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│ ChildWorkflow │──┐
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│ (run 1 of 5) │ │
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└─────────────────────┘ │
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│ │ ContinueAsNew
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▼ │
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┌─────────────────────┐ │
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│ ChildWorkflow │──┤
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│ (run 2 of 5) │ │
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└─────────────────────┘ │
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│ │
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... ...
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│ │
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▼ │
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┌─────────────────────┐ │
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│ ChildWorkflow │◀─┘
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│ (run 5 of 5) │
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└─────────────────────┘
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│
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│ Returns result
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▼
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┌─────────────────────┐
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│ ParentWorkflow │
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│ completes │
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└─────────────────────┘
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```
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1. Parent workflow starts a child workflow
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2. Child workflow uses `ContinueAsNew` to restart itself 5 times
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3. After 5 runs, child completes and returns result to parent
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### Key Concept: Child Workflow Options
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```go
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cwo := workflow.ChildWorkflowOptions{
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WorkflowID: childID,
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ExecutionStartToCloseTimeout: time.Minute,
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}
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ctx = workflow.WithChildOptions(ctx, cwo)
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err := workflow.ExecuteChildWorkflow(ctx, ChildWorkflow, args...).Get(ctx, &result)
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```
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### Key Concept: ContinueAsNew
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```go
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// Instead of recursion (which grows history), use ContinueAsNew
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return "", workflow.NewContinueAsNewError(ctx, ChildWorkflow, newArgs...)
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```
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ContinueAsNew starts a new workflow run with fresh history, avoiding unbounded history growth.
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## References
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* The website: https://cadenceworkflow.io
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* Cadence's server: https://github.com/uber/cadence
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* Cadence's Go client: https://github.com/uber-go/cadence-client
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‎new_samples/childworkflow/childworkflow.go‎

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package main
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import (
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"errors"
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"fmt"
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"time"
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"go.uber.org/cadence/workflow"
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"go.uber.org/zap"
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)
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// ParentWorkflow demonstrates invoking a child workflow from a parent.
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// The parent waits for the child to complete before finishing.
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func ParentWorkflow(ctx workflow.Context) error {
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logger := workflow.GetLogger(ctx)
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logger.Info("ParentWorkflow started")
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execution := workflow.GetInfo(ctx).WorkflowExecution
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// Parent can specify its own ID for child execution
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childID := fmt.Sprintf("child_workflow:%v", execution.RunID)
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cwo := workflow.ChildWorkflowOptions{
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WorkflowID: childID,
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ExecutionStartToCloseTimeout: time.Minute,
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}
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ctx = workflow.WithChildOptions(ctx, cwo)
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// Execute child workflow and wait for result
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var result string
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err := workflow.ExecuteChildWorkflow(ctx, ChildWorkflow, 0, 5).Get(ctx, &result)
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if err != nil {
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logger.Error("Child workflow failed", zap.Error(err))
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return err
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}
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logger.Info("ParentWorkflow completed", zap.String("result", result))
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return nil
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}
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// ChildWorkflow demonstrates ContinueAsNew pattern.
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// It runs multiple times, restarting itself with ContinueAsNew until runCount reaches 0.
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func ChildWorkflow(ctx workflow.Context, totalCount, runCount int) (string, error) {
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logger := workflow.GetLogger(ctx)
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logger.Info("ChildWorkflow started", zap.Int("totalCount", totalCount), zap.Int("runCount", runCount))
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if runCount <= 0 {
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logger.Error("Invalid run count", zap.Int("runCount", runCount))
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return "", errors.New("invalid run count")
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}
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totalCount++
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runCount--
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if runCount == 0 {
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result := fmt.Sprintf("Child workflow completed after %d runs", totalCount)
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logger.Info("ChildWorkflow completed", zap.String("result", result))
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return result, nil
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}
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// ContinueAsNew: start a new run with fresh history
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logger.Info("ChildWorkflow continuing as new", zap.Int("remainingRuns", runCount))
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return "", workflow.NewContinueAsNewError(ctx, ChildWorkflow, totalCount, runCount)
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}
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‎new_samples/childworkflow/generator/README.md‎

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<!-- THIS IS A GENERATED FILE -->
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<!-- PLEASE DO NOT EDIT -->
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# Sample Generator
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This folder is NOT part of the actual sample. It exists only for contributors who work on this sample. Please disregard it if you are trying to learn about Cadence.
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To create a better learning experience for Cadence users, each sample folder is designed to be self contained. Users can view every part of writing and running workflows, including:
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* Cadence client initialization
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* Worker with workflow and activity registrations
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* Workflow starter
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* and the workflow code itself
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Some samples may have more or fewer parts depending on what they need to demonstrate.
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In most cases, the workflow code (e.g. `workflow.go`) is the part that users care about. The rest is boilerplate needed to run that workflow. For each sample folder, the workflow code should be written by hand. The boilerplate can be generated. Keeping all parts inside one folder gives early learners more value because they can see everything together rather than jumping across directories.
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## Contributing
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* When creating a new sample, follow the steps mentioned in the README file in the main samples folder.
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* To update the sample workflow code, edit the workflow file directly.
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* To update the worker, client, or other boilerplate logic, edit the generator file. If your change applies to all samples, update the common generator file inside the `template` folder. Edit the generator file in this folder only when the change should affect this sample alone.

‎new_samples/childworkflow/generator/README_specific.md‎

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## Child Workflow Sample
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This sample demonstrates **parent-child workflow relationships** and the **ContinueAsNew** pattern.
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### Start the Workflow
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```bash
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cadence --env development \
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--domain cadence-samples \
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workflow start \
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--tl cadence-samples-worker \
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--et 60 \
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--workflow_type cadence_samples.ParentWorkflow
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```
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### What Happens
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```
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┌─────────────────────┐
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│ ParentWorkflow │
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└──────────┬──────────┘
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│
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│ ExecuteChildWorkflow
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▼
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┌─────────────────────┐
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│ ChildWorkflow │──┐
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│ (run 1 of 5) │ │
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└─────────────────────┘ │
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│ │ ContinueAsNew
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▼ │
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┌─────────────────────┐ │
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│ ChildWorkflow │──┤
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│ (run 2 of 5) │ │
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└─────────────────────┘ │
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│ │
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... ...
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│ │
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▼ │
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┌─────────────────────┐ │
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│ ChildWorkflow │◀─┘
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│ (run 5 of 5) │
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└─────────────────────┘
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│
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│ Returns result
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▼
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┌─────────────────────┐
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│ ParentWorkflow │
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│ completes │
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└─────────────────────┘
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```
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1. Parent workflow starts a child workflow
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2. Child workflow uses `ContinueAsNew` to restart itself 5 times
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3. After 5 runs, child completes and returns result to parent
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### Key Concept: Child Workflow Options
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```go
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cwo := workflow.ChildWorkflowOptions{
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WorkflowID: childID,
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ExecutionStartToCloseTimeout: time.Minute,
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}
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ctx = workflow.WithChildOptions(ctx, cwo)
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err := workflow.ExecuteChildWorkflow(ctx, ChildWorkflow, args...).Get(ctx, &result)
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```
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### Key Concept: ContinueAsNew
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```go
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// Instead of recursion (which grows history), use ContinueAsNew
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return "", workflow.NewContinueAsNewError(ctx, ChildWorkflow, newArgs...)
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```
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ContinueAsNew starts a new workflow run with fresh history, avoiding unbounded history growth.
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‎new_samples/childworkflow/generator/generate.go‎

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package main
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import "github.com/uber-common/cadence-samples/new_samples/template"
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func main() {
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data := template.TemplateData{
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SampleName: "Child Workflow",
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Workflows: []string{"ParentWorkflow", "ChildWorkflow"},
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Activities: []string{},
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}
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template.GenerateAll(data)
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}
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‎new_samples/childworkflow/main.go‎

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// THIS IS A GENERATED FILE
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// PLEASE DO NOT EDIT
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package main
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import (
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"fmt"
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"os"
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"os/signal"
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"syscall"
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)
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func main() {
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StartWorker()
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done := make(chan os.Signal, 1)
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signal.Notify(done, syscall.SIGINT)
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fmt.Println("Cadence worker started, press ctrl+c to terminate...")
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<-done
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}

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