Add updated signal and dynamic workflow samples (#78)

Author: chopincode

new_samples/README.md

@@ -9,7 +9,7 @@ These are some samples to demonstrate various capabilities of Cadence client and
 1. Run the Cadence server: https://github.com/uber/cadence/blob/master/README.md
 2. Register the `cadence-samples` domain: https://cadenceworkflow.io/docs/cli/#quick-start or https://github.com/uber/cadence/blob/master/tools/cli/README.md
 
-
+Detailed workflow histories can be viewed on Cadence UI. Go to `localhost:8088` on your browser for more details.
 
 ## Steps to run samples
 Simply start the go binary by running
@@ -30,4 +30,60 @@ cadence --env development \
   --et 60 \
   --input '{"message":"Uber"}'
 ```
-Try to inspect the log message for the output.
+Try to inspect the log message for the output.
+
+### Signal Workflow
+This workflow demonstrate a basic signal workflow. It takes your name as input parameter
+and greet you based on languages you pick. To start the workflow, try the following CLI.
+
+```bash
+cadence --env development \
+  --domain cadence-samples \
+  workflow start \
+  --workflow_type cadence_samples.SignalGreeterMultiLanguageWorkflow \
+  --tl cadence-samples-worker \
+  --et 6000 \
+  --input '{"name":"Uber"}'
+```
+
+A workflow ID and run ID will be return in your terminal. Copy the workflow ID and replace
+to the CLI below to trigger the signal. Try to change the input language value and inspect what
+happens in the log. Also, try to inspect what happened after you interact with the signal multiple times.
+
+```bash
+cadence --env development \
+  --domain cadence-samples \
+  workflow signal \
+  --workflow_id <Your workflow ID> \
+  --name "language" \
+  --input '"english"'
+```
+
+To cancel the workflow, try the following CLI.
+
+```bash
+cadence --env development \
+  --domain cadence-samples \
+  workflow signal \
+  --workflow_id <Your workflow ID> \
+  --name "cancel" \
+  --input 'true'
+```
+The workflow should have a status of fail.
+
+### Dynamic workflow
+This dynamic workflow is very similar to the Hello World workflow above, but instead of passing the
+function definition to the activity execution step, we can directly pass an activity name registered to the
+worker to run the workflow. Here is a sample CLI.
+
+```bash
+cadence --env development \
+  --domain cadence-samples \
+  workflow start \
+  --workflow_type cadence_samples.DynamicWorkflow \
+  --tl cadence-samples-worker \
+  --et 60 \
+  --input '{"message":"Uber"}'
+```
+Try to inspect the log message for the output.
+

new_samples/worker/worker.go

@@ -43,6 +43,14 @@ func StartWorker() {
 	w.RegisterWorkflowWithOptions(workflows.HelloWorldWorkflow, workflow.RegisterOptions{Name: "cadence_samples.HelloWorldWorkflow"})
 	w.RegisterActivityWithOptions(workflows.HelloWorldActivity, activity.RegisterOptions{Name: "cadence_samples.HelloWorldActivity"})
 
+	// Signal workflow registration
+	w.RegisterWorkflowWithOptions(workflows.SignalGreeterMultiLanguageWorkflow, workflow.RegisterOptions{Name: "cadence_samples.SignalGreeterMultiLanguageWorkflow"})
+	w.RegisterActivityWithOptions(workflows.GenerateGreetingMessage, activity.RegisterOptions{Name: "cadence_samples.GenerateGreetingMessage"})
+
+	// Dynamic workflow registration
+	w.RegisterWorkflowWithOptions(workflows.DynamicWorkflow, workflow.RegisterOptions{Name: "cadence_samples.DynamicWorkflow"})
+	w.RegisterActivityWithOptions(workflows.DynamicGreetingActivity, activity.RegisterOptions{Name: "cadence_samples.DynamicGreetingActivity"})
+
 	err := w.Start()
 	if err != nil {
 		panic("Failed to start worker: " + err.Error())

new_samples/workflows/dynamic_workflow.go

@@ -0,0 +1,42 @@
+package workflows
+
+import (
+	"context"
+	"go.uber.org/cadence/activity"
+	"go.uber.org/cadence/workflow"
+	"go.uber.org/zap"
+	"time"
+)
+
+const DynamicGreetingActivityName = "cadence_samples.DynamicGreetingActivity"
+
+type dynamicWorkflowInput struct {
+	Message string `json:"message"`
+}
+
+func DynamicWorkflow(ctx workflow.Context, input dynamicWorkflowInput) (string, error) {
+	ao := workflow.ActivityOptions{
+		ScheduleToStartTimeout: time.Minute,
+		StartToCloseTimeout:    time.Minute,
+	}
+	ctx = workflow.WithActivityOptions(ctx, ao)
+
+	logger := workflow.GetLogger(ctx)
+	logger.Info("DynamicWorkflow started")
+
+	var greetingMsg string
+	err := workflow.ExecuteActivity(ctx, DynamicGreetingActivityName, input.Message).Get(ctx, &greetingMsg)
+	if err != nil {
+		logger.Error("DynamicGreetingActivity failed", zap.Error(err))
+		return "", err
+	}
+
+	logger.Info("Workflow result", zap.String("greeting", greetingMsg))
+	return greetingMsg, nil
+}
+
+func DynamicGreetingActivity(ctx context.Context, message string) (string, error) {
+	logger := activity.GetLogger(ctx)
+	logger.Info("DynamicGreetingActivity started.")
+	return "Hello, " + message, nil
+}

new_samples/workflows/signal_greeter_multi_language.go

@@ -0,0 +1,92 @@
+package workflows
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"go.uber.org/cadence/activity"
+	"go.uber.org/cadence/workflow"
+	"go.uber.org/zap"
+	"time"
+)
+
+// A workflow execution cannot receive infinite number of signals due to history limit
+// By default 10000 is MaximumSignalsPerExecution which can be configured by DynamicConfig of Cadence cluster.
+// But it's recommended to do continueAsNew after receiving certain number of signals(in production, use a number <1000)
+const (
+	MaxSignalCount = 3
+
+	LanguageChan = "language"
+	CancelChan   = "cancel"
+)
+
+type person struct {
+	Name string `json:"name"`
+}
+
+func SignalGreeterMultiLanguageWorkflow(ctx workflow.Context, person person) error {
+	ao := workflow.ActivityOptions{
+		ScheduleToStartTimeout: time.Minute * 60,
+		StartToCloseTimeout:    time.Minute * 60,
+	}
+	ctx = workflow.WithActivityOptions(ctx, ao)
+	logger := workflow.GetLogger(ctx)
+	logger.Info("SignalGreeterMultiLanguageWorkflow started, ", zap.String("Name", person.Name))
+
+	signalCount := 0
+
+	var language string
+	var canceled bool
+	languageChan := workflow.GetSignalChannel(ctx, LanguageChan)
+	cancelChan := workflow.GetSignalChannel(ctx, CancelChan)
+	for {
+		s := workflow.NewSelector(ctx)
+		s.AddReceive(languageChan, func(ch workflow.Channel, ok bool) {
+			if ok {
+				ch.Receive(ctx, &language)
+				signalCount += 1
+			}
+		})
+
+		s.AddReceive(cancelChan, func(ch workflow.Channel, ok bool) {
+			if ok {
+				ch.Receive(ctx, &canceled)
+			}
+		})
+		s.Select(ctx)
+
+		if canceled {
+			return errors.New("signal workflow canceled")
+		}
+		if signalCount >= MaxSignalCount {
+			return workflow.NewContinueAsNewError(ctx, SignalGreeterMultiLanguageWorkflow, person)
+		}
+
+		var greeting string
+		err := workflow.ExecuteActivity(ctx, GenerateGreetingMessage, language, person.Name).Get(ctx, &greeting)
+		if err != nil {
+			return err
+		}
+
+		logger.Info("Greeting message", zap.String("Greeting", greeting))
+	}
+}
+
+func GenerateGreetingMessage(ctx context.Context, language, name string) (string, error) {
+	logger := activity.GetLogger(ctx)
+	logger.Info("GenerateGreetingMessage started")
+	var greeting string
+	if language == "english" {
+		greeting = "Hello"
+	}
+	if language == "spanish" {
+		greeting = "Hola"
+	}
+	if language == "french" {
+		greeting = "bonjour"
+	}
+	if greeting == "" {
+		return "", errors.New("currently only support english, spanish and french")
+	}
+	return fmt.Sprintf("%s %s!", greeting, name), nil
+}