Allow starting workflows by name

Author: cschleiden

client/client.go

@@ -44,9 +44,17 @@ func New(backend backend.Backend) *Client {
 
 // CreateWorkflowInstance creates a new workflow instance of the given workflow.
 func (c *Client) CreateWorkflowInstance(ctx context.Context, options WorkflowInstanceOptions, wf workflow.Workflow, args ...any) (*workflow.Instance, error) {
-	// Check arguments
-	if err := a.ParamsMatch(wf, args...); err != nil {
-		return nil, err
+	var workflowName string
+
+	if name, ok := wf.(string); ok {
+		workflowName = name
+	} else {
+		workflowName = fn.Name(wf)
+
+		// Check arguments if actual workflow function given here
+		if err := a.ParamsMatch(wf, args...); err != nil {
+			return nil, err
+		}
 	}
 
 	inputs, err := a.ArgsToInputs(c.backend.Converter(), args...)
@@ -57,8 +65,6 @@ func (c *Client) CreateWorkflowInstance(ctx context.Context, options WorkflowIns
 	wfi := core.NewWorkflowInstance(options.InstanceID, uuid.NewString())
 	metadata := &workflow.Metadata{}
 
-	workflowName := fn.Name(wf)
-
 	// Start new span for the workflow instance
 	ctx, span := c.backend.Tracer().Start(ctx, fmt.Sprintf("CreateWorkflowInstance: %s", workflowName), trace.WithAttributes(
 		attribute.String(log.InstanceIDKey, wfi.InstanceID),

client/client_test.go

@@ -12,6 +12,7 @@ import (
 	"github.com/cschleiden/go-workflows/backend/converter"
 	"github.com/cschleiden/go-workflows/backend/history"
 	"github.com/cschleiden/go-workflows/core"
+	"github.com/cschleiden/go-workflows/internal/metrics"
 	"github.com/cschleiden/go-workflows/workflow"
 	"github.com/google/uuid"
 	"github.com/stretchr/testify/mock"
@@ -40,6 +41,38 @@ func Test_Client_CreateWorkflowInstance_ParamMismatch(t *testing.T) {
 	b.AssertExpectations(t)
 }
 
+func Test_Client_CreateWorkflowInstance_NameGiven(t *testing.T) {
+	ctx := context.Background()
+
+	b := &backend.MockBackend{}
+	b.On("Converter").Return(converter.DefaultConverter)
+	b.On("Logger").Return(slog.Default())
+	b.On("Tracer").Return(trace.NewNoopTracerProvider().Tracer("test"))
+	b.On("Metrics").Return(metrics.NewNoopMetricsClient())
+	b.On("ContextPropagators").Return(nil)
+	b.On("CreateWorkflowInstance", mock.Anything, mock.Anything, mock.MatchedBy(func(event *history.Event) bool {
+		if event.Type != history.EventType_WorkflowExecutionStarted {
+			return false
+		}
+
+		a := event.Attributes.(*history.ExecutionStartedAttributes)
+
+		return a.Name == "workflowName"
+	})).Return(nil, nil)
+
+	c := &Client{
+		backend: b,
+		clock:   clock.New(),
+	}
+
+	result, err := c.CreateWorkflowInstance(ctx, WorkflowInstanceOptions{
+		InstanceID: "id",
+	}, "workflowName", "foo")
+	require.NotZero(t, result)
+	require.NoError(t, err)
+	b.AssertExpectations(t)
+}
+
 func Test_Client_GetWorkflowResultTimeout(t *testing.T) {
 	instance := core.NewWorkflowInstance(uuid.NewString(), "test")
 

workflow/subworkflow.go

@@ -50,19 +50,24 @@ func createSubWorkflowInstance[TResult any](ctx Context, options SubWorkflowOpti
 	}
 
 	// Check return type
-	if err := a.ReturnTypeMatch[TResult](wf); err != nil {
-		f.Set(*new(TResult), err)
-		return f
-	}
+	var workflowName string
+	if name, ok := wf.(string); ok {
+		workflowName = name
+	} else {
+		workflowName = fn.Name(wf)
+
+		if err := a.ReturnTypeMatch[TResult](wf); err != nil {
+			f.Set(*new(TResult), err)
+			return f
+		}
 
-	// Check arguments
-	if err := a.ParamsMatch(wf, args...); err != nil {
-		f.Set(*new(TResult), err)
-		return f
+		// Check arguments
+		if err := a.ParamsMatch(wf, args...); err != nil {
+			f.Set(*new(TResult), err)
+			return f
+		}
 	}
 
-	name := fn.Name(wf)
-
 	cv := contextvalue.Converter(ctx)
 	inputs, err := a.ArgsToInputs(cv, args...)
 	if err != nil {
@@ -74,9 +79,9 @@ func createSubWorkflowInstance[TResult any](ctx Context, options SubWorkflowOpti
 	scheduleEventID := wfState.GetNextScheduleEventID()
 
 	ctx, span := workflowtracer.Tracer(ctx).Start(ctx,
-		fmt.Sprintf("CreateSubworkflowInstance: %s", name),
+		fmt.Sprintf("CreateSubworkflowInstance: %s", workflowName),
 		trace.WithAttributes(
-			attribute.String(log.WorkflowNameKey, name),
+			attribute.String(log.WorkflowNameKey, workflowName),
 			attribute.Int64(log.ScheduleEventIDKey, scheduleEventID),
 			attribute.Int(log.AttemptKey, attempt),
 		))
@@ -90,7 +95,7 @@ func createSubWorkflowInstance[TResult any](ctx Context, options SubWorkflowOpti
 		return f
 	}
 
-	cmd := command.NewScheduleSubWorkflowCommand(scheduleEventID, wfState.Instance(), options.InstanceID, name, inputs, metadata)
+	cmd := command.NewScheduleSubWorkflowCommand(scheduleEventID, wfState.Instance(), options.InstanceID, workflowName, inputs, metadata)
 
 	wfState.AddCommand(cmd)
 	wfState.TrackFuture(scheduleEventID, workflowstate.AsDecodingSettable(cv, f))

workflow/subworkflow_test.go

@@ -15,6 +15,25 @@ import (
 	"go.opentelemetry.io/otel/trace"
 )
 
+func Test_createSubWorkflowInstance_NameAsString(t *testing.T) {
+	ctx := sync.Background()
+	ctx = contextvalue.WithConverter(ctx, converter.DefaultConverter)
+	ctx = workflowstate.WithWorkflowState(
+		ctx,
+		workflowstate.NewWorkflowState(core.NewWorkflowInstance("a", ""), slog.Default(), clock.New()),
+	)
+	ctx = workflowtracer.WithWorkflowTracer(ctx, workflowtracer.New(trace.NewNoopTracerProvider().Tracer("test")))
+
+	c := sync.NewCoroutine(ctx, func(ctx Context) error {
+		createSubWorkflowInstance[int](ctx, DefaultSubWorkflowOptions, 1, "workflowName", "foo")
+		return nil
+	})
+
+	c.Execute()
+	require.NoError(t, c.Error())
+	require.True(t, c.Finished())
+}
+
 func Test_createSubWorkflowInstance_ParamMismatch(t *testing.T) {
 	wf := func(Context, int) (int, error) {
 		return 42, nil