[Workflow] Make workflow engine configurable (and other improvements)

pkg/apis/configuration/v1alpha1/types.go

@@ -63,6 +63,22 @@ type ConfigurationSpec struct {
 	LoggingSpec *LoggingSpec `json:"logging,omitempty"`
 	// +optional
 	WasmSpec *WasmSpec `json:"wasm,omitempty"`
+	// +optional
+	WorkflowSpec *WorkflowSpec `json:"workflow,omitempty"`
+}
+
+// WorkflowSpec defines the configuration for Dapr workflows.
+type WorkflowSpec struct {
+	// maxConcurrentWorkflowInvocations is the maximum number of concurrent workflow invocations that can be scheduled by a single Dapr instance.
+	// Attempted invocations beyond this will be queued until the number of concurrent invocations drops below this value.
+	// If omitted, the default value of 100 will be used.
+	// +optional
+	MaxConcurrentWorkflowInvocations int32 `json:"maxConcurrentWorkflowInvocations,omitempty"`
+	// maxConcurrentActivityInvocations is the maximum number of concurrent activities that can be processed by a single Dapr instance.
+	// Attempted invocations beyond this will be queued until the number of concurrent invocations drops below this value.
+	// If omitted, the default value of 100 will be used.
+	// +optional
+	MaxConcurrentActivityInvocations int32 `json:"maxConcurrentActivityInvocations,omitempty"`
 }
 
 // APISpec describes the configuration for Dapr APIs.

pkg/config/configuration.go

@@ -60,6 +60,9 @@
 	DefaultNamespace    = "default"
 	ActionPolicyApp     = "app"
 	ActionPolicyGlobal  = "global"
+
+	defaultMaxWorkflowConcurrentInvocations = 100
+	defaultMaxActivityConcurrentInvocations = 100
 )
 
 // Configuration is an internal (and duplicate) representation of Dapr's Configuration CRD.
@@ -112,6 +115,33 @@
 	ComponentsSpec      *ComponentsSpec     `json:"components,omitempty" yaml:"components,omitempty"`
 	LoggingSpec         *LoggingSpec        `json:"logging,omitempty" yaml:"logging,omitempty"`
 	WasmSpec            *WasmSpec           `json:"wasm,omitempty" yaml:"wasm,omitempty"`
+	WorkflowSpec        *WorkflowSpec       `json:"workflow,omitempty" yaml:"workflow,omitempty"`
+}
+
+// WorkflowSpec defines the configuration for Dapr workflows.
+type WorkflowSpec struct {
+	// maxConcurrentWorkflowInvocations is the maximum number of concurrent workflow invocations that can be scheduled by a single Dapr instance.
+	// Attempted invocations beyond this will be queued until the number of concurrent invocations drops below this value.
+	// If omitted, the default value of 100 will be used.
+	MaxConcurrentWorkflowInvocations int32 `json:"maxConcurrentWorkflowInvocations,omitempty" yaml:"maxConcurrentWorkflowInvocations,omitempty"`
+	// maxConcurrentActivityInvocations is the maximum number of concurrent activities that can be processed by a single Dapr instance.
+	// Attempted invocations beyond this will be queued until the number of concurrent invocations drops below this value.
+	// If omitted, the default value of 100 will be used.
+	MaxConcurrentActivityInvocations int32 `json:"maxConcurrentActivityInvocations,omitempty" yaml:"maxConcurrentActivityInvocations,omitempty"`
+}
+
+func (w *WorkflowSpec) GetMaxConcurrentWorkflowInvocations() int32 {
+	if w == nil || w.MaxConcurrentWorkflowInvocations <= 0 {
+		return defaultMaxWorkflowConcurrentInvocations
+	}
+	return w.MaxConcurrentWorkflowInvocations
+}
+
+func (w *WorkflowSpec) GetMaxConcurrentActivityInvocations() int32 {
+	if w == nil || w.MaxConcurrentActivityInvocations <= 0 {
+		return defaultMaxActivityConcurrentInvocations
+	}
+	return w.MaxConcurrentActivityInvocations
 }
 
 type SecretsSpec struct {
@@ -363,6 +393,10 @@
 				DefaultAction: AllowAccess,
 				TrustDomain:   "public",
 			},
+			WorkflowSpec: &WorkflowSpec{
+				MaxConcurrentWorkflowInvocations: defaultMaxWorkflowConcurrentInvocations,
+				MaxConcurrentActivityInvocations: defaultMaxActivityConcurrentInvocations,
+			},
 		},
 	}
 }
@@ -582,6 +616,18 @@
 	return *c.Spec.LoggingSpec.APILogging
 }
 
+// GetWorkflowSpec returns the Workflow spec.
+// It's a short-hand that includes nil-checks for safety.
+func (c *Configuration) GetWorkflowSpec() WorkflowSpec {
+	if c == nil || c.Spec.WorkflowSpec == nil {
+		return WorkflowSpec{
+			MaxConcurrentWorkflowInvocations: defaultMaxWorkflowConcurrentInvocations,
+			MaxConcurrentActivityInvocations: defaultMaxActivityConcurrentInvocations,
+		}
+	}
+	return *c.Spec.WorkflowSpec
+}
+
 // ToYAML returns the Configuration represented as YAML.
 func (c *Configuration) ToYAML() (string, error) {
 	b, err := yaml.Marshal(c)

pkg/config/configuration_test.go

@@ -175,6 +175,25 @@ func TestLoadStandaloneConfiguration(t *testing.T) {
 		assert.Equal(t, "1h", mtlsSpec.AllowedClockSkew)
 	})
 
+	t.Run("workflow spec - configured", func(t *testing.T) {
+		config, err := LoadStandaloneConfiguration("./testdata/workflow_config.yaml")
+		require.NoError(t, err)
+		workflowSpec := config.GetWorkflowSpec()
+		assert.Equal(t, int32(32), workflowSpec.MaxConcurrentWorkflowInvocations)
+		assert.Equal(t, int32(64), workflowSpec.MaxConcurrentActivityInvocations)
+	})
+
+	t.Run("workflow spec - defaults", func(t *testing.T) {
+		// Intentionally loading an unrelated config file to test defaults
+		config, err := LoadStandaloneConfiguration("./testdata/mtls_config.yaml")
+		require.NoError(t, err)
+		workflowSpec := config.GetWorkflowSpec()
+
+		// These are the documented default values. Changes to these defaults require changes to
+		assert.Equal(t, int32(100), workflowSpec.MaxConcurrentWorkflowInvocations)
+		assert.Equal(t, int32(100), workflowSpec.MaxConcurrentActivityInvocations)
+	})
+
 	t.Run("multiple configurations", func(t *testing.T) {
 		config, err := LoadStandaloneConfiguration("./testdata/feature_config.yaml", "./testdata/mtls_config.yaml")
 		require.NoError(t, err)

pkg/config/testdata/override_gen.yaml

@@ -31,3 +31,6 @@ spec:
     features:
         - name: Test.Feature
           enabled: true
+    workflow:
+        maxConcurrentWorkflowInvocations: 100
+        maxConcurrentActivityInvocations: 100

pkg/config/testdata/override_spec_gen.yaml

@@ -12,3 +12,6 @@ accessControl:
 features:
     - name: Test.Feature
       enabled: true
+workflow:
+    maxConcurrentWorkflowInvocations: 100
+    maxConcurrentActivityInvocations: 100

pkg/config/testdata/workflow_config.yaml

@@ -0,0 +1,9 @@
+apiVersion: dapr.io/v1alpha1
+kind: Configuration
+metadata:
+  name: daprsystem
+  namespace: default
+spec:
+  workflow:
+    maxConcurrentWorkflowInvocations: 32
+    maxConcurrentActivityInvocations: 64

pkg/runtime/runtime.go

@@ -177,7 +177,7 @@
 
 	grpc := createGRPCManager(sec, runtimeConfig, globalConfig)
 
-	wfe := wfengine.NewWorkflowEngine(wfengine.NewWorkflowConfig(runtimeConfig.id))
+	wfe := wfengine.NewWorkflowEngine(runtimeConfig.id, globalConfig.GetWorkflowSpec())
 	wfe.ConfigureGrpcExecutor()
 
 	channels := channels.New(channels.Options{
@@ -584,8 +584,8 @@
 			a.daprUniversalAPI.SetActorRuntime(a.actor)
 		}
 	} else {
-		// If actors are not enabled, still invoke SetActorRuntime on the workflow engine with `nil` to unblock the goroutine
-		a.workflowEngine.SetActorRuntime(a.actor)
+		// If actors are not enabled, still invoke SetActorRuntime on the workflow engine with `nil` to unblock startup
+		a.workflowEngine.SetActorRuntime(nil)
 	}
 
 	// We set actors as initialized whether we have an actors runtime or not

pkg/runtime/wfengine/README.md

@@ -64,7 +64,7 @@ DEBU[0000] activity-processor: waiting for new work items...       app_id=wfapp
 Unit tests can be run using the following `go` command from the repo root. Depending on the speed of your development machine, these tests should complete in less than 30 seconds.
 
 ```bash
-go test ./pkg/runtime/wfengine/...
+go test ./pkg/runtime/wfengine/... -tags=unit
 ```
 
 If you're using VS Code, you can also run tests directly from the IDE.

pkg/runtime/wfengine/activity.go

@@ -37,12 +37,12 @@
 
 type activityActor struct {
 	actorRuntime     actors.Actors
-	scheduler        workflowScheduler
+	scheduler        activityScheduler
 	statesCache      sync.Map
 	cachingDisabled  bool
 	defaultTimeout   time.Duration
 	reminderInterval time.Duration
-	config           wfConfig
+	config           actorsBackendConfig
 }
 
 // ActivityRequest represents a request by a worklow to invoke an activity.
@@ -54,13 +54,16 @@
 	EventPayload []byte
 }
 
+// activityScheduler is a func interface for pushing activity work items into the backend
+type activityScheduler func(ctx context.Context, wi *backend.ActivityWorkItem) error
+
 // NewActivityActor creates an internal activity actor for executing workflow activity logic.
-func NewActivityActor(scheduler workflowScheduler, config wfConfig) *activityActor {
+func NewActivityActor(scheduler activityScheduler, backendConfig actorsBackendConfig) *activityActor {
 	return &activityActor{
 		scheduler:        scheduler,
 		defaultTimeout:   1 * time.Hour,
 		reminderInterval: 1 * time.Minute,
-		config:           config,
+		config:           backendConfig,
 	}
 }
 
@@ -114,24 +117,26 @@
 	defer cancelTimeout()
 
 	if err := a.executeActivity(timeoutCtx, actorID, reminderName, state.EventPayload); err != nil {
-		if errors.Is(err, context.DeadlineExceeded) {
+		var recoverableErr *recoverableError
+		switch {
+		case errors.Is(err, context.DeadlineExceeded):
 			wfLogger.Warnf("%s: execution of '%s' timed-out and will be retried later: %v", actorID, reminderName, err)
-
 			// Returning nil signals that we want the execution to be retried in the next period interval
 			return nil
-		} else if _, ok := err.(recoverableError); ok {
+		case errors.Is(err, context.Canceled):
+			wfLogger.Warnf("%s: received cancellation signal while waiting for activity execution '%s'", actorID, reminderName)
+			// Returning nil signals that we want the execution to be retried in the next period interval
+			return nil
+		case errors.As(err, &recoverableErr):
 			wfLogger.Warnf("%s: execution failed with a recoverable error and will be retried later: %v", actorID, err)
-
 			// Returning nil signals that we want the execution to be retried in the next period interval
 			return nil
-		} else {
+		default:
 			wfLogger.Errorf("%s: execution failed with a non-recoverable error: %v", actorID, err)
 			// TODO: Reply with a failure - this requires support from durabletask-go to produce TaskFailure results
 		}
 	}
 
-	// TODO: Purge actor state based on some data retention policy
-
 	// We delete the reminder on success and on non-recoverable errors.
 	return actors.ErrReminderCanceled
 }
@@ -162,7 +167,7 @@
 	//       introduce some kind of heartbeat protocol to help identify such cases.
 	callback := make(chan bool)
 	wi.Properties[CallbackChannelProperty] = callback
-	if err = a.scheduler.ScheduleActivity(ctx, wi); err != nil {
+	if err = a.scheduler(ctx, wi); err != nil {
 		if errors.Is(err, context.DeadlineExceeded) {
 			return newRecoverableError(fmt.Errorf("timed-out trying to schedule an activity execution - this can happen if too many activities are running in parallel or if the workflow engine isn't running: %w", err))
 		}
@@ -177,7 +182,7 @@
 			if !t.Stop() {
 				<-t.C
 			}
-			return ctx.Err()
+			return ctx.Err() // will be retried
 		case <-t.C:
 			if deadline, ok := ctx.Deadline(); ok {
 				wfLogger.Warnf("%s: '%s' is still running - will keep waiting until %v", actorID, name, deadline)
@@ -191,7 +196,7 @@
 			if completed {
 				break loop
 			} else {
-				return newRecoverableError(errExecutionAborted)
+				return newRecoverableError(errExecutionAborted) // AbandonActivityWorkItem was called
 			}
 		}
 	}