pkg/workflows/sdk: add WorkflowSpecFactory.BeginSerial/BeginAsync

pkg/workflows/sdk/builder.go

@@ -15,12 +15,22 @@ type WorkflowSpecFactory struct {
 	emptyNames     bool
 	badCapTypes    []string
 	fns            map[string]func(runtime Runtime, request capabilities.CapabilityRequest) (capabilities.CapabilityResponse, error)
+	serialMode     bool
+	prevRefs       []string
 }
 
 func (w *WorkflowSpecFactory) GetFn(name string) func(sdk Runtime, request capabilities.CapabilityRequest) (capabilities.CapabilityResponse, error) {
 	return w.fns[name]
 }
 
+func (w *WorkflowSpecFactory) BeginSerial() {
+	w.serialMode = true
+}
+
+func (w *WorkflowSpecFactory) BeginAsync() {
+	w.serialMode = false
+}
+
 type CapDefinition[O any] interface {
 	Ref() any
 	self() CapDefinition[O]
@@ -98,6 +108,15 @@ type NewWorkflowParams struct {
 	Name  string
 }
 
+// NewSerialWorkflowSpecFactory returns a new WorkflowSpecFactory in Serial mode.
+// This is the same as calling NewWorkflowSpecFactory then WorkflowSpecFactory.BeginSerial.
+func NewSerialWorkflowSpecFactory(params NewWorkflowParams) *WorkflowSpecFactory {
+	f := NewWorkflowSpecFactory(params)
+	f.BeginSerial()
+	return f
+}
+
+// NewWorkflowSpecFactory returns a new NewWorkflowSpecFactory.
 func NewWorkflowSpecFactory(
 	params NewWorkflowParams,
 ) *WorkflowSpecFactory {
@@ -119,6 +138,16 @@ func NewWorkflowSpecFactory(
 // AddTo is meant to be called by generated code
 func (step *Step[O]) AddTo(w *WorkflowSpecFactory) CapDefinition[O] {
 	stepDefinition := step.Definition
+
+	if w.serialMode {
+		// ensure we depend on each previous step
+		for _, prevRef := range w.prevRefs {
+			if !stepDefinition.Inputs.HasRef(prevRef) {
+				stepDefinition.Condition = fmt.Sprintf("$(%s.success)", prevRef)
+			}
+		}
+	}
+
 	stepRef := stepDefinition.Ref
 	if w.names[stepRef] && stepDefinition.CapabilityType != capabilities.CapabilityTypeTarget {
 		w.duplicateNames[stepRef] = true
@@ -143,7 +172,14 @@ func (step *Step[O]) AddTo(w *WorkflowSpecFactory) CapDefinition[O] {
 		w.badCapTypes = append(w.badCapTypes, stepDefinition.ID)
 	}
 
-	return &capDefinitionImpl[O]{ref: fmt.Sprintf("$(%s.outputs)", step.Definition.Ref)}
+	c := &capDefinitionImpl[O]{ref: fmt.Sprintf("$(%s.outputs)", step.Definition.Ref)}
+
+	if w.serialMode {
+		w.prevRefs = []string{step.Definition.Ref}
+	} else {
+		w.prevRefs = append(w.prevRefs, step.Definition.Ref)
+	}
+	return c
 }
 
 // AccessField is meant to be used by generated code

pkg/workflows/sdk/testdata/fixtures/charts/builder_serial.md

@@ -0,0 +1,28 @@
+```mermaid
+flowchart
+
+	trigger[\"<b>trigger</b><br>trigger<br><i>(basic-test-trigger[at]1.0.0)</i>"/]
+	
+	compute["<b>compute</b><br>action<br><i>(custom_compute[at]1.0.0)</i>"]
+	get-bar -- Value --> compute 
+			get-baz -- Value --> compute 
+			get-foo -- Value --> compute 
+			
+	get-bar["<b>get-bar</b><br>action<br><i>(custom_compute[at]1.0.0)</i>"]
+	get-foo -..-> get-bar
+	trigger -- cool_output --> get-bar 
+			
+	get-baz["<b>get-baz</b><br>action<br><i>(custom_compute[at]1.0.0)</i>"]
+	get-bar -..-> get-baz
+	trigger -- cool_output --> get-baz 
+			
+	get-foo["<b>get-foo</b><br>action<br><i>(custom_compute[at]1.0.0)</i>"]
+	trigger -- cool_output --> get-foo 
+			
+	consensus[["<b>consensus</b><br>consensus<br><i>(offchain_reporting[at]1.0.0)</i>"]]
+	compute -- Value --> consensus 
+			
+	unnamed6[/"target<br><i>(id)</i>"\]
+	consensus --> unnamed6
+			
+```

pkg/workflows/sdk/workflow_spec.go

@@ -128,10 +128,11 @@ func (os outputs) addOutput(s string) {
 //
 // Within the workflow spec, they are called "Capability Properties".
 type StepDefinition struct {
-	ID     string
-	Ref    string
-	Inputs StepInputs
-	Config map[string]any
+	ID        string
+	Ref       string
+	Condition string
+	Inputs    StepInputs
+	Config    map[string]any
 
 	CapabilityType capabilities.CapabilityType
 }
@@ -193,6 +194,10 @@ var tmpl = template.Must(template.New("").Funcs(map[string]any{
 	{{ else -}}
 	{{ $ref }}["{{$name}}"]
 	{{ end -}}
+	{{ $condRef := parseRef .Condition -}}
+	{{ if $condRef -}}
+		{{ $condRef }} -..-> {{ $step.Ref }}
+	{{ end -}}
 	{{ if .Inputs.OutputRef -}}
 	{{ .Inputs.OutputRef }} --> {{ $step.Ref }}
 	{{ else -}}

pkg/workflows/sdk/workflow_spec_test.go

@@ -67,9 +67,13 @@ func TestWorkflowSpecFormatChart(t *testing.T) {
 		{"notstreamssepolia", notStreamSepoliaWorkflowSpec},
 		{"serial", serialWorkflowSpec},
 		{"parallel", parallelWorkflowSpec},
+		{"parallel_serialized", parallelSerializedWorkflowSpec},
 		{"builder_parallel", buildSimpleWorkflowSpec(
 			sdk.NewWorkflowSpecFactory(sdk.NewWorkflowParams{Owner: "test", Name: "parallel"}),
 		).MustSpec(t)},
+		{"builder_serial", buildSimpleWorkflowSpec(
+			sdk.NewSerialWorkflowSpecFactory(sdk.NewWorkflowParams{Owner: "test", Name: "serial"}),
+		).MustSpec(t)},
 	} {
 		t.Run(tt.name, func(t *testing.T) {
 			requireEqualChart(t, tt.name, tt.workflow)
@@ -386,3 +390,86 @@ var parallelWorkflowSpec = sdk.WorkflowSpec{
 		},
 	},
 }
+
+var parallelSerializedWorkflowSpec = sdk.WorkflowSpec{
+	Name:  "parallel-serialized",
+	Owner: "owner",
+	Triggers: []sdk.StepDefinition{
+		{
+			ID:             "[email protected]",
+			Ref:            "trigger-chain-event",
+			Inputs:         sdk.StepInputs{},
+			Config:         map[string]any{"maxFrequencyMs": 5000},
+			CapabilityType: capabilities.CapabilityTypeTrigger,
+		},
+	},
+	Actions: []sdk.StepDefinition{
+		{
+			ID:  "[email protected]",
+			Ref: "get-foo",
+			Inputs: sdk.StepInputs{
+				Mapping: map[string]any{"Arg0": "$(trigger-chain-event.outputs)"},
+			},
+			CapabilityType: capabilities.CapabilityTypeAction,
+		},
+		{
+			ID:  "[email protected]",
+			Ref: "compute-foo",
+			Inputs: sdk.StepInputs{
+				Mapping: map[string]any{"Arg0": "$(get-foo.outputs)"},
+			},
+			CapabilityType: capabilities.CapabilityTypeAction,
+		},
+		{
+			ID:        "[email protected]",
+			Ref:       "get-bar",
+			Condition: "$(compute-foo.success)",
+			Inputs: sdk.StepInputs{
+				Mapping: map[string]any{"Arg0": "$(trigger-chain-event.outputs)"},
+			},
+			CapabilityType: capabilities.CapabilityTypeAction,
+		},
+		{
+			ID:  "[email protected]",
+			Ref: "compute-bar",
+			Inputs: sdk.StepInputs{
+				Mapping: map[string]any{"Arg0": "$(get-bar.outputs)"},
+			},
+			CapabilityType: capabilities.CapabilityTypeAction,
+		},
+		{
+			ID:        "[email protected]",
+			Ref:       "read-token-price",
+			Condition: "$(compute-bar.success)",
+			Inputs: sdk.StepInputs{
+				Mapping: map[string]any{"Arg0": "$(trigger-chain-event.outputs)"},
+			},
+			CapabilityType: capabilities.CapabilityTypeAction,
+		},
+	},
+	Consensus: []sdk.StepDefinition{
+		{
+			ID:  "[email protected]",
+			Ref: "data-feeds-report",
+			Inputs: sdk.StepInputs{
+				Mapping: map[string]any{
+					"observations": []string{
+						"$(compute-foo.outputs.Value)",
+						"$(compute-bar.outputs.Value)",
+					},
+					"token_price": "$(read-token-price.outputs.Value)",
+				},
+			},
+			CapabilityType: capabilities.CapabilityTypeConsensus,
+		},
+	},
+	Targets: []sdk.StepDefinition{
+		{
+			ID: "[email protected]",
+			Inputs: sdk.StepInputs{
+				Mapping: map[string]any{"signed_report": "$(data-feeds-report.outputs)"},
+			},
+			CapabilityType: capabilities.CapabilityTypeTarget,
+		},
+	},
+}

pkg/workflows/testdata/fixtures/workflows/marshalling/workflow_2_spec.json

@@ -5,6 +5,7 @@
     {
       "ID": "[email protected]",
       "Ref": "report_data",
+      "Condition": "",
       "Inputs": {
         "OutputRef": "",
         "Mapping": null
@@ -18,6 +19,7 @@
     {
       "ID": "trigger_test:aaShouldBeFirst_true:chain_ethereum:[email protected]",
       "Ref": "",
+      "Condition": "",
       "Inputs": {
         "OutputRef": "",
         "Mapping": {
@@ -34,6 +36,7 @@
     {
       "ID": "[email protected]",
       "Ref": "",
+      "Condition": "",
       "Inputs": {
         "OutputRef": "",
         "Mapping": {