feat(backend): Add Semaphore and Mutex fields to Workflow CR

- Added `Semaphore` and `Mutex` fields to the Workflow Spec to support concurrency control mechanisms directly within workflows.
- Introduced a new environment variable, `SEMAPHORE_CONFIGMAP_NAME`, to the API Server deployment for managing semaphore configurations.
- Added an empty ConfigMap manifest for semaphores to facilitate initial setup and testing.

Signed-off-by: ddalvi <ddalvi@redhat.com>

backend/src/apiserver/template/v2_template.go

@@ -74,6 +74,33 @@ func NewGenericScheduledWorkflow(modelJob *model.Job) (*scheduledworkflow.Schedu
 	}, nil
 }
 
+// func getKubernetesSpec(platformSpec map[string]*pipelinespec.SinglePlatformSpec) *pipelinespec.SinglePlatformSpec {
+// 	var kubernetesSpec *pipelinespec.SinglePlatformSpec
+
+// 	// Check for "kubernetes" key in the platformSpec map
+// 	if platformSpec != nil {
+// 		if platform, ok := platformSpec["kubernetes"]; ok && platform != nil {
+// 			kubernetesSpec = platform
+// 		}
+// 	}
+// 	return kubernetesSpec
+// }
+
+func getPipelineOptions(platform *pipelinespec.SinglePlatformSpec) *argocompiler.Options {
+	var pipelineOptions *argocompiler.Options
+
+	if platform != nil && platform.PipelineConfig != nil {
+		pipelineOptions = &argocompiler.Options{}
+		if platform.PipelineConfig.SemaphoreKey != "" {
+			pipelineOptions.SemaphoreKey = platform.PipelineConfig.SemaphoreKey
+		}
+		if platform.PipelineConfig.MutexName != "" {
+			pipelineOptions.MutexName = platform.PipelineConfig.MutexName
+		}
+	}
+	return pipelineOptions
+}
+
 // Converts modelJob to ScheduledWorkflow.
 func (t *V2Spec) ScheduledWorkflow(modelJob *model.Job) (*scheduledworkflow.ScheduledWorkflow, error) {
 	job := &pipelinespec.PipelineJob{}
@@ -98,17 +125,19 @@ func (t *V2Spec) ScheduledWorkflow(modelJob *model.Job) (*scheduledworkflow.Sche
 		return nil, util.Wrap(err, "invalid pipeline job inputs")
 	}
 
+	// kubernetesSpec := getKubernetesSpec(t.platformSpec.Platforms)
 	// Pick out Kubernetes platform configs
 	var kubernetesSpec *pipelinespec.SinglePlatformSpec
 	if t.platformSpec != nil {
 		if _, ok := t.platformSpec.Platforms["kubernetes"]; ok {
 			kubernetesSpec = t.platformSpec.Platforms["kubernetes"]
 		}
 	}
+	pipelineOptions := getPipelineOptions(kubernetesSpec)
 
 	var obj interface{}
 	if util.CurrentExecutionType() == util.ArgoWorkflow {
-		obj, err = argocompiler.Compile(job, kubernetesSpec, nil)
+		obj, err = argocompiler.Compile(job, kubernetesSpec, pipelineOptions)
 	} else if util.CurrentExecutionType() == util.TektonPipelineRun {
 		obj, err = tektoncompiler.Compile(job, kubernetesSpec, &tektoncompiler.Options{LauncherImage: Launcher})
 	}
@@ -305,17 +334,20 @@ func (t *V2Spec) RunWorkflow(modelRun *model.Run, options RunWorkflowOptions) (u
 	if err = t.validatePipelineJobInputs(job); err != nil {
 		return nil, util.Wrap(err, "invalid pipeline job inputs")
 	}
+
 	// Pick out Kubernetes platform configs
 	var kubernetesSpec *pipelinespec.SinglePlatformSpec
 	if t.platformSpec != nil {
 		if _, ok := t.platformSpec.Platforms["kubernetes"]; ok {
 			kubernetesSpec = t.platformSpec.Platforms["kubernetes"]
 		}
 	}
+	// kubernetesSpec := getKubernetesSpec(t.platformSpec.Platforms)
+	pipelineOptions := getPipelineOptions(kubernetesSpec)
 
 	var obj interface{}
 	if util.CurrentExecutionType() == util.ArgoWorkflow {
-		obj, err = argocompiler.Compile(job, kubernetesSpec, nil)
+		obj, err = argocompiler.Compile(job, kubernetesSpec, pipelineOptions)
 	} else if util.CurrentExecutionType() == util.TektonPipelineRun {
 		obj, err = tektoncompiler.Compile(job, kubernetesSpec, nil)
 	}

backend/src/v2/compiler/argocompiler/argo.go

@@ -19,9 +19,11 @@ import (
 	"encoding/hex"
 	"encoding/json"
 	"fmt"
-	"github.com/kubeflow/pipelines/backend/src/apiserver/common"
+	"os"
 	"strings"
 
+	"github.com/kubeflow/pipelines/backend/src/apiserver/common"
+
 	wfapi "github.com/argoproj/argo-workflows/v3/pkg/apis/workflow/v1alpha1"
 	"github.com/kubeflow/pipelines/api/v2alpha1/go/pipelinespec"
 	"github.com/kubeflow/pipelines/backend/src/v2/compiler"
@@ -41,6 +43,16 @@ type Options struct {
 	// optional
 	PipelineRoot string
 	// TODO(Bobgy): add an option -- dev mode, ImagePullPolicy should only be Always in dev mode.
+	SemaphoreKey string
+	MutexName    string
+}
+
+func getSemaphoreConfigMapName() string {
+	const defaultConfigMapName = "semaphore-config"
+	if name := os.Getenv("SEMAPHORE_CONFIGMAP_NAME"); name != "" {
+		return name
+	}
+	return defaultConfigMapName
 }
 
 func Compile(jobArg *pipelinespec.PipelineJob, kubernetesSpecArg *pipelinespec.SinglePlatformSpec, opts *Options) (*wfapi.Workflow, error) {
@@ -87,22 +99,13 @@ func Compile(jobArg *pipelinespec.PipelineJob, kubernetesSpecArg *pipelinespec.S
 		}
 	}
 
-	// initialization
 	wf := &wfapi.Workflow{
 		TypeMeta: k8smeta.TypeMeta{
 			APIVersion: "argoproj.io/v1alpha1",
 			Kind:       "Workflow",
 		},
 		ObjectMeta: k8smeta.ObjectMeta{
 			GenerateName: retrieveLastValidString(spec.GetPipelineInfo().GetName()) + "-",
-			// Note, uncomment the following during development to view argo inputs/outputs in KFP UI.
-			// TODO(Bobgy): figure out what annotations we should use for v2 engine.
-			// For now, comment this annotation, so that in KFP UI, it shows argo input/output params/artifacts
-			// suitable for debugging.
-			//
-			// Annotations: map[string]string{
-			// 	"pipelines.kubeflow.org/v2_pipeline": "true",
-			// },
 		},
 		Spec: wfapi.WorkflowSpec{
 			PodMetadata: &wfapi.Metadata{
@@ -120,6 +123,29 @@ func Compile(jobArg *pipelinespec.PipelineJob, kubernetesSpecArg *pipelinespec.S
 			Entrypoint:         tmplEntrypoint,
 		},
 	}
+
+	sync := &wfapi.Synchronization{}
+	if opts != nil && opts.SemaphoreKey != "" {
+		sync.Semaphore = &wfapi.SemaphoreRef{
+			ConfigMapKeyRef: &k8score.ConfigMapKeySelector{
+				LocalObjectReference: k8score.LocalObjectReference{
+					Name: getSemaphoreConfigMapName(),
+				},
+				Key: opts.SemaphoreKey,
+			},
+		}
+	}
+
+	if opts != nil && opts.MutexName != "" {
+		sync.Mutex = &wfapi.Mutex{
+			Name: opts.MutexName,
+		}
+	}
+
+	if sync.Semaphore != nil || sync.Mutex != nil {
+		wf.Spec.Synchronization = sync
+	}
+
 	c := &workflowCompiler{
 		wf:        wf,
 		templates: make(map[string]*wfapi.Template),

backend/src/v2/compiler/visitor.go

@@ -109,7 +109,7 @@ func (state *pipelineDFS) dfs(name string, component *pipelinespec.ComponentSpec
 		}
 
 		// Add kubernetes spec to annotation
-		if state.kubernetesSpec != nil {
+		if state.kubernetesSpec != nil && state.kubernetesSpec.DeploymentSpec != nil {
 			kubernetesExecSpec, ok := state.kubernetesSpec.DeploymentSpec.Executors[executorLabel]
 			if ok {
 				state.visitor.AddKubernetesSpec(name, kubernetesExecSpec)

manifests/kustomize/base/pipeline/kustomization.yaml

@@ -15,6 +15,7 @@ resources:
   - ml-pipeline-scheduledworkflow-role.yaml
   - ml-pipeline-scheduledworkflow-rolebinding.yaml
   - ml-pipeline-scheduledworkflow-sa.yaml
+  - ml-pipeline-semaphore-configmap.yaml
   - ml-pipeline-ui-deployment.yaml
   - ml-pipeline-ui-configmap.yaml
   - ml-pipeline-ui-role.yaml

manifests/kustomize/base/pipeline/ml-pipeline-apiserver-deployment.yaml

@@ -30,6 +30,8 @@ spec:
               fieldPath: metadata.namespace
         - name: OBJECTSTORECONFIG_SECURE
           value: "false"
+        - name: SEMAPHORE_CONFIGMAP_NAME
+          value: "semaphore-config"
         - name: OBJECTSTORECONFIG_BUCKETNAME
           valueFrom:
             configMapKeyRef:

manifests/kustomize/base/pipeline/ml-pipeline-semaphore-configmap.yaml

@@ -0,0 +1,29 @@
+kind: ConfigMap
+apiVersion: v1
+metadata:
+  name: semaphore-config
+data: {}
+---
+apiVersion: batch/v1
+kind: Job
+metadata:
+  name: semaphore-configmap-init
+  namespace: kubeflow
+spec:
+  template:
+    spec:
+      containers:
+        - name: create-configmap
+          image: bitnami/kubectl:latest
+          command:
+            - /bin/sh
+            - -c
+            - |
+              if ! kubectl get configmap semaphore-config -n kubeflow > /dev/null 2>&1; then
+                echo "Creating semaphore-config ConfigMap..."
+                kubectl create configmap semaphore-config -n kubeflow --from-literal=init=""
+              else
+                echo "ConfigMap semaphore-config already exists. Skipping creation."
+              fi
+      restartPolicy: OnFailure
+  backoffLimit: 3