✨ add grpc option for cloudevents client.

cloudevents/README.md

@@ -21,7 +21,7 @@ client the developers need to provide
     cluster URL and appending the controller name. Similarly, a RESTful service can select a unique name or generate a
     unique ID in the associated database for its source identification.
     - `CloudEventsOptions`, it provides cloudevents clients to send/receive cloudevents based on different event
-    protocol. We have supported the MQTT protocol (`mqtt.NewSourceOptions`), developers can use it directly.
+    protocol. We have supported [MQTT protocol (`mqtt.NewSourceOptions`)](./generic/options/mqtt) and [gRPC protocol (`grpc.NewSourceOptions`)](./generic/options/grpc) developers can use it directly.
 
 2. A resource lister (`generic.Lister`), it is used to list the resource objects on the source when resyncing the
 resources between sources and agents, for example, a hub controller can list the resources from the resource informers,
@@ -39,7 +39,7 @@ package.
 5. Resource handler methods (`generic.ResourceHandler`), they are used to handle the resources status after the client
 received the resources status from agents.
 
-for example:
+for example, build a generic client on the source using MQTT protocol with the following code:
 
 ```golang
 // build a client for the source1
@@ -71,7 +71,7 @@ this client the developers need to provide
     agent name.
     - `clusterName`, it is the name of a managed cluster on which the agent runs.
     - `CloudEventsOptions`, it provides cloudevents clients to send/receive cloudevents based on different event
-    protocol. We have supported the MQTT protocol (`mqtt.NewAgentOptions`), developers can use it directly.
+    protocol. We have supported [MQTT protocol (`mqtt.NewAgentOptions`)](./generic/options/mqtt) and [gRPC protocol (`grpc.NewAgentOptions`)](./generic/options/grpc) , developers can use it directly.
 
 2. A resource lister (`generic.Lister`), it is used to list the resource objects on a managed cluster when resyncing the
 resources between sources and agents, for example, a work agent can list its works from its work informers.
@@ -88,7 +88,7 @@ package.
 5. Resource handler methods (`generic.ResourceHandler`), they are used to handle the resources after the client received
 the resources from sources.
 
-for example:
+for example, build a generic client on the source using MQTT protocol with the following code:
 
 ```golang
 // build a client for a work agent on the cluster1

cloudevents/generic/options/grpc/agentoptions.go

@@ -0,0 +1,76 @@
+package grpc
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	cloudevents "github.com/cloudevents/sdk-go/v2"
+	cecontext "github.com/cloudevents/sdk-go/v2/context"
+
+	"open-cluster-management.io/api/cloudevents/generic/options"
+	"open-cluster-management.io/api/cloudevents/generic/options/grpc/protocol"
+	"open-cluster-management.io/api/cloudevents/generic/types"
+)
+
+type grpcAgentOptions struct {
+	GRPCOptions
+	errorChan   chan error // grpc client connection doesn't have error channel, it will handle reconnecting automatically
+	clusterName string
+}
+
+func NewAgentOptions(grpcOptions *GRPCOptions, clusterName, agentID string) *options.CloudEventsAgentOptions {
+	return &options.CloudEventsAgentOptions{
+		CloudEventsOptions: &grpcAgentOptions{
+			GRPCOptions: *grpcOptions,
+			errorChan:   make(chan error),
+			clusterName: clusterName,
+		},
+		AgentID:     agentID,
+		ClusterName: clusterName,
+	}
+}
+
+func (o *grpcAgentOptions) WithContext(ctx context.Context, evtCtx cloudevents.EventContext) (context.Context, error) {
+	eventType, err := types.ParseCloudEventsType(evtCtx.GetType())
+	if err != nil {
+		return nil, fmt.Errorf("unsupported event type %s, %v", eventType, err)
+	}
+
+	if eventType.Action == types.ResyncRequestAction {
+		// agent publishes event to spec resync topic to request to get resources spec from all sources
+		topic := strings.Replace(SpecResyncTopic, "+", o.clusterName, -1)
+		return cecontext.WithTopic(ctx, topic), nil
+	}
+
+	// agent publishes event to status topic to send the resource status from a specified cluster
+	originalSource, err := evtCtx.GetExtension(types.ExtensionOriginalSource)
+	if err != nil {
+		return nil, err
+	}
+
+	statusTopic := strings.Replace(StatusTopic, "+", fmt.Sprintf("%s", originalSource), 1)
+	statusTopic = strings.Replace(statusTopic, "+", o.clusterName, -1)
+	return cecontext.WithTopic(ctx, statusTopic), nil
+}
+
+func (o *grpcAgentOptions) Client(ctx context.Context) (cloudevents.Client, error) {
+	receiver, err := o.GetCloudEventsClient(
+		ctx,
+		protocol.WithPublishOption(&protocol.PublishOption{}),
+		protocol.WithSubscribeOption(&protocol.SubscribeOption{
+			Topics: []string{
+				replaceNth(SpecTopic, "+", o.clusterName, 2), // receiving the resources spec from sources with spec topic
+				StatusResyncTopic, // receiving the resources status resync request from sources with status resync topic
+			},
+		}),
+	)
+	if err != nil {
+		return nil, err
+	}
+	return receiver, nil
+}
+
+func (o *grpcAgentOptions) ErrorChan() <-chan error {
+	return o.errorChan
+}

cloudevents/generic/options/grpc/agentoptions_test.go

@@ -0,0 +1,123 @@
+package grpc
+
+import (
+	"context"
+	"testing"
+
+	cloudevents "github.com/cloudevents/sdk-go/v2"
+	cloudeventscontext "github.com/cloudevents/sdk-go/v2/context"
+
+	"open-cluster-management.io/api/cloudevents/generic/types"
+)
+
+var mockEventDataType = types.CloudEventsDataType{
+	Group:    "resources.test",
+	Version:  "v1",
+	Resource: "mockresources",
+}
+
+func TestAgentContext(t *testing.T) {
+	cases := []struct {
+		name          string
+		event         cloudevents.Event
+		expectedTopic string
+		assertError   func(error)
+	}{
+		{
+			name: "unsupported event",
+			event: func() cloudevents.Event {
+				evt := cloudevents.NewEvent()
+				evt.SetType("unsupported")
+				return evt
+			}(),
+			assertError: func(err error) {
+				if err == nil {
+					t.Errorf("expected error, but failed")
+				}
+			},
+		},
+		{
+			name: "resync specs",
+			event: func() cloudevents.Event {
+				eventType := types.CloudEventsType{
+					CloudEventsDataType: mockEventDataType,
+					SubResource:         types.SubResourceSpec,
+					Action:              types.ResyncRequestAction,
+				}
+
+				evt := cloudevents.NewEvent()
+				evt.SetType(eventType.String())
+				evt.SetExtension("clustername", "cluster1")
+				return evt
+			}(),
+			expectedTopic: "sources/clusters/cluster1/specresync",
+			assertError: func(err error) {
+				if err != nil {
+					t.Errorf("unexpected error %v", err)
+				}
+			},
+		},
+		{
+			name: "send status no original source",
+			event: func() cloudevents.Event {
+				eventType := types.CloudEventsType{
+					CloudEventsDataType: mockEventDataType,
+					SubResource:         types.SubResourceStatus,
+					Action:              "test",
+				}
+
+				evt := cloudevents.NewEvent()
+				evt.SetSource("hub1")
+				evt.SetType(eventType.String())
+				return evt
+			}(),
+			assertError: func(err error) {
+				if err == nil {
+					t.Errorf("expected error, but failed")
+				}
+			},
+		},
+		{
+			name: "send status",
+			event: func() cloudevents.Event {
+				eventType := types.CloudEventsType{
+					CloudEventsDataType: mockEventDataType,
+					SubResource:         types.SubResourceStatus,
+					Action:              "test",
+				}
+
+				evt := cloudevents.NewEvent()
+				evt.SetSource("agent")
+				evt.SetType(eventType.String())
+				evt.SetExtension("originalsource", "hub1")
+				return evt
+			}(),
+			expectedTopic: "sources/hub1/clusters/cluster1/status",
+			assertError: func(err error) {
+				if err != nil {
+					t.Errorf("unexpected error %v", err)
+				}
+			},
+		},
+	}
+
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			agentOptions := &grpcAgentOptions{clusterName: "cluster1"}
+			ctx, err := agentOptions.WithContext(context.TODO(), c.event.Context)
+			c.assertError(err)
+
+			topic := func(ctx context.Context) string {
+				if ctx == nil {
+					return ""
+				}
+
+				return cloudeventscontext.TopicFrom(ctx)
+			}(ctx)
+
+			if topic != c.expectedTopic {
+				t.Errorf("expected %s, but got %s", c.expectedTopic, topic)
+			}
+		})
+	}
+}