Plugins: Add logs for plugin proto client retrieval (#93527)

pkg/plugins/backendplugin/grpcplugin/client_proto.go

@@ -15,7 +15,7 @@ import (
 )
 
 var (
-	errClientNotStarted = errors.New("plugin client has not been started")
+	errClientNotAvailable = errors.New("plugin client is not available")
 )
 
 var _ ProtoClient = (*protoClient)(nil)
@@ -36,7 +36,6 @@ type ProtoClient interface {
 	Logger() log.Logger
 	Start(context.Context) error
 	Stop(context.Context) error
-	Running(context.Context) bool
 }
 
 type protoClient struct {
@@ -44,9 +43,20 @@ type protoClient struct {
 	pluginVersion string
 	pluginJSON    plugins.JSONData
 
+	state pluginState
+
 	mu sync.RWMutex
 }
 
+type pluginState int
+
+const (
+	pluginStateNotStarted pluginState = iota
+	pluginStateStartSuccess
+	pluginStateStartFail
+	pluginStateStopped
+)
+
 type ProtoClientOpts struct {
 	PluginJSON     plugins.JSONData
 	ExecutablePath string
@@ -68,12 +78,12 @@ func NewProtoClient(opts ProtoClientOpts) (ProtoClient, error) {
 		func() []string { return opts.Env },
 	)
 
-	return &protoClient{plugin: p, pluginVersion: opts.PluginJSON.Info.Version, pluginJSON: opts.PluginJSON}, nil
+	return &protoClient{plugin: p, pluginVersion: opts.PluginJSON.Info.Version, pluginJSON: opts.PluginJSON, state: pluginStateNotStarted}, nil
 }
 
 func (r *protoClient) PID(ctx context.Context) (string, error) {
 	if _, exists := r.client(ctx); !exists {
-		return "", errClientNotStarted
+		return "", errClientNotAvailable
 	}
 	return r.plugin.client.ID(), nil
 }
@@ -101,40 +111,60 @@ func (r *protoClient) Logger() log.Logger {
 func (r *protoClient) Start(ctx context.Context) error {
 	r.mu.Lock()
 	defer r.mu.Unlock()
-	return r.plugin.Start(ctx)
+
+	err := r.plugin.Start(ctx)
+	if err != nil {
+		r.state = pluginStateStartFail
+		return err
+	}
+
+	r.state = pluginStateStartSuccess
+	return nil
 }
 
 func (r *protoClient) Stop(ctx context.Context) error {
 	r.mu.Lock()
 	defer r.mu.Unlock()
+	r.state = pluginStateStopped
 	return r.plugin.Stop(ctx)
 }
 
-func (r *protoClient) Running(_ context.Context) bool {
+func (r *protoClient) client(ctx context.Context) (*ClientV2, bool) {
 	r.mu.RLock()
 	defer r.mu.RUnlock()
-	return !r.plugin.Exited()
-}
 
-func (r *protoClient) client(ctx context.Context) (*ClientV2, bool) {
+	logger := r.Logger().FromContext(ctx)
-	if !r.Running(ctx) {
+	if r.state == pluginStateNotStarted {
+		logger.Debug("Plugin client has not been started yet")
+		return nil, false
+	}
+
+	if r.state == pluginStateStartFail {
+		logger.Debug("Plugin client failed to start")
+		return nil, false
+	}
+
+	if r.state == pluginStateStopped {
+		logger.Debug("Plugin client has stopped")
+		return nil, false
+	}
+
+	if r.plugin.Exited() {
+		logger.Debug("Plugin client has exited")
 		return nil, false
 	}
 
-	r.mu.RLock()
 	if r.plugin.pluginClient == nil {
-		r.mu.RUnlock()
 		return nil, false
 	}
 	pc := r.plugin.pluginClient
-	r.mu.RUnlock()
 	return pc, true
 }
 
 func (r *protoClient) QueryData(ctx context.Context, in *pluginv2.QueryDataRequest, opts ...grpc.CallOption) (*pluginv2.QueryDataResponse, error) {
 	c, exists := r.client(ctx)
 	if !exists {
-		return nil, errClientNotStarted
+		return nil, errClientNotAvailable
 	}
 	return c.DataClient.QueryData(ctx, in, opts...)
 }
@@ -142,7 +172,7 @@ func (r *protoClient) QueryData(ctx context.Context, in *pluginv2.QueryDataReque
 func (r *protoClient) CallResource(ctx context.Context, in *pluginv2.CallResourceRequest, opts ...grpc.CallOption) (pluginv2.Resource_CallResourceClient, error) {
 	c, exists := r.client(ctx)
 	if !exists {
-		return nil, errClientNotStarted
+		return nil, errClientNotAvailable
 	}
 	return c.ResourceClient.CallResource(ctx, in, opts...)
 }
@@ -150,7 +180,7 @@ func (r *protoClient) CallResource(ctx context.Context, in *pluginv2.CallResourc
 func (r *protoClient) CheckHealth(ctx context.Context, in *pluginv2.CheckHealthRequest, opts ...grpc.CallOption) (*pluginv2.CheckHealthResponse, error) {
 	c, exists := r.client(ctx)
 	if !exists {
-		return nil, errClientNotStarted
+		return nil, errClientNotAvailable
 	}
 	return c.DiagnosticsClient.CheckHealth(ctx, in, opts...)
 }
@@ -158,7 +188,7 @@ func (r *protoClient) CheckHealth(ctx context.Context, in *pluginv2.CheckHealthR
 func (r *protoClient) CollectMetrics(ctx context.Context, in *pluginv2.CollectMetricsRequest, opts ...grpc.CallOption) (*pluginv2.CollectMetricsResponse, error) {
 	c, exists := r.client(ctx)
 	if !exists {
-		return nil, errClientNotStarted
+		return nil, errClientNotAvailable
 	}
 	return c.DiagnosticsClient.CollectMetrics(ctx, in, opts...)
 }
@@ -166,7 +196,7 @@ func (r *protoClient) CollectMetrics(ctx context.Context, in *pluginv2.CollectMe
 func (r *protoClient) SubscribeStream(ctx context.Context, in *pluginv2.SubscribeStreamRequest, opts ...grpc.CallOption) (*pluginv2.SubscribeStreamResponse, error) {
 	c, exists := r.client(ctx)
 	if !exists {
-		return nil, errClientNotStarted
+		return nil, errClientNotAvailable
 	}
 	return c.StreamClient.SubscribeStream(ctx, in, opts...)
 }
@@ -174,7 +204,7 @@ func (r *protoClient) SubscribeStream(ctx context.Context, in *pluginv2.Subscrib
 func (r *protoClient) RunStream(ctx context.Context, in *pluginv2.RunStreamRequest, opts ...grpc.CallOption) (pluginv2.Stream_RunStreamClient, error) {
 	c, exists := r.client(ctx)
 	if !exists {
-		return nil, errClientNotStarted
+		return nil, errClientNotAvailable
 	}
 	return c.StreamClient.RunStream(ctx, in, opts...)
 }
@@ -182,7 +212,7 @@ func (r *protoClient) RunStream(ctx context.Context, in *pluginv2.RunStreamReque
 func (r *protoClient) PublishStream(ctx context.Context, in *pluginv2.PublishStreamRequest, opts ...grpc.CallOption) (*pluginv2.PublishStreamResponse, error) {
 	c, exists := r.client(ctx)
 	if !exists {
-		return nil, errClientNotStarted
+		return nil, errClientNotAvailable
 	}
 	return c.StreamClient.PublishStream(ctx, in, opts...)
 }
@@ -190,7 +220,7 @@ func (r *protoClient) PublishStream(ctx context.Context, in *pluginv2.PublishStr
 func (r *protoClient) ValidateAdmission(ctx context.Context, in *pluginv2.AdmissionRequest, opts ...grpc.CallOption) (*pluginv2.ValidationResponse, error) {
 	c, exists := r.client(ctx)
 	if !exists {
-		return nil, errClientNotStarted
+		return nil, errClientNotAvailable
 	}
 	return c.AdmissionClient.ValidateAdmission(ctx, in, opts...)
 }
@@ -198,7 +228,7 @@ func (r *protoClient) ValidateAdmission(ctx context.Context, in *pluginv2.Admiss
 func (r *protoClient) MutateAdmission(ctx context.Context, in *pluginv2.AdmissionRequest, opts ...grpc.CallOption) (*pluginv2.MutationResponse, error) {
 	c, exists := r.client(ctx)
 	if !exists {
-		return nil, errClientNotStarted
+		return nil, errClientNotAvailable
 	}
 	return c.AdmissionClient.MutateAdmission(ctx, in, opts...)
 }
@@ -206,7 +236,7 @@ func (r *protoClient) MutateAdmission(ctx context.Context, in *pluginv2.Admissio
 func (r *protoClient) ConvertObjects(ctx context.Context, in *pluginv2.ConversionRequest, opts ...grpc.CallOption) (*pluginv2.ConversionResponse, error) {
 	c, exists := r.client(ctx)
 	if !exists {
-		return nil, errClientNotStarted
+		return nil, errClientNotAvailable
 	}
 	return c.ConversionClient.ConvertObjects(ctx, in, opts...)
 }