Logging and metrics handler middlewares (#1117)

Adds logging and metrics handler middlewares that (for now) can be used from Grafana.
grafana · Oct 17, 2024 · 1c86e1e · 1c86e1e
1 parent b745241
commit 1c86e1e
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diff --git a/backend/logger_middleware.go b/backend/logger_middleware.go
@@ -0,0 +1,223 @@
+package backend
+
+import (
+	"context"
+	"errors"
+	"time"
+
+	"github.com/grafana/grafana-plugin-sdk-go/backend/log"
+)
+
+// NewLoggerMiddleware creates a new HandlerMiddleware that will
+// log requests.
+func NewLoggerMiddleware(logger log.Logger, extractLogParamsFn func(ctx context.Context, pCtx PluginContext) []any) HandlerMiddleware {
+	return HandlerMiddlewareFunc(func(next Handler) Handler {
+		return &loggerMiddleware{
+			BaseHandler:        NewBaseHandler(next),
+			logger:             logger,
+			extractLogParamsFn: extractLogParamsFn,
+		}
+	})
+}
+
+type loggerMiddleware struct {
+	BaseHandler
+	logger             log.Logger
+	extractLogParamsFn func(ctx context.Context, pCtx PluginContext) []any
+}
+
+func (m *loggerMiddleware) logRequest(ctx context.Context, pCtx PluginContext, fn handlerWrapperFunc) error {
+	start := time.Now()
+	logParams := []any{}
+
+	if m.extractLogParamsFn != nil {
+		logParams = append(logParams, m.extractLogParamsFn(ctx, pCtx)...)
+	}
+
+	ctxLogger := m.logger.FromContext(ctx)
+	ctxLogger.Debug("Plugin Request Started", logParams...)
+
+	status, err := fn(ctx)
+	logParams = append(logParams, "status", status.String(), "duration", time.Since(start).String())
+	if err != nil {
+		logParams = append(logParams, "error", err)
+	}
+	logParams = append(logParams, "statusSource", string(ErrorSourceFromContext(ctx)))
+
+	logFunc := ctxLogger.Info
+
+	if status > RequestStatusCancelled {
+		logFunc = ctxLogger.Error
+	}
+
+	logFunc("Plugin Request Completed", logParams...)
+
+	return err
+}
+
+func (m *loggerMiddleware) QueryData(ctx context.Context, req *QueryDataRequest) (*QueryDataResponse, error) {
+	if req == nil {
+		return m.BaseHandler.QueryData(ctx, req)
+	}
+
+	var resp *QueryDataResponse
+	err := m.logRequest(ctx, req.PluginContext, func(ctx context.Context) (RequestStatus, error) {
+		var innerErr error
+		resp, innerErr = m.BaseHandler.QueryData(ctx, req)
+
+		status := RequestStatusFromQueryDataResponse(resp, innerErr)
+		if innerErr != nil {
+			return status, innerErr
+		} else if resp == nil {
+			return RequestStatusError, errors.New("both response and error are nil, but one must be provided")
+		}
+
+		ctxLogger := m.logger.FromContext(ctx)
+		for refID, dr := range resp.Responses {
+			if dr.Error != nil {
+				logParams := []any{
+					"refID", refID,
+					"status", int(dr.Status),
+					"error", dr.Error,
+					"statusSource", dr.ErrorSource.String(),
+				}
+				ctxLogger.Error("Partial data response error", logParams...)
+			}
+		}
+
+		return status, nil
+	})
+
+	return resp, err
+}
+
+func (m *loggerMiddleware) CallResource(ctx context.Context, req *CallResourceRequest, sender CallResourceResponseSender) error {
+	if req == nil {
+		return m.BaseHandler.CallResource(ctx, req, sender)
+	}
+
+	err := m.logRequest(ctx, req.PluginContext, func(ctx context.Context) (RequestStatus, error) {
+		innerErr := m.BaseHandler.CallResource(ctx, req, sender)
+		return RequestStatusFromError(innerErr), innerErr
+	})
+
+	return err
+}
+
+func (m *loggerMiddleware) CheckHealth(ctx context.Context, req *CheckHealthRequest) (*CheckHealthResult, error) {
+	if req == nil {
+		return m.BaseHandler.CheckHealth(ctx, req)
+	}
+
+	var resp *CheckHealthResult
+	err := m.logRequest(ctx, req.PluginContext, func(ctx context.Context) (RequestStatus, error) {
+		var innerErr error
+		resp, innerErr = m.BaseHandler.CheckHealth(ctx, req)
+		return RequestStatusFromError(innerErr), innerErr
+	})
+
+	return resp, err
+}
+
+func (m *loggerMiddleware) CollectMetrics(ctx context.Context, req *CollectMetricsRequest) (*CollectMetricsResult, error) {
+	if req == nil {
+		return m.BaseHandler.CollectMetrics(ctx, req)
+	}
+
+	var resp *CollectMetricsResult
+	err := m.logRequest(ctx, req.PluginContext, func(ctx context.Context) (RequestStatus, error) {
+		var innerErr error
+		resp, innerErr = m.BaseHandler.CollectMetrics(ctx, req)
+		return RequestStatusFromError(innerErr), innerErr
+	})
+
+	return resp, err
+}
+
+func (m *loggerMiddleware) SubscribeStream(ctx context.Context, req *SubscribeStreamRequest) (*SubscribeStreamResponse, error) {
+	if req == nil {
+		return m.BaseHandler.SubscribeStream(ctx, req)
+	}
+
+	var resp *SubscribeStreamResponse
+	err := m.logRequest(ctx, req.PluginContext, func(ctx context.Context) (RequestStatus, error) {
+		var innerErr error
+		resp, innerErr = m.BaseHandler.SubscribeStream(ctx, req)
+		return RequestStatusFromError(innerErr), innerErr
+	})
+
+	return resp, err
+}
+
+func (m *loggerMiddleware) PublishStream(ctx context.Context, req *PublishStreamRequest) (*PublishStreamResponse, error) {
+	if req == nil {
+		return m.BaseHandler.PublishStream(ctx, req)
+	}
+
+	var resp *PublishStreamResponse
+	err := m.logRequest(ctx, req.PluginContext, func(ctx context.Context) (RequestStatus, error) {
+		var innerErr error
+		resp, innerErr = m.BaseHandler.PublishStream(ctx, req)
+		return RequestStatusFromError(innerErr), innerErr
+	})
+
+	return resp, err
+}
+
+func (m *loggerMiddleware) RunStream(ctx context.Context, req *RunStreamRequest, sender *StreamSender) error {
+	if req == nil {
+		return m.BaseHandler.RunStream(ctx, req, sender)
+	}
+
+	err := m.logRequest(ctx, req.PluginContext, func(ctx context.Context) (RequestStatus, error) {
+		innerErr := m.BaseHandler.RunStream(ctx, req, sender)
+		return RequestStatusFromError(innerErr), innerErr
+	})
+
+	return err
+}
+
+func (m *loggerMiddleware) ValidateAdmission(ctx context.Context, req *AdmissionRequest) (*ValidationResponse, error) {
+	if req == nil {
+		return m.BaseHandler.ValidateAdmission(ctx, req)
+	}
+
+	var resp *ValidationResponse
+	err := m.logRequest(ctx, req.PluginContext, func(ctx context.Context) (RequestStatus, error) {
+		var innerErr error
+		resp, innerErr = m.BaseHandler.ValidateAdmission(ctx, req)
+		return RequestStatusFromError(innerErr), innerErr
+	})
+
+	return resp, err
+}
+
+func (m *loggerMiddleware) MutateAdmission(ctx context.Context, req *AdmissionRequest) (*MutationResponse, error) {
+	if req == nil {
+		return m.BaseHandler.MutateAdmission(ctx, req)
+	}
+
+	var resp *MutationResponse
+	err := m.logRequest(ctx, req.PluginContext, func(ctx context.Context) (RequestStatus, error) {
+		var innerErr error
+		resp, innerErr = m.BaseHandler.MutateAdmission(ctx, req)
+		return RequestStatusFromError(innerErr), innerErr
+	})
+
+	return resp, err
+}
+
+func (m *loggerMiddleware) ConvertObjects(ctx context.Context, req *ConversionRequest) (*ConversionResponse, error) {
+	if req == nil {
+		return m.BaseHandler.ConvertObjects(ctx, req)
+	}
+
+	var resp *ConversionResponse
+	err := m.logRequest(ctx, req.PluginContext, func(ctx context.Context) (RequestStatus, error) {
+		var innerErr error
+		resp, innerErr = m.BaseHandler.ConvertObjects(ctx, req)
+		return RequestStatusFromError(innerErr), innerErr
+	})
+
+	return resp, err
+}
diff --git a/backend/metrics_middleware.go b/backend/metrics_middleware.go
@@ -0,0 +1,154 @@
+package backend
+
+import (
+	"context"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+// NewMetricsMiddleware creates a new HandlerMiddleware that will
+// record metrics for requests.
+func NewMetricsMiddleware(registerer prometheus.Registerer, namespace string, includePluginID bool) HandlerMiddleware {
+	labelNames := []string{"endpoint", "status", "status_source"}
+
+	if includePluginID {
+		labelNames = append(labelNames, "plugin_id")
+	}
+
+	requestCounter := prometheus.NewCounterVec(prometheus.CounterOpts{
+		Namespace: namespace,
+		Subsystem: "plugin",
+		Name:      "request_total",
+		Help:      "The total amount of plugin requests",
+	}, labelNames)
+
+	registerer.MustRegister(requestCounter)
+
+	return HandlerMiddlewareFunc(func(next Handler) Handler {
+		return &metricsMiddleware{
+			BaseHandler:     NewBaseHandler(next),
+			requestCounter:  requestCounter,
+			includePluginID: includePluginID,
+		}
+	})
+}
+
+type metricsMiddleware struct {
+	BaseHandler
+	requestCounter  *prometheus.CounterVec
+	includePluginID bool
+}
+
+func (m *metricsMiddleware) instrumentRequest(ctx context.Context, pCtx PluginContext, fn handlerWrapperFunc) error {
+	status, err := fn(ctx)
+	endpoint := EndpointFromContext(ctx)
+
+	labelValues := []string{endpoint.String(), status.String(), string(ErrorSourceFromContext(ctx))}
+
+	if m.includePluginID {
+		labelValues = append(labelValues, pCtx.PluginID)
+	}
+
+	m.requestCounter.WithLabelValues(labelValues...).Inc()
+	return err
+}
+
+func (m *metricsMiddleware) QueryData(ctx context.Context, req *QueryDataRequest) (*QueryDataResponse, error) {
+	var resp *QueryDataResponse
+	err := m.instrumentRequest(ctx, req.PluginContext, func(ctx context.Context) (RequestStatus, error) {
+		var innerErr error
+		resp, innerErr = m.BaseHandler.QueryData(ctx, req)
+		return RequestStatusFromQueryDataResponse(resp, innerErr), innerErr
+	})
+
+	return resp, err
+}
+
+func (m *metricsMiddleware) CallResource(ctx context.Context, req *CallResourceRequest, sender CallResourceResponseSender) error {
+	return m.instrumentRequest(ctx, req.PluginContext, func(ctx context.Context) (RequestStatus, error) {
+		innerErr := m.BaseHandler.CallResource(ctx, req, sender)
+		return RequestStatusFromError(innerErr), innerErr
+	})
+}
+
+func (m *metricsMiddleware) CheckHealth(ctx context.Context, req *CheckHealthRequest) (*CheckHealthResult, error) {
+	var resp *CheckHealthResult
+	err := m.instrumentRequest(ctx, req.PluginContext, func(ctx context.Context) (RequestStatus, error) {
+		var innerErr error
+		resp, innerErr = m.BaseHandler.CheckHealth(ctx, req)
+		return RequestStatusFromError(innerErr), innerErr
+	})
+
+	return resp, err
+}
+
+func (m *metricsMiddleware) CollectMetrics(ctx context.Context, req *CollectMetricsRequest) (*CollectMetricsResult, error) {
+	var resp *CollectMetricsResult
+	err := m.instrumentRequest(ctx, req.PluginContext, func(ctx context.Context) (RequestStatus, error) {
+		var innerErr error
+		resp, innerErr = m.BaseHandler.CollectMetrics(ctx, req)
+		return RequestStatusFromError(innerErr), innerErr
+	})
+	return resp, err
+}
+
+func (m *metricsMiddleware) SubscribeStream(ctx context.Context, req *SubscribeStreamRequest) (*SubscribeStreamResponse, error) {
+	var resp *SubscribeStreamResponse
+	err := m.instrumentRequest(ctx, req.PluginContext, func(ctx context.Context) (RequestStatus, error) {
+		var innerErr error
+		resp, innerErr = m.BaseHandler.SubscribeStream(ctx, req)
+		return RequestStatusFromError(innerErr), innerErr
+	})
+	return resp, err
+}
+
+func (m *metricsMiddleware) PublishStream(ctx context.Context, req *PublishStreamRequest) (*PublishStreamResponse, error) {
+	var resp *PublishStreamResponse
+	err := m.instrumentRequest(ctx, req.PluginContext, func(ctx context.Context) (RequestStatus, error) {
+		var innerErr error
+		resp, innerErr = m.BaseHandler.PublishStream(ctx, req)
+		return RequestStatusFromError(innerErr), innerErr
+	})
+	return resp, err
+}
+
+func (m *metricsMiddleware) RunStream(ctx context.Context, req *RunStreamRequest, sender *StreamSender) error {
+	err := m.instrumentRequest(ctx, req.PluginContext, func(ctx context.Context) (RequestStatus, error) {
+		innerErr := m.BaseHandler.RunStream(ctx, req, sender)
+		return RequestStatusFromError(innerErr), innerErr
+	})
+	return err
+}
+
+func (m *metricsMiddleware) ValidateAdmission(ctx context.Context, req *AdmissionRequest) (*ValidationResponse, error) {
+	var resp *ValidationResponse
+	err := m.instrumentRequest(ctx, req.PluginContext, func(ctx context.Context) (RequestStatus, error) {
+		var innerErr error
+		resp, innerErr = m.BaseHandler.ValidateAdmission(ctx, req)
+		return RequestStatusFromError(innerErr), innerErr
+	})
+
+	return resp, err
+}
+
+func (m *metricsMiddleware) MutateAdmission(ctx context.Context, req *AdmissionRequest) (*MutationResponse, error) {
+	var resp *MutationResponse
+	err := m.instrumentRequest(ctx, req.PluginContext, func(ctx context.Context) (RequestStatus, error) {
+		var innerErr error
+		resp, innerErr = m.BaseHandler.MutateAdmission(ctx, req)
+		return RequestStatusFromError(innerErr), innerErr
+	})
+
+	return resp, err
+}
+
+func (m *metricsMiddleware) ConvertObjects(ctx context.Context, req *ConversionRequest) (*ConversionResponse, error) {
+	var resp *ConversionResponse
+	err := m.instrumentRequest(ctx, req.PluginContext, func(ctx context.Context) (RequestStatus, error) {
+		var innerErr error
+		resp, innerErr = m.BaseHandler.ConvertObjects(ctx, req)
+		return RequestStatusFromError(innerErr), innerErr
+	})
+
+	return resp, err
+}