Implement internal plugin metric collection

pkg/datasource/datasource.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 
 	"github.com/alexanderzobnin/grafana-zabbix/pkg/httpclient"
+	"github.com/alexanderzobnin/grafana-zabbix/pkg/metrics"
 	"github.com/alexanderzobnin/grafana-zabbix/pkg/settings"
 	"github.com/alexanderzobnin/grafana-zabbix/pkg/zabbix"
 	"github.com/alexanderzobnin/grafana-zabbix/pkg/zabbixapi"
@@ -104,6 +105,7 @@ func (ds *ZabbixDatasource) CheckHealth(ctx context.Context, req *backend.CheckH
 }
 
 func (ds *ZabbixDatasource) QueryData(ctx context.Context, req *backend.QueryDataRequest) (*backend.QueryDataResponse, error) {
+	metrics.DataSourceQueryTotal.WithLabelValues("metrics").Inc()
 	qdr := backend.NewQueryDataResponse()
 
 	zabbixDS, err := ds.getDSInstance(req.PluginContext)

pkg/metrics/metrics.go

@@ -0,0 +1,53 @@
+// This package contains internal plugin metrics exposed
+// by Grafana at /api/plugins/alexanderzobnin-zabbix-datasource/metrics
+// in Prometheus format
+
+package metrics
+
+import "github.com/prometheus/client_golang/prometheus"
+
+var (
+	// DataSourceQueryTotal is metric counter for getting total number of data source queries
+	DataSourceQueryTotal *prometheus.CounterVec
+
+	// ZabbixAPIQueryTotal is metric counter for getting total number of zabbix API queries
+	ZabbixAPIQueryTotal *prometheus.CounterVec
+
+	// CacheHitTotal is metric counter for getting total number of cache hits for requests
+	CacheHitTotal *prometheus.CounterVec
+)
+
+func init() {
+	DataSourceQueryTotal = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Name:      "datasource_query_total",
+			Help:      "Total number of data source queries.",
+			Namespace: "zabbix_datasource",
+		},
+		[]string{"query_type"},
+	)
+
+	ZabbixAPIQueryTotal = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Name:      "zabbix_api_query_total",
+			Help:      "Total number of Zabbix API queries.",
+			Namespace: "zabbix_datasource",
+		},
+		[]string{"method"},
+	)
+
+	CacheHitTotal = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Name:      "cache_hit_total",
+			Help:      "Total number of cache hits.",
+			Namespace: "zabbix_datasource",
+		},
+		[]string{"method"},
+	)
+
+	prometheus.MustRegister(
+		DataSourceQueryTotal,
+		ZabbixAPIQueryTotal,
+		CacheHitTotal,
+	)
+}

pkg/zabbix/zabbix.go

@@ -5,6 +5,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/alexanderzobnin/grafana-zabbix/pkg/metrics"
 	"github.com/alexanderzobnin/grafana-zabbix/pkg/settings"
 	"github.com/alexanderzobnin/grafana-zabbix/pkg/zabbixapi"
 	"github.com/bitly/go-simplejson"
@@ -67,6 +68,7 @@ func (ds *Zabbix) Request(ctx context.Context, apiReq *ZabbixAPIRequest) (*simpl
 			ds.cache.SetAPIRequest(apiReq, resultJson)
 		}
 	} else {
+		metrics.CacheHitTotal.WithLabelValues(apiReq.Method).Inc()
 		var ok bool
 		resultJson, ok = cachedResult.(*simplejson.Json)
 		if !ok {

pkg/zabbixapi/zabbix_api.go

@@ -10,6 +10,7 @@ import (
 	"net/http"
 	"net/url"
 
+	"github.com/alexanderzobnin/grafana-zabbix/pkg/metrics"
 	"github.com/bitly/go-simplejson"
 	"github.com/grafana/grafana-plugin-sdk-go/backend/log"
 	"golang.org/x/net/context/ctxhttp"
@@ -106,6 +107,8 @@ func (api *ZabbixAPI) request(ctx context.Context, method string, params ZabbixA
 		return nil, err
 	}
 
+	metrics.ZabbixAPIQueryTotal.WithLabelValues(method).Inc()
+
 	req.Header.Set("Content-Type", "application/json")
 	req.Header.Set("User-Agent", "Grafana/grafana-zabbix")