#487 request size metric added

metric/controller.go

@@ -14,6 +14,7 @@ var (
 	SecondsBucketsDetailedNano = prometheus.ExponentialBuckets(0.000005, 2, 19) // covers range from 5ns to 1.3ms
 	SecondsBucketsDetailed     = prometheus.ExponentialBuckets(0.0005, 2, 16)   // covers range from 500us to 16.384s
 	SecondsBucketsLong         = prometheus.ExponentialBuckets(0.005, 2, 16)    // covers range from 5ms to 163.84s
+	RequestsSize               = prometheus.ExponentialBuckets(100, 10, 5)      // covers range from 100B to 1MB
 )
 
 type Ctl struct {

plugin/input/http/http.go

@@ -1,6 +1,7 @@
 package http
 
 import (
+	"bytes"
 	"fmt"
 	"io"
 	"net"
@@ -110,6 +111,7 @@ type Plugin struct {
 	bulkRequestsDoneTotal prometheus.Counter
 	requestsInProgress    prometheus.Gauge
 	processBulkSeconds    prometheus.Observer
+	requestsSize          prometheus.Observer
 
 	metaTemplater *metadata.MetaTemplater
 }
@@ -304,10 +306,11 @@ func (p *Plugin) Start(config pipeline.AnyConfig, params *pipeline.InputPluginPa
 }
 
 func (p *Plugin) registerMetrics(ctl *metric.Ctl) {
-	p.bulkRequestsDoneTotal = ctl.RegisterCounter("bulk_requests_done_total", "")
+	p.bulkRequestsDoneTotal = ctl.RegisterCounter("bulk_requests_done_total", "Total http bulk requests done")
 	p.requestsInProgress = ctl.RegisterGauge("requests_in_progress", "")
 	p.processBulkSeconds = ctl.RegisterHistogram("process_bulk_seconds", "", metric.SecondsBucketsDetailed)
 	p.errorsTotal = ctl.RegisterCounter("input_http_errors", "Total http errors")
+	p.requestsSize = ctl.RegisterHistogram("requests_size", "", metric.RequestsSize)
 
 	if p.config.Auth.Strategy_ != StrategyDisabled {
 		httpAuthTotal := ctl.RegisterCounterVec("http_auth_success_total", "", "secret_name")
@@ -475,6 +478,8 @@ func (p *Plugin) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 }
 
 func (p *Plugin) serveBulk(w http.ResponseWriter, r *http.Request, meta metadata.MetaData) {
+	var err error
+
 	if r.Method != http.MethodPost {
 		http.Error(w, "", http.StatusMethodNotAllowed)
 		return
@@ -483,6 +488,14 @@ func (p *Plugin) serveBulk(w http.ResponseWriter, r *http.Request, meta metadata
 	start := time.Now()
 	p.requestsInProgress.Inc()
 
+	r.Body, err = p.calculateRequestSize(r.Body)
+	if err != nil {
+		p.errorsTotal.Inc()
+		p.logger.Error("can't read body", zap.Error(err))
+		http.Error(w, "can't read body", http.StatusBadRequest)
+		return
+	}
+
 	reader := io.Reader(r.Body)
 	if r.Header.Get("Content-Encoding") == "gzip" {
 		zr, err := p.acquireGzipReader(reader)
@@ -642,6 +655,22 @@ func (p *Plugin) putGzipReader(reader *gzip.Reader) {
 	p.gzipReaderPool.Put(reader)
 }
 
+func (p *Plugin) calculateRequestSize(reqBody io.Reader) (io.ReadCloser, error) {
+	bodyBytes, err := io.ReadAll(reqBody)
+	if err != nil {
+		return nil, err
+	}
+
+	bodySize := len(bodyBytes)
+	p.requestsSize.Observe(float64(bodySize))
+
+	return io.NopCloser(bytes.NewBuffer(bodyBytes)), nil
+}
+
+func resetRequestBody() {
+
+}
+
 func getUserIP(r *http.Request) net.IP {
 	var userIP string
 	switch {