package metrics import ( "io" "net/http" "strings" "sync" "sync/atomic" "time" "github.com/prometheus/client_golang/prometheus" ) type ( // HTTPAPIStats holds statistics information about // the API given in the requests. HTTPAPIStats struct { apiStats map[string]int sync.RWMutex } // HTTPStats holds statistics information about // HTTP requests made by all clients. HTTPStats struct { currentS3Requests HTTPAPIStats totalS3Requests HTTPAPIStats totalS3Errors HTTPAPIStats totalInputBytes uint64 totalOutputBytes uint64 } readCounter struct { io.ReadCloser countBytes uint64 } writeCounter struct { http.ResponseWriter countBytes uint64 } responseWrapper struct { sync.Once http.ResponseWriter statusCode int startTime time.Time } ) const systemPath = "/system" var ( httpStatsMetric = new(HTTPStats) httpRequestsDuration = prometheus.NewHistogramVec( prometheus.HistogramOpts{ Name: "frostfs_s3_request_seconds", Help: "Time taken by requests served by current FrostFS S3 Gate instance", Buckets: []float64{.05, .1, .25, .5, 1, 2.5, 5, 10}, }, []string{"api"}, ) ) // Collects HTTP metrics for FrostFS S3 Gate in Prometheus specific format // and sends to the given channel. func collectHTTPMetrics(ch chan<- prometheus.Metric) { for api, value := range httpStatsMetric.currentS3Requests.Load() { ch <- prometheus.MustNewConstMetric( prometheus.NewDesc( prometheus.BuildFQName("frostfs_s3", "requests", "current"), "Total number of running s3 requests in current FrostFS S3 Gate instance", []string{"api"}, nil), prometheus.CounterValue, float64(value), api, ) } for api, value := range httpStatsMetric.totalS3Requests.Load() { ch <- prometheus.MustNewConstMetric( prometheus.NewDesc( prometheus.BuildFQName("frostfs_s3", "requests", "total"), "Total number of s3 requests in current FrostFS S3 Gate instance", []string{"api"}, nil), prometheus.CounterValue, float64(value), api, ) } for api, value := range httpStatsMetric.totalS3Errors.Load() { ch <- prometheus.MustNewConstMetric( prometheus.NewDesc( prometheus.BuildFQName("frostfs_s3", "errors", "total"), "Total number of s3 errors in current FrostFS S3 Gate instance", []string{"api"}, nil), prometheus.CounterValue, float64(value), api, ) } } // APIStats wraps http handler for api with basic statistics collection. func APIStats(api string, f http.HandlerFunc) http.HandlerFunc { return func(w http.ResponseWriter, r *http.Request) { httpStatsMetric.currentS3Requests.Inc(api) defer httpStatsMetric.currentS3Requests.Dec(api) in := &readCounter{ReadCloser: r.Body} out := &writeCounter{ResponseWriter: w} r.Body = in statsWriter := &responseWrapper{ ResponseWriter: out, startTime: time.Now(), } f.ServeHTTP(statsWriter, r) // Time duration in secs since the call started. // We don't need to do nanosecond precision here // simply for the fact that it is not human readable. durationSecs := time.Since(statsWriter.startTime).Seconds() httpStatsMetric.updateStats(api, statsWriter, r, durationSecs) atomic.AddUint64(&httpStatsMetric.totalInputBytes, in.countBytes) atomic.AddUint64(&httpStatsMetric.totalOutputBytes, out.countBytes) } } // Inc increments the api stats counter. func (stats *HTTPAPIStats) Inc(api string) { if stats == nil { return } stats.Lock() defer stats.Unlock() if stats.apiStats == nil { stats.apiStats = make(map[string]int) } stats.apiStats[api]++ } // Dec increments the api stats counter. func (stats *HTTPAPIStats) Dec(api string) { if stats == nil { return } stats.Lock() defer stats.Unlock() if val, ok := stats.apiStats[api]; ok && val > 0 { stats.apiStats[api]-- } } // Load returns the recorded stats. func (stats *HTTPAPIStats) Load() map[string]int { stats.Lock() defer stats.Unlock() var apiStats = make(map[string]int, len(stats.apiStats)) for k, v := range stats.apiStats { apiStats[k] = v } return apiStats } func (st *HTTPStats) getInputBytes() uint64 { return atomic.LoadUint64(&st.totalInputBytes) } func (st *HTTPStats) getOutputBytes() uint64 { return atomic.LoadUint64(&st.totalOutputBytes) } // Update statistics from http request and response data. func (st *HTTPStats) updateStats(api string, w http.ResponseWriter, r *http.Request, durationSecs float64) { var code int if res, ok := w.(*responseWrapper); ok { code = res.statusCode } // A successful request has a 2xx response code successReq := code >= http.StatusOK && code < http.StatusMultipleChoices if !strings.HasSuffix(r.URL.Path, systemPath) { st.totalS3Requests.Inc(api) if !successReq && code != 0 { st.totalS3Errors.Inc(api) } } if r.Method == http.MethodGet { // Increment the prometheus http request response histogram with appropriate label httpRequestsDuration.With(prometheus.Labels{"api": api}).Observe(durationSecs) } } // WriteHeader -- writes http status code. func (w *responseWrapper) WriteHeader(code int) { w.Do(func() { w.statusCode = code w.ResponseWriter.WriteHeader(code) }) } // Flush -- calls the underlying Flush. func (w *responseWrapper) Flush() { if f, ok := w.ResponseWriter.(http.Flusher); ok { f.Flush() } } func (w *writeCounter) Write(p []byte) (int, error) { n, err := w.ResponseWriter.Write(p) atomic.AddUint64(&w.countBytes, uint64(n)) return n, err } func (r *readCounter) Read(p []byte) (int, error) { n, err := r.ReadCloser.Read(p) atomic.AddUint64(&r.countBytes, uint64(n)) return n, err }