Add /:stats support

cmd/processRequest.go

@@ -28,6 +28,8 @@ type RequestProcessor struct {
 	peakRequest30 sync.Map
 	peakRequest60 sync.Map
 	lruCache      *lru.Cache
+	stats         *Stats
+	router        Router
 }
 
 // NewRequestProcessor returns new RequestProcessor.
@@ -37,9 +39,15 @@ func NewRequestProcessor() (*RequestProcessor, error) {
 		return nil, err
 	}
 
-	return &RequestProcessor{
+	rp := &RequestProcessor{
 		lruCache: lruCache,
-	}, nil
+		stats:    NewStats(),
+	}
+
+	// Initialize routes.
+	rp.router.AddPath("/:stats", rp.stats)
+
+	return rp, nil
 }
 
 // Start starts async request processor jobs, such as peak handling.
@@ -53,11 +61,23 @@ func (rp *RequestProcessor) ProcessRequest(r *http.Request) (*ResponseWithHeader
 		err      error
 	)
 
+	rp.stats.Inc("total")
+
+	// Main routing logic.
+	if rh := rp.router.Route(r); rh != nil {
+		result := rh.Response(r)
+		if result != nil {
+			return result, nil
+		}
+	}
+
 	if resp, ok := redirectInsecure(r); ok {
+		rp.stats.Inc("redirects")
 		return resp, nil
 	}
 
 	if dontCache(r) {
+		rp.stats.Inc("uncached")
 		return get(r)
 	}
 
@@ -69,6 +89,7 @@ func (rp *RequestProcessor) ProcessRequest(r *http.Request) (*ResponseWithHeader
 
 	cacheBody, ok := rp.lruCache.Get(cacheDigest)
 	if ok {
+		rp.stats.Inc("cache1")
 		cacheEntry := cacheBody.(ResponseWithHeader)
 
 		// if after all attempts we still have no answer,
@@ -93,7 +114,17 @@ func (rp *RequestProcessor) ProcessRequest(r *http.Request) (*ResponseWithHeader
 	}
 
 	if !foundInCache {
+		// Handling query.
+		format := r.URL.Query().Get("format")
+		if len(format) != 0 {
+			rp.stats.Inc("format")
+			if format == "j1" {
+				rp.stats.Inc("format=j1")
+			}
+		}
+
 		rp.lruCache.Add(cacheDigest, ResponseWithHeader{InProgress: true})
+
 		response, err = get(r)
 		if err != nil {
 			return nil, err

cmd/stat.go

@@ -1,40 +1,85 @@
 package main
 
-// import (
-// 	"log"
-// 	"sync"
-// 	"time"
-// )
-//
-// type safeCounter struct {
-// 	v   map[int]int
-// 	mux sync.Mutex
-// }
-//
-// func (c *safeCounter) inc(key int) {
-// 	c.mux.Lock()
-// 	c.v[key]++
-// 	c.mux.Unlock()
-// }
-//
-// // func (c *safeCounter) val(key int) int {
-// // 	c.mux.Lock()
-// // 	defer c.mux.Unlock()
-// // 	return c.v[key]
-// // }
-// //
-// // func (c *safeCounter) reset(key int) int {
-// // 	c.mux.Lock()
-// // 	defer c.mux.Unlock()
-// // 	result := c.v[key]
-// // 	c.v[key] = 0
-// // 	return result
-// // }
-//
-// var queriesPerMinute safeCounter
-//
-// func printStat() {
-// 	_, min, _ := time.Now().Clock()
-// 	queriesPerMinute.inc(min)
-// 	log.Printf("Processed %d requests\n", min)
-// }
+import (
+	"bytes"
+	"fmt"
+	"net/http"
+	"sync"
+	"time"
+)
+
+// Stats holds processed requests statistics.
+type Stats struct {
+	m         sync.Mutex
+	v         map[string]int
+	startTime time.Time
+}
+
+// NewStats returns new Stats.
+func NewStats() *Stats {
+	return &Stats{
+		v:         map[string]int{},
+		startTime: time.Now(),
+	}
+}
+
+// Inc key by one.
+func (c *Stats) Inc(key string) {
+	c.m.Lock()
+	c.v[key]++
+	c.m.Unlock()
+}
+
+// Get current key counter value.
+func (c *Stats) Get(key string) int {
+	c.m.Lock()
+	defer c.m.Unlock()
+	return c.v[key]
+}
+
+// Reset key counter.
+func (c *Stats) Reset(key string) int {
+	c.m.Lock()
+	defer c.m.Unlock()
+	result := c.v[key]
+	c.v[key] = 0
+	return result
+}
+
+// Show returns current statistics formatted as []byte.
+func (c *Stats) Show() []byte {
+	var (
+		b bytes.Buffer
+	)
+
+	c.m.Lock()
+	defer c.m.Unlock()
+
+	uptime := time.Since(c.startTime) / time.Second
+
+	fmt.Fprintf(&b, "%-20s: %v\n", "Running since", c.startTime.Format(time.RFC3339))
+	fmt.Fprintf(&b, "%-20s: %d\n", "Uptime (min)", uptime/60)
+
+	fmt.Fprintf(&b, "%-20s: %d\n", "Total queries", c.v["total"])
+	if uptime != 0 {
+		fmt.Fprintf(&b, "%-20s: %d\n", "Throughput (QpM)", c.v["total"]*60/int(uptime))
+	}
+
+	fmt.Fprintf(&b, "%-20s: %d\n", "Cache L1 queries", c.v["cache1"])
+	if c.v["total"] != 0 {
+		fmt.Fprintf(&b, "%-20s: %d\n", "Cache L1 queries (%)", (100*c.v["cache1"])/c.v["total"])
+	}
+
+	fmt.Fprintf(&b, "%-20s: %d\n", "Upstream queries", c.v["total"]-c.v["cache1"])
+	fmt.Fprintf(&b, "%-20s: %d\n", "Queries with format", c.v["format"])
+	fmt.Fprintf(&b, "%-20s: %d\n", "Queries with format=j1", c.v["format=j1"])
+
+	return b.Bytes()
+}
+
+func (c *Stats) Response(*http.Request) *ResponseWithHeader {
+	return &ResponseWithHeader{
+		Body:       c.Show(),
+		StatusCode: 200,
+	}
+}