all: add rate limiting feature, refactor a bit and fix rounding errors

This commit:
  - adds rate limiting feature;
  - refactors and moves around some stuff;
  - cleans up README.md;
  - fixes two rounding errors in bombardier.go and stats.go.

After a little research rate limiting were implemented with little to
no impact on performance.

Updates #14

Author: codesenberg

README.md

@@ -4,8 +4,8 @@ bombardier is a HTTP(S) benchmarking tool. It is written in Go programming langu
 Tested on go1.6 and higher. Use go1.7+ for best performance.
 
 ##Installation
-You can grab the latest version in the [releases](https://github.com/codesenberg/bombardier/releases) section.
-Alternatively, just run:
+You can grab binaries in the [releases](https://github.com/codesenberg/bombardier/releases) section.
+Alternatively, to get latest and greatest run:
 
 `go get -u github.com/codesenberg/bombardier`
 
@@ -14,32 +14,9 @@ Alternatively, just run:
 bombardier [<flags>] <url>
 ```
 
-Flags:
-```
-      --help                    Show context-sensitive help (also try
-                                --help-long and --help-man).
-  -c, --connections=125         Maximum number of concurrent connections
-  -t, --timeout=2s              Socket/request timeout
-  -l, --latencies               Print latency statistics
-  -m, --method=GET              Request method
-  -b, --body=""                 Request body
-      --cert=""                 Path to the client's TLS Certificate
-      --key=""                  Path to the client's TLS Certificate Private Key
+For a more detailed information about flags consult [GoDoc](http://godoc.org/github.com/codesenberg/bombardier).
 
-  -k, --insecure                Controls whether a client verifies the server's
-                                certificate chain and host name
-  -H, --headers=[] ...          HTTP headers to use(can be repeated)
-  -n, --requests=[<pos. int.>]  Number of requests
-  -d, --duration=10s            Duration of test
-```
-Args:
-```
-  <url>  Target's URL
-```
-To set multiple headers just repeat the `H` flag, like so:
-```
-bombardier -H 'First: Value1' -H 'Second: Value2' -H 'Third: Value3' http://somehost:8080
-```
+##Examples
 Example of running `bombardier` against [this server](https://godoc.org/github.com/codesenberg/bombardier/cmd/utils/simplebenchserver):
 ```
 > bombardier -c 125 -n 10000000 http://localhost:8080

args_parser.go

@@ -8,15 +8,6 @@ import (
 	"github.com/alecthomas/kingpin"
 )
 
-const (
-	decBase = 10
-)
-
-var (
-	emptyConf = config{}
-	parser    = newKingpinParser()
-)
-
 type argsParser interface {
 	parse([]string) (config, error)
 }
@@ -37,6 +28,7 @@ type kingpinParser struct {
 	body      string
 	certPath  string
 	keyPath   string
+	rate      *nullableUint64
 }
 
 func newKingpinParser() argsParser {
@@ -53,6 +45,7 @@ func newKingpinParser() argsParser {
 		keyPath:   "",
 		insecure:  false,
 		url:       "",
+		rate:      new(nullableUint64),
 	}
 
 	app := kingpin.New("", "Fast cross-platform HTTP benchmarking tool").
@@ -90,18 +83,23 @@ func newKingpinParser() argsParser {
 		BoolVar(&kparser.insecure)
 
 	app.Flag("header", "HTTP headers to use(can be repeated)").
-		PlaceHolder("[]").
+		PlaceHolder("\"K: V\"").
 		Short('H').
 		SetValue(kparser.headers)
 	app.Flag("requests", "Number of requests").
-		PlaceHolder("[<pos. int.>]").
+		PlaceHolder("[pos. int.]").
 		Short('n').
 		SetValue(kparser.numReqs)
 	app.Flag("duration", "Duration of test").
 		PlaceHolder(defaultTestDuration.String()).
 		Short('d').
 		SetValue(kparser.duration)
 
+	app.Flag("rate", "Rate limit in requests per second").
+		PlaceHolder("[pos. int.]").
+		Short('r').
+		SetValue(kparser.rate)
+
 	app.Arg("url", "Target's URL").Required().
 		StringVar(&kparser.url)
 
@@ -128,5 +126,6 @@ func (k *kingpinParser) parse(args []string) (config, error) {
 		certPath:       k.certPath,
 		printLatencies: k.latencies,
 		insecure:       k.insecure,
+		rate:           k.rate.val,
 	}, nil
 }

bombardier.go

@@ -18,6 +18,7 @@ type bombardier struct {
 	conf           config
 	requestHeaders *fasthttp.RequestHeader
 	barrier        completionBarrier
+	ratelimiter    limiter
 	workers        sync.WaitGroup
 
 	bytesTotal int64
@@ -75,6 +76,13 @@ func newBombardier(c config) (*bombardier, error) {
 	} else {
 		b.barrier = newTimedCompletionBarrier(*b.conf.duration)
 	}
+
+	if b.conf.rate != nil {
+		b.ratelimiter = newBucketLimiter(*b.conf.rate)
+	} else {
+		b.ratelimiter = &nooplimiter{}
+	}
+
 	b.out = os.Stdout
 
 	tlsConfig, err := generateTLSConfig(c)
@@ -168,8 +176,13 @@ func (b *bombardier) performSingleRequest() {
 }
 
 func (b *bombardier) worker() {
+	done := b.barrier.done()
 	for b.barrier.tryGrabWork() {
+		if b.ratelimiter.pace(done) == brk {
+			break
+		}
 		b.performSingleRequest()
+		b.barrier.jobDone()
 	}
 }
 
@@ -194,6 +207,11 @@ func (b *bombardier) barUpdater() {
 }
 
 func (b *bombardier) rateMeter() {
+	requestsInterval := 10 * time.Millisecond
+	if b.conf.rate != nil {
+		requestsInterval, _ = estimate(*b.conf.rate, rateLimitInterval)
+	}
+	requestsInterval += 10 * time.Millisecond
 	ticker := time.NewTicker(requestsInterval)
 	defer ticker.Stop()
 	tick := ticker.C
@@ -219,7 +237,9 @@ func (b *bombardier) recordRps() {
 	b.reqs = 0
 	b.start = time.Now()
 	b.rpl.Unlock()
-	b.requests.record(uint64(float64(reqs) / duration.Seconds()))
+
+	reqsf := float64(reqs) / duration.Seconds()
+	b.requests.record(round(reqsf))
 }
 
 func (b *bombardier) bombard() {
@@ -299,18 +319,6 @@ func (b *bombardier) disableOutput() {
 	b.bar.NotPrint = true
 }
 
-const (
-	maxRps           = 10000000
-	requestsInterval = 100 * time.Millisecond
-	defaultTimeout   = 2 * time.Second
-
-	exitFailure = 1
-)
-
-var (
-	version = "unspecified"
-)
-
 func main() {
 	cfg, err := parser.parse(os.Args)
 	if err != nil {

bombardier_performance_test.go

@@ -1,5 +1,3 @@
-// +build go1.7
-
 package main
 
 import (
@@ -11,35 +9,55 @@ import (
 
 var serverPort = flag.String("port", "8080", "port to use for benchmarks")
 
-func BenchmarkBombardier(b *testing.B) {
+var (
+	longDuration = 9001 * time.Hour
+	highRate     = uint64(1000000)
+)
+
+func BenchmarkBombardierSingleReqPerf(b *testing.B) {
 	addr := "localhost:" + *serverPort
-	b.Run("single-req-perf", benchmarkFireRequest(addr))
+	benchmarkFireRequest(config{
+		numConns:       defaultNumberOfConns,
+		numReqs:        nil,
+		duration:       &longDuration,
+		url:            "http://" + addr,
+		headers:        new(headersList),
+		timeout:        defaultTimeout,
+		method:         "GET",
+		body:           "",
+		printLatencies: false,
+	}, b)
 }
 
-func benchmarkFireRequest(addr string) func(bm *testing.B) {
-	return func(bm *testing.B) {
-		longDuration := 9001 * time.Hour
-		b, e := newBombardier(config{
-			numConns:       defaultNumberOfConns,
-			numReqs:        nil,
-			duration:       &longDuration,
-			url:            "http://" + addr,
-			headers:        new(headersList),
-			timeout:        defaultTimeout,
-			method:         "GET",
-			body:           "",
-			printLatencies: false,
-		})
-		if e != nil {
-			bm.Error(e)
-		}
-		b.disableOutput()
-		bm.SetParallelism(int(defaultNumberOfConns) / runtime.NumCPU())
-		bm.ResetTimer()
-		bm.RunParallel(func(pb *testing.PB) {
-			for pb.Next() {
-				b.performSingleRequest()
-			}
-		})
+func BenchmarkBombardierRateLimitPerf(b *testing.B) {
+	addr := "localhost:" + *serverPort
+	benchmarkFireRequest(config{
+		numConns:       defaultNumberOfConns,
+		numReqs:        nil,
+		duration:       &longDuration,
+		url:            "http://" + addr,
+		headers:        new(headersList),
+		timeout:        defaultTimeout,
+		method:         "GET",
+		body:           "",
+		printLatencies: false,
+		rate:           &highRate,
+	}, b)
+}
+
+func benchmarkFireRequest(c config, bm *testing.B) {
+	b, e := newBombardier(c)
+	if e != nil {
+		bm.Error(e)
 	}
+	b.disableOutput()
+	bm.SetParallelism(int(defaultNumberOfConns) / runtime.NumCPU())
+	bm.ResetTimer()
+	bm.RunParallel(func(pb *testing.PB) {
+		done := b.barrier.done()
+		for pb.Next() {
+			b.ratelimiter.pace(done)
+			b.performSingleRequest()
+		}
+	})
 }

bombardier_test.go

@@ -29,7 +29,6 @@ func TestBombardierShouldFireSpecifiedNumberOfRequests(t *testing.T) {
 	b, e := newBombardier(config{
 		numConns: defaultNumberOfConns,
 		numReqs:  &numReqs,
-		duration: nil,
 		url:      s.URL,
 		headers:  noHeaders,
 		timeout:  defaultTimeout,
@@ -60,7 +59,6 @@ func TestBombardierShouldFinish(t *testing.T) {
 	desiredTestDuration := 1 * time.Second
 	b, e := newBombardier(config{
 		numConns: defaultNumberOfConns,
-		numReqs:  nil,
 		duration: &desiredTestDuration,
 		url:      s.URL,
 		headers:  noHeaders,
@@ -106,7 +104,6 @@ func TestBombardierShouldSendHeaders(t *testing.T) {
 	b, e := newBombardier(config{
 		numConns: defaultNumberOfConns,
 		numReqs:  &numReqs,
-		duration: nil,
 		url:      s.URL,
 		headers:  &requestHeaders,
 		timeout:  defaultTimeout,
@@ -143,7 +140,6 @@ func TestBombardierHttpCodeRecording(t *testing.T) {
 	b, e := newBombardier(config{
 		numConns: defaultNumberOfConns,
 		numReqs:  &numReqs,
-		duration: nil,
 		url:      s.URL,
 		headers:  new(headersList),
 		timeout:  defaultTimeout,
@@ -217,7 +213,6 @@ func TestBombardierThroughputRecording(t *testing.T) {
 	b, e := newBombardier(config{
 		numConns: defaultNumberOfConns,
 		numReqs:  &numReqs,
-		duration: nil,
 		url:      s.URL,
 		headers:  new(headersList),
 		timeout:  defaultTimeout,
@@ -255,7 +250,6 @@ func TestBombardierStatsPrinting(t *testing.T) {
 	b, e := newBombardier(config{
 		numConns:       defaultNumberOfConns,
 		numReqs:        &numReqs,
-		duration:       nil,
 		url:            s.URL,
 		headers:        new(headersList),
 		timeout:        defaultTimeout,
@@ -284,7 +278,6 @@ func TestBombardierErrorIfFailToReadClientCert(t *testing.T) {
 	_, e := newBombardier(config{
 		numConns:       defaultNumberOfConns,
 		numReqs:        &numReqs,
-		duration:       nil,
 		url:            "http://localhost",
 		headers:        new(headersList),
 		timeout:        defaultTimeout,
@@ -350,7 +343,6 @@ func TestBombardierClientCerts(t *testing.T) {
 	b, e := newBombardier(config{
 		numConns:       defaultNumberOfConns,
 		numReqs:        &numReqs,
-		duration:       nil,
 		url:            "https://localhost:8080/",
 		headers:        new(headersList),
 		timeout:        defaultTimeout,
@@ -377,3 +369,38 @@ func TestBombardierClientCerts(t *testing.T) {
 		t.Error(err)
 	}
 }
+
+func TestBombardierRateLimiting(t *testing.T) {
+	responseSize := 1024
+	response := bytes.Repeat([]byte{'a'}, responseSize)
+	s := httptest.NewServer(
+		http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+			_, err := rw.Write(response)
+			if err != nil {
+				t.Error(err)
+			}
+		}),
+	)
+	rate := uint64(10000)
+	testDuration := 1 * time.Second
+	b, e := newBombardier(config{
+		numConns: defaultNumberOfConns,
+		duration: &testDuration,
+		url:      s.URL,
+		headers:  new(headersList),
+		timeout:  defaultTimeout,
+		method:   "GET",
+		body:     "",
+		rate:     &rate,
+	})
+	if e != nil {
+		t.Error(e)
+		return
+	}
+	b.disableOutput()
+	b.bombard()
+	if float64(b.req2xx) < float64(rate)*0.75 ||
+		float64(b.req2xx) > float64(rate)*1.25 {
+		t.Error(rate, b.req2xx)
+	}
+}

client_cert_test.go

@@ -1,6 +1,8 @@
 package main
 
-import "testing"
+import (
+	"testing"
+)
 
 func TestGenerateTLSConfig(t *testing.T) {
 	expectations := []struct {