server: Accept a latency distribution on the commandline (#45)

* make `distribution` and `percentiles` top-level modules

* Support a per-instance latency distribution configured on the server.

* update README

README.md

@@ -8,16 +8,16 @@ Strest client and server implementations for gRPC.
 
 To run the client and server locally, first start the server.
 
-```bash
-$ go run main.go server
+```
+$ strest-grpc server
 starting gRPC server on :11111
 ```
 
 Next run the client. By default, the client will send as many request as it can
 on a single connection for 10 seconds, and exit with a performance report.
 
-```bash
-$ go run main.go client --address localhost:11111
+```
+$ strest-grpc client --address localhost:11111
 2017-05-12T16:17:40-07:00  98.2KB    354/0 10s L:   0 [ 89  97 ]  102 J:   0   0
 {
   "good": 354,
@@ -40,12 +40,10 @@ $ go run main.go client --address localhost:11111
 
 ### Usage
 
-Use the `--help` flag for usage information.
-
 #### Commands
 
-```bash
-$ go run main.go --help
+```
+$ strest-grpc --help
 A load tester for stress testing grpc intermediaries.
 
 Find more information at https://github.com/buoyantio/strest-grpc.
@@ -68,8 +66,8 @@ Use "strest-grpc [command] --help" for more information about a command.
 
 #### Client
 
-```bash
-$ go run main.go client --help
+```
+$ strest-grpc client --help
 run the strest-grpc client
 
 Usage:
@@ -102,29 +100,30 @@ Global Flags:
 
 #### Server
 
-```bash
-$ go run main.go server --help
+```
+$ strest-grpc server --help
 run the strest-grpc server
 
 Usage:
   strest-grpc server [flags]
 
 Flags:
-      --address string          address to serve on (default ":11111")
-  -h, --help                    help for server
-      --metricAddr string       address to serve metrics on
-      --tlsCertFile string      the path to the trust certificate
-      --tlsPrivKeyFile string   the path to the server's private key
-  -u, --unix                    use Unix Domain Sockets instead of TCP
+      --address string              address to serve on (default ":11111")
+  -h, --help                        help for server
+      --latencyPercentiles string   response latency percentile distribution added to client latencies. (e.g. 50=10,100=100) (default "100=0")
+      --metricAddr string           address to serve metrics on
+      --tlsCertFile string          the path to the trust certificate
+      --tlsPrivKeyFile string       the path to the server's private key
+  -u, --unix                        use Unix Domain Sockets instead of TCP
 
 Global Flags:
   -l, --logLevel string   log level, must be one of: panic, fatal, error, warn, info, debug (default "info")
 ```
 
 #### Max-RPS
 
-```bash
-$ go run main.go max-rps --help
+```
+$ strest-grpc max-rps --help
 compute max RPS
 
 Usage:
@@ -144,15 +143,15 @@ Global Flags:
 
 To build the strest-grpc binaries and archives, run:
 
-```bash
+```
 ./bin/release.sh [VERSION TAG]
 ```
 
 That will create `strest-grpc` binaries and archives in `./release`.
 
 To build a docker image, run:
 
-```bash
+```
 $ docker build -t buoyantio/strest-grpc:latest .
 ```
 

client/client.go

@@ -17,8 +17,8 @@ import (
 	"syscall"
 	"time"
 
-	"github.com/buoyantio/strest-grpc/client/distribution"
-	"github.com/buoyantio/strest-grpc/client/percentiles"
+	"github.com/buoyantio/strest-grpc/distribution"
+	"github.com/buoyantio/strest-grpc/percentiles"
 	pb "github.com/buoyantio/strest-grpc/protos"
 	"github.com/codahale/hdrhistogram"
 	"github.com/prometheus/client_golang/prometheus"

cmd/server.go

@@ -21,6 +21,7 @@ func init() {
 	flags := serverCmd.Flags()
 	flags.StringVar(&serverCfg.Address, "address", ":11111", "address to serve on")
 	flags.StringVar(&serverCfg.MetricAddr, "metricAddr", "", "address to serve metrics on")
+	flags.StringVar(&serverCfg.LatencyPercentiles, "latencyPercentiles", "100=0", "response latency percentile distribution added to client latencies. (e.g. 50=10,100=100)")
 	flags.BoolVarP(&serverCfg.UseUnixAddr, "unix", "u", false, "use Unix Domain Sockets instead of TCP")
 	flags.StringVar(&serverCfg.TLSCertFile, "tlsCertFile", "", "the path to the trust certificate")
 	flags.StringVar(&serverCfg.TLSPrivKeyFile, "tlsPrivKeyFile", "", "the path to the server's private key")

client/distribution/distribution_test.go → distribution/distribution_test.go

@@ -3,7 +3,7 @@ package distribution_test
 import (
 	"testing"
 
-	"github.com/buoyantio/strest-grpc/client/distribution"
+	"github.com/buoyantio/strest-grpc/distribution"
 	. "gopkg.in/check.v1"
 )
 

client/percentiles/percentiles_test.go → percentiles/percentiles_test.go

@@ -1,9 +1,10 @@
 package percentiles_test
 
 import (
-	"github.com/buoyantio/strest-grpc/client/percentiles"
-	. "gopkg.in/check.v1"
 	"testing"
+
+	"github.com/buoyantio/strest-grpc/percentiles"
+	. "gopkg.in/check.v1"
 )
 
 // Hook up gocheck into the "go test" runner.

server/server.go

@@ -9,7 +9,8 @@ import (
 	"net/http"
 	"time"
 
-	"github.com/buoyantio/strest-grpc/client/distribution"
+	"github.com/buoyantio/strest-grpc/distribution"
+	"github.com/buoyantio/strest-grpc/percentiles"
 	pb "github.com/buoyantio/strest-grpc/protos"
 	"github.com/buoyantio/strest-grpc/server/random_string"
 	"github.com/prometheus/client_golang/prometheus"
@@ -22,7 +23,9 @@ import (
 	"google.golang.org/grpc/status"
 )
 
-type server struct{}
+type server struct {
+	latencyDistribution distribution.Distribution
+}
 
 var (
 	promRequests = prometheus.NewCounter(prometheus.CounterOpts{
@@ -57,8 +60,10 @@ func registerMetrics() {
 func (s *server) Get(ctx context.Context, in *pb.ResponseSpec) (*pb.ResponseReply, error) {
 	var src = rand.NewSource(time.Now().UnixNano())
 	r := rand.New(src)
-	if in.Latency > 0 {
-		time.Sleep(time.Duration(in.Latency) * time.Millisecond)
+	latency := s.latencyDistribution.Get(r.Int31() % 1000)
+	latency = latency + in.Latency
+	if latency > 0 {
+		time.Sleep(time.Duration(latency) * time.Millisecond)
 	}
 	promRequests.Inc()
 	promResponses.Inc()
@@ -146,13 +151,14 @@ func (s *server) StreamingGet(stream pb.Responder_StreamingGetServer) error {
 	}
 }
 
-// Configuration for a server
+// Config holds the commandline configuration for the server.
 type Config struct {
-	Address        string
-	UseUnixAddr    bool
-	MetricAddr     string
-	TLSCertFile    string
-	TLSPrivKeyFile string
+	Address            string
+	UseUnixAddr        bool
+	MetricAddr         string
+	LatencyPercentiles string
+	TLSCertFile        string
+	TLSPrivKeyFile     string
 }
 
 func (cfg *Config) serveMetrics() {
@@ -168,9 +174,9 @@ func (cfg *Config) serveMetrics() {
 func (cfg *Config) af() string {
 	if cfg.UseUnixAddr {
 		return "unix"
-	} else {
-		return "tcp"
 	}
+
+	return "tcp"
 }
 
 func (cfg *Config) tlsCreds() (credentials.TransportCredentials, error) {
@@ -180,10 +186,19 @@ func (cfg *Config) tlsCreds() (credentials.TransportCredentials, error) {
 	return nil, nil
 }
 
-// run the server
+// Run processes commandline configuration and runs the server.
 func (cfg Config) Run() {
 	rand.Seed(time.Now().UnixNano())
 
+	latencyPercentiles, err := percentiles.ParsePercentiles(cfg.LatencyPercentiles)
+	if err != nil {
+		log.Fatalf("latencyPercentiles was not valid: %v", err)
+	}
+	latencyDistribution, err := distribution.FromMap(latencyPercentiles)
+	if err != nil {
+		log.Fatalf("unable to create latency distribution: %v", err)
+	}
+
 	cfg.serveMetrics()
 
 	fmt.Println("starting gRPC server on", cfg.Address)
@@ -205,6 +220,6 @@ func (cfg Config) Run() {
 
 	s := grpc.NewServer(opts...)
 
-	pb.RegisterResponderServer(s, new(server))
+	pb.RegisterResponderServer(s, &server{latencyDistribution})
 	s.Serve(lis)
 }