From 819eaca09e4680c9fc5c26c5c5f82d3715430e6c Mon Sep 17 00:00:00 2001
From: Alex Dadgar <alex.dadgar@gmail.com>
Date: Tue, 17 May 2016 18:05:00 -0700
Subject: [PATCH] Use codegen for json marshalling: 20% faster, 12% less bytes
 allocated, 85% less allocations

---
 command/agent/agent_test.go |  4 +--
 command/agent/http.go       | 21 +++++++++++----
 command/agent/http_test.go  | 54 ++++++++++++++++++++++++++++++++++---
 3 files changed, 69 insertions(+), 10 deletions(-)

diff --git a/command/agent/agent_test.go b/command/agent/agent_test.go
index ae470bf62b44..a01b493918d2 100644
--- a/command/agent/agent_test.go
+++ b/command/agent/agent_test.go
@@ -18,7 +18,7 @@ func getPort() int {
 	return int(atomic.AddUint32(&nextPort, 1))
 }
 
-func tmpDir(t *testing.T) string {
+func tmpDir(t testing.TB) string {
 	dir, err := ioutil.TempDir("", "nomad")
 	if err != nil {
 		t.Fatalf("err: %v", err)
@@ -26,7 +26,7 @@ func tmpDir(t *testing.T) string {
 	return dir
 }
 
-func makeAgent(t *testing.T, cb func(*Config)) (string, *Agent) {
+func makeAgent(t testing.TB, cb func(*Config)) (string, *Agent) {
 	dir := tmpDir(t)
 	conf := DevConfig()
 
diff --git a/command/agent/http.go b/command/agent/http.go
index bf2f95b78c5e..413f611dd3a1 100644
--- a/command/agent/http.go
+++ b/command/agent/http.go
@@ -1,6 +1,7 @@
 package agent
 
 import (
+	"bytes"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -12,6 +13,7 @@ import (
 	"time"
 
 	"github.com/hashicorp/nomad/nomad/structs"
+	"github.com/ugorji/go/codec"
 )
 
 const (
@@ -25,6 +27,13 @@ const (
 	scadaHTTPAddr = "SCADA"
 )
 
+var (
+	// jsonHandle and jsonHandlePretty are the codec handles to JSON encode
+	// structs. The pretty handle will add indents for easier human consumption.
+	jsonHandle       = &codec.JsonHandle{}
+	jsonHandlePretty = &codec.JsonHandle{Indent: 4}
+)
+
 // HTTPServer is used to wrap an Agent and expose it over an HTTP interface
 type HTTPServer struct {
 	agent    *Agent
@@ -183,20 +192,22 @@ func (s *HTTPServer) wrap(handler func(resp http.ResponseWriter, req *http.Reque
 
 		// Write out the JSON object
 		if obj != nil {
-			var buf []byte
+			var buf bytes.Buffer
 			if prettyPrint {
-				buf, err = json.MarshalIndent(obj, "", "    ")
+				enc := codec.NewEncoder(&buf, jsonHandlePretty)
+				err = enc.Encode(obj)
 				if err == nil {
-					buf = append(buf, "\n"...)
+					buf.Write([]byte("\n"))
 				}
 			} else {
-				buf, err = json.Marshal(obj)
+				enc := codec.NewEncoder(&buf, jsonHandle)
+				err = enc.Encode(obj)
 			}
 			if err != nil {
 				goto HAS_ERR
 			}
 			resp.Header().Set("Content-Type", "application/json")
-			resp.Write(buf)
+			resp.Write(buf.Bytes())
 		}
 	}
 	return f
diff --git a/command/agent/http_test.go b/command/agent/http_test.go
index 634e7f68923d..aa71add72085 100644
--- a/command/agent/http_test.go
+++ b/command/agent/http_test.go
@@ -13,12 +13,13 @@ import (
 	"testing"
 	"time"
 
+	"github.com/hashicorp/nomad/nomad/mock"
 	"github.com/hashicorp/nomad/nomad/structs"
 	"github.com/hashicorp/nomad/testutil"
 )
 
 type TestServer struct {
-	T      *testing.T
+	T      testing.TB
 	Dir    string
 	Agent  *Agent
 	Server *HTTPServer
@@ -30,9 +31,25 @@ func (s *TestServer) Cleanup() {
 	os.RemoveAll(s.Dir)
 }
 
-func makeHTTPServer(t *testing.T, cb func(c *Config)) *TestServer {
+// makeHTTPServerNoLogs returns a test server with full logging.
+func makeHTTPServer(t testing.TB, cb func(c *Config)) *TestServer {
+	return makeHTTPServerWithWriter(t, nil, cb)
+}
+
+// makeHTTPServerNoLogs returns a test server which only prints agent logs and
+// no http server logs
+func makeHTTPServerNoLogs(t testing.TB, cb func(c *Config)) *TestServer {
+	return makeHTTPServerWithWriter(t, ioutil.Discard, cb)
+}
+
+// makeHTTPServerWithWriter returns a test server whose logs will be written to
+// the passed writer. If the writer is nil, the logs are written to stderr.
+func makeHTTPServerWithWriter(t testing.TB, w io.Writer, cb func(c *Config)) *TestServer {
 	dir, agent := makeAgent(t, cb)
-	srv, err := NewHTTPServer(agent, agent.config, agent.logOutput)
+	if w == nil {
+		w = agent.logOutput
+	}
+	srv, err := NewHTTPServer(agent, agent.config, w)
 	if err != nil {
 		t.Fatalf("err: %v", err)
 	}
@@ -45,6 +62,37 @@ func makeHTTPServer(t *testing.T, cb func(c *Config)) *TestServer {
 	return s
 }
 
+func BenchmarkHTTPRequests(b *testing.B) {
+	s := makeHTTPServerNoLogs(b, func(c *Config) {
+		c.Client.Enabled = false
+	})
+	defer s.Cleanup()
+
+	job := mock.Job()
+	var allocs []*structs.Allocation
+	count := 1000
+	for i := 0; i < count; i++ {
+		alloc := mock.Alloc()
+		alloc.Job = job
+		alloc.JobID = job.ID
+		alloc.Name = fmt.Sprintf("my-job.web[%d]", i)
+		allocs = append(allocs, alloc)
+	}
+
+	handler := func(resp http.ResponseWriter, req *http.Request) (interface{}, error) {
+		return allocs[:count], nil
+	}
+	b.ResetTimer()
+
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			resp := httptest.NewRecorder()
+			req, _ := http.NewRequest("GET", "/v1/kv/key", nil)
+			s.Server.wrap(handler)(resp, req)
+		}
+	})
+}
+
 func TestSetIndex(t *testing.T) {
 	resp := httptest.NewRecorder()
 	setIndex(resp, 1000)