Switch from encoding/json -> jsoniter (#570)

* Switch from encoding/json -> jsoniter

Signed-off-by: Thomas Jackson <jacksontj.89@gmail.com>

api/client_test.go

@@ -20,8 +20,6 @@ import (
 	"net/http/httptest"
 	"net/url"
 	"testing"
-
-	"github.com/prometheus/tsdb/testutil"
 )
 
 func TestConfig(t *testing.T) {
@@ -148,7 +146,9 @@ func TestDoGetFallback(t *testing.T) {
 	defer server.Close()
 
 	u, err := url.Parse(server.URL)
-	testutil.Ok(t, err)
+	if err != nil {
+		t.Fatal(err)
+	}
 	client := &httpClient{client: *(server.Client())}
 
 	// Do a post, and ensure that the post succeeds.
@@ -158,7 +158,7 @@ func TestDoGetFallback(t *testing.T) {
 	}
 	resp := &testResponse{}
 	if err := json.Unmarshal(b, resp); err != nil {
-		testutil.Ok(t, err)
+		t.Fatal(err)
 	}
 	if resp.Method != http.MethodPost {
 		t.Fatalf("Mismatch method")
@@ -174,7 +174,7 @@ func TestDoGetFallback(t *testing.T) {
 		t.Fatalf("Error doing local request: %v", err)
 	}
 	if err := json.Unmarshal(b, resp); err != nil {
-		testutil.Ok(t, err)
+		t.Fatal(err)
 	}
 	if resp.Method != http.MethodGet {
 		t.Fatalf("Mismatch method")

api/prometheus/v1/api.go

@@ -17,18 +17,105 @@ package v1
 
 import (
 	"context"
-	"encoding/json"
 	"errors"
 	"fmt"
+	"math"
 	"net/http"
 	"strconv"
 	"strings"
 	"time"
+	"unsafe"
+
+	json "github.com/json-iterator/go"
 
-	"github.com/prometheus/client_golang/api"
 	"github.com/prometheus/common/model"
+
+	"github.com/prometheus/client_golang/api"
 )
 
+func init() {
+	json.RegisterTypeEncoderFunc("model.SamplePair", marshalPointJSON, marshalPointJSONIsEmpty)
+	json.RegisterTypeDecoderFunc("model.SamplePair", unMarshalPointJSON)
+}
+
+func unMarshalPointJSON(ptr unsafe.Pointer, iter *json.Iterator) {
+	p := (*model.SamplePair)(ptr)
+	if !iter.ReadArray() {
+		iter.ReportError("unmarshal model.SamplePair", "SamplePair must be [timestamp, value]")
+		return
+	}
+	t := iter.ReadNumber()
+	if err := p.Timestamp.UnmarshalJSON([]byte(t)); err != nil {
+		iter.ReportError("unmarshal model.SamplePair", err.Error())
+		return
+	}
+	if !iter.ReadArray() {
+		iter.ReportError("unmarshal model.SamplePair", "SamplePair missing value")
+		return
+	}
+
+	f, err := strconv.ParseFloat(iter.ReadString(), 64)
+	if err != nil {
+		iter.ReportError("unmarshal model.SamplePair", err.Error())
+		return
+	}
+	p.Value = model.SampleValue(f)
+
+	if iter.ReadArray() {
+		iter.ReportError("unmarshal model.SamplePair", "SamplePair has too many values, must be [timestamp, value]")
+		return
+	}
+}
+
+func marshalPointJSON(ptr unsafe.Pointer, stream *json.Stream) {
+	p := *((*model.SamplePair)(ptr))
+	stream.WriteArrayStart()
+	// Write out the timestamp as a float divided by 1000.
+	// This is ~3x faster than converting to a float.
+	t := int64(p.Timestamp)
+	if t < 0 {
+		stream.WriteRaw(`-`)
+		t = -t
+	}
+	stream.WriteInt64(t / 1000)
+	fraction := t % 1000
+	if fraction != 0 {
+		stream.WriteRaw(`.`)
+		if fraction < 100 {
+			stream.WriteRaw(`0`)
+		}
+		if fraction < 10 {
+			stream.WriteRaw(`0`)
+		}
+		stream.WriteInt64(fraction)
+	}
+	stream.WriteMore()
+	stream.WriteRaw(`"`)
+
+	// Taken from https://github.com/json-iterator/go/blob/master/stream_float.go#L71 as a workaround
+	// to https://github.com/json-iterator/go/issues/365 (jsoniter, to follow json standard, doesn't allow inf/nan)
+	buf := stream.Buffer()
+	abs := math.Abs(float64(p.Value))
+	fmt := byte('f')
+	// Note: Must use float32 comparisons for underlying float32 value to get precise cutoffs right.
+	if abs != 0 {
+		if abs < 1e-6 || abs >= 1e21 {
+			fmt = 'e'
+			fmt = 'e'
+		}
+	}
+	buf = strconv.AppendFloat(buf, float64(p.Value), fmt, -1, 64)
+	stream.SetBuffer(buf)
+
+	stream.WriteRaw(`"`)
+	stream.WriteArrayEnd()
+
+}
+
+func marshalPointJSONIsEmpty(ptr unsafe.Pointer) bool {
+	return false
+}
+
 const (
 	statusAPIError = 422
 

api/prometheus/v1/api_bench_test.go

@@ -0,0 +1,112 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package v1
+
+import (
+	"encoding/json"
+	"strconv"
+	"testing"
+	"time"
+
+	jsoniter "github.com/json-iterator/go"
+
+	"github.com/prometheus/common/model"
+)
+
+func generateData(timeseries, datapoints int) model.Matrix {
+	m := make(model.Matrix, 0)
+
+	for i := 0; i < timeseries; i++ {
+		lset := map[model.LabelName]model.LabelValue{
+			model.MetricNameLabel: model.LabelValue("timeseries_" + strconv.Itoa(i)),
+		}
+		now := model.Now()
+		values := make([]model.SamplePair, datapoints)
+
+		for x := datapoints; x > 0; x-- {
+			values[x-1] = model.SamplePair{
+				// Set the time back assuming a 15s interval. Since this is used for
+				// Marshal/Unmarshal testing the actual interval doesn't matter.
+				Timestamp: now.Add(time.Second * -15 * time.Duration(x)),
+				Value:     model.SampleValue(float64(x)),
+			}
+		}
+
+		ss := &model.SampleStream{
+			Metric: model.Metric(lset),
+			Values: values,
+		}
+
+		m = append(m, ss)
+	}
+	return m
+}
+
+func BenchmarkSamplesJsonSerialization(b *testing.B) {
+	for _, timeseriesCount := range []int{10, 100, 1000} {
+		b.Run(strconv.Itoa(timeseriesCount), func(b *testing.B) {
+			for _, datapointCount := range []int{10, 100, 1000} {
+				b.Run(strconv.Itoa(datapointCount), func(b *testing.B) {
+					data := generateData(timeseriesCount, datapointCount)
+
+					dataBytes, err := json.Marshal(data)
+					if err != nil {
+						b.Fatalf("Error marshaling: %v", err)
+					}
+
+					b.Run("marshal", func(b *testing.B) {
+						b.Run("encoding/json", func(b *testing.B) {
+							b.ReportAllocs()
+							for i := 0; i < b.N; i++ {
+								if _, err := json.Marshal(data); err != nil {
+									b.Fatal(err)
+								}
+							}
+						})
+
+						b.Run("jsoniter", func(b *testing.B) {
+							b.ReportAllocs()
+							for i := 0; i < b.N; i++ {
+								if _, err := jsoniter.Marshal(data); err != nil {
+									b.Fatal(err)
+								}
+							}
+						})
+					})
+
+					b.Run("unmarshal", func(b *testing.B) {
+						b.Run("encoding/json", func(b *testing.B) {
+							b.ReportAllocs()
+							var m model.Matrix
+							for i := 0; i < b.N; i++ {
+								if err := json.Unmarshal(dataBytes, &m); err != nil {
+									b.Fatal(err)
+								}
+							}
+						})
+
+						b.Run("jsoniter", func(b *testing.B) {
+							b.ReportAllocs()
+							var m model.Matrix
+							for i := 0; i < b.N; i++ {
+								if err := jsoniter.Unmarshal(dataBytes, &m); err != nil {
+									b.Fatal(err)
+								}
+							}
+						})
+					})
+				})
+			}
+		})
+	}
+}

api/prometheus/v1/api_test.go

@@ -15,19 +15,22 @@ package v1
 
 import (
 	"context"
-	"encoding/json"
 	"errors"
 	"fmt"
+	"math"
 	"net/http"
 	"net/url"
 	"reflect"
 	"strings"
 	"testing"
 	"time"
 
-	"github.com/prometheus/client_golang/api"
+	json "github.com/json-iterator/go"
+
 	"github.com/prometheus/common/model"
 	"github.com/prometheus/tsdb/testutil"
+
+	"github.com/prometheus/client_golang/api"
 )
 
 type apiTest struct {
@@ -792,7 +795,7 @@ func TestAPIClientDo(t *testing.T) {
 			response: "bad json",
 			expectedErr: &Error{
 				Type: ErrBadResponse,
-				Msg:  "invalid character 'b' looking for beginning of value",
+				Msg:  "readObjectStart: expect { or n, but found b, error found in #1 byte of ...|bad json|..., bigger context ...|bad json|...",
 			},
 		},
 		{
@@ -882,3 +885,99 @@ func TestAPIClientDo(t *testing.T) {
 
 	}
 }
+
+func TestSamplesJsonSerialization(t *testing.T) {
+	tests := []struct {
+		point    model.SamplePair
+		expected string
+	}{
+		{
+			point:    model.SamplePair{0, 0},
+			expected: `[0,"0"]`,
+		},
+		{
+			point:    model.SamplePair{1, 20},
+			expected: `[0.001,"20"]`,
+		},
+		{
+			point:    model.SamplePair{10, 20},
+			expected: `[0.010,"20"]`,
+		},
+		{
+			point:    model.SamplePair{100, 20},
+			expected: `[0.100,"20"]`,
+		},
+		{
+			point:    model.SamplePair{1001, 20},
+			expected: `[1.001,"20"]`,
+		},
+		{
+			point:    model.SamplePair{1010, 20},
+			expected: `[1.010,"20"]`,
+		},
+		{
+			point:    model.SamplePair{1100, 20},
+			expected: `[1.100,"20"]`,
+		},
+		{
+			point:    model.SamplePair{12345678123456555, 20},
+			expected: `[12345678123456.555,"20"]`,
+		},
+		{
+			point:    model.SamplePair{-1, 20},
+			expected: `[-0.001,"20"]`,
+		},
+		{
+			point:    model.SamplePair{0, model.SampleValue(math.NaN())},
+			expected: `[0,"NaN"]`,
+		},
+		{
+			point:    model.SamplePair{0, model.SampleValue(math.Inf(1))},
+			expected: `[0,"+Inf"]`,
+		},
+		{
+			point:    model.SamplePair{0, model.SampleValue(math.Inf(-1))},
+			expected: `[0,"-Inf"]`,
+		},
+		{
+			point:    model.SamplePair{0, model.SampleValue(1.2345678e6)},
+			expected: `[0,"1234567.8"]`,
+		},
+		{
+			point:    model.SamplePair{0, 1.2345678e-6},
+			expected: `[0,"0.0000012345678"]`,
+		},
+		{
+			point:    model.SamplePair{0, 1.2345678e-67},
+			expected: `[0,"1.2345678e-67"]`,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.expected, func(t *testing.T) {
+			b, err := json.Marshal(test.point)
+			if err != nil {
+				t.Fatal(err)
+			}
+			if string(b) != test.expected {
+				t.Fatalf("Mismatch marshal expected=%s actual=%s", test.expected, string(b))
+			}
+
+			// To test Unmarshal we will Unmarshal then re-Marshal this way we
+			// can do a string compare, otherwise Nan values don't show equivalence
+			// properly.
+			var sp model.SamplePair
+			if err = json.Unmarshal(b, &sp); err != nil {
+				t.Fatal(err)
+			}
+
+			b, err = json.Marshal(sp)
+			if err != nil {
+				t.Fatal(err)
+			}
+			if string(b) != test.expected {
+				t.Fatalf("Mismatch marshal expected=%s actual=%s", test.expected, string(b))
+			}
+		})
+	}
+}