Start to use json-iterator to improve marshalling of HistogramBucket

Signed-off-by: Jeanette Tan <[email protected]>

Author: zenador

go.mod

@@ -5,6 +5,7 @@ go 1.17
 require (
 	github.com/go-kit/log v0.2.1
 	github.com/golang/protobuf v1.5.2
+	github.com/json-iterator/go v1.1.12
 	github.com/julienschmidt/httprouter v1.3.0
 	github.com/matttproud/golang_protobuf_extensions v1.0.4
 	github.com/mwitkow/go-conntrack v0.0.0-20190716064945-2f068394615f
@@ -23,6 +24,8 @@ require (
 	github.com/cespare/xxhash/v2 v2.1.2 // indirect
 	github.com/go-logfmt/logfmt v0.5.1 // indirect
 	github.com/jpillora/backoff v1.0.0 // indirect
+	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
+	github.com/modern-go/reflect2 v1.0.2 // indirect
 	github.com/prometheus/procfs v0.8.0 // indirect
 	github.com/stretchr/testify v1.8.0 // indirect
 	golang.org/x/sys v0.3.0 // indirect

go.sum

@@ -139,6 +139,7 @@ github.com/jpillora/backoff v1.0.0/go.mod h1:J/6gKK9jxlEcS3zixgDgUAsiuZ7yrSoa/FX
 github.com/json-iterator/go v1.1.6/go.mod h1:+SdeFBvtyEkXs7REEP0seUULqWtbJapLOCVDaaPEHmU=
 github.com/json-iterator/go v1.1.10/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/uOdHXbAo4=
 github.com/json-iterator/go v1.1.11/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/uOdHXbAo4=
+github.com/json-iterator/go v1.1.12 h1:PV8peI4a0ysnczrg+LtxykD8LfKY9ML6u2jnxaEnrnM=
 github.com/json-iterator/go v1.1.12/go.mod h1:e30LSqwooZae/UwlEbR2852Gd8hjQvJoHmT4TnhNGBo=
 github.com/jstemmer/go-junit-report v0.0.0-20190106144839-af01ea7f8024/go.mod h1:6v2b51hI/fHJwM22ozAgKL4VKDeJcHhJFhtBdhmNjmU=
 github.com/jstemmer/go-junit-report v0.9.1/go.mod h1:Brl9GWCQeLvo8nXZwPNNblvFj/XSXhF0NWZEnDohbsk=
@@ -159,9 +160,11 @@ github.com/matttproud/golang_protobuf_extensions v1.0.1/go.mod h1:D8He9yQNgCq6Z5
 github.com/matttproud/golang_protobuf_extensions v1.0.4 h1:mmDVorXM7PCGKw94cs5zkfA9PSy5pEvNWRP0ET0TIVo=
 github.com/matttproud/golang_protobuf_extensions v1.0.4/go.mod h1:BSXmuO+STAnVfrANrmjBb36TMTDstsz7MSK+HVaYKv4=
 github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
+github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd h1:TRLaZ9cD/w8PVh93nsPXa1VrQ6jlwL5oN8l14QlcNfg=
 github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
 github.com/modern-go/reflect2 v0.0.0-20180701023420-4b7aa43c6742/go.mod h1:bx2lNnkwVCuqBIxFjflWJWanXIb3RllmbCylyMrvgv0=
 github.com/modern-go/reflect2 v1.0.1/go.mod h1:bx2lNnkwVCuqBIxFjflWJWanXIb3RllmbCylyMrvgv0=
+github.com/modern-go/reflect2 v1.0.2 h1:xBagoLtFs94CBntxluKeaWgTMpvLxC4ur3nMaC9Gz0M=
 github.com/modern-go/reflect2 v1.0.2/go.mod h1:yWuevngMOJpCy52FWWMvUC8ws7m/LJsjYzDa0/r8luk=
 github.com/mwitkow/go-conntrack v0.0.0-20161129095857-cc309e4a2223/go.mod h1:qRWi+5nqEBWmkhHvq77mSJWrCKwh8bxhgT7d/eI7P4U=
 github.com/mwitkow/go-conntrack v0.0.0-20190716064945-2f068394615f h1:KUppIJq7/+SVif2QVs3tOP0zanoHgBEVAwHxUSIzRqU=

model/value_histogram.go

@@ -18,8 +18,15 @@ import (
 	"fmt"
 	"strconv"
 	"strings"
+	"unsafe"
+
+	jsoniter "github.com/json-iterator/go"
 )
 
+func init() {
+	jsoniter.RegisterTypeEncoderFunc("model.HistogramBucket", marshalHistogramBucketJSON, marshalHistogramBucketJSONIsEmpty)
+}
+
 type FloatString float64
 
 func (v FloatString) String() string {
@@ -49,24 +56,14 @@ type HistogramBucket struct {
 	Count      FloatString
 }
 
-func (s HistogramBucket) MarshalJSON() ([]byte, error) {
-	b, err := json.Marshal(s.Boundaries)
-	if err != nil {
-		return nil, err
-	}
-	l, err := json.Marshal(s.Lower)
-	if err != nil {
-		return nil, err
-	}
-	u, err := json.Marshal(s.Upper)
-	if err != nil {
-		return nil, err
-	}
-	c, err := json.Marshal(s.Count)
-	if err != nil {
-		return nil, err
-	}
-	return []byte(fmt.Sprintf("[%s,%s,%s,%s]", b, l, u, c)), nil
+// marshalHistogramBucketJSON writes fmt.Sprintf("[%s,%s,%s,%s]", b.Boundaries, b.Lower, b.Upper, b.Count).
+func marshalHistogramBucketJSON(ptr unsafe.Pointer, stream *jsoniter.Stream) {
+	b := *((*HistogramBucket)(ptr))
+	MarshalHistogramBucket(b, stream)
+}
+
+func marshalHistogramBucketJSONIsEmpty(ptr unsafe.Pointer) bool {
+	return false
 }
 
 func (s *HistogramBucket) UnmarshalJSON(buf []byte) error {
@@ -140,14 +137,15 @@ type SampleHistogramPair struct {
 }
 
 func (s SampleHistogramPair) MarshalJSON() ([]byte, error) {
-	t, err := json.Marshal(s.Timestamp)
+	jsoni := jsoniter.ConfigCompatibleWithStandardLibrary
+	t, err := jsoni.Marshal(s.Timestamp)
 	if err != nil {
 		return nil, err
 	}
 	if s.Histogram == nil {
 		return nil, fmt.Errorf("histogram is nil")
 	}
-	v, err := json.Marshal(s.Histogram)
+	v, err := jsoni.Marshal(s.Histogram)
 	if err != nil {
 		return nil, err
 	}

model/value_marshal.go

@@ -0,0 +1,78 @@
+// Copyright 2013 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 model
+
+import (
+	"math"
+	"strconv"
+
+	jsoniter "github.com/json-iterator/go"
+)
+
+// from https://github.com/prometheus/prometheus/blob/main/util/jsonutil/marshal.go
+// MarshalTimestamp marshals a point timestamp using the passed jsoniter stream.
+func MarshalTimestamp(t int64, stream *jsoniter.Stream) {
+	// Write out the timestamp as a float divided by 1000.
+	// This is ~3x faster than converting to a float.
+	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)
+	}
+}
+
+// adapted from https://github.com/prometheus/prometheus/blob/main/util/jsonutil/marshal.go
+// MarshalValue marshals a point value using the passed jsoniter stream.
+func MarshalValue(f FloatString, stream *jsoniter.Stream) {
+	v := float64(f)
+	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(v)
+	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'
+		}
+	}
+	buf = strconv.AppendFloat(buf, v, fmt, -1, 64)
+	stream.SetBuffer(buf)
+	stream.WriteRaw(`"`)
+}
+
+// adapted from https://github.com/prometheus/prometheus/blob/main/web/api/v1/api.go
+func MarshalHistogramBucket(b HistogramBucket, stream *jsoniter.Stream) {
+	stream.WriteArrayStart()
+	stream.WriteInt32(b.Boundaries)
+	stream.WriteMore()
+	MarshalValue(b.Lower, stream)
+	stream.WriteMore()
+	MarshalValue(b.Upper, stream)
+	stream.WriteMore()
+	MarshalValue(b.Count, stream)
+	stream.WriteArrayEnd()
+}