VictoriaMetrics/vendor/github.com/prometheus/common/model/value_marshal.go
2023-02-21 18:07:26 -08:00

132 lines
3.6 KiB
Go

// 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"
"unsafe"
jsoniter "github.com/json-iterator/go"
)
func marshalJSONIsEmpty(ptr unsafe.Pointer) bool {
return false
}
// 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)
}
}
// MarshalValue marshals a point value using the passed jsoniter stream.
func MarshalValue(v float64, stream *jsoniter.Stream) {
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(`"`)
}
// MarshalHistogramBucket writes something like: [ 3, "-0.25", "0.25", "3"]
// See MarshalHistogram to understand what the numbers mean
func MarshalHistogramBucket(b HistogramBucket, stream *jsoniter.Stream) {
stream.WriteArrayStart()
stream.WriteInt32(b.Boundaries)
stream.WriteMore()
MarshalValue(float64(b.Lower), stream)
stream.WriteMore()
MarshalValue(float64(b.Upper), stream)
stream.WriteMore()
MarshalValue(float64(b.Count), stream)
stream.WriteArrayEnd()
}
// MarshalHistogram writes something like:
//
// {
// "count": "42",
// "sum": "34593.34",
// "buckets": [
// [ 3, "-0.25", "0.25", "3"],
// [ 0, "0.25", "0.5", "12"],
// [ 0, "0.5", "1", "21"],
// [ 0, "2", "4", "6"]
// ]
// }
//
// The 1st element in each bucket array determines if the boundaries are
// inclusive (AKA closed) or exclusive (AKA open):
//
// 0: lower exclusive, upper inclusive
// 1: lower inclusive, upper exclusive
// 2: both exclusive
// 3: both inclusive
//
// The 2nd and 3rd elements are the lower and upper boundary. The 4th element is
// the bucket count.
func MarshalHistogram(h SampleHistogram, stream *jsoniter.Stream) {
stream.WriteObjectStart()
stream.WriteObjectField(`count`)
MarshalValue(float64(h.Count), stream)
stream.WriteMore()
stream.WriteObjectField(`sum`)
MarshalValue(float64(h.Sum), stream)
bucketFound := false
for _, bucket := range h.Buckets {
if bucket.Count == 0 {
continue // No need to expose empty buckets in JSON.
}
stream.WriteMore()
if !bucketFound {
stream.WriteObjectField(`buckets`)
stream.WriteArrayStart()
}
bucketFound = true
MarshalHistogramBucket(*bucket, stream)
}
if bucketFound {
stream.WriteArrayEnd()
}
stream.WriteObjectEnd()
}