prometheus/web/api/v1/json_codec.go

232 lines
6.1 KiB
Go

// Copyright 2016 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 (
"unsafe"
jsoniter "github.com/json-iterator/go"
"github.com/prometheus/prometheus/model/exemplar"
"github.com/prometheus/prometheus/model/labels"
"github.com/prometheus/prometheus/promql"
"github.com/prometheus/prometheus/util/jsonutil"
)
func init() {
jsoniter.RegisterTypeEncoderFunc("promql.Series", marshalSeriesJSON, marshalSeriesJSONIsEmpty)
jsoniter.RegisterTypeEncoderFunc("promql.Sample", marshalSampleJSON, marshalSampleJSONIsEmpty)
jsoniter.RegisterTypeEncoderFunc("promql.FPoint", marshalFPointJSON, marshalPointJSONIsEmpty)
jsoniter.RegisterTypeEncoderFunc("promql.HPoint", marshalHPointJSON, marshalPointJSONIsEmpty)
jsoniter.RegisterTypeEncoderFunc("exemplar.Exemplar", marshalExemplarJSON, marshalExemplarJSONEmpty)
jsoniter.RegisterTypeEncoderFunc("labels.Labels", unsafeMarshalLabelsJSON, labelsIsEmpty)
}
// JSONCodec is a Codec that encodes API responses as JSON.
type JSONCodec struct{}
func (j JSONCodec) ContentType() MIMEType {
return MIMEType{Type: "application", SubType: "json"}
}
func (j JSONCodec) CanEncode(_ *Response) bool {
return true
}
func (j JSONCodec) Encode(resp *Response) ([]byte, error) {
json := jsoniter.ConfigCompatibleWithStandardLibrary
return json.Marshal(resp)
}
// marshalSeriesJSON writes something like the following:
//
// {
// "metric" : {
// "__name__" : "up",
// "job" : "prometheus",
// "instance" : "localhost:9090"
// },
// "values": [
// [ 1435781451.781, "1" ],
// < more values>
// ],
// "histograms": [
// [ 1435781451.781, { < histogram, see jsonutil.MarshalHistogram > } ],
// < more histograms >
// ],
// },
func marshalSeriesJSON(ptr unsafe.Pointer, stream *jsoniter.Stream) {
s := *((*promql.Series)(ptr))
stream.WriteObjectStart()
stream.WriteObjectField(`metric`)
marshalLabelsJSON(s.Metric, stream)
for i, p := range s.Floats {
stream.WriteMore()
if i == 0 {
stream.WriteObjectField(`values`)
stream.WriteArrayStart()
}
marshalFPointJSON(unsafe.Pointer(&p), stream)
}
if len(s.Floats) > 0 {
stream.WriteArrayEnd()
}
for i, p := range s.Histograms {
stream.WriteMore()
if i == 0 {
stream.WriteObjectField(`histograms`)
stream.WriteArrayStart()
}
marshalHPointJSON(unsafe.Pointer(&p), stream)
}
if len(s.Histograms) > 0 {
stream.WriteArrayEnd()
}
stream.WriteObjectEnd()
}
func marshalSeriesJSONIsEmpty(unsafe.Pointer) bool {
return false
}
// marshalSampleJSON writes something like the following for normal value samples:
//
// {
// "metric" : {
// "__name__" : "up",
// "job" : "prometheus",
// "instance" : "localhost:9090"
// },
// "value": [ 1435781451.781, "1.234" ]
// },
//
// For histogram samples, it writes something like this:
//
// {
// "metric" : {
// "__name__" : "up",
// "job" : "prometheus",
// "instance" : "localhost:9090"
// },
// "histogram": [ 1435781451.781, { < histogram, see jsonutil.MarshalHistogram > } ]
// },
func marshalSampleJSON(ptr unsafe.Pointer, stream *jsoniter.Stream) {
s := *((*promql.Sample)(ptr))
stream.WriteObjectStart()
stream.WriteObjectField(`metric`)
marshalLabelsJSON(s.Metric, stream)
stream.WriteMore()
if s.H == nil {
stream.WriteObjectField(`value`)
} else {
stream.WriteObjectField(`histogram`)
}
stream.WriteArrayStart()
jsonutil.MarshalTimestamp(s.T, stream)
stream.WriteMore()
if s.H == nil {
jsonutil.MarshalFloat(s.F, stream)
} else {
jsonutil.MarshalHistogram(s.H, stream)
}
stream.WriteArrayEnd()
stream.WriteObjectEnd()
}
func marshalSampleJSONIsEmpty(unsafe.Pointer) bool {
return false
}
// marshalFPointJSON writes `[ts, "1.234"]`.
func marshalFPointJSON(ptr unsafe.Pointer, stream *jsoniter.Stream) {
p := *((*promql.FPoint)(ptr))
stream.WriteArrayStart()
jsonutil.MarshalTimestamp(p.T, stream)
stream.WriteMore()
jsonutil.MarshalFloat(p.F, stream)
stream.WriteArrayEnd()
}
// marshalHPointJSON writes `[ts, { < histogram, see jsonutil.MarshalHistogram > } ]`.
func marshalHPointJSON(ptr unsafe.Pointer, stream *jsoniter.Stream) {
p := *((*promql.HPoint)(ptr))
stream.WriteArrayStart()
jsonutil.MarshalTimestamp(p.T, stream)
stream.WriteMore()
jsonutil.MarshalHistogram(p.H, stream)
stream.WriteArrayEnd()
}
func marshalPointJSONIsEmpty(unsafe.Pointer) bool {
return false
}
// marshalExemplarJSON writes.
//
// {
// labels: <labels>,
// value: "<string>",
// timestamp: <float>
// }
func marshalExemplarJSON(ptr unsafe.Pointer, stream *jsoniter.Stream) {
p := *((*exemplar.Exemplar)(ptr))
stream.WriteObjectStart()
// "labels" key.
stream.WriteObjectField(`labels`)
marshalLabelsJSON(p.Labels, stream)
// "value" key.
stream.WriteMore()
stream.WriteObjectField(`value`)
jsonutil.MarshalFloat(p.Value, stream)
// "timestamp" key.
stream.WriteMore()
stream.WriteObjectField(`timestamp`)
jsonutil.MarshalTimestamp(p.Ts, stream)
stream.WriteObjectEnd()
}
func marshalExemplarJSONEmpty(unsafe.Pointer) bool {
return false
}
func unsafeMarshalLabelsJSON(ptr unsafe.Pointer, stream *jsoniter.Stream) {
labelsPtr := (*labels.Labels)(ptr)
marshalLabelsJSON(*labelsPtr, stream)
}
func marshalLabelsJSON(lbls labels.Labels, stream *jsoniter.Stream) {
stream.WriteObjectStart()
i := 0
lbls.Range(func(v labels.Label) {
if i != 0 {
stream.WriteMore()
}
i++
stream.WriteString(v.Name)
stream.WriteRaw(`:`)
stream.WriteString(v.Value)
})
stream.WriteObjectEnd()
}
func labelsIsEmpty(ptr unsafe.Pointer) bool {
labelsPtr := (*labels.Labels)(ptr)
return labelsPtr.IsEmpty()
}