89 lines
2.5 KiB
Go
89 lines
2.5 KiB
Go
// Copyright 2015 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 expfmt
|
|
|
|
import (
|
|
"fmt"
|
|
"io"
|
|
"net/http"
|
|
|
|
"github.com/golang/protobuf/proto"
|
|
"github.com/matttproud/golang_protobuf_extensions/pbutil"
|
|
"github.com/prometheus/common/internal/bitbucket.org/ww/goautoneg"
|
|
|
|
dto "github.com/prometheus/client_model/go"
|
|
)
|
|
|
|
// Encoder types encode metric families into an underlying wire protocol.
|
|
type Encoder interface {
|
|
Encode(*dto.MetricFamily) error
|
|
}
|
|
|
|
type encoder func(*dto.MetricFamily) error
|
|
|
|
func (e encoder) Encode(v *dto.MetricFamily) error {
|
|
return e(v)
|
|
}
|
|
|
|
// Negotiate returns the Content-Type based on the given Accept header.
|
|
// If no appropriate accepted type is found, FmtText is returned.
|
|
func Negotiate(h http.Header) Format {
|
|
for _, ac := range goautoneg.ParseAccept(h.Get(hdrAccept)) {
|
|
// Check for protocol buffer
|
|
if ac.Type+"/"+ac.SubType == ProtoType && ac.Params["proto"] == ProtoProtocol {
|
|
switch ac.Params["encoding"] {
|
|
case "delimited":
|
|
return FmtProtoDelim
|
|
case "text":
|
|
return FmtProtoText
|
|
case "compact-text":
|
|
return FmtProtoCompact
|
|
}
|
|
}
|
|
// Check for text format.
|
|
ver := ac.Params["version"]
|
|
if ac.Type == "text" && ac.SubType == "plain" && (ver == TextVersion || ver == "") {
|
|
return FmtText
|
|
}
|
|
}
|
|
return FmtText
|
|
}
|
|
|
|
// NewEncoder returns a new encoder based on content type negotiation.
|
|
func NewEncoder(w io.Writer, format Format) Encoder {
|
|
switch format {
|
|
case FmtProtoDelim:
|
|
return encoder(func(v *dto.MetricFamily) error {
|
|
_, err := pbutil.WriteDelimited(w, v)
|
|
return err
|
|
})
|
|
case FmtProtoCompact:
|
|
return encoder(func(v *dto.MetricFamily) error {
|
|
_, err := fmt.Fprintln(w, v.String())
|
|
return err
|
|
})
|
|
case FmtProtoText:
|
|
return encoder(func(v *dto.MetricFamily) error {
|
|
_, err := fmt.Fprintln(w, proto.MarshalTextString(v))
|
|
return err
|
|
})
|
|
case FmtText:
|
|
return encoder(func(v *dto.MetricFamily) error {
|
|
_, err := MetricFamilyToText(w, v)
|
|
return err
|
|
})
|
|
}
|
|
panic("expfmt.NewEncoder: unknown format")
|
|
}
|