1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
|
// 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
}
// Closer is implemented by Encoders that need to be closed to finalize
// encoding. (For example, OpenMetrics needs a final `# EOF` line.)
//
// Note that all Encoder implementations returned from this package implement
// Closer, too, even if the Close call is a no-op. This happens in preparation
// for adding a Close method to the Encoder interface directly in a (mildly
// breaking) release in the future.
type Closer interface {
Close() error
}
type encoderCloser struct {
encode func(*dto.MetricFamily) error
close func() error
}
func (ec encoderCloser) Encode(v *dto.MetricFamily) error {
return ec.encode(v)
}
func (ec encoderCloser) Close() error {
return ec.close()
}
// Negotiate returns the Content-Type based on the given Accept header. If no
// appropriate accepted type is found, FmtText is returned (which is the
// Prometheus text format). This function will never negotiate FmtOpenMetrics,
// as the support is still experimental. To include the option to negotiate
// FmtOpenMetrics, use NegotiateOpenMetrics.
func Negotiate(h http.Header) Format {
for _, ac := range goautoneg.ParseAccept(h.Get(hdrAccept)) {
ver := ac.Params["version"]
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
}
}
if ac.Type == "text" && ac.SubType == "plain" && (ver == TextVersion || ver == "") {
return FmtText
}
}
return FmtText
}
// NegotiateIncludingOpenMetrics works like Negotiate but includes
// FmtOpenMetrics as an option for the result. Note that this function is
// temporary and will disappear once FmtOpenMetrics is fully supported and as
// such may be negotiated by the normal Negotiate function.
func NegotiateIncludingOpenMetrics(h http.Header) Format {
for _, ac := range goautoneg.ParseAccept(h.Get(hdrAccept)) {
ver := ac.Params["version"]
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
}
}
if ac.Type == "text" && ac.SubType == "plain" && (ver == TextVersion || ver == "") {
return FmtText
}
if ac.Type+"/"+ac.SubType == OpenMetricsType && (ver == OpenMetricsVersion || ver == "") {
return FmtOpenMetrics
}
}
return FmtText
}
// NewEncoder returns a new encoder based on content type negotiation. All
// Encoder implementations returned by NewEncoder also implement Closer, and
// callers should always call the Close method. It is currently only required
// for FmtOpenMetrics, but a future (breaking) release will add the Close method
// to the Encoder interface directly. The current version of the Encoder
// interface is kept for backwards compatibility.
func NewEncoder(w io.Writer, format Format) Encoder {
switch format {
case FmtProtoDelim:
return encoderCloser{
encode: func(v *dto.MetricFamily) error {
_, err := pbutil.WriteDelimited(w, v)
return err
},
close: func() error { return nil },
}
case FmtProtoCompact:
return encoderCloser{
encode: func(v *dto.MetricFamily) error {
_, err := fmt.Fprintln(w, v.String())
return err
},
close: func() error { return nil },
}
case FmtProtoText:
return encoderCloser{
encode: func(v *dto.MetricFamily) error {
_, err := fmt.Fprintln(w, proto.MarshalTextString(v))
return err
},
close: func() error { return nil },
}
case FmtText:
return encoderCloser{
encode: func(v *dto.MetricFamily) error {
_, err := MetricFamilyToText(w, v)
return err
},
close: func() error { return nil },
}
case FmtOpenMetrics:
return encoderCloser{
encode: func(v *dto.MetricFamily) error {
_, err := MetricFamilyToOpenMetrics(w, v)
return err
},
close: func() error {
_, err := FinalizeOpenMetrics(w)
return err
},
}
}
panic(fmt.Errorf("expfmt.NewEncoder: unknown format %q", format))
}
|
