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
|
// SPDX-License-Identifier: GPL-3.0-or-later
package prometheus
import (
"bufio"
"bytes"
"compress/gzip"
"fmt"
"io"
"net/http"
"net/url"
"os"
"path/filepath"
"github.com/netdata/netdata/go/go.d.plugin/pkg/prometheus/selector"
"github.com/netdata/netdata/go/go.d.plugin/pkg/web"
)
type (
// Prometheus is a helper for scrape and parse prometheus format metrics.
Prometheus interface {
// ScrapeSeries and parse prometheus format metrics
ScrapeSeries() (Series, error)
Scrape() (MetricFamilies, error)
HTTPClient() *http.Client
}
prometheus struct {
client *http.Client
request web.Request
filepath string
sr selector.Selector
parser promTextParser
buf *bytes.Buffer
gzipr *gzip.Reader
bodyBuf *bufio.Reader
}
)
const (
acceptHeader = `text/plain;version=0.0.4;q=1,*/*;q=0.1`
userAgentHeader = `netdata/go.d.plugin`
)
// New creates a Prometheus instance.
func New(client *http.Client, request web.Request) Prometheus {
return &prometheus{
client: client,
request: request,
buf: bytes.NewBuffer(make([]byte, 0, 16000)),
}
}
// NewWithSelector creates a Prometheus instance with the selector.
func NewWithSelector(client *http.Client, request web.Request, sr selector.Selector) Prometheus {
p := &prometheus{
client: client,
request: request,
sr: sr,
buf: bytes.NewBuffer(make([]byte, 0, 16000)),
parser: promTextParser{sr: sr},
}
if v, err := url.Parse(request.URL); err == nil && v.Scheme == "file" {
p.filepath = filepath.Join(v.Host, v.Path)
}
return p
}
func (p *prometheus) HTTPClient() *http.Client {
return p.client
}
// ScrapeSeries scrapes metrics, parses and sorts
func (p *prometheus) ScrapeSeries() (Series, error) {
p.buf.Reset()
if err := p.fetch(p.buf); err != nil {
return nil, err
}
return p.parser.parseToSeries(p.buf.Bytes())
}
func (p *prometheus) Scrape() (MetricFamilies, error) {
p.buf.Reset()
if err := p.fetch(p.buf); err != nil {
return nil, err
}
return p.parser.parseToMetricFamilies(p.buf.Bytes())
}
func (p *prometheus) fetch(w io.Writer) error {
// TODO: should be a separate text file prom client
if p.filepath != "" {
f, err := os.Open(p.filepath)
if err != nil {
return err
}
defer f.Close()
_, err = io.Copy(w, f)
return err
}
req, err := web.NewHTTPRequest(p.request)
if err != nil {
return err
}
req.Header.Add("Accept", acceptHeader)
req.Header.Add("Accept-Encoding", "gzip")
req.Header.Set("User-Agent", userAgentHeader)
resp, err := p.client.Do(req)
if err != nil {
return err
}
defer func() {
_, _ = io.Copy(io.Discard, resp.Body)
_ = resp.Body.Close()
}()
if resp.StatusCode != http.StatusOK {
return fmt.Errorf("server '%s' returned HTTP status code %d (%s)", req.URL, resp.StatusCode, resp.Status)
}
if resp.Header.Get("Content-Encoding") != "gzip" {
_, err = io.Copy(w, resp.Body)
return err
}
if p.gzipr == nil {
p.bodyBuf = bufio.NewReader(resp.Body)
p.gzipr, err = gzip.NewReader(p.bodyBuf)
if err != nil {
return err
}
} else {
p.bodyBuf.Reset(resp.Body)
_ = p.gzipr.Reset(p.bodyBuf)
}
_, err = io.Copy(w, p.gzipr)
_ = p.gzipr.Close()
return err
}
|
