-
Notifications
You must be signed in to change notification settings - Fork 1.2k
/
push.go
356 lines (326 loc) · 11.7 KB
/
push.go
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
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
// 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 push provides functions to push metrics to a Pushgateway. It uses a
// builder approach. Create a Pusher with New and then add the various options
// by using its methods, finally calling Add or Push, like this:
//
// // Easy case:
// push.New("http://example.org/metrics", "my_job").Gatherer(myRegistry).Push()
//
// // Complex case:
// push.New("http://example.org/metrics", "my_job").
// Collector(myCollector1).
// Collector(myCollector2).
// Grouping("zone", "xy").
// Client(&myHTTPClient).
// BasicAuth("top", "secret").
// Add()
//
// See the examples section for more detailed examples.
//
// See the documentation of the Pushgateway to understand the meaning of
// the grouping key and the differences between Push and Add:
// https://github.com/prometheus/pushgateway
package push
import (
"bytes"
"context"
"encoding/base64"
"errors"
"fmt"
"io"
"net/http"
"net/url"
"strings"
"github.com/prometheus/common/expfmt"
"github.com/prometheus/common/model"
"github.com/prometheus/client_golang/prometheus"
)
const (
contentTypeHeader = "Content-Type"
// base64Suffix is appended to a label name in the request URL path to
// mark the following label value as base64 encoded.
base64Suffix = "@base64"
)
var errJobEmpty = errors.New("job name is empty")
// HTTPDoer is an interface for the one method of http.Client that is used by Pusher
type HTTPDoer interface {
Do(*http.Request) (*http.Response, error)
}
// Pusher manages a push to the Pushgateway. Use New to create one, configure it
// with its methods, and finally use the Add or Push method to push.
type Pusher struct {
error error
url, job string
grouping map[string]string
gatherers prometheus.Gatherers
registerer prometheus.Registerer
client HTTPDoer
header http.Header
useBasicAuth bool
username, password string
expfmt expfmt.Format
}
// New creates a new Pusher to push to the provided URL with the provided job
// name (which must not be empty). You can use just host:port or ip:port as url,
// in which case “http://” is added automatically. Alternatively, include the
// schema in the URL. However, do not include the “/metrics/jobs/…” part.
func New(url, job string) *Pusher {
var (
reg = prometheus.NewRegistry()
err error
)
if job == "" {
err = errJobEmpty
}
if !strings.Contains(url, "://") {
url = "http://" + url
}
url = strings.TrimSuffix(url, "/")
return &Pusher{
error: err,
url: url,
job: job,
grouping: map[string]string{},
gatherers: prometheus.Gatherers{reg},
registerer: reg,
client: &http.Client{},
expfmt: expfmt.NewFormat(expfmt.TypeProtoDelim),
}
}
// Push collects/gathers all metrics from all Collectors and Gatherers added to
// this Pusher. Then, it pushes them to the Pushgateway configured while
// creating this Pusher, using the configured job name and any added grouping
// labels as grouping key. All previously pushed metrics with the same job and
// other grouping labels will be replaced with the metrics pushed by this
// call. (It uses HTTP method “PUT” to push to the Pushgateway.)
//
// Push returns the first error encountered by any method call (including this
// one) in the lifetime of the Pusher.
func (p *Pusher) Push() error {
return p.push(context.Background(), http.MethodPut)
}
// PushContext is like Push but includes a context.
//
// If the context expires before HTTP request is complete, an error is returned.
func (p *Pusher) PushContext(ctx context.Context) error {
return p.push(ctx, http.MethodPut)
}
// Add works like push, but only previously pushed metrics with the same name
// (and the same job and other grouping labels) will be replaced. (It uses HTTP
// method “POST” to push to the Pushgateway.)
func (p *Pusher) Add() error {
return p.push(context.Background(), http.MethodPost)
}
// AddContext is like Add but includes a context.
//
// If the context expires before HTTP request is complete, an error is returned.
func (p *Pusher) AddContext(ctx context.Context) error {
return p.push(ctx, http.MethodPost)
}
// Gatherer adds a Gatherer to the Pusher, from which metrics will be gathered
// to push them to the Pushgateway. The gathered metrics must not contain a job
// label of their own.
//
// For convenience, this method returns a pointer to the Pusher itself.
func (p *Pusher) Gatherer(g prometheus.Gatherer) *Pusher {
p.gatherers = append(p.gatherers, g)
return p
}
// Collector adds a Collector to the Pusher, from which metrics will be
// collected to push them to the Pushgateway. The collected metrics must not
// contain a job label of their own.
//
// For convenience, this method returns a pointer to the Pusher itself.
func (p *Pusher) Collector(c prometheus.Collector) *Pusher {
if p.error == nil {
p.error = p.registerer.Register(c)
}
return p
}
// Error returns the error that was encountered.
func (p *Pusher) Error() error {
return p.error
}
// Grouping adds a label pair to the grouping key of the Pusher, replacing any
// previously added label pair with the same label name. Note that setting any
// labels in the grouping key that are already contained in the metrics to push
// will lead to an error.
//
// For convenience, this method returns a pointer to the Pusher itself.
func (p *Pusher) Grouping(name, value string) *Pusher {
if p.error == nil {
if !model.LabelName(name).IsValid() {
p.error = fmt.Errorf("grouping label has invalid name: %s", name)
return p
}
p.grouping[name] = value
}
return p
}
// Client sets a custom HTTP client for the Pusher. For convenience, this method
// returns a pointer to the Pusher itself.
// Pusher only needs one method of the custom HTTP client: Do(*http.Request).
// Thus, rather than requiring a fully fledged http.Client,
// the provided client only needs to implement the HTTPDoer interface.
// Since *http.Client naturally implements that interface, it can still be used normally.
func (p *Pusher) Client(c HTTPDoer) *Pusher {
p.client = c
return p
}
// Header sets a custom HTTP header for the Pusher's client. For convenience, this method
// returns a pointer to the Pusher itself.
func (p *Pusher) Header(header http.Header) *Pusher {
p.header = header
return p
}
// BasicAuth configures the Pusher to use HTTP Basic Authentication with the
// provided username and password. For convenience, this method returns a
// pointer to the Pusher itself.
func (p *Pusher) BasicAuth(username, password string) *Pusher {
p.useBasicAuth = true
p.username = username
p.password = password
return p
}
// Format configures the Pusher to use an encoding format given by the
// provided expfmt.Format. The default format is expfmt.FmtProtoDelim and
// should be used with the standard Prometheus Pushgateway. Custom
// implementations may require different formats. For convenience, this
// method returns a pointer to the Pusher itself.
func (p *Pusher) Format(format expfmt.Format) *Pusher {
p.expfmt = format
return p
}
// Delete sends a “DELETE” request to the Pushgateway configured while creating
// this Pusher, using the configured job name and any added grouping labels as
// grouping key. Any added Gatherers and Collectors added to this Pusher are
// ignored by this method.
//
// Delete returns the first error encountered by any method call (including this
// one) in the lifetime of the Pusher.
func (p *Pusher) Delete() error {
if p.error != nil {
return p.error
}
req, err := http.NewRequest(http.MethodDelete, p.fullURL(), nil)
if err != nil {
return err
}
if p.header != nil {
req.Header = p.header
}
if p.useBasicAuth {
req.SetBasicAuth(p.username, p.password)
}
resp, err := p.client.Do(req)
if err != nil {
return err
}
defer resp.Body.Close()
if resp.StatusCode != http.StatusAccepted {
body, _ := io.ReadAll(resp.Body) // Ignore any further error as this is for an error message only.
return fmt.Errorf("unexpected status code %d while deleting %s: %s", resp.StatusCode, p.fullURL(), body)
}
return nil
}
func (p *Pusher) push(ctx context.Context, method string) error {
if p.error != nil {
return p.error
}
mfs, err := p.gatherers.Gather()
if err != nil {
return err
}
buf := &bytes.Buffer{}
enc := expfmt.NewEncoder(buf, p.expfmt)
// Check for pre-existing grouping labels:
for _, mf := range mfs {
for _, m := range mf.GetMetric() {
for _, l := range m.GetLabel() {
if l.GetName() == "job" {
return fmt.Errorf("pushed metric %s (%s) already contains a job label", mf.GetName(), m)
}
if _, ok := p.grouping[l.GetName()]; ok {
return fmt.Errorf(
"pushed metric %s (%s) already contains grouping label %s",
mf.GetName(), m, l.GetName(),
)
}
}
}
if err := enc.Encode(mf); err != nil {
return fmt.Errorf(
"failed to encode metric family %s, error is %w",
mf.GetName(), err)
}
}
req, err := http.NewRequestWithContext(ctx, method, p.fullURL(), buf)
if err != nil {
return err
}
if p.header != nil {
req.Header = p.header
}
if p.useBasicAuth {
req.SetBasicAuth(p.username, p.password)
}
req.Header.Set(contentTypeHeader, string(p.expfmt))
resp, err := p.client.Do(req)
if err != nil {
return err
}
defer resp.Body.Close()
// Depending on version and configuration of the PGW, StatusOK or StatusAccepted may be returned.
if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusAccepted {
body, _ := io.ReadAll(resp.Body) // Ignore any further error as this is for an error message only.
return fmt.Errorf("unexpected status code %d while pushing to %s: %s", resp.StatusCode, p.fullURL(), body)
}
return nil
}
// fullURL assembles the URL used to push/delete metrics and returns it as a
// string. The job name and any grouping label values containing a '/' will
// trigger a base64 encoding of the affected component and proper suffixing of
// the preceding component. Similarly, an empty grouping label value will be
// encoded as base64 just with a single `=` padding character (to avoid an empty
// path component). If the component does not contain a '/' but other special
// characters, the usual url.QueryEscape is used for compatibility with older
// versions of the Pushgateway and for better readability.
func (p *Pusher) fullURL() string {
urlComponents := []string{}
if encodedJob, base64 := encodeComponent(p.job); base64 {
urlComponents = append(urlComponents, "job"+base64Suffix, encodedJob)
} else {
urlComponents = append(urlComponents, "job", encodedJob)
}
for ln, lv := range p.grouping {
if encodedLV, base64 := encodeComponent(lv); base64 {
urlComponents = append(urlComponents, ln+base64Suffix, encodedLV)
} else {
urlComponents = append(urlComponents, ln, encodedLV)
}
}
return fmt.Sprintf("%s/metrics/%s", p.url, strings.Join(urlComponents, "/"))
}
// encodeComponent encodes the provided string with base64.RawURLEncoding in
// case it contains '/' and as "=" in case it is empty. If neither is the case,
// it uses url.QueryEscape instead. It returns true in the former two cases.
func encodeComponent(s string) (string, bool) {
if s == "" {
return "=", true
}
if strings.Contains(s, "/") {
return base64.RawURLEncoding.EncodeToString([]byte(s)), true
}
return url.QueryEscape(s), false
}