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Commit ed8bc523 authored by Kevin Lyda's avatar Kevin Lyda :speech_balloon: Committed by Niall Sheridan
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Initial pass at prometheus support. (#56)

parent 9c344a0a
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with 3580 additions and 3 deletions
......@@ -5,5 +5,5 @@ tmp
/cashier
/cashierd
signing_key
signing_key*
http.log
......@@ -33,12 +33,14 @@ import (
"github.com/nsheridan/cashier/server/auth/gitlab"
"github.com/nsheridan/cashier/server/auth/google"
"github.com/nsheridan/cashier/server/config"
"github.com/nsheridan/cashier/server/metrics"
"github.com/nsheridan/cashier/server/signer"
"github.com/nsheridan/cashier/server/static"
"github.com/nsheridan/cashier/server/store"
"github.com/nsheridan/cashier/server/templates"
"github.com/nsheridan/cashier/server/wkfs/vaultfs"
"github.com/nsheridan/wkfs/s3"
"github.com/prometheus/client_golang/prometheus/promhttp"
"github.com/sid77/drop"
)
......@@ -374,6 +376,8 @@ func main() {
}
// Unprivileged section
metrics.Register()
var authprovider auth.Provider
switch conf.Auth.Provider {
case "google":
......@@ -416,6 +420,7 @@ func main() {
r.Methods("POST").Path("/admin/revoke").Handler(CSRF(appHandler{ctx, revokeCertHandler}))
r.Methods("GET").Path("/admin/certs").Handler(CSRF(appHandler{ctx, listAllCertsHandler}))
r.Methods("GET").Path("/admin/certs.json").Handler(appHandler{ctx, listCertsJSONHandler})
r.Methods("GET").Path("/metrics").Handler(promhttp.Handler())
r.PathPrefix("/").Handler(http.FileServer(static.FS(false)))
h := handlers.LoggingHandler(logfile, r)
......
......
......@@ -7,6 +7,7 @@ import (
"github.com/nsheridan/cashier/server/auth"
"github.com/nsheridan/cashier/server/config"
"github.com/nsheridan/cashier/server/metrics"
githubapi "github.com/google/go-github/github"
"golang.org/x/oauth2"
......@@ -73,6 +74,7 @@ func (c *Config) Valid(token *oauth2.Token) bool {
if c.organization == "" {
// There's no organization and the token is valid. Can only reach here
// if there's a user whitelist set and the user is in the whitelist.
metrics.M.AuthValid.WithLabelValues("github").Inc()
return true
}
client := githubapi.NewClient(c.newClient(token))
......@@ -80,6 +82,9 @@ func (c *Config) Valid(token *oauth2.Token) bool {
if err != nil {
return false
}
if member {
metrics.M.AuthValid.WithLabelValues("github").Inc()
}
return member
}
......@@ -108,6 +113,7 @@ func (c *Config) Exchange(code string) (*oauth2.Token, error) {
if t.Expiry.Unix() <= 0 {
t.Expiry = time.Now().Add(1 * time.Hour)
}
metrics.M.AuthExchange.WithLabelValues("github").Inc()
return t, nil
}
......
......
......@@ -6,6 +6,7 @@ import (
"github.com/nsheridan/cashier/server/auth"
"github.com/nsheridan/cashier/server/config"
"github.com/nsheridan/cashier/server/metrics"
gitlabapi "github.com/xanzy/go-gitlab"
"golang.org/x/oauth2"
......@@ -78,6 +79,7 @@ func (c *Config) Valid(token *oauth2.Token) bool {
return false
}
if c.allusers {
metrics.M.AuthValid.WithLabelValues("gitlab").Inc()
return true
}
if len(c.whitelist) > 0 && !c.whitelist[c.Username(token)] {
......@@ -86,6 +88,7 @@ func (c *Config) Valid(token *oauth2.Token) bool {
if c.group == "" {
// There's no group and token is valid. Can only reach
// here if user whitelist is set and user is in whitelist.
metrics.M.AuthValid.WithLabelValues("gitlab").Inc()
return true
}
client := gitlabapi.NewOAuthClient(nil, token.AccessToken)
......@@ -96,6 +99,7 @@ func (c *Config) Valid(token *oauth2.Token) bool {
}
for _, g := range groups {
if g.Path == c.group {
metrics.M.AuthValid.WithLabelValues("gitlab").Inc()
return true
}
}
......@@ -118,7 +122,11 @@ func (c *Config) StartSession(state string) *auth.Session {
// Exchange authorizes the session and returns an access token.
func (c *Config) Exchange(code string) (*oauth2.Token, error) {
return c.config.Exchange(oauth2.NoContext, code)
t, err := c.config.Exchange(oauth2.NoContext, code)
if err == nil {
metrics.M.AuthExchange.WithLabelValues("gitlab").Inc()
}
return t, err
}
// Username retrieves the username of the Gitlab user.
......
......
......@@ -8,6 +8,7 @@ import (
"github.com/nsheridan/cashier/server/auth"
"github.com/nsheridan/cashier/server/config"
"github.com/nsheridan/cashier/server/metrics"
"golang.org/x/oauth2"
"golang.org/x/oauth2/google"
......@@ -90,6 +91,7 @@ func (c *Config) Valid(token *oauth2.Token) bool {
if c.domain != "" && ui.Hd != c.domain {
return false
}
metrics.M.AuthValid.WithLabelValues("google").Inc()
return true
}
......@@ -109,7 +111,11 @@ func (c *Config) StartSession(state string) *auth.Session {
// Exchange authorizes the session and returns an access token.
func (c *Config) Exchange(code string) (*oauth2.Token, error) {
return c.config.Exchange(oauth2.NoContext, code)
t, err := c.config.Exchange(oauth2.NoContext, code)
if err == nil {
metrics.M.AuthExchange.WithLabelValues("google").Inc()
}
return t, err
}
// Email retrieves the email address of the user.
......
......
package metrics
import (
"github.com/prometheus/client_golang/prometheus"
)
// Metrics collects the metrics.
type Metrics struct {
AuthValid,
AuthExchange,
Errs *prometheus.CounterVec
}
// M structure to collect all metrics together.
var M Metrics
// Register metrics and metrics page.
func Register() {
M = Metrics{
AuthValid: prometheus.NewCounterVec(prometheus.CounterOpts{
Namespace: "cashier",
Subsystem: "auth",
Name: "valid_total",
Help: "Auth Valid calls",
}, []string{"module"}),
AuthExchange: prometheus.NewCounterVec(prometheus.CounterOpts{
Namespace: "cashier",
Subsystem: "auth",
Name: "exchange_total",
Help: "Auth Exchange calls",
}, []string{"module"}),
Errs: prometheus.NewCounterVec(prometheus.CounterOpts{
Namespace: "cashier",
Subsystem: "sys",
Name: "error_total",
Help: "Error counts by module",
}, []string{"module"}),
}
prometheus.MustRegister(M.Errs)
prometheus.MustRegister(M.AuthValid)
prometheus.MustRegister(M.AuthExchange)
}
Copyright (C) 2013 Blake Mizerany
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:
The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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// Package quantile computes approximate quantiles over an unbounded data
// stream within low memory and CPU bounds.
//
// A small amount of accuracy is traded to achieve the above properties.
//
// Multiple streams can be merged before calling Query to generate a single set
// of results. This is meaningful when the streams represent the same type of
// data. See Merge and Samples.
//
// For more detailed information about the algorithm used, see:
//
// Effective Computation of Biased Quantiles over Data Streams
//
// http://www.cs.rutgers.edu/~muthu/bquant.pdf
package quantile
import (
"math"
"sort"
)
// Sample holds an observed value and meta information for compression. JSON
// tags have been added for convenience.
type Sample struct {
Value float64 `json:",string"`
Width float64 `json:",string"`
Delta float64 `json:",string"`
}
// Samples represents a slice of samples. It implements sort.Interface.
type Samples []Sample
func (a Samples) Len() int { return len(a) }
func (a Samples) Less(i, j int) bool { return a[i].Value < a[j].Value }
func (a Samples) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
type invariant func(s *stream, r float64) float64
// NewLowBiased returns an initialized Stream for low-biased quantiles
// (e.g. 0.01, 0.1, 0.5) where the needed quantiles are not known a priori, but
// error guarantees can still be given even for the lower ranks of the data
// distribution.
//
// The provided epsilon is a relative error, i.e. the true quantile of a value
// returned by a query is guaranteed to be within (1±Epsilon)*Quantile.
//
// See http://www.cs.rutgers.edu/~muthu/bquant.pdf for time, space, and error
// properties.
func NewLowBiased(epsilon float64) *Stream {
ƒ := func(s *stream, r float64) float64 {
return 2 * epsilon * r
}
return newStream(ƒ)
}
// NewHighBiased returns an initialized Stream for high-biased quantiles
// (e.g. 0.01, 0.1, 0.5) where the needed quantiles are not known a priori, but
// error guarantees can still be given even for the higher ranks of the data
// distribution.
//
// The provided epsilon is a relative error, i.e. the true quantile of a value
// returned by a query is guaranteed to be within 1-(1±Epsilon)*(1-Quantile).
//
// See http://www.cs.rutgers.edu/~muthu/bquant.pdf for time, space, and error
// properties.
func NewHighBiased(epsilon float64) *Stream {
ƒ := func(s *stream, r float64) float64 {
return 2 * epsilon * (s.n - r)
}
return newStream(ƒ)
}
// NewTargeted returns an initialized Stream concerned with a particular set of
// quantile values that are supplied a priori. Knowing these a priori reduces
// space and computation time. The targets map maps the desired quantiles to
// their absolute errors, i.e. the true quantile of a value returned by a query
// is guaranteed to be within (Quantile±Epsilon).
//
// See http://www.cs.rutgers.edu/~muthu/bquant.pdf for time, space, and error properties.
func NewTargeted(targets map[float64]float64) *Stream {
ƒ := func(s *stream, r float64) float64 {
var m = math.MaxFloat64
var f float64
for quantile, epsilon := range targets {
if quantile*s.n <= r {
f = (2 * epsilon * r) / quantile
} else {
f = (2 * epsilon * (s.n - r)) / (1 - quantile)
}
if f < m {
m = f
}
}
return m
}
return newStream(ƒ)
}
// Stream computes quantiles for a stream of float64s. It is not thread-safe by
// design. Take care when using across multiple goroutines.
type Stream struct {
*stream
b Samples
sorted bool
}
func newStream(ƒ invariant) *Stream {
x := &stream{ƒ: ƒ}
return &Stream{x, make(Samples, 0, 500), true}
}
// Insert inserts v into the stream.
func (s *Stream) Insert(v float64) {
s.insert(Sample{Value: v, Width: 1})
}
func (s *Stream) insert(sample Sample) {
s.b = append(s.b, sample)
s.sorted = false
if len(s.b) == cap(s.b) {
s.flush()
}
}
// Query returns the computed qth percentiles value. If s was created with
// NewTargeted, and q is not in the set of quantiles provided a priori, Query
// will return an unspecified result.
func (s *Stream) Query(q float64) float64 {
if !s.flushed() {
// Fast path when there hasn't been enough data for a flush;
// this also yields better accuracy for small sets of data.
l := len(s.b)
if l == 0 {
return 0
}
i := int(math.Ceil(float64(l) * q))
if i > 0 {
i -= 1
}
s.maybeSort()
return s.b[i].Value
}
s.flush()
return s.stream.query(q)
}
// Merge merges samples into the underlying streams samples. This is handy when
// merging multiple streams from separate threads, database shards, etc.
//
// ATTENTION: This method is broken and does not yield correct results. The
// underlying algorithm is not capable of merging streams correctly.
func (s *Stream) Merge(samples Samples) {
sort.Sort(samples)
s.stream.merge(samples)
}
// Reset reinitializes and clears the list reusing the samples buffer memory.
func (s *Stream) Reset() {
s.stream.reset()
s.b = s.b[:0]
}
// Samples returns stream samples held by s.
func (s *Stream) Samples() Samples {
if !s.flushed() {
return s.b
}
s.flush()
return s.stream.samples()
}
// Count returns the total number of samples observed in the stream
// since initialization.
func (s *Stream) Count() int {
return len(s.b) + s.stream.count()
}
func (s *Stream) flush() {
s.maybeSort()
s.stream.merge(s.b)
s.b = s.b[:0]
}
func (s *Stream) maybeSort() {
if !s.sorted {
s.sorted = true
sort.Sort(s.b)
}
}
func (s *Stream) flushed() bool {
return len(s.stream.l) > 0
}
type stream struct {
n float64
l []Sample
ƒ invariant
}
func (s *stream) reset() {
s.l = s.l[:0]
s.n = 0
}
func (s *stream) insert(v float64) {
s.merge(Samples{{v, 1, 0}})
}
func (s *stream) merge(samples Samples) {
// TODO(beorn7): This tries to merge not only individual samples, but
// whole summaries. The paper doesn't mention merging summaries at
// all. Unittests show that the merging is inaccurate. Find out how to
// do merges properly.
var r float64
i := 0
for _, sample := range samples {
for ; i < len(s.l); i++ {
c := s.l[i]
if c.Value > sample.Value {
// Insert at position i.
s.l = append(s.l, Sample{})
copy(s.l[i+1:], s.l[i:])
s.l[i] = Sample{
sample.Value,
sample.Width,
math.Max(sample.Delta, math.Floor(s.ƒ(s, r))-1),
// TODO(beorn7): How to calculate delta correctly?
}
i++
goto inserted
}
r += c.Width
}
s.l = append(s.l, Sample{sample.Value, sample.Width, 0})
i++
inserted:
s.n += sample.Width
r += sample.Width
}
s.compress()
}
func (s *stream) count() int {
return int(s.n)
}
func (s *stream) query(q float64) float64 {
t := math.Ceil(q * s.n)
t += math.Ceil(s.ƒ(s, t) / 2)
p := s.l[0]
var r float64
for _, c := range s.l[1:] {
r += p.Width
if r+c.Width+c.Delta > t {
return p.Value
}
p = c
}
return p.Value
}
func (s *stream) compress() {
if len(s.l) < 2 {
return
}
x := s.l[len(s.l)-1]
xi := len(s.l) - 1
r := s.n - 1 - x.Width
for i := len(s.l) - 2; i >= 0; i-- {
c := s.l[i]
if c.Width+x.Width+x.Delta <= s.ƒ(s, r) {
x.Width += c.Width
s.l[xi] = x
// Remove element at i.
copy(s.l[i:], s.l[i+1:])
s.l = s.l[:len(s.l)-1]
xi -= 1
} else {
x = c
xi = i
}
r -= c.Width
}
}
func (s *stream) samples() Samples {
samples := make(Samples, len(s.l))
copy(samples, s.l)
return samples
}
Apache License
Version 2.0, January 2004
http://www.apache.org/licenses/
TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
1. Definitions.
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APPENDIX: How to apply the Apache License to your work.
To apply the Apache License to your work, attach the following
boilerplate notice, with the fields enclosed by brackets "{}"
replaced with your own identifying information. (Don't include
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Copyright {yyyy} {name of copyright owner}
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
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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.
Copyright 2012 Matt T. Proud (matt.proud@gmail.com)
all:
cover:
go test -cover -v -coverprofile=cover.dat ./...
go tool cover -func cover.dat
.PHONY: cover
// Copyright 2013 Matt T. Proud
//
// 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 pbutil
import (
"encoding/binary"
"errors"
"io"
"github.com/golang/protobuf/proto"
)
var errInvalidVarint = errors.New("invalid varint32 encountered")
// ReadDelimited decodes a message from the provided length-delimited stream,
// where the length is encoded as 32-bit varint prefix to the message body.
// It returns the total number of bytes read and any applicable error. This is
// roughly equivalent to the companion Java API's
// MessageLite#parseDelimitedFrom. As per the reader contract, this function
// calls r.Read repeatedly as required until exactly one message including its
// prefix is read and decoded (or an error has occurred). The function never
// reads more bytes from the stream than required. The function never returns
// an error if a message has been read and decoded correctly, even if the end
// of the stream has been reached in doing so. In that case, any subsequent
// calls return (0, io.EOF).
func ReadDelimited(r io.Reader, m proto.Message) (n int, err error) {
// Per AbstractParser#parsePartialDelimitedFrom with
// CodedInputStream#readRawVarint32.
var headerBuf [binary.MaxVarintLen32]byte
var bytesRead, varIntBytes int
var messageLength uint64
for varIntBytes == 0 { // i.e. no varint has been decoded yet.
if bytesRead >= len(headerBuf) {
return bytesRead, errInvalidVarint
}
// We have to read byte by byte here to avoid reading more bytes
// than required. Each read byte is appended to what we have
// read before.
newBytesRead, err := r.Read(headerBuf[bytesRead : bytesRead+1])
if newBytesRead == 0 {
if err != nil {
return bytesRead, err
}
// A Reader should not return (0, nil), but if it does,
// it should be treated as no-op (according to the
// Reader contract). So let's go on...
continue
}
bytesRead += newBytesRead
// Now present everything read so far to the varint decoder and
// see if a varint can be decoded already.
messageLength, varIntBytes = proto.DecodeVarint(headerBuf[:bytesRead])
}
messageBuf := make([]byte, messageLength)
newBytesRead, err := io.ReadFull(r, messageBuf)
bytesRead += newBytesRead
if err != nil {
return bytesRead, err
}
return bytesRead, proto.Unmarshal(messageBuf, m)
}
// Copyright 2013 Matt T. Proud
//
// 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 pbutil provides record length-delimited Protocol Buffer streaming.
package pbutil
// Copyright 2013 Matt T. Proud
//
// 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 pbutil
import (
"encoding/binary"
"io"
"github.com/golang/protobuf/proto"
)
// WriteDelimited encodes and dumps a message to the provided writer prefixed
// with a 32-bit varint indicating the length of the encoded message, producing
// a length-delimited record stream, which can be used to chain together
// encoded messages of the same type together in a file. It returns the total
// number of bytes written and any applicable error. This is roughly
// equivalent to the companion Java API's MessageLite#writeDelimitedTo.
func WriteDelimited(w io.Writer, m proto.Message) (n int, err error) {
buffer, err := proto.Marshal(m)
if err != nil {
return 0, err
}
var buf [binary.MaxVarintLen32]byte
encodedLength := binary.PutUvarint(buf[:], uint64(len(buffer)))
sync, err := w.Write(buf[:encodedLength])
if err != nil {
return sync, err
}
n, err = w.Write(buffer)
return n + sync, err
}
Apache License
Version 2.0, January 2004
http://www.apache.org/licenses/
TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
1. Definitions.
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Prometheus instrumentation library for Go applications
Copyright 2012-2015 The Prometheus Authors
This product includes software developed at
SoundCloud Ltd. (http://soundcloud.com/).
The following components are included in this product:
perks - a fork of https://github.com/bmizerany/perks
https://github.com/beorn7/perks
Copyright 2013-2015 Blake Mizerany, Björn Rabenstein
See https://github.com/beorn7/perks/blob/master/README.md for license details.
Go support for Protocol Buffers - Google's data interchange format
http://github.com/golang/protobuf/
Copyright 2010 The Go Authors
See source code for license details.
Support for streaming Protocol Buffer messages for the Go language (golang).
https://github.com/matttproud/golang_protobuf_extensions
Copyright 2013 Matt T. Proud
Licensed under the Apache License, Version 2.0
See [![go-doc](https://godoc.org/github.com/prometheus/client_golang/prometheus?status.svg)](https://godoc.org/github.com/prometheus/client_golang/prometheus).
// Copyright 2014 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 prometheus
// Collector is the interface implemented by anything that can be used by
// Prometheus to collect metrics. A Collector has to be registered for
// collection. See Registerer.Register.
//
// The stock metrics provided by this package (Gauge, Counter, Summary,
// Histogram, Untyped) are also Collectors (which only ever collect one metric,
// namely itself). An implementer of Collector may, however, collect multiple
// metrics in a coordinated fashion and/or create metrics on the fly. Examples
// for collectors already implemented in this library are the metric vectors
// (i.e. collection of multiple instances of the same Metric but with different
// label values) like GaugeVec or SummaryVec, and the ExpvarCollector.
type Collector interface {
// Describe sends the super-set of all possible descriptors of metrics
// collected by this Collector to the provided channel and returns once
// the last descriptor has been sent. The sent descriptors fulfill the
// consistency and uniqueness requirements described in the Desc
// documentation. (It is valid if one and the same Collector sends
// duplicate descriptors. Those duplicates are simply ignored. However,
// two different Collectors must not send duplicate descriptors.) This
// method idempotently sends the same descriptors throughout the
// lifetime of the Collector. If a Collector encounters an error while
// executing this method, it must send an invalid descriptor (created
// with NewInvalidDesc) to signal the error to the registry.
Describe(chan<- *Desc)
// Collect is called by the Prometheus registry when collecting
// metrics. The implementation sends each collected metric via the
// provided channel and returns once the last metric has been sent. The
// descriptor of each sent metric is one of those returned by
// Describe. Returned metrics that share the same descriptor must differ
// in their variable label values. This method may be called
// concurrently and must therefore be implemented in a concurrency safe
// way. Blocking occurs at the expense of total performance of rendering
// all registered metrics. Ideally, Collector implementations support
// concurrent readers.
Collect(chan<- Metric)
}
// selfCollector implements Collector for a single Metric so that the Metric
// collects itself. Add it as an anonymous field to a struct that implements
// Metric, and call init with the Metric itself as an argument.
type selfCollector struct {
self Metric
}
// init provides the selfCollector with a reference to the metric it is supposed
// to collect. It is usually called within the factory function to create a
// metric. See example.
func (c *selfCollector) init(self Metric) {
c.self = self
}
// Describe implements Collector.
func (c *selfCollector) Describe(ch chan<- *Desc) {
ch <- c.self.Desc()
}
// Collect implements Collector.
func (c *selfCollector) Collect(ch chan<- Metric) {
ch <- c.self
}
// Copyright 2014 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 prometheus
import (
"errors"
)
// Counter is a Metric that represents a single numerical value that only ever
// goes up. That implies that it cannot be used to count items whose number can
// also go down, e.g. the number of currently running goroutines. Those
// "counters" are represented by Gauges.
//
// A Counter is typically used to count requests served, tasks completed, errors
// occurred, etc.
//
// To create Counter instances, use NewCounter.
type Counter interface {
Metric
Collector
// Inc increments the counter by 1. Use Add to increment it by arbitrary
// non-negative values.
Inc()
// Add adds the given value to the counter. It panics if the value is <
// 0.
Add(float64)
}
// CounterOpts is an alias for Opts. See there for doc comments.
type CounterOpts Opts
// NewCounter creates a new Counter based on the provided CounterOpts.
func NewCounter(opts CounterOpts) Counter {
desc := NewDesc(
BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
opts.Help,
nil,
opts.ConstLabels,
)
result := &counter{value: value{desc: desc, valType: CounterValue, labelPairs: desc.constLabelPairs}}
result.init(result) // Init self-collection.
return result
}
type counter struct {
value
}
func (c *counter) Add(v float64) {
if v < 0 {
panic(errors.New("counter cannot decrease in value"))
}
c.value.Add(v)
}
// CounterVec is a Collector that bundles a set of Counters that all share the
// same Desc, but have different values for their variable labels. This is used
// if you want to count the same thing partitioned by various dimensions
// (e.g. number of HTTP requests, partitioned by response code and
// method). Create instances with NewCounterVec.
//
// CounterVec embeds MetricVec. See there for a full list of methods with
// detailed documentation.
type CounterVec struct {
*MetricVec
}
// NewCounterVec creates a new CounterVec based on the provided CounterOpts and
// partitioned by the given label names. At least one label name must be
// provided.
func NewCounterVec(opts CounterOpts, labelNames []string) *CounterVec {
desc := NewDesc(
BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
opts.Help,
labelNames,
opts.ConstLabels,
)
return &CounterVec{
MetricVec: newMetricVec(desc, func(lvs ...string) Metric {
result := &counter{value: value{
desc: desc,
valType: CounterValue,
labelPairs: makeLabelPairs(desc, lvs),
}}
result.init(result) // Init self-collection.
return result
}),
}
}
// GetMetricWithLabelValues replaces the method of the same name in
// MetricVec. The difference is that this method returns a Counter and not a
// Metric so that no type conversion is required.
func (m *CounterVec) GetMetricWithLabelValues(lvs ...string) (Counter, error) {
metric, err := m.MetricVec.GetMetricWithLabelValues(lvs...)
if metric != nil {
return metric.(Counter), err
}
return nil, err
}
// GetMetricWith replaces the method of the same name in MetricVec. The
// difference is that this method returns a Counter and not a Metric so that no
// type conversion is required.
func (m *CounterVec) GetMetricWith(labels Labels) (Counter, error) {
metric, err := m.MetricVec.GetMetricWith(labels)
if metric != nil {
return metric.(Counter), err
}
return nil, err
}
// WithLabelValues works as GetMetricWithLabelValues, but panics where
// GetMetricWithLabelValues would have returned an error. By not returning an
// error, WithLabelValues allows shortcuts like
// myVec.WithLabelValues("404", "GET").Add(42)
func (m *CounterVec) WithLabelValues(lvs ...string) Counter {
return m.MetricVec.WithLabelValues(lvs...).(Counter)
}
// With works as GetMetricWith, but panics where GetMetricWithLabels would have
// returned an error. By not returning an error, With allows shortcuts like
// myVec.With(Labels{"code": "404", "method": "GET"}).Add(42)
func (m *CounterVec) With(labels Labels) Counter {
return m.MetricVec.With(labels).(Counter)
}
// CounterFunc is a Counter whose value is determined at collect time by calling a
// provided function.
//
// To create CounterFunc instances, use NewCounterFunc.
type CounterFunc interface {
Metric
Collector
}
// NewCounterFunc creates a new CounterFunc based on the provided
// CounterOpts. The value reported is determined by calling the given function
// from within the Write method. Take into account that metric collection may
// happen concurrently. If that results in concurrent calls to Write, like in
// the case where a CounterFunc is directly registered with Prometheus, the
// provided function must be concurrency-safe. The function should also honor
// the contract for a Counter (values only go up, not down), but compliance will
// not be checked.
func NewCounterFunc(opts CounterOpts, function func() float64) CounterFunc {
return newValueFunc(NewDesc(
BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
opts.Help,
nil,
opts.ConstLabels,
), CounterValue, function)
}
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