124 lines
3.1 KiB
Go
124 lines
3.1 KiB
Go
// Copyright 2019 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package refresh
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import (
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"context"
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"errors"
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"time"
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"github.com/go-kit/log"
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"github.com/go-kit/log/level"
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"github.com/prometheus/client_golang/prometheus"
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"github.com/prometheus/prometheus/discovery/targetgroup"
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)
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var (
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failuresCount = prometheus.NewCounterVec(
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prometheus.CounterOpts{
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Name: "prometheus_sd_refresh_failures_total",
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Help: "Number of refresh failures for the given SD mechanism.",
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},
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[]string{"mechanism"},
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)
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duration = prometheus.NewSummaryVec(
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prometheus.SummaryOpts{
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Name: "prometheus_sd_refresh_duration_seconds",
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Help: "The duration of a refresh in seconds for the given SD mechanism.",
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Objectives: map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001},
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},
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[]string{"mechanism"},
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)
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)
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func init() {
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prometheus.MustRegister(duration, failuresCount)
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}
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// Discovery implements the Discoverer interface.
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type Discovery struct {
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logger log.Logger
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interval time.Duration
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refreshf func(ctx context.Context) ([]*targetgroup.Group, error)
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failures prometheus.Counter
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duration prometheus.Observer
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}
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// NewDiscovery returns a Discoverer function that calls a refresh() function at every interval.
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func NewDiscovery(l log.Logger, mech string, interval time.Duration, refreshf func(ctx context.Context) ([]*targetgroup.Group, error)) *Discovery {
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if l == nil {
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l = log.NewNopLogger()
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}
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return &Discovery{
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logger: l,
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interval: interval,
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refreshf: refreshf,
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failures: failuresCount.WithLabelValues(mech),
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duration: duration.WithLabelValues(mech),
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}
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}
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// Run implements the Discoverer interface.
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func (d *Discovery) Run(ctx context.Context, ch chan<- []*targetgroup.Group) {
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// Get an initial set right away.
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tgs, err := d.refresh(ctx)
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if err != nil {
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if !errors.Is(ctx.Err(), context.Canceled) {
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level.Error(d.logger).Log("msg", "Unable to refresh target groups", "err", err.Error())
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}
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} else {
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select {
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case ch <- tgs:
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case <-ctx.Done():
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return
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}
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}
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ticker := time.NewTicker(d.interval)
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defer ticker.Stop()
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for {
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select {
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case <-ticker.C:
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tgs, err := d.refresh(ctx)
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if err != nil {
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if !errors.Is(ctx.Err(), context.Canceled) {
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level.Error(d.logger).Log("msg", "Unable to refresh target groups", "err", err.Error())
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}
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continue
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}
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select {
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case ch <- tgs:
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case <-ctx.Done():
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return
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}
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case <-ctx.Done():
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return
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}
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}
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}
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func (d *Discovery) refresh(ctx context.Context) ([]*targetgroup.Group, error) {
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now := time.Now()
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defer d.duration.Observe(time.Since(now).Seconds())
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tgs, err := d.refreshf(ctx)
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if err != nil {
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d.failures.Inc()
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}
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return tgs, err
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}
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