prometheus/discovery/refresh/refresh.go
TJ Hoplock 6ebfbd2d54 chore!: adopt log/slog, remove go-kit/log
For: #14355

This commit updates Prometheus to adopt stdlib's log/slog package in
favor of go-kit/log. As part of converting to use slog, several other
related changes are required to get prometheus working, including:
- removed unused logging util func `RateLimit()`
- forward ported the util/logging/Deduper logging by implementing a small custom slog.Handler that does the deduping before chaining log calls to the underlying real slog.Logger
- move some of the json file logging functionality to use prom/common package functionality
- refactored some of the new json file logging for scraping
- changes to promql.QueryLogger interface to swap out logging methods for relevant slog sugar wrappers
- updated lots of tests that used/replicated custom logging functionality, attempting to keep the logical goal of the tests consistent after the transition
- added a healthy amount of `if logger == nil { $makeLogger }` type conditional checks amongst various functions where none were provided -- old code that used the go-kit/log.Logger interface had several places where there were nil references when trying to use functions like `With()` to add keyvals on the new *slog.Logger type

Signed-off-by: TJ Hoplock <t.hoplock@gmail.com>
2024-10-07 15:58:50 -04:00

118 lines
2.8 KiB
Go

// Copyright 2019 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 refresh
import (
"context"
"errors"
"log/slog"
"time"
"github.com/prometheus/common/promslog"
"github.com/prometheus/prometheus/discovery"
"github.com/prometheus/prometheus/discovery/targetgroup"
)
type Options struct {
Logger *slog.Logger
Mech string
Interval time.Duration
RefreshF func(ctx context.Context) ([]*targetgroup.Group, error)
MetricsInstantiator discovery.RefreshMetricsInstantiator
}
// Discovery implements the Discoverer interface.
type Discovery struct {
logger *slog.Logger
interval time.Duration
refreshf func(ctx context.Context) ([]*targetgroup.Group, error)
metrics *discovery.RefreshMetrics
}
// NewDiscovery returns a Discoverer function that calls a refresh() function at every interval.
func NewDiscovery(opts Options) *Discovery {
m := opts.MetricsInstantiator.Instantiate(opts.Mech)
var logger *slog.Logger
if opts.Logger == nil {
logger = promslog.NewNopLogger()
} else {
logger = opts.Logger
}
d := Discovery{
logger: logger,
interval: opts.Interval,
refreshf: opts.RefreshF,
metrics: m,
}
return &d
}
// Run implements the Discoverer interface.
func (d *Discovery) Run(ctx context.Context, ch chan<- []*targetgroup.Group) {
// Get an initial set right away.
tgs, err := d.refresh(ctx)
if err != nil {
if !errors.Is(ctx.Err(), context.Canceled) {
d.logger.Error("Unable to refresh target groups", "err", err.Error())
}
} else {
select {
case ch <- tgs:
case <-ctx.Done():
return
}
}
ticker := time.NewTicker(d.interval)
defer ticker.Stop()
for {
select {
case <-ticker.C:
tgs, err := d.refresh(ctx)
if err != nil {
if !errors.Is(ctx.Err(), context.Canceled) {
d.logger.Error("Unable to refresh target groups", "err", err.Error())
}
continue
}
select {
case ch <- tgs:
case <-ctx.Done():
return
}
case <-ctx.Done():
return
}
}
}
func (d *Discovery) refresh(ctx context.Context) ([]*targetgroup.Group, error) {
now := time.Now()
defer func() {
d.metrics.Duration.Observe(time.Since(now).Seconds())
}()
tgs, err := d.refreshf(ctx)
if err != nil {
d.metrics.Failures.Inc()
}
return tgs, err
}