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prometheus-operator/cmd/prometheus-config-reloader/main.go

111 lines
3.2 KiB
Go

// Copyright 2016 The prometheus-operator 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 main
import (
"context"
"fmt"
"os"
"regexp"
"strings"
"github.com/prometheus-operator/prometheus-operator/pkg/version"
"github.com/go-kit/kit/log"
"github.com/oklog/run"
"github.com/thanos-io/thanos/pkg/reloader"
"gopkg.in/alecthomas/kingpin.v2"
)
const (
logFormatLogfmt = "logfmt"
logFormatJson = "json"
statefulsetOrdinalEnvvar = "STATEFULSET_ORDINAL_NUMBER"
statefulsetOrdinalFromEnvvarDefault = "POD_NAME"
)
var (
availableLogFormats = []string{
logFormatLogfmt,
logFormatJson,
}
)
func main() {
app := kingpin.New("prometheus-config-reloader", "")
cfgFile := app.Flag("config-file", "config file watched by the reloader").
String()
cfgSubstFile := app.Flag("config-envsubst-file", "output file for environment variable substituted config file").
String()
rulesDir := app.Flag("rules-dir", "Rules directory to watch non-recursively").Strings()
createStatefulsetOrdinalFrom := app.Flag(
"statefulset-ordinal-from-envvar",
fmt.Sprintf("parse this environment variable to create %s, containing the statefulset ordinal number", statefulsetOrdinalEnvvar)).
Default(statefulsetOrdinalFromEnvvarDefault).String()
logFormat := app.Flag(
"log-format",
fmt.Sprintf("Log format to use. Possible values: %s", strings.Join(availableLogFormats, ", "))).
Default(logFormatLogfmt).String()
reloadURL := app.Flag("reload-url", "reload URL to trigger Prometheus reload on").
Default("http://127.0.0.1:9090/-/reload").URL()
if _, err := app.Parse(os.Args[1:]); err != nil {
fmt.Fprintln(os.Stderr, err)
os.Exit(2)
}
logger := log.NewLogfmtLogger(log.NewSyncWriter(os.Stdout))
if *logFormat == logFormatJson {
logger = log.NewJSONLogger(log.NewSyncWriter(os.Stdout))
}
logger = log.With(logger, "ts", log.DefaultTimestampUTC)
logger = log.With(logger, "caller", log.DefaultCaller)
if createStatefulsetOrdinalFrom != nil {
if err := createOrdinalEnvvar(*createStatefulsetOrdinalFrom); err != nil {
logger.Log("msg", fmt.Sprintf("Failed setting %s", statefulsetOrdinalEnvvar))
}
}
logger.Log("msg", fmt.Sprintf("Starting prometheus-config-reloader version '%v'.", version.Version))
var g run.Group
{
ctx, cancel := context.WithCancel(context.Background())
rel := reloader.New(logger, *reloadURL, *cfgFile, *cfgSubstFile, *rulesDir)
g.Add(func() error {
return rel.Watch(ctx)
}, func(error) {
cancel()
})
}
if err := g.Run(); err != nil {
fmt.Fprintln(os.Stderr, err)
os.Exit(1)
}
}
func createOrdinalEnvvar(fromName string) error {
reg := regexp.MustCompile(`\d+$`)
val := reg.FindString(os.Getenv(fromName))
return os.Setenv(statefulsetOrdinalEnvvar, val)
}