json_exporter/cmd/main.go
SuperQ 2b8fbee030
Update build
* Update go to 1.20.
* Update Prometheus CI orb.
* Add landing page.
* Update Go modules.
* Update golangci-lint.

Signed-off-by: SuperQ <superq@gmail.com>
2023-04-01 12:06:31 +02:00

153 lines
4.7 KiB
Go

// Copyright 2020 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 cmd
import (
"context"
"encoding/json"
"fmt"
"net/http"
"os"
"github.com/alecthomas/kingpin/v2"
"github.com/go-kit/log"
"github.com/go-kit/log/level"
"github.com/prometheus-community/json_exporter/config"
"github.com/prometheus-community/json_exporter/exporter"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promhttp"
"github.com/prometheus/common/promlog"
"github.com/prometheus/common/promlog/flag"
"github.com/prometheus/common/version"
"github.com/prometheus/exporter-toolkit/web"
"github.com/prometheus/exporter-toolkit/web/kingpinflag"
)
var (
configFile = kingpin.Flag("config.file", "JSON exporter configuration file.").Default("config.yml").ExistingFile()
configCheck = kingpin.Flag("config.check", "If true validate the config file and then exit.").Default("false").Bool()
metricsPath = kingpin.Flag(
"web.telemetry-path",
"Path under which to expose metrics.",
).Default("/metrics").String()
toolkitFlags = kingpinflag.AddFlags(kingpin.CommandLine, ":7979")
)
func Run() {
promlogConfig := &promlog.Config{}
flag.AddFlags(kingpin.CommandLine, promlogConfig)
kingpin.Version(version.Print("json_exporter"))
kingpin.HelpFlag.Short('h')
kingpin.Parse()
logger := promlog.New(promlogConfig)
level.Info(logger).Log("msg", "Starting json_exporter", "version", version.Info())
level.Info(logger).Log("msg", "Build context", "build", version.BuildContext())
level.Info(logger).Log("msg", "Loading config file", "file", *configFile)
config, err := config.LoadConfig(*configFile)
if err != nil {
level.Error(logger).Log("msg", "Error loading config", "err", err)
os.Exit(1)
}
configJSON, err := json.Marshal(config)
if err != nil {
level.Error(logger).Log("msg", "Failed to marshal config to JSON", "err", err)
}
level.Info(logger).Log("msg", "Loaded config file", "config", string(configJSON))
if *configCheck {
os.Exit(0)
}
http.Handle(*metricsPath, promhttp.Handler())
http.HandleFunc("/probe", func(w http.ResponseWriter, req *http.Request) {
probeHandler(w, req, logger, config)
})
if *metricsPath != "/" && *metricsPath != "" {
landingConfig := web.LandingConfig{
Name: "JSON Exporter",
Description: "Prometheus Exporter for converting json to metrics",
Version: version.Info(),
Links: []web.LandingLinks{
{
Address: *metricsPath,
Text: "Metrics",
},
},
}
landingPage, err := web.NewLandingPage(landingConfig)
if err != nil {
level.Error(logger).Log("err", err)
os.Exit(1)
}
http.Handle("/", landingPage)
}
server := &http.Server{}
if err := web.ListenAndServe(server, toolkitFlags, logger); err != nil {
level.Error(logger).Log("msg", "Failed to start the server", "err", err)
os.Exit(1)
}
}
func probeHandler(w http.ResponseWriter, r *http.Request, logger log.Logger, config config.Config) {
ctx, cancel := context.WithCancel(r.Context())
defer cancel()
r = r.WithContext(ctx)
module := r.URL.Query().Get("module")
if module == "" {
module = "default"
}
if _, ok := config.Modules[module]; !ok {
http.Error(w, fmt.Sprintf("Unknown module %q", module), http.StatusBadRequest)
level.Debug(logger).Log("msg", "Unknown module", "module", module)
return
}
registry := prometheus.NewPedanticRegistry()
metrics, err := exporter.CreateMetricsList(config.Modules[module])
if err != nil {
level.Error(logger).Log("msg", "Failed to create metrics list from config", "err", err)
}
jsonMetricCollector := exporter.JSONMetricCollector{JSONMetrics: metrics}
jsonMetricCollector.Logger = logger
target := r.URL.Query().Get("target")
if target == "" {
http.Error(w, "Target parameter is missing", http.StatusBadRequest)
return
}
fetcher := exporter.NewJSONFetcher(ctx, logger, config.Modules[module], r.URL.Query())
data, err := fetcher.FetchJSON(target)
if err != nil {
http.Error(w, "Failed to fetch JSON response. TARGET: "+target+", ERROR: "+err.Error(), http.StatusServiceUnavailable)
return
}
jsonMetricCollector.Data = data
registry.MustRegister(jsonMetricCollector)
h := promhttp.HandlerFor(registry, promhttp.HandlerOpts{})
h.ServeHTTP(w, r)
}