json_exporter/cmd/main.go

143 lines
3.7 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"
"time"
"github.com/prometheus-community/json_exporter/config"
"github.com/prometheus-community/json_exporter/internal"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promhttp"
log "github.com/sirupsen/logrus"
"github.com/urfave/cli"
)
var (
defaultOpts = []cli.Flag{
cli.IntFlag{
Name: "port",
Usage: "The port number used to expose metrics via http",
Value: 7979,
},
cli.StringFlag{
Name: "log-level",
Usage: "Set Logging level",
Value: "info",
},
}
)
func MakeApp() *cli.App {
app := cli.NewApp()
app.Name = "json_exporter"
app.Version = internal.Version
app.Usage = "A prometheus exporter for scraping metrics from JSON REST API endpoints"
app.UsageText = "[OPTIONS] CONFIG_PATH"
app.Action = main
app.Flags = defaultOpts
return app
}
func main(c *cli.Context) {
setupLogging(c.String("log-level"))
internal.Init(c)
config, err := config.LoadConfig(c.Args()[0])
if err != nil {
log.Fatal(err)
}
configJson, err := json.MarshalIndent(config, "", "\t")
if err != nil {
log.Errorf("Failed to marshal loaded config to JSON. ERROR: '%s'", err)
}
log.Infof("Config:\n%s", string(configJson))
http.Handle("/metrics", promhttp.Handler())
http.HandleFunc("/probe", func(w http.ResponseWriter, req *http.Request) {
probeHandler(w, req, config)
})
if err := http.ListenAndServe(fmt.Sprintf(":%d", c.Int("port")), nil); err != nil {
log.Fatal(err)
}
}
func probeHandler(w http.ResponseWriter, r *http.Request, config config.Config) {
ctx, cancel := context.WithTimeout(r.Context(), time.Duration(config.Global.TimeoutSeconds*float64(time.Second)))
defer cancel()
r = r.WithContext(ctx)
registry := prometheus.NewPedanticRegistry()
metrics, err := internal.CreateMetricsList(registry, config)
if err != nil {
log.Fatalf("Failed to create metrics from config. Error: %s", err)
}
probeSuccessGauge := prometheus.NewGauge(prometheus.GaugeOpts{
Name: "probe_success",
Help: "Displays whether or not the probe was a success",
})
probeDurationGauge := prometheus.NewGauge(prometheus.GaugeOpts{
Name: "probe_duration_seconds",
Help: "Returns how long the probe took to complete in seconds",
})
target := r.URL.Query().Get("target")
if target == "" {
http.Error(w, "Target parameter is missing", http.StatusBadRequest)
return
}
start := time.Now()
registry.MustRegister(probeSuccessGauge)
registry.MustRegister(probeDurationGauge)
data, err := internal.FetchJson(ctx, target, config.Headers)
if err != nil {
log.Error(err)
duration := time.Since(start).Seconds()
log.Errorf("Probe failed. duration_seconds: %f", duration)
} else {
internal.Scrape(metrics, data)
duration := time.Since(start).Seconds()
probeDurationGauge.Set(duration)
probeSuccessGauge.Set(1)
}
h := promhttp.HandlerFor(registry, promhttp.HandlerOpts{})
h.ServeHTTP(w, r)
}
func setupLogging(level string) {
log.SetFormatter(&log.TextFormatter{
FullTimestamp: true,
})
logLevel, err := log.ParseLevel(level)
if err != nil {
log.Fatalf("could not set log level to '%s';err:<%s>", level, err)
}
log.SetLevel(logLevel)
}