89 lines
2.2 KiB
Go
89 lines
2.2 KiB
Go
package main
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import (
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"context"
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"encoding/json"
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"flag"
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"fmt"
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"net/http"
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"net/url"
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"time"
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"github.com/prometheus/client_golang/prometheus"
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"github.com/prometheus/client_golang/prometheus/promhttp"
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log "github.com/sirupsen/logrus"
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)
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func probeTwitter(ctx context.Context, target string, registry *prometheus.Registry) (success bool) {
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followersGauge := prometheus.NewGaugeVec(prometheus.GaugeOpts{
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Name: "twitter_followers",
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Help: "The number of followers of the twitter account.",
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},
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[]string{"screen_name"})
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registry.MustRegister(followersGauge)
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res, err := http.Get(fmt.Sprintf("https://cdn.syndication.twimg.com/widgets/followbutton/info.json?screen_names=%s", url.QueryEscape(target)))
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if err != nil {
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log.Errorf("fetching url: %s", err)
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return false
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}
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data := []struct {
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FollowersCount int `json:"followers_count"`
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}{}
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if err := json.NewDecoder(res.Body).Decode(&data); err != nil {
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log.Errorf("decoding json: %s", err)
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return false
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}
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switch l := len(data); {
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case l == 0:
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log.Errorf("No data returned. Does screen name exist?")
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return false
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case l > 1:
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log.Errorf("Unexpected (>1) results returned. WTF twitter??")
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return false
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}
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followersGauge.With(prometheus.Labels{"screen_name": target}).Set(float64(data[0].FollowersCount))
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return true
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}
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func twitterHandler(w http.ResponseWriter, r *http.Request) {
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username := r.URL.Query().Get("username")
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if username == "" {
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http.Error(w, "username parameter is missing", http.StatusBadRequest)
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return
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}
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reg := prometheus.NewRegistry()
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ctx, cancel := context.WithTimeout(r.Context(), time.Duration(5*time.Second))
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defer cancel()
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if success := probeTwitter(ctx, username, reg); !success {
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log.Error("Probe failed!")
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}
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h := promhttp.HandlerFor(reg, promhttp.HandlerOpts{})
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h.ServeHTTP(w, r)
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}
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func bail(err error) {
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if err != nil {
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log.Fatal(err)
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}
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}
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func main() {
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var listenAddr string
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flag.StringVar(&listenAddr, "listen", "0.0.0.0:9700", "Address to listen on")
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flag.Parse()
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http.Handle("/metrics", promhttp.Handler())
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http.HandleFunc("/probe", func(w http.ResponseWriter, r *http.Request) {
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twitterHandler(w, r)
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})
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log.Infof("Listening on %s", listenAddr)
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bail(http.ListenAndServe(listenAddr, nil))
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}
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