Initial HTTP prober

diff --git a/main.go b/main.go
new file mode 100644 (file)
index 0000000..7257254
--- /dev/null
+++ b/main.go
@@ -0,0 +1,76 @@
+package main
+
+import (
+       "flag"
+       "fmt"
+       "net/http"
+       "time"
+
+       "github.com/prometheus/client_golang/prometheus"
+)
+
+var addr = flag.String("web.listen-address", ":8080", "The address to listen on for HTTP requests.")
+
+type Config struct {
+  Modules map[string]Module `yaml:"modules"`
+}
+
+type Module struct {
+  Prober string  `yaml:"prober"`
+  Timeout time.Duration `yaml:"timeout"`
+  Config interface{} `yaml:"config"`
+}
+
+type HTTPProbe struct {
+  // Defaults to 2xx.
+  ValidStatusCodes []int `yaml:"valid_status_codes"`
+  FollowRedirects bool `yaml:"follow_redirects"`
+  FailIfSSL bool `yaml:"fail_if_ssl"`
+  FailIfNotSSL bool `yaml:"fail_if_not_ssl"`
+}
+
+func probeHTTP(target string, w http.ResponseWriter) (success bool) {
+       var isSSL int
+       resp, err := http.Get(target)
+       if err == nil {
+               if 200 >= resp.StatusCode && resp.StatusCode < 300 {
+                       success = true
+               }
+               defer resp.Body.Close()
+       }
+       if resp.TLS != nil {
+               isSSL = 1
+       }
+       fmt.Fprintf(w, "probe_http_status_code %d\n", resp.StatusCode)
+       fmt.Fprintf(w, "probe_http_content_length %d\n", resp.ContentLength)
+       fmt.Fprintf(w, "probe_http_ssl %d\n", isSSL)
+       return
+}
+
+func probeHandler(w http.ResponseWriter, r *http.Request) {
+       params := r.URL.Query()
+       target := params.Get("target")
+       module := params.Get("module")
+       if target == "" {
+               http.Error(w, "Target parameter is missing", 400)
+               return
+       }
+       if module == "" {
+               module = "http2xx"
+       }
+       start := time.Now()
+       success := probeHTTP(target, w)
+       fmt.Fprintf(w, "probe_duration_seconds %f\n", float64(time.Now().Sub(start))/1e9)
+       if success {
+               fmt.Fprintf(w, "probe_success %d\n", 1)
+       } else {
+               fmt.Fprintf(w, "probe_success %d\n", 0)
+       }
+}
+
+func main() {
+       flag.Parse()
+       http.Handle("/metrics", prometheus.Handler())
+       http.HandleFunc("/probe", probeHandler)
+       http.ListenAndServe(*addr, nil)
+}