Detect and notify users when they try to use this _as_ alertman

Since people keep doing it.

See: benjojo#18
See: benjojo#13
See: benjojo#14

and a handful of discord DM's

Author: benjojo

detect-misconfig.go

@@ -0,0 +1,29 @@
+package main
+
+import "encoding/json"
+
+type rawPromAlert struct {
+	Annotations struct {
+		Description string `json:"description"`
+		Summary     string `json:"summary"`
+	} `json:"annotations"`
+	EndsAt       string            `json:"endsAt"`
+	GeneratorURL string            `json:"generatorURL"`
+	Labels       map[string]string `json:"labels"`
+	StartsAt     string            `json:"startsAt"`
+	Status       string            `json:"status"`
+}
+
+func isRawPromAlert(b []byte) bool {
+	alertTest := make([]rawPromAlert, 0)
+	err := json.Unmarshal(b, &alertTest)
+	if err == nil {
+		if len(alertTest) != 0 {
+			if alertTest[0].Status == "" {
+				// Ok it's more than likely then
+				return true
+			}
+		}
+	}
+	return false
+}

main.go

@@ -109,6 +109,34 @@ func main() {
 		amo := alertManOut{}
 		err = json.Unmarshal(b, &amo)
 		if err != nil {
+			if isRawPromAlert(b) {
+				badString := `This program is suppose to be fed by alertmanager.` + "\n" +
+					`It is not a replacement for alertmanager, it is a ` + "\n" +
+					`webhook target for it. Please read the README.md  ` + "\n" +
+					`for guidance on how to configure it for alertmanager` + "\n" +
+					`or https://prometheus.io/docs/alerting/latest/configuration/#webhook_config`
+
+				log.Print(`/!\ -- You have misconfigured this software -- /!\`)
+				log.Print(`--- --                                      -- ---`)
+				log.Print(badString)
+
+				DO := discordOut{
+					Content: "",
+					Embeds: []discordEmbed{
+						{
+							Title:       "You have misconfigured this software",
+							Description: badString,
+							Color:       ColorGrey,
+							Fields:      []discordEmbedField{},
+						},
+					},
+				}
+
+				DOD, _ := json.Marshal(DO)
+				http.Post(*whURL, "application/json", bytes.NewReader(DOD))
+				return
+			}
+
 			if len(b) > 1024 {
 				log.Printf("Failed to unpack inbound alert request - %s...", string(b[:1023]))