Add alertmanager parser

dev/alertmanager-example.json

@@ -0,0 +1,30 @@
+{
+  "receiver": "xmpp-email",
+  "status": "firing",
+  "alerts": [
+    {
+      "status": "firing",
+      "labels": {
+        "alertname": "testalert",
+        "instance": "test.net",
+        "severity": "critical"
+      },
+      "annotations": { "summary": "Simple test" },
+      "startsAt": "2021-02-27T18:38:56Z",
+      "endsAt": "0001-01-01T00:00:00Z",
+      "generatorURL": "http://local-example-alert/testalert",
+      "fingerprint": "d4baf2738cfc5a30"
+    }
+  ],
+  "groupLabels": { "instance": "test.net", "severity": "critical" },
+  "commonLabels": {
+    "alertname": "testalert",
+    "instance": "test.net",
+    "severity": "critical"
+  },
+  "commonAnnotations": { "summary": "Simple test" },
+  "externalURL": "http://127.0.0.1:9093",
+  "version": "4",
+  "groupKey": "{}/{severity=\"critical\"}:{instance=\"test.net\", severity=\"critical\"}",
+  "truncatedAlerts": 0
+}

main.go

@@ -154,6 +154,7 @@ func main() {
 	// initialize handlers with accociated parser functions
 	http.Handle("/grafana", newMessageHandler(messages, parser.GrafanaParserFunc))
 	http.Handle("/slack", newMessageHandler(messages, parser.SlackParserFunc))
+	http.Handle("/alertmanager", newMessageHandler(messages, parser.AlertmanagerParserFunc))
 
 	// listen for requests
 	_ = http.ListenAndServe(":4321", nil)

parser/alertmanager.go

@@ -0,0 +1,55 @@
+package parser
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+)
+
+func AlertmanagerParserFunc(r *http.Request) (string, error) {
+	// get alert data from request
+	body, err := ioutil.ReadAll(r.Body)
+	if err != nil {
+		return "", errors.New(readErr)
+	}
+
+	payload := &struct {
+		Alerts []struct {
+			Status      string            `json:"status"`
+			Labels      map[string]string `json:"labels"`
+			Annotations map[string]string `json:"annotations"`
+		} `json:"alerts"`
+	}{}
+
+	// parse body into the alert struct
+	err = json.Unmarshal(body, &payload)
+	if err != nil {
+		return "", errors.New(parseErr)
+	}
+
+	// contruct alert message
+	var message string
+	for _, alert := range payload.Alerts {
+		if alert.Status == "resolved" {
+			message = "Resolved" + "\n"
+		} else {
+			message = "Firing" + "\n"
+		}
+
+		message += "Labels" + "\n"
+		for key, label := range alert.Labels {
+			message += fmt.Sprintf("%s = %s\n", key, label)
+		}
+
+		message += "Annotations" + "\n"
+		for key, annotation := range alert.Annotations {
+			message += fmt.Sprintf("%s = %s\n", key, annotation)
+		}
+
+		message += "\n"
+	}
+
+	return message, nil
+}