Add ntfy email support

Implements: https://todo.xenrox.net/~xenrox/ntfy-alertmanager/15

README.md

@@ -16,9 +16,9 @@ You can specify the configuration file location with the `--config` flag. By def
 the configuration file will be read from `/etc/ntfy-alertmanager/config`. The format
 of this file is [scfg].
 
-ntfy-alertmanager has support for setting ntfy [priority], [tags], [icon] and [action buttons]
+ntfy-alertmanager has support for setting ntfy [priority], [tags], [icon], [action buttons]
-(which can be used to create an Alertmanager silence).
+(which can be used to create an Alertmanager silence) and [email notifications].
-Define a decreasing order of labels in the config file and map those labels to tags, priority or an icon.
+Define a decreasing order of labels in the config file and map those labels to tags, priority, an icon or an email address.
 
 -   For priority and icon the first found value will be chosen. An icon for "resolved" alerts will take precedence.
 -   Tags are added together.
@@ -47,6 +47,8 @@ labels {
         priority 5
         tags "rotating_light"
         icon "https://foo.com/critical.png"
+        # Forward messages which severity "critical" to the specified email address.
+        email-address foo@bar.com
     }
 
     severity "info" {
@@ -73,6 +75,8 @@ ntfy {
     # ntfy authentication via access tokens (https://docs.ntfy.sh/publish/#access-tokens)
     # Either access-token or a user/password combination can be used - not both.
     access-token foobar
+    # Forward all messages to the specified email address.
+    email-address foo@bar.com
 }
 
 alertmanager {
@@ -135,6 +139,7 @@ or write to me directly on matrix [@xenrox:xenrox.net].
 [tags]: https://ntfy.sh/docs/publish/#tags-emojis
 [icon]: https://docs.ntfy.sh/publish/#icons
 [action buttons]: https://docs.ntfy.sh/publish/#action-buttons
+[email notifications]: https://docs.ntfy.sh/publish/#e-mail-notifications
 [issue tracker]: https://todo.xenrox.net/~xenrox/ntfy-alertmanager
 [mailing list]: https://lists.xenrox.net/~xenrox/public-inbox
 [@xenrox:xenrox.net]: https://matrix.to/#/@xenrox:xenrox.net

config.go

@@ -42,6 +42,7 @@ type ntfyConfig struct {
 	User         string
 	Password     string
 	AccessToken  string
+	emailAddress string
 }
 
 type labels struct {
@@ -53,6 +54,7 @@ type labelConfig struct {
 	Priority     string
 	Tags         []string
 	Icon         string
+	emailAddress string
 }
 
 type cacheConfig struct {
@@ -201,6 +203,13 @@ func readConfig(path string) (*config, error) {
 					}
 				}
 
+				d = labelDir.Children.Get("email-address")
+				if d != nil {
+					if err := d.ParseParams(&labelConfig.emailAddress); err != nil {
+						return nil, err
+					}
+				}
+
 				labels[fmt.Sprintf("%s:%s", labelName, name)] = *labelConfig
 			}
 		}
@@ -251,6 +260,13 @@ func readConfig(path string) (*config, error) {
 		return nil, errors.New("ntfy: cannot use both an access-token and a user/password at the same time")
 	}
 
+	d = ntfyDir.Children.Get("email-address")
+	if d != nil {
+		if err := d.ParseParams(&config.ntfy.emailAddress); err != nil {
+			return nil, err
+		}
+	}
+
 	cacheDir := cfg.Get("cache")
 
 	if cacheDir != nil {

config_test.go

@@ -24,6 +24,7 @@ labels {
         priority 5
         tags "rotating_light"
         icon "https://foo.com/critical.png"
+        email-address foo@bar.com
     }
 
     severity "info" {
@@ -70,7 +71,12 @@ cache {
 		ntfy:        ntfyConfig{Topic: "https://ntfy.sh/alertmanager-alerts", User: "user", Password: "pass"},
 		labels: labels{Order: []string{"severity", "instance"},
 			Label: map[string]labelConfig{
-				"severity:critical":    {Priority: "5", Tags: []string{"rotating_light"}, Icon: "https://foo.com/critical.png"},
+				"severity:critical": {
+					Priority:     "5",
+					Tags:         []string{"rotating_light"},
+					Icon:         "https://foo.com/critical.png",
+					emailAddress: "foo@bar.com",
+				},
 				"severity:info":        {Priority: "1"},
 				"instance:example.com": {Tags: []string{"computer", "example"}},
 			},

main.go

@@ -51,6 +51,7 @@ type notification struct {
 	priority     string
 	tags         string
 	icon         string
+	emailAddress string
 	silenceBody  string
 	fingerprint  string
 	status       string
@@ -100,6 +101,8 @@ func (br *bridge) singleAlertNotifications(p *payload) []*notification {
 			n.icon = br.cfg.resolved.Icon
 		}
 
+		n.emailAddress = br.cfg.ntfy.emailAddress
+
 		for _, labelName := range br.cfg.labels.Order {
 			val, ok := alert.Labels[labelName]
 			if !ok {
@@ -119,6 +122,10 @@ func (br *bridge) singleAlertNotifications(p *payload) []*notification {
 				n.icon = labelConfig.Icon
 			}
 
+			if n.emailAddress == "" {
+				n.emailAddress = labelConfig.emailAddress
+			}
+
 			for _, val := range labelConfig.Tags {
 				if !sliceContains(tags, val) {
 					tags = append(tags, val)
@@ -197,6 +204,8 @@ func (br *bridge) multiAlertNotification(p *payload) *notification {
 		n.icon = br.cfg.resolved.Icon
 	}
 
+	n.emailAddress = br.cfg.ntfy.emailAddress
+
 	for _, labelName := range br.cfg.labels.Order {
 		val, ok := p.CommonLabels[labelName]
 		if !ok {
@@ -216,6 +225,10 @@ func (br *bridge) multiAlertNotification(p *payload) *notification {
 			n.icon = labelConfig.Icon
 		}
 
+		if n.emailAddress == "" {
+			n.emailAddress = labelConfig.emailAddress
+		}
+
 		for _, val := range labelConfig.Tags {
 			if !sliceContains(tags, val) {
 				tags = append(tags, val)
@@ -270,6 +283,10 @@ func (br *bridge) publish(n *notification) error {
 		req.Header.Set("X-Tags", n.tags)
 	}
 
+	if n.emailAddress != "" {
+		req.Header.Set("X-Email", n.emailAddress)
+	}
+
 	if n.silenceBody != "" {
 		url := br.cfg.BaseURL + "/silences"