Add option for resolved template

This introduces a "msg_template_resolved" option, allowing a custom
template for resolved messages to be defined. If the option is not
set, the existing "msg_template" will apply as before.
This allows users to define different templates for firing and
resolved events.

Signed-off-by: Georg Pfuetzenreuter <mail@georg-pfuetzenreuter.net>

README.md

@@ -61,6 +61,9 @@ use_privmsg: yes
 #
 # The formatting is based on golang's text/template .
 msg_template: "Alert {{ .Labels.alertname }} on {{ .Labels.instance }} is {{ .Status }}"
+# By default, firing and resolved messages use the template defined as msg_template.
+# Define msg_template_resolved to define a different template for resolved messages.
+# msg_template_resolved: "Resolved: {{ .Labels.alertname }} on {{ .Labels.instance }}"
 # Note: When sending only one message per alert group the default
 # msg_template is set to
 # "Alert {{ .GroupLabels.alertname }} for {{ .GroupLabels.job }} is {{ .Status }}"

config.go

@@ -45,6 +45,7 @@ type Config struct {
 	IRCVerifySSL    bool         `yaml:"irc_verify_ssl"`
 	IRCChannels     []IRCChannel `yaml:"irc_channels"`
 	MsgTemplate     string       `yaml:"msg_template"`
+	MsgTemplateResolved string   `yaml:"msg_template_resolved"`
 	MsgOnce         bool         `yaml:"msg_once_per_alert_group"`
 	UsePrivmsg      bool         `yaml:"use_privmsg"`
 	AlertBufferSize int          `yaml:"alert_buffer_size"`
@@ -99,6 +100,9 @@ func LoadConfig(configFile string) (*Config, error) {
 			config.MsgTemplate = defaultMsgTemplate
 		}
 	}
+	if config.MsgTemplateResolved == "" {
+		config.MsgTemplateResolved = config.MsgTemplate
+	}
 
 	loadedConfig, _ := yaml.Marshal(config)
 	logging.Debug("Loaded config:\n%s", loadedConfig)

format.go

@@ -27,6 +27,7 @@ import (
 
 type Formatter struct {
 	MsgTemplate *template.Template
+	MsgTemplateResolved *template.Template
 	MsgOnce     bool
 }
 
@@ -44,16 +45,27 @@ func NewFormatter(config *Config) (*Formatter, error) {
 	if err != nil {
 		return nil, err
 	}
+	tmplresolved, err := template.New("msg").Funcs(funcMap).Parse(config.MsgTemplateResolved)
+	if err != nil {
+		return nil, err
+	}
 	return &Formatter{
 		MsgTemplate: tmpl,
+		MsgTemplateResolved: tmplresolved,
 		MsgOnce:     config.MsgOnce,
 	}, nil
 }
 
-func (f *Formatter) FormatMsg(ircChannel string, data interface{}) []string {
+func (f *Formatter) FormatMsg(ircChannel string, data interface{}, status string) []string {
 	output := bytes.Buffer{}
 	var msg string
-	if err := f.MsgTemplate.Execute(&output, data); err != nil {
+	var msgtemplate *template.Template
+	if status == "resolved" {
+		msgtemplate = f.MsgTemplateResolved
+	} else {
+		msgtemplate = f.MsgTemplate
+	}
+	if err := msgtemplate.Execute(&output, data); err != nil {
 		msg_bytes, _ := json.Marshal(data)
 		msg = string(msg_bytes)
 		logging.Error("Could not apply msg template on alert (%s): %s",
@@ -75,13 +87,13 @@ func (f *Formatter) GetMsgsFromAlertMessage(ircChannel string,
 	data *promtmpl.Data) []AlertMsg {
 	msgs := []AlertMsg{}
 	if f.MsgOnce {
-		for _, msg := range f.FormatMsg(ircChannel, data) {
+		for _, msg := range f.FormatMsg(ircChannel, data, data.Status) {
 			msgs = append(msgs,
 				AlertMsg{Channel: ircChannel, Alert: msg})
 		}
 	} else {
 		for _, alert := range data.Alerts {
-			for _, msg := range f.FormatMsg(ircChannel, alert) {
+			for _, msg := range f.FormatMsg(ircChannel, alert, data.Status) {
 				msgs = append(msgs,
 					AlertMsg{Channel: ircChannel, Alert: msg})
 			}

format_test.go

@@ -133,3 +133,20 @@ func TestMultilineTemplates(t *testing.T) {
 
 	CreateFormatterAndCheckOutput(t, &testingConfig, expectedAlertMsgs)
 }
+
+func TestResolvedTemplate(t *testing.T) {
+	testingConfig := Config{
+		MsgTemplateResolved: "Resolved: {{ .Labels.alertname }}",
+	}
+	expectedAlertMsgs := []AlertMsg{
+		AlertMsg{
+			Channel: "#somechannel",
+			Alert:   "Resolved: airDown",
+		},
+		AlertMsg{
+			Channel: "#somechannel",
+			Alert:   "Resolved: airDown",
+		},
+	}
+	CreateFormatterAndCheckOutput(t, &testingConfig, expectedAlertMsgs)
+}