Implement initial email notifications

config/notifies.go

@@ -36,6 +36,13 @@ var (
 			Fallback:  "slack_default_fallback",
 		},
 	}
+
+	DefaultEmailConfig = EmailConfig{
+		Templates: EmailTemplates{
+			HTML:  "email_default_html",
+			Plain: "email_default_plain",
+		},
+	}
 )
 
 // Configuration for notification via PagerDuty.
@@ -63,12 +70,21 @@ func (c *PagerdutyConfig) UnmarshalYAML(unmarshal func(interface{}) error) error
 // Configuration for notification via mail.
 type EmailConfig struct {
 	// Email address to notify.
-	Email string `yaml:"email"`
+	Email     string `yaml:"email"`
+	Smarthost string `yaml:"smarthost,omitempty"`
+	Sender    string `yaml:"sender"`
+
+	Templates EmailTemplates `yaml:"templates"`
 
 	// Catches all undefined fields and must be empty after parsing.
 	XXX map[string]interface{} `yaml:",inline"`
 }
 
+type EmailTemplates struct {
+	HTML  string `yaml:"html"`
+	Plain string `yaml:"plain"`
+}
+
 // UnmarshalYAML implements the yaml.Unmarshaler interface.
 func (c *EmailConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	type plain EmailConfig
@@ -78,6 +94,12 @@ func (c *EmailConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	if c.Email == "" {
 		return fmt.Errorf("missing email address in email config")
 	}
+	if c.Sender == "" {
+		return fmt.Errorf("missing SMTP sender in email config")
+	}
+	if c.Smarthost == "" {
+		return fmt.Errorf("missing smart host in email config")
+	}
 	return checkOverflow(c.XXX, "email config")
 }
 

main.go

@@ -17,12 +17,12 @@ import (
 	"database/sql"
 	"flag"
 	"fmt"
+	"html/template"
 	"net/http"
 	"os"
 	"os/signal"
 	"path/filepath"
 	"syscall"
-	"text/template"
 
 	"github.com/prometheus/common/log"
 	"github.com/prometheus/common/route"

notify/impl.go

@@ -2,10 +2,16 @@ package notify
 
 import (
 	"bytes"
+	"crypto/tls"
 	"encoding/json"
 	"fmt"
+	"html/template"
+	"net"
 	"net/http"
-	"text/template"
+	"net/smtp"
+	"os"
+	"strings"
+	"time"
 
 	"github.com/prometheus/common/log"
 	"github.com/prometheus/common/model"
@@ -31,8 +37,11 @@ func Build(confs []*config.NotificationConfig) map[string]Notifier {
 				Notifier: NewWebhook(wc),
 			})
 		}
-		for range nc.EmailConfigs {
-			all = append(all, &LogNotifier{Log: log.With("name", nc.Name)})
+		for _, ec := range nc.EmailConfigs {
+			all = append(all, &LogNotifier{
+				Log:      log.With("notifier", "email"),
+				Notifier: NewEmail(ec),
+			})
 		}
 
 		res[nc.Name] = all
@@ -81,6 +90,97 @@ func (w *Webhook) Notify(ctx context.Context, alerts ...*types.Alert) error {
 	return nil
 }
 
+type Email struct {
+	conf *config.EmailConfig
+}
+
+func NewEmail(ec *config.EmailConfig) *Email {
+	return &Email{conf: ec}
+}
+
+func (n *Email) auth(mechs string) (smtp.Auth, *tls.Config, error) {
+	username := os.Getenv("SMTP_AUTH_USERNAME")
+
+	for _, mech := range strings.Split(mechs, " ") {
+		switch mech {
+		case "CRAM-MD5":
+			secret := os.Getenv("SMTP_AUTH_SECRET")
+			if secret == "" {
+				continue
+			}
+			return smtp.CRAMMD5Auth(username, secret), nil, nil
+
+		case "PLAIN":
+			password := os.Getenv("SMTP_AUTH_PASSWORD")
+			if password == "" {
+				continue
+			}
+			identity := os.Getenv("SMTP_AUTH_IDENTITY")
+
+			// We need to know the hostname for both auth and TLS.
+			host, _, err := net.SplitHostPort(n.conf.Smarthost)
+			if err != nil {
+				return nil, nil, fmt.Errorf("invalid address: %s", err)
+			}
+			var (
+				auth = smtp.PlainAuth(identity, username, password, host)
+				cfg  = &tls.Config{ServerName: host}
+			)
+			return auth, cfg, nil
+		}
+	}
+	return nil, nil, nil
+}
+
+func (n *Email) Notify(ctx context.Context, as ...*types.Alert) error {
+	// Connect to the SMTP smarthost.
+	c, err := smtp.Dial(n.conf.Smarthost)
+	if err != nil {
+		return err
+	}
+	defer c.Quit()
+
+	if ok, mech := c.Extension("AUTH"); ok {
+		auth, tlsConf, err := n.auth(mech)
+		if err != nil {
+			return err
+		}
+		if tlsConf != nil {
+			if err := c.StartTLS(tlsConf); err != nil {
+				return fmt.Errorf("starttls failed: %s", err)
+			}
+		}
+		if auth != nil {
+			if err := c.Auth(auth); err != nil {
+				return fmt.Errorf("%T failed: %s", auth, err)
+			}
+		}
+	}
+
+	c.Mail(n.conf.Sender)
+	c.Rcpt(n.conf.Email)
+
+	// Send the email body.
+	wc, err := c.Data()
+	if err != nil {
+		return err
+	}
+	defer wc.Close()
+
+	// TODO(fabxc): do a multipart write that considers the plain template.
+	return tmpl.ExecuteTemplate(wc, n.conf.Templates.HTML, struct {
+		Alerts model.Alerts
+		From   string
+		To     string
+		Date   string
+	}{
+		Alerts: types.Alerts(as...),
+		From:   n.conf.Sender,
+		To:     n.conf.Email,
+		Date:   time.Now().Format(time.RFC1123Z),
+	})
+}
+
 type Slack struct {
 	conf *config.SlackConfig
 }
@@ -112,14 +212,13 @@ type slackAttachmentField struct {
 }
 
 func (n *Slack) Notify(ctx context.Context, as ...*types.Alert) error {
+	alerts := types.Alerts(as...)
 	var (
-		alerts = types.Alerts(as...)
 		color  = n.conf.ColorResolved
-		status = string(model.AlertResolved)
+		status = string(alerts.Status())
 	)
 	if alerts.HasFiring() {
 		color = n.conf.ColorFiring
-		status = string(model.AlertFiring)
 	}
 
 	var title, link, pretext, text, fallback bytes.Buffer

notify/notify.go

@@ -86,10 +86,13 @@ func (ns Notifiers) Notify(ctx context.Context, alerts ...*types.Alert) error {
 	var wg sync.WaitGroup
 	wg.Add(len(ns))
 
+	failed := false
+
 	for _, n := range ns {
 		go func(n Notifier) {
 			err := n.Notify(ctx, alerts...)
 			if err != nil {
+				failed = true
 				log.Errorf("Error on notify: %s", err)
 			}
 			wg.Done()
@@ -98,7 +101,7 @@ func (ns Notifiers) Notify(ctx context.Context, alerts ...*types.Alert) error {
 
 	wg.Wait()
 
-	return nil
+	return fmt.Errorf("some errors occurred")
 }
 
 type RetryNotifier struct {