feat: publish standalone worker

Separate worker packaging and service lifecycle from the control plane.

internal/notifier/email.go

@@ -0,0 +1,88 @@
+// Package notifier provides functionality.
+package notifier
+
+import (
+	"crypto/tls"
+	"errors"
+	"fmt"
+	"net/mail"
+
+	"github.com/microcosm-cc/bluemonday"
+	"gopkg.in/gomail.v2"
+
+	"rsgit.ru/rsmon/rsmon/app/models"
+)
+
+// SendEmail provides functionality.
+func SendEmail(to, subject, body string) error {
+	p := bluemonday.StripTagsPolicy()
+	cred, err := firstSMTPCredential()
+	if err != nil {
+		return err
+	}
+
+	fromAddr := &mail.Address{Name: cred.fromName, Address: cred.fromAddress}
+	from := fromAddr.String()
+
+	m := gomail.NewMessage()
+	m.SetHeader("From", from)
+	m.SetHeader("To", to)
+	m.SetHeader("Subject", subject)
+	// m.SetBody("text/html", body)
+	m.AddAlternative("text/plain", p.Sanitize(body))
+	m.AddAlternative("text/html", body)
+
+	d := gomail.NewDialer(
+		cred.server,
+		cred.port,
+		cred.login,
+		cred.password,
+	)
+	if cred.insecureSkipVerify {
+		d.TLSConfig = &tls.Config{InsecureSkipVerify: true}
+	}
+
+	return d.DialAndSend(m)
+}
+
+type smtpCredential struct {
+	server             string
+	port               int
+	login              string
+	password           string
+	fromName           string
+	fromAddress        string
+	insecureSkipVerify bool
+}
+
+func firstSMTPCredential() (*smtpCredential, error) {
+	creds, err := models.EnabledCredentialsByKind(models.CredentialKindSMTP)
+	if err != nil {
+		return nil, err
+	}
+	if len(creds) == 0 {
+		return nil, errors.New("smtp credential is not configured")
+	}
+	c := &creds[0]
+	password, err := c.GetSecret()
+	if err != nil {
+		return nil, fmt.Errorf("smtp credential secret: %w", err)
+	}
+	out := &smtpCredential{password: password, insecureSkipVerify: c.InsecureSkipVerify}
+	if c.Server != nil {
+		out.server = *c.Server
+	}
+	if c.Port != nil {
+		out.port = *c.Port
+	}
+	if c.Login != nil {
+		out.login = *c.Login
+	}
+	if c.FromName != nil {
+		out.fromName = *c.FromName
+	}
+	if c.FromAddr != nil {
+		out.fromAddress = *c.FromAddr
+	}
+	return out, nil
+}