feat(service): Add SendGrid service

README.md

@@ -66,6 +66,7 @@ _ = notifier.Send(
 - *Microsoft Teams*
 - *Plivo*
 - *Pushbullet*
+- *SendGrid*
 - *Slack*
 - *Telegram*
 - *Twitter*

go.mod

@@ -9,10 +9,11 @@ require (
 	github.com/dghubble/go-twitter v0.0.0-20201011215211-4b180d0cc78d
 	github.com/dghubble/oauth1 v0.7.0
 	github.com/go-telegram-bot-api/telegram-bot-api v4.6.4+incompatible
-	github.com/google/go-querystring v1.0.0 // indirect
 	github.com/jordan-wright/email v4.0.1-0.20210109023952-943e75fe5223+incompatible
 	github.com/pkg/errors v0.9.1
 	github.com/plivo/plivo-go v5.5.1+incompatible
+	github.com/sendgrid/rest v2.6.2+incompatible // indirect
+	github.com/sendgrid/sendgrid-go v3.7.2+incompatible
 	github.com/sirupsen/logrus v1.7.0 // indirect
 	github.com/slack-go/slack v0.8.0
 	github.com/stretchr/testify v1.7.0

go.sum

@@ -33,6 +33,10 @@ github.com/plivo/plivo-go v5.5.1+incompatible h1:LtZaUNHjSrNzBCHAe/IdDBnLGlyZB+W
 github.com/plivo/plivo-go v5.5.1+incompatible/go.mod h1:OhnI9crdl6O+D94Lp1lvuwJoA3KUH39J6IM+j3HwCBE=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/sendgrid/rest v2.6.2+incompatible h1:zGMNhccsPkIc8SvU9x+qdDz2qhFoGUPGGC4mMvTondA=
+github.com/sendgrid/rest v2.6.2+incompatible/go.mod h1:kXX7q3jZtJXK5c5qK83bSGMdV6tsOE70KbHoqJls4lE=
+github.com/sendgrid/sendgrid-go v3.7.2+incompatible h1:ePQr9ns8so+28whk+gLKRYiyI5IiCESkDIqy7cjiwLg=
+github.com/sendgrid/sendgrid-go v3.7.2+incompatible/go.mod h1:QRQt+LX/NmgVEvmdRw0VT/QgUn499+iza2FnDca9fg8=
 github.com/sirupsen/logrus v1.7.0 h1:ShrD1U9pZB12TX0cVy0DtePoCH97K8EtX+mg7ZARUtM=
 github.com/sirupsen/logrus v1.7.0/go.mod h1:yWOB1SBYBC5VeMP7gHvWumXLIWorT60ONWic61uBYv0=
 github.com/slack-go/slack v0.8.0 h1:ANyLY5KHLV+MxLJDQum2IuHTLwbCbDtaWY405X1EU9U=

service/sendgrid/sendgrid.go

@@ -0,0 +1,67 @@
+package sendgrid
+
+import (
+	"net/http"
+
+	"github.com/pkg/errors"
+
+	"github.com/sendgrid/sendgrid-go"
+	"github.com/sendgrid/sendgrid-go/helpers/mail"
+)
+
+// SendGrid struct holds necessary data to communicate with the SendGrid API.
+type SendGrid struct {
+	client            *sendgrid.Client
+	senderAddress     string
+	senderName        string
+	receiverAddresses []string
+}
+
+// New returns a new instance of a SendGrid notification service.
+// You will need a SendGrid API key.
+// See https://sendgrid.com/docs/for-developers/sending-email/api-getting-started/
+func New(apiKey, senderAddress, senderName string) *SendGrid {
+	return &SendGrid{
+		client:            sendgrid.NewSendClient(apiKey),
+		senderAddress:     senderAddress,
+		senderName:        senderName,
+		receiverAddresses: []string{},
+	}
+}
+
+// AddReceivers takes email addresses and adds them to the internal address list. The Send method will send
+// a given message to all those addresses.
+func (s *SendGrid) AddReceivers(addresses ...string) {
+	s.receiverAddresses = append(s.receiverAddresses, addresses...)
+}
+
+// Send takes a message subject and a message body and sends them to all previously set chats. Message body supports
+// html as markup language.
+func (s SendGrid) Send(subject, message string) error {
+	from := mail.NewEmail(s.senderName, s.senderAddress)
+	content := mail.NewContent("text/html", message)
+
+	// Create a new personalization instance to be able to add multiple receiver addresses.
+	personalization := mail.NewPersonalization()
+	personalization.Subject = subject
+
+	for _, receiverAddress := range s.receiverAddresses {
+		personalization.AddTos(mail.NewEmail(receiverAddress, receiverAddress))
+	}
+
+	mailMessage := mail.NewV3Mail()
+	mailMessage.AddPersonalizations(personalization)
+	mailMessage.AddContent(content)
+	mailMessage.SetFrom(from)
+
+	resp, err := s.client.Send(mailMessage)
+	if err != nil {
+		return errors.Wrap(err, "failed to send mail using SendGrid service")
+	}
+
+	if resp.StatusCode != http.StatusAccepted {
+		return errors.New("the SendGrid endpoint did not accept the message")
+	}
+
+	return nil
+}