support for SendGrid payments/balance emails

docs/SETTINGS.md

@@ -32,3 +32,5 @@ Here are the descriptions of values available to use in the `settings` table:
 | FUNCTION_LNDHUB | DISABLE | system level switch for using LNDHUB in place of LND |
 | LNDHUB_URL | | URL for the LNDHUB service |
 | FUNCTION_INTERNAL_API | DISABLE | system level switch for activating the internal API |
+| SENDGRID_API_KEY      | | User API Key from SendGrid.com             |
+| SENDGRID_EMAIL_SENDER | | Single Sender email address verified by SendGrid |

email/email.go

@@ -1,15 +1,18 @@
 package email
 
 import (
+	"strconv"
+	"strings"
+
 	"github.com/aws/aws-sdk-go/aws"
 	"github.com/aws/aws-sdk-go/aws/awserr"
 	"github.com/aws/aws-sdk-go/aws/credentials"
 	"github.com/aws/aws-sdk-go/aws/session"
 	"github.com/aws/aws-sdk-go/service/ses"
 	"github.com/boltcard/boltcard/db"
+	"github.com/sendgrid/sendgrid-go"
+	"github.com/sendgrid/sendgrid-go/helpers/mail"
 	log "github.com/sirupsen/logrus"
-	"strconv"
-	"strings"
 )
 
 func Send_balance_email(recipient_email string, card_id int) {
@@ -86,9 +89,29 @@ func Send_balance_email(recipient_email string, card_id int) {
 }
 
 // https://docs.aws.amazon.com/sdk-for-go/v1/developer-guide/ses-example-send-email.html
+// https://github.com/sendgrid/sendgrid-go
 
 func Send_email(recipient string, subject string, htmlBody string, textBody string) {
 
+	send_grid_api_key := db.Get_setting("SENDGRID_API_KEY")
+	send_grid_email_sender := db.Get_setting("SENDGRID_EMAIL_SENDER")
+	if send_grid_api_key != "" && send_grid_email_sender != "" {
+		from := mail.NewEmail("", send_grid_email_sender)
+		subject := subject
+		to := mail.NewEmail("", recipient)
+		plainTextContent := textBody
+		htmlContent := htmlBody
+		message := mail.NewSingleEmail(from, subject, to, plainTextContent, htmlContent)
+		client := sendgrid.NewSendClient(send_grid_api_key)
+		response, err := client.Send(message)
+		if err != nil {
+			log.Warn(err.Error())
+		} else {
+			log.WithFields(log.Fields{"result": response}).Info("email sent")
+		}
+
+	} else {
+
 		aws_ses_id := db.Get_setting("AWS_SES_ID")
 		aws_ses_secret := db.Get_setting("AWS_SES_SECRET")
 		sender := db.Get_setting("AWS_SES_EMAIL_FROM")
@@ -152,4 +175,5 @@ func Send_email(recipient string, subject string, htmlBody string, textBody stri
 		}
 
 		log.WithFields(log.Fields{"result": result}).Info("email sent")
+	}
 }

go.mod

@@ -97,6 +97,8 @@ require (
 	github.com/prometheus/common v0.37.0 // indirect
 	github.com/prometheus/procfs v0.8.0 // indirect
 	github.com/rogpeppe/fastuuid v1.2.0 // indirect
+	github.com/sendgrid/rest v2.6.9+incompatible // indirect
+	github.com/sendgrid/sendgrid-go v3.12.0+incompatible // indirect
 	github.com/soheilhy/cmux v0.1.5 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
 	github.com/stretchr/objx v0.5.0 // indirect

go.sum

@@ -607,6 +607,10 @@ github.com/russross/blackfriday/v2 v2.0.1/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQD
 github.com/ryanuber/columnize v0.0.0-20160712163229-9b3edd62028f/go.mod h1:sm1tb6uqfes/u+d4ooFouqFdy9/2g9QGwK3SQygK0Ts=
 github.com/satori/go.uuid v1.2.0/go.mod h1:dA0hQrYB0VpLJoorglMZABFdXlWrHn1NEOzdhQKdks0=
 github.com/sean-/seed v0.0.0-20170313163322-e2103e2c3529/go.mod h1:DxrIzT+xaE7yg65j358z/aeFdxmN0P9QXhEzd20vsDc=
+github.com/sendgrid/rest v2.6.9+incompatible h1:1EyIcsNdn9KIisLW50MKwmSRSK+ekueiEMJ7NEoxJo0=
+github.com/sendgrid/rest v2.6.9+incompatible/go.mod h1:kXX7q3jZtJXK5c5qK83bSGMdV6tsOE70KbHoqJls4lE=
+github.com/sendgrid/sendgrid-go v3.12.0+incompatible h1:/N2vx18Fg1KmQOh6zESc5FJB8pYwt5QFBDflYPh1KVg=
+github.com/sendgrid/sendgrid-go v3.12.0+incompatible/go.mod h1:QRQt+LX/NmgVEvmdRw0VT/QgUn499+iza2FnDca9fg8=
 github.com/shopspring/decimal v0.0.0-20180709203117-cd690d0c9e24/go.mod h1:M+9NzErvs504Cn4c5DxATwIqPbtswREoFCre64PpcG4=
 github.com/shopspring/decimal v1.2.0 h1:abSATXmQEYyShuxI4/vyW3tV1MrKAJzCZ/0zLUXYbsQ=
 github.com/shopspring/decimal v1.2.0/go.mod h1:DKyhrW/HYNuLGql+MJL6WCR6knT2jwCFRcu2hWCYk4o=

sql/settings.sql

@@ -29,3 +29,5 @@ INSERT INTO settings (name, value) VALUES ('EMAIL_MAX_TXS', '');
 INSERT INTO settings (name, value) VALUES ('FUNCTION_LNDHUB', '');
 INSERT INTO settings (name, value) VALUES ('LNDHUB_URL', '');
 INSERT INTO settings (name, value) VALUES ('FUNCTION_INTERNAL_API', '');
+INSERT INTO settings (name, value) VALUES ('SENDGRID_API_KEY', '');
+INSERT INTO settings (name, value) VALUES ('SENDGRID_EMAIL_SENDER', '');