all it is left is template one; refine config management

.gitignore

@@ -14,4 +14,5 @@
 # Dependency directories (remove the comment below to include it)
 # vendor/
 
-*.pb.go
+*.pb.go
+app.env

README.md

@@ -1,2 +1,11 @@
 # email-microservice
 gRPC based emailing service
+
+## Environment Variables
+```
+SMTP_HOST:                  SMTP host
+SMTP_PORT:                  SMTP port
+SMTP_SENDER:                SMTP user
+SMTP_PASSWORD:              SMTP password
+PORT:                       Port to listen on
+```

email.proto

@@ -2,13 +2,6 @@ syntax = "proto3";
 
 option go_package= "/src";
 
-message SendEmailRequest {
-    repeated string receipients = 1;
-    string subject = 2;
-    string body = 3;
-    repeated Attachment attachments = 4;
-}
-
 message Attachment {
     string base64Data = 1;
 }
@@ -18,6 +11,34 @@ message ResponseMessage {
     string ack = 2;
 }
 
+message Recipients {
+    repeated string to = 1;
+    repeated string cc = 2;
+    repeated string bcc = 3;
+}
+
+message SendEmailRequest {
+    Recipients recipients = 1;
+    string subject = 2;
+    string body = 3;
+    string contentType = 4;
+    repeated Attachment attachments = 5;
+}
+
+message RawSendEmailRequest {
+    repeated string recipients = 1;
+    bytes body = 3;
+}
+
+message SendEmailWithTemplateRequest {
+    Recipients recipients = 1;
+    string template_name = 2;
+    repeated Attachment attachments = 3;
+    map<string, string> template_params = 4;
+}
+
 service EmailService {
     rpc SendEmail(SendEmailRequest) returns(ResponseMessage) {}
-}
+    rpc SendRawEmail(RawSendEmailRequest) returns(ResponseMessage) {}
+    rpc SendEmailWithTemplate(SendEmailWithTemplateRequest) returns(ResponseMessage) {}
+}

examples/email_client.go → examples/raw.go

@@ -9,7 +9,7 @@ import (
 	"google.golang.org/grpc"
 )
 
-const address = "localhost:55055"
+const address = "localhost:5555"
 
 var client src.EmailServiceClient
 
@@ -21,19 +21,18 @@ func init() {
 	if err != nil {
 		log.Fatalf("error connecting to server: %v", err)
 	}
-	defer connection.Close()
 	client = src.NewEmailServiceClient(connection)
 }
 
 func main() {
-	sendEmail("Hey there!!", []string{"crossphoton@gmail.com"})
+	sendEmail("Hey there!!", []string{"adiag1200@gmail.com", "cs19b1003@iiitr.ac.in"})
 }
 
 func sendEmail(body string, receivers []string) {
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
 	defer cancel()
 
-	res, err := client.SendEmail(ctx, &src.SendEmailRequest{Receipients: receivers, Body: body})
+	res, err := client.SendRawEmail(ctx, &src.RawSendEmailRequest{Recipients: receivers, Body: []byte(body)})
 	if err != nil {
 		log.Fatalf("request failed: %v", err)
 	} else {

go.mod

@@ -2,13 +2,29 @@ module github.com/crossphoton/email-microservice
 
 go 1.17
 
-require google.golang.org/grpc v1.42.0
+require (
+	github.com/spf13/viper v1.9.0
+	github.com/xhit/go-simple-mail/v2 v2.10.0
+	google.golang.org/grpc v1.42.0
+	google.golang.org/protobuf v1.27.1
+)
 
 require (
-	github.com/golang/protobuf v1.5.0 // indirect
-	golang.org/x/net v0.0.0-20200822124328-c89045814202 // indirect
-	golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd // indirect
-	golang.org/x/text v0.3.0 // indirect
-	google.golang.org/genproto v0.0.0-20200526211855-cb27e3aa2013 // indirect
-	google.golang.org/protobuf v1.27.1 // indirect
+	github.com/fsnotify/fsnotify v1.5.1 // indirect
+	github.com/golang/protobuf v1.5.2 // indirect
+	github.com/hashicorp/hcl v1.0.0 // indirect
+	github.com/magiconair/properties v1.8.5 // indirect
+	github.com/mitchellh/mapstructure v1.4.2 // indirect
+	github.com/pelletier/go-toml v1.9.4 // indirect
+	github.com/spf13/afero v1.6.0 // indirect
+	github.com/spf13/cast v1.4.1 // indirect
+	github.com/spf13/jwalterweatherman v1.1.0 // indirect
+	github.com/spf13/pflag v1.0.5 // indirect
+	github.com/subosito/gotenv v1.2.0 // indirect
+	golang.org/x/net v0.0.0-20210503060351-7fd8e65b6420 // indirect
+	golang.org/x/sys v0.0.0-20210823070655-63515b42dcdf // indirect
+	golang.org/x/text v0.3.6 // indirect
+	google.golang.org/genproto v0.0.0-20210828152312-66f60bf46e71 // indirect
+	gopkg.in/ini.v1 v1.63.2 // indirect
+	gopkg.in/yaml.v2 v2.4.0 // indirect
 )

main.go

@@ -1,16 +1,36 @@
 package main
 
 import (
+	"fmt"
 	"log"
 	"net"
 
 	"github.com/crossphoton/email-microservice/src"
+	"github.com/spf13/viper"
 	grpc "google.golang.org/grpc"
 )
 
-const (
-	PORT = ":55055"
-)
+type Config struct {
+	Port int `mapstructure:"PORT"`
+}
+
+var config Config
+
+func init() {
+	viper.AddConfigPath(".")
+	viper.SetConfigType("env")
+	viper.SetConfigName("app")
+	viper.AutomaticEnv()
+	err := viper.ReadInConfig()
+	if err != nil {
+		if _, ok := err.(viper.ConfigFileNotFoundError); ok {
+		} else {
+			log.Fatalf("error reading config file: %v", err)
+		}
+	}
+
+	viper.Unmarshal(&config)
+}
 
 func main() {
 	// Registering service
@@ -19,14 +39,14 @@ func main() {
 	src.RegisterEmailServiceServer(server, &emailServer)
 
 	// Listening to port
-	listener, err := net.Listen("tcp", PORT)
+	listener, err := net.Listen("tcp", fmt.Sprintf(":%d", config.Port))
 	if err != nil {
-		log.Fatalf("cannot listen on %s : %v", PORT, err)
+		log.Fatalf("cannot listen on %s : %v", config.Port, err)
 	}
 	defer listener.Close()
 
 	// Starting server
-	log.Printf("starting server on %v", PORT)
+	log.Printf("starting server on %v", config.Port)
 	if err := server.Serve(listener); err != nil {
 		log.Fatalf("cannor start server: %v", err)
 	}

sample.env

@@ -0,0 +1,5 @@
+SMTP_HOST=smtp.gmail.com
+SMTP_PORT=587
+SMTP_EMAIL=crossphoton@gmail.com
+SMTP_PASSWORD=password
+PORT=5555

src/config.go

@@ -0,0 +1,55 @@
+package src
+
+import (
+	"crypto/tls"
+	"log"
+	"time"
+
+	"github.com/spf13/viper"
+	mail "github.com/xhit/go-simple-mail/v2"
+)
+
+type Config struct {
+	SMTPHost     string `mapstructure:"SMTP_HOST"`
+	SMTPPort     int    `mapstructure:"SMTP_PORT"`
+	SMTPEmail    string `mapstructure:"SMTP_EMAIL"`
+	SMTPPassword string `mapstructure:"SMTP_PASSWORD"`
+}
+
+var (
+	config Config
+)
+
+func init() {
+	viper.AddConfigPath(".")
+	viper.AddConfigPath("../")
+	viper.SetConfigType("env")
+	viper.SetConfigName("app")
+	viper.AutomaticEnv()
+	err := viper.ReadInConfig()
+	if err != nil {
+		if _, ok := err.(viper.ConfigFileNotFoundError); ok {
+		} else {
+			log.Fatalf("error reading config file: %v", err)
+		}
+	}
+
+	viper.Unmarshal(&config)
+
+	smtpServer := mail.NewSMTPClient()
+	smtpServer.Host = config.SMTPHost
+	smtpServer.Port = config.SMTPPort
+	smtpServer.Username = config.SMTPEmail
+	smtpServer.Password = config.SMTPPassword
+	smtpServer.Encryption = mail.EncryptionSTARTTLS
+
+	smtpServer.KeepAlive = true
+	smtpServer.ConnectTimeout = 10 * time.Second
+	smtpServer.SendTimeout = 10 * time.Second
+	smtpServer.TLSConfig = &tls.Config{InsecureSkipVerify: true}
+
+	smtpClient, err = smtpServer.Connect()
+	if err != nil {
+		log.Fatalf("connection to remote smtp server failed: %v", err)
+	}
+}

src/server.go

@@ -4,34 +4,59 @@ import (
 	"context"
 	"fmt"
 	"log"
-	"net/smtp"
+
+	mail "github.com/xhit/go-simple-mail/v2"
 )
 
+var smtpClient *mail.SMTPClient
+
 type EmailServer struct {
 	UnimplementedEmailServiceServer
 }
 
 func (s *EmailServer) SendEmail(ctx context.Context, req *SendEmailRequest) (*ResponseMessage, error) {
-	smtpHost := "smtp.gmail.com"
-	smtpPort := "587"
-
-	// Sender data.
-	from := "email@gmail.com"
-	password := "password"
-
-	auth := smtp.PlainAuth("", from, password, smtpHost)
-	err := smtp.SendMail(
-		fmt.Sprintf("%s:%s", smtpHost, smtpPort),
-		auth,
-		from,
-		req.GetReceipients(),
-		[]byte(req.GetBody()),
-	)
+	email := mail.NewMSG()
+
+	// Add receivers
+	email.
+		AddTo(req.Recipients.To...).
+		AddCc(req.Recipients.Cc...).
+		AddBcc(req.Recipients.Bcc...).
+		SetSubject(req.Subject)
+
+	// Set content type
+	if req.ContentType == "text/html" {
+		email.SetBody(mail.TextHTML, req.GetBody())
+	} else {
+		email.SetBody(mail.TextPlain, req.GetBody())
+	}
+
+	// Check for errors
+	if email.Error != nil {
+		return nil, fmt.Errorf("email format error: %v", email.Error)
+	}
 
+	// Send the email
+	err := email.Send(smtpClient)
 	if err != nil {
-		log.Println(err)
-		return nil, err
+		log.Printf("err: error sending email: %v", err)
+		return nil, fmt.Errorf("error sending email: %v", err)
 	}
 
 	return &ResponseMessage{Success: true, Ack: "mail sent successfully"}, nil
 }
+
+func (s *EmailServer) SendRawEmail(ctx context.Context, req *RawSendEmailRequest) (*ResponseMessage, error) {
+	// Sending email
+	err := mail.SendMessage(config.SMTPEmail, req.Recipients, string(req.Body), smtpClient)
+	if err != nil {
+		log.Printf("err: error sending email: %v", err)
+		return nil, fmt.Errorf("error sending email: %v", err)
+	}
+
+	return &ResponseMessage{Ack: "email sent successfully", Success: true}, nil
+}
+
+func (s *EmailServer) SendEmailWithTemplate(ctx context.Context, req *SendEmailWithTemplateRequest) (*ResponseMessage, error) {
+	return nil, fmt.Errorf("not implemented")
+}