sendgrid

Example demonstrates basic SendGrid usage.

package main

import (
	"context"
	"log"
	"os"

	"github.com/ftrinciante/gomail"
	"github.com/ftrinciante/gomail/provider/sendgrid"
)

func main() {
	// Create SendGrid provider
	provider := sendgrid.New(sendgrid.Config{
		APIKey: os.Getenv("SENDGRID_API_KEY"),
		From:   "noreply@example.com",
	})

	// Create client
	client := gomail.NewClient(provider)
	defer client.Close()

	// Create message
	msg := &gomail.Message{
		To:      []string{"user@example.com"},
		Subject: "Hello from SendGrid",
		Body:    "<h1>Welcome!</h1><p>This email was sent via SendGrid.</p>",
		IsHTML:  true,
	}

	// Send email
	if err := client.Send(context.Background(), msg); err != nil {
		log.Fatalf("Failed to send email: %v", err)
	}

	log.Println("Email sent successfully via SendGrid!")
}

Output:

Example_ccAndBcc demonstrates using CC and BCC.

package main

import (
	"context"
	"log"
	"os"

	"github.com/ftrinciante/gomail"
	"github.com/ftrinciante/gomail/provider/sendgrid"
)

func main() {
	provider := sendgrid.New(sendgrid.Config{
		APIKey: os.Getenv("SENDGRID_API_KEY"),
		From:   "noreply@example.com",
	})

	client := gomail.NewClient(provider)
	defer client.Close()

	msg := &gomail.Message{
		To:      []string{"primary@example.com"},
		CC:      []string{"manager@example.com"},
		BCC:     []string{"archive@example.com"},
		Subject: "Team Update",
		Body:    "This is a team notification.",
		IsHTML:  false,
	}

	if err := client.Send(context.Background(), msg); err != nil {
		log.Fatalf("Failed to send: %v", err)
	}
}

Output:

Example_customHeaders demonstrates adding custom headers.

package main

import (
	"context"
	"log"
	"os"

	"github.com/ftrinciante/gomail"
	"github.com/ftrinciante/gomail/provider/sendgrid"
)

func main() {
	provider := sendgrid.New(sendgrid.Config{
		APIKey: os.Getenv("SENDGRID_API_KEY"),
		From:   "noreply@example.com",
	})

	client := gomail.NewClient(provider)
	defer client.Close()

	msg := &gomail.Message{
		To:      []string{"user@example.com"},
		Subject: "Custom Headers",
		Body:    "This email has custom headers.",
		IsHTML:  false,
		Headers: map[string]string{
			"X-Priority":    "1",
			"X-Application": "MyApp",
			"X-User-ID":     "12345",
		},
	}

	if err := client.Send(context.Background(), msg); err != nil {
		log.Fatalf("Failed to send: %v", err)
	}
}

Output:

Example_dockerSecrets demonstrates loading config from Docker secrets.

package main

import (
	"context"
	"log"
	"os"

	"github.com/ftrinciante/gomail"
	"github.com/ftrinciante/gomail/provider/sendgrid"
)

func main() {
	// Read API key from Docker secret
	apiKeyBytes, err := os.ReadFile("/run/secrets/sendgrid_api_key")
	if err != nil {
		log.Fatalf("Failed to read API key secret: %v", err)
	}

	// Read from email from Docker secret
	fromEmailBytes, err := os.ReadFile("/run/secrets/sendgrid_from_email")
	if err != nil {
		log.Fatalf("Failed to read from email secret: %v", err)
	}

	provider := sendgrid.New(sendgrid.Config{
		APIKey: string(apiKeyBytes),
		From:   string(fromEmailBytes),
	})

	client := gomail.NewClient(provider)
	defer client.Close()

	msg := &gomail.Message{
		To:      []string{"user@example.com"},
		Subject: "Docker Secrets",
		Body:    "Configuration loaded from Docker secrets.",
		IsHTML:  false,
	}

	if err := client.Send(context.Background(), msg); err != nil {
		log.Fatalf("Failed to send: %v", err)
	}
}

Output:

Example_environmentConfig demonstrates loading config from environment.

package main

import (
	"context"
	"log"
	"os"

	"github.com/ftrinciante/gomail"
	"github.com/ftrinciante/gomail/provider/sendgrid"
)

func main() {
	// Load configuration from environment variables
	config := sendgrid.Config{
		APIKey: os.Getenv("SENDGRID_API_KEY"),
		From:   os.Getenv("SENDGRID_FROM_EMAIL"),
	}

	// Validate required config
	if config.APIKey == "" {
		log.Fatal("SENDGRID_API_KEY environment variable is required")
	}
	if config.From == "" {
		log.Fatal("SENDGRID_FROM_EMAIL environment variable is required")
	}

	provider := sendgrid.New(config)
	client := gomail.NewClient(provider)
	defer client.Close()

	msg := &gomail.Message{
		To:      []string{"user@example.com"},
		Subject: "Environment Config",
		Body:    "Configuration loaded from environment variables.",
		IsHTML:  false,
	}

	if err := client.Send(context.Background(), msg); err != nil {
		log.Fatalf("Failed to send: %v", err)
	}
}

Output:

Example_errorHandling demonstrates proper error handling.

package main

import (
	"context"
	"log"
	"os"

	"github.com/ftrinciante/gomail"
	"github.com/ftrinciante/gomail/provider/sendgrid"
)

func main() {
	provider := sendgrid.New(sendgrid.Config{
		APIKey: os.Getenv("SENDGRID_API_KEY"),
		From:   "noreply@example.com",
	})

	client := gomail.NewClient(provider)
	defer client.Close()

	msg := &gomail.Message{
		To:      []string{"user@example.com"},
		Subject: "Test",
		Body:    "Test email",
		IsHTML:  false,
	}

	if err := client.Send(context.Background(), msg); err != nil {
		// Check if it's a SendError
		if sendErr, ok := err.(*gomail.SendError); ok {
			log.Printf("Provider: %s", sendErr.Provider)
			log.Printf("Error: %s", sendErr.Message)
			if sendErr.Err != nil {
				log.Printf("Underlying error: %v", sendErr.Err)
			}
		} else {
			log.Printf("Unexpected error: %v", err)
		}
		return
	}

	log.Println("Email sent successfully!")
}

Output:

Example_htmlEmail demonstrates sending HTML emails.

package main

import (
	"context"
	"log"
	"os"

	"github.com/ftrinciante/gomail"
	"github.com/ftrinciante/gomail/provider/sendgrid"
)

func main() {
	provider := sendgrid.New(sendgrid.Config{
		APIKey: os.Getenv("SENDGRID_API_KEY"),
		From:   "noreply@example.com",
	})

	client := gomail.NewClient(provider)
	defer client.Close()

	html := `
<!DOCTYPE html>
<html>
<head>
    <style>
        .header { background: #007bff; color: white; padding: 20px; }
        .content { padding: 20px; }
    </style>
</head>
<body>
    <div class="header">
        <h1>Welcome to Our Service!</h1>
    </div>
    <div class="content">
        <p>Thank you for signing up.</p>
        <a href="https://example.com">Get Started</a>
    </div>
</body>
</html>
	`

	msg := &gomail.Message{
		To:      []string{"newuser@example.com"},
		Subject: "Welcome Aboard!",
		Body:    html,
		IsHTML:  true,
	}

	if err := client.Send(context.Background(), msg); err != nil {
		log.Fatalf("Failed to send: %v", err)
	}
}

Output: