easily email an attachment without reading from disk

memory-attachment.go

package main
 
import (
	"fmt"
	"bytes"
	"io/ioutil"
	"github.com/mailgun/mailgun-go"
)
 
func main() {
	gun := mailgun.NewMailgun("valid-mailgun-domain", "private-mailgun-key", "public-mailgun-key")

        // Create a new io.ReadCloser that reads an in-memory byte array buffer.
	buf := &bytes.Buffer{}
	buf.Write([]byte("these are the file contents"))
	rc := ioutil.NopCloser(buf)

	m := mailgun.NewMessage("from@example.com", "Subject", "message body", "to@example.com")
	m.AddReaderAttachment("my-file.txt", rc)
	
	response, id, _ := gun.Send(m)
	fmt.Printf("Response ID: %s\n", id)
	fmt.Printf("Message from server: %s\n", response)
}