sendmail/main.go

package main

import (
	"bufio"
	"flag"
	"fmt"
	"os"
	"strings"
	"time"
)

var noVersion = "dev"
var version string

func readFromConsole(result chan string) {
	var text, line string
	var err error
	counter := 0
	reader := bufio.NewReader(os.Stdin)
	for counter < 3 {
		line, err = reader.ReadString('\n')
		if line == "\n" {
			counter++
		} else {
			counter = 0
		}
		text += fmt.Sprintf("%s\n", line)
	}
	if err != nil {
		Error.F("Error in reading text from console\n%s", err)
		os.Exit(1)
	}
	result <- strings.TrimRight(text, "\n")
	return
}

func toList(input string) []string {
	var result = []string{}
	list := strings.Split(input, ",")
	for _, element := range list {
		if element != "" {
			result = append(result, element)
		}
	}
	return result
}

func initializeConfig(configPath, section string) *Config {
	if configPath == "" {
		configPath = "/etc/sendmail.toml"

		// Ignore non existing config only if `-conf` not used on command line.
		if _, err := os.Stat(configPath); os.IsNotExist(err) {
			return NewConfig()
		}
	}

	config, err := readConfig(configPath, section)
	if err != nil {
		if os.IsNotExist(err) {
			Error.F("Error in parsing the configuration\n%s", err)
			os.Exit(-2)
		}
	}

	Debug.F("---\nConfig from %s\n%s", configPath, *config)
	return config
}

func main() {
	var err error
	var configPath, section, serverAddress, user, password, to, cc, bcc, from, subject, text string
	var encryption, dbg, versionFlag, interactive bool
	var serverPortAux int
	var serverPort int64

	flag.BoolVar(&versionFlag, "version", false, "Prints the version and exits")
	flag.StringVar(&configPath, "conf", "", "Path to a config file (defaults to /etc/sendmail.toml)")
	flag.StringVar(&section, "section", "default", "Section of the conf to read (defaults to \"default\")")
	flag.BoolVar(&dbg, "dbg", false, "Enable debugging output")
	flag.BoolVar(&interactive, "interactive", false, "Assume composing mail manually, do not timeout waiting input")
	flag.StringVar(&serverAddress, "server-address", "", "The SMTP server address")
	flag.IntVar(&serverPortAux, "server-port", 0, "The SMTP server")
	flag.BoolVar(&encryption, "force-ssl", false, "Force the use of ssl (defalut: false)")
	flag.StringVar(&user, "user", "", "The user to authenticate with to the server")
	flag.StringVar(&password, "password", "", "The password to authenticate with to the server")
	flag.StringVar(&to, "to", "", "Comma-separated list of recipient(s)")
	flag.StringVar(&cc, "cc", "", "Comma-separated list of carbon-copy recipient(s)")
	flag.StringVar(&bcc, "bcc", "", "Comma-separated list of blind carbon-copy recipient(s)")
	flag.StringVar(&from, "from", "", "Sender of the mail (used as default account user to log in on the SMTP server)")
	flag.StringVar(&subject, "sub", "", "Subject of the mail")
	flag.Parse()

	LogInit(dbg)

	if versionFlag {
		showVersion := noVersion
		if version != "" {
			showVersion = version
		}
		Info.F("Version: %s", showVersion)
		os.Exit(0)
	}

	if flag.NArg() == 0 {
		result := make(chan string, 1)
		go readFromConsole(result)
		if interactive {
			text = <-result
		} else {
			select {
			case text = <-result:
				Info.Ln("text read from console")
			case <-time.After(5 * time.Second):
				Error.Ln("timeout reading from console")
				os.Exit(3)
			}
		}
	} else {
		for _, arg := range flag.Args() {
			text += fmt.Sprintf("%s\n", arg)
		}
	}

	serverPort = int64(serverPortAux)
	Debug.F(
		`
---
parameters:
	conf: %s
	dbg: %t
	address: %s
	port: %d
	encryption: %t
	user: %s
	password: %s
	to: %s
	from: %s
	subject: %s`,
		configPath,
		dbg,
		serverAddress,
		serverPort,
		encryption,
		user,
		password,
		to,
		from,
		subject,
	)

	config := initializeConfig(configPath, section)
	config.Server.Merge("Address", serverAddress)
	config.Server.Merge("Port", serverPort)
	config.Server.Merge("Encryption", encryption)
	config.Server.Merge("User", user)
	config.Server.Merge("Password", password)
	config.Merge("From", from)
	config.Merge("To", toList(to))
	config.Merge("Cc", toList(cc))
	config.Merge("Bcc", toList(bcc))
	config.Merge("Subject", subject)
	config.Merge("Text", text)

	Debug.F("---\nPre-validation config\n%s", config)
	err = config.Validate()
	if err != nil {
		Error.F("Config validation failed:\n%s\n", err)
		os.Exit(1)
	}

	Info.F("Sending mail | to: %s", config.To)
	SendMail(config)
}