config.go

/*
	smtp-dkim-signer - SMTP-proxy that DKIM-signs e-mails before submission.
	Copyright (C) 2018 - 2020, Marc Hoersken <info@marc-hoersken.de>

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/

package main

import (
	"time"

	"github.com/spf13/viper"
)

var defaultHeaderKeys = []string{
	"From", "Reply-To", "Subject", "Date", "To", "Cc",
	"In-Reply-To", "References", "Message-ID",
	"Resent-Date", "Resent-From", "Resent-To", "Resent-Cc",
	"List-Id", "List-Help", "List-Unsubscribe", "List-Subscribe",
	"List-Post", "List-Owner", "List-Archive",
}

type configAcmeLe struct {
	Agreed        bool
	Contact       string
	Challenge     string
	ChallengeHost string
	ChallengePort int
}

type configTLS struct {
	CertPath string
	KeyPath  string
}

type configVHost struct {
	Domain      string
	Upstream    string
	Selector    string
	PrivKeyPath string
	HeaderCan   string
	BodyCan     string
	HeaderKeys  []string
}

type configLogging struct {
	Level string
}

type configRollbar struct {
	AccessToken string
	Environment string
}

type config struct {
	Address           string
	Domain            string
	UseSMTPS          bool
	LetsEncrypt       *configAcmeLe
	TLS               *configTLS
	ReadTimeout       time.Duration
	WriteTimeout      time.Duration
	MaxMessageBytes   int
	MaxRecipients     int
	AllowInsecureAuth bool
	VirtualHosts      []*configVHost
	HeaderKeys        []string

	Logging *configLogging
	Rollbar *configRollbar
}

func loadConfig() (*config, error) {
	vpr := viper.GetViper()
	vpr.SetDefault("UseSMTPS", false)
	vpr.SetDefault("LetsEncrypt.Agreed", false)
	vpr.SetDefault("LetsEncrypt.Challenge", "http")
	vpr.SetDefault("ReadTimeout", 10*time.Second)
	vpr.SetDefault("WriteTimeout", 10*time.Second)
	vpr.SetDefault("MaxRecipients", 50)
	vpr.SetDefault("AllowInsecureAuth", false)
	vpr.SetDefault("HeaderKeys", defaultHeaderKeys)
	vpr.SetConfigName("smtp-dkim-signer")
	vpr.AddConfigPath("/etc/smtp-dkim-signer/")
	vpr.AddConfigPath("$HOME/.smtp-dkim-signer")
	vpr.AddConfigPath(".")
	err := vpr.ReadInConfig()
	if err != nil {
		return nil, err
	}

	var cfg config
	err = vpr.UnmarshalExact(&cfg)
	if err != nil {
		return nil, err
	}
	return &cfg, nil
}