Use configuration file

.gitignore

@@ -1,3 +1,3 @@
 *.log
-mailing
-maildir/
+cmd/mailing/mailing
+tmp/

cmd/mailing/config.go

@@ -0,0 +1,59 @@
+package main
+
+import (
+	"encoding/json"
+	"log"
+	"os"
+
+	"github.com/kelseyhightower/envconfig"
+	"github.com/pelletier/go-toml"
+)
+
+// Config holds the program configuration
+type Config struct {
+	FQDN       string
+	SMTP       string
+	Cert       string
+	Key        string
+	Maildir    string
+	Trace      string
+	Blocklists Blocklists
+}
+
+// Blocklists holds the configuration of blocklists
+type Blocklists struct {
+	DNS struct {
+		IP     []string
+		Domain []string
+	}
+}
+
+func defaultConfig() Config {
+	// In the future this will set values that are not in
+	// the default configuration file.
+	return Config{}
+}
+
+func readConfig(filename string) Config {
+	config := defaultConfig()
+
+	// Read in TOML config
+	// nolint: gosec // config file can be anywhere
+	file, err := os.Open(filename)
+	if err != nil {
+		log.Fatal(err)
+	}
+	decoder := toml.NewDecoder(file)
+	err = decoder.Decode(&config)
+	if err != nil {
+		log.Fatalf("cannot read %s: %s", filename, err)
+	}
+	// Override with environment variables
+	err = envconfig.Process("mailing", &config)
+	if err != nil {
+		log.Fatalf("cannot override config: %s", err)
+	}
+	js, _ := json.MarshalIndent(config, "", "  ")
+	log.Println("config:", string(js))
+	return config
+}

cmd/mailing/main.go

@@ -0,0 +1,33 @@
+package main
+
+import (
+	"flag"
+	"log"
+
+	"gitlab.com/alienscience/mailing/smtp"
+)
+
+var (
+	configFile = flag.String("config", "mailing.toml", "configuration file")
+)
+
+func main() {
+	flag.Parse()
+	config := readConfig(*configFile)
+	handler, err := newSMTPHandler(config.Blocklists, config.Maildir)
+	if err != nil {
+		log.Fatal(err)
+	}
+	server, err := smtp.NewServer(
+		smtp.WithFqdn(config.FQDN),
+		smtp.WithHandler(handler),
+		smtp.WithAddress(config.SMTP),
+		smtp.WithTLS(config.Cert, config.Key),
+		smtp.WithTracer(tracer(config.Trace)),
+	)
+	if err != nil {
+		log.Fatal(err)
+	}
+	log.Printf("%s SMTP server starting on %s", config.FQDN, config.SMTP)
+	server.ListenAndServe()
+}

cmd/mailing/smtp_handler.go

@@ -15,13 +15,14 @@ type smtpHandler struct {
 	mailstore *store.Mailstore
 }
 
-func newSMTPHandler(blocklists []string, maildir string) (*smtpHandler, error) {
+func newSMTPHandler(blocklists Blocklists, maildir string) (*smtpHandler, error) {
 	mailstore, err := store.NewMailstore(maildir)
 	if err != nil {
 		return nil, err
 	}
+	ipBlocklists := blocklists.DNS.IP
 	return &smtpHandler{
-		mxDNS:     mxdns.NewMxDNS(blocklists...),
+		mxDNS:     mxdns.NewMxDNS(ipBlocklists...),
 		mailstore: mailstore,
 	}, nil
 }

configs/mailing.toml

@@ -0,0 +1,36 @@
+
+# All settings at the top level can be overridden by an environment variables e.g
+# MAILING_FQDN="mail.example.org"
+
+# Fully qualified domain name of the mail server
+fqdn ="localhost"
+
+# SMTP address to listen on. Use ":25" to listen on all interfaces.
+smtp = "127.0.0.1:8025"
+
+# TLS Certificate file
+cert = "test/certs/cert.pem"
+
+# TLS Certificate key
+key = "test/certs/key.pem"
+
+# Directory where mail will be stored
+maildir = "tmp/maildir"
+
+# Directory where SMTP trace files will be stored
+# Comment this out to turn off tracing
+trace = "tmp/trace"
+
+[blocklists.dns]
+# DNS blocklists that are queried by IP address
+ip = [
+  "zen.spamhaus.org",
+  "dnsbl-1.uceprotect.net",
+  "b.barracuda.central.org",
+  "cbl.abuseat.org",
+  "spam.dnsbl.sorbs.net"
+]
+# DNS blocklists that are queried by domain
+domain = [
+  "dbl.spamhaus.org"
+]

go.mod

@@ -6,7 +6,9 @@ require (
 	github.com/etcd-io/bbolt v1.3.3 // indirect
 	github.com/google/go-cmp v0.4.0
 	github.com/google/uuid v1.1.1
+	github.com/kelseyhightower/envconfig v1.4.0
 	github.com/namsral/flag v1.7.4-pre
+	github.com/pelletier/go-toml v1.7.0
 	gitlab.com/alienscience/parser v0.0.0-20200430105728-00f56c127330
 	go.etcd.io/bbolt v1.3.3
 	gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c

go.sum

@@ -1,11 +1,17 @@
+github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/etcd-io/bbolt v1.3.3 h1:gSJmxrs37LgTqR/oyJBWok6k6SvXEUerFTbltIhXkBM=
 github.com/etcd-io/bbolt v1.3.3/go.mod h1:ZF2nL25h33cCyBtcyWeZ2/I3HQOfTP+0PIEvHjkjCrw=
 github.com/google/go-cmp v0.4.0 h1:xsAVV57WRhGj6kEIi8ReJzQlHHqcBYCElAvkovg3B/4=
 github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/uuid v1.1.1 h1:Gkbcsh/GbpXz7lPftLA3P6TYMwjCLYm83jiFQZF/3gY=
 github.com/google/uuid v1.1.1/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/kelseyhightower/envconfig v1.4.0 h1:Im6hONhd3pLkfDFsbRgu68RDNkGF1r3dvMUtDTo2cv8=
+github.com/kelseyhightower/envconfig v1.4.0/go.mod h1:cccZRl6mQpaq41TPp5QxidR+Sa3axMbJDNb//FQX6Gg=
 github.com/namsral/flag v1.7.4-pre h1:b2ScHhoCUkbsq0d2C15Mv+VU8bl8hAXV8arnWiOHNZs=
 github.com/namsral/flag v1.7.4-pre/go.mod h1:OXldTctbM6SWH1K899kPZcf65KxJiD7MsceFUpB5yDo=
+github.com/pelletier/go-toml v1.7.0 h1:7utD74fnzVc/cpcyy8sjrlFr5vYpypUixARcHIMIGuI=
+github.com/pelletier/go-toml v1.7.0/go.mod h1:vwGMzjaWMwyfHwgIBhI2YUM4fB6nL6lVAvS1LBMMhTE=
 gitlab.com/alienscience/parser v0.0.0-20200307061714-ec2be86e273c h1:K+Fg60Yl9163ymLEtmyed4detme82ypT4/3Yro1x/SM=
 gitlab.com/alienscience/parser v0.0.0-20200307061714-ec2be86e273c/go.mod h1:M8FwZu4WH1chcF1Ku5d8P7pvLSjY/a+j9pVUjp4mfdM=
 gitlab.com/alienscience/parser v0.0.0-20200428102854-a44c299feeeb h1:RhMX3jR6GrLItVi9e92Pc7KnIEcEdOxeZasqxBQ86XM=
@@ -21,5 +27,6 @@ go.etcd.io/bbolt v1.3.3/go.mod h1:IbVyRI1SCnLcuJnV2u8VeU0CEYM7e686BmAb1XKL+uU=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

main.go

@@ -1,41 +0,0 @@
-package main
-
-import (
-	"log"
-	"strings"
-
-	"github.com/namsral/flag"
-	"gitlab.com/alienscience/mailing/smtp"
-)
-
-const defaultBlocklists = "zen.spamhaus.org,dnsbl-1.uceprotect.net,b.barracudacentral.org"
-
-var (
-	fqdn        = flag.String("fqdn", "localhost", "fully qualified domain name")
-	smtpAddress = flag.String("smtp", ":8025", "smtp listen address")
-	certFile    = flag.String("cert", "test-certs/cert.pem", "certificate file")
-	keyFile     = flag.String("key", "test-certs/key.pem", "certificate key file")
-	blocklists  = flag.String("blocklists", defaultBlocklists, "SMTP blocklists")
-	maildir     = flag.String("maildir", "maildir", "write mail messages to this directory")
-	traceDir    = flag.String("tracedir", ".", "write trace files to this directory")
-)
-
-func main() {
-	flag.Parse()
-	handler, err := newSMTPHandler(strings.Split(*blocklists, ","), *maildir)
-	if err != nil {
-		log.Fatal(err)
-	}
-	server, err := smtp.NewServer(
-		smtp.WithFqdn(*fqdn),
-		smtp.WithHandler(handler),
-		smtp.WithAddress(*smtpAddress),
-		smtp.WithTLS(*certFile, *keyFile),
-		smtp.WithTracer(tracer(*traceDir)),
-	)
-	if err != nil {
-		log.Fatal(err)
-	}
-	log.Printf("%s SMTP server starting on %s", *fqdn, *smtpAddress)
-	server.ListenAndServe()
-}

scripts/run.sh

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+cmd/mailing/mailing -config configs/mailing.toml