Allow geoip files to passed in as arguments

Paths to geoip files can now be passed in as arguments.
These values will default to /usr/share/tor/geoip(6), which is where the
Debian tor-geoip package installs database files

broker/broker.go

@@ -230,18 +230,24 @@ func main() {
 	var acmeEmail string
 	var acmeHostnamesCommas string
 	var addr string
+        var geoipDatabase string
+        var geoip6Database string
 	var disableTLS bool
 
 	flag.StringVar(&acmeEmail, "acme-email", "", "optional contact email for Let's Encrypt notifications")
 	flag.StringVar(&acmeHostnamesCommas, "acme-hostnames", "", "comma-separated hostnames for TLS certificate")
 	flag.StringVar(&addr, "addr", ":443", "address to listen on")
+        flag.StringVar(&geoipDatabase, "geoipdb", "/usr/share/tor/geoip", "path to correctly formatted geoip database mapping IPv4 address ranges to country codes")
+        flag.StringVar(&geoip6Database, "geoip6db", "/usr/share/tor/geoip6", "path to correctly formatted geoip database mapping IPv6 address ranges to country codes")
 	flag.BoolVar(&disableTLS, "disable-tls", false, "don't use HTTPS")
 	flag.Parse()
 
 	log.SetFlags(log.LstdFlags | log.LUTC)
 
 	ctx := NewBrokerContext()
 
+        ctx.metrics.LoadGeoipDatabases(geoipDatabase, geoip6Database)
+
 	go ctx.Broker()
 
 	http.HandleFunc("/robots.txt", robotsTxtHandler)

broker/metrics.go

@@ -47,13 +47,12 @@ func (m Metrics) UpdateCountryStats(addr string) {
 
 }
 
-func NewMetrics() *Metrics {
-	m := new(Metrics)
+func (m Metrics) LoadGeoipDatabases(geoipDB string, geoip6DB string) {
 
         // Load geoip databases
         log.Println("Loading geoip databases")
         tablev4 := new(GeoIPv4Table)
-        err := GeoIPLoadFile(tablev4, "./geoip")
+        err := GeoIPLoadFile(tablev4, geoipDB)
         if err != nil {
             m.tablev4 = nil
             log.Println("Failed to load geoip database ")
@@ -62,13 +61,17 @@ func NewMetrics() *Metrics {
         }
 
         tablev6 := new(GeoIPv6Table)
-        err = GeoIPLoadFile(tablev6, "./geoip6")
+        err = GeoIPLoadFile(tablev6, geoip6DB)
         if err != nil {
             m.tablev6 = nil
-            log.Println("Failed to load geoip database ")
+            log.Println("Failed to load geoip6 database ")
         } else {
             m.tablev6 = tablev6
         }
+}
+
+func NewMetrics() *Metrics {
+	m := new(Metrics)
 
         m.countryStats = CountryStats{
             counts: make(map[string]int),