Implement env.URL config type

This type was added for better error handling of the
Webserver.HostName config property.

cmd/tegola/cmd/server.go

@@ -39,13 +39,9 @@ var serverCmd = &cobra.Command{
 			serverPort = string(conf.Webserver.Port)
 		}
 
-		if conf.Webserver.HostName != "" {
-			hostname, err := url.Parse(string(conf.Webserver.HostName))
-			if err != nil {
-				log.Fatalf("unable to parse webserver.hostname: %s", err)
-			}
-
-			server.HostName = hostname
+		if conf.Webserver.HostName.Host != "" {
+			u := url.URL(conf.Webserver.HostName)
+			server.HostName = &u
 		}
 
 		// set our server version

cmd/tegola_lambda/main.go

@@ -90,13 +90,9 @@ func init() {
 
 	// set our server version
 	server.Version = build.Version
-	if conf.Webserver.HostName != "" {
-		hostname, err := url.Parse(string(conf.Webserver.HostName))
-		if err != nil {
-			log.Fatalf("unable to parse webserver.hostname: %s", err)
-		}
-
-		server.HostName = hostname
+	if conf.Webserver.HostName.Host != "" {
+		u := url.URL(conf.Webserver.HostName)
+		server.HostName = &u
 	}
 
 	// set user defined response headers

config/config.go

@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"io"
 	"net/http"
-	"net/url"
 	"os"
 	"strings"
 	"time"
@@ -72,7 +71,7 @@ type Config struct {
 
 // Webserver represents the config options for the webserver part of Tegola
 type Webserver struct {
-	HostName      env.String `toml:"hostname"`
+	HostName      env.URL    `toml:"hostname"`
 	Port          env.String `toml:"port"`
 	URIPrefix     env.String `toml:"uri_prefix"`
 	Headers       env.Dict   `toml:"headers"`
@@ -333,17 +332,6 @@ func (c *Config) Validate() error {
 		}
 	}
 
-	// if HostName is set, validate it
-	if string(c.Webserver.HostName) != "" {
-		_, err := url.Parse(string(c.Webserver.HostName))
-		if err != nil {
-			return ErrInvalidHostName{
-				HostName: string(c.Webserver.HostName),
-				Err:      err,
-			}
-		}
-	}
-
 	return nil
 }