rename initProxy to launchProxy

remove double log on error

add some explanatory comments.

.dockerignore

@@ -1,6 +1,6 @@
 *
 !cmd/
-!pkg/
+!*.go
 
 !go.mod
 !go.sum

cmd/q3rcon-proxy/main.go

@@ -4,14 +4,16 @@ import (
 	"context"
 	"fmt"
 	"os"
+	"strconv"
 	"strings"
 	"time"
 
-	"github.com/onyx-and-iris/q3rcon-proxy/pkg/udpproxy"
+	udpproxy "github.com/onyx-and-iris/q3rcon-proxy"
 	log "github.com/sirupsen/logrus"
 	"github.com/urfave/cli/v3"
 )
 
+// proxyConfig holds the configuration for a single UDP proxy server.
 type proxyConfig struct {
 	proxyHost      string
 	targetHost     string
@@ -41,6 +43,27 @@ func main() {
 				Usage:    "Proxy and target ports (proxy:target)",
 				Sources:  cli.EnvVars("Q3RCON_PORTS_MAPPING"),
 				Required: true,
+				Action: func(ctx context.Context, cmd *cli.Command, v string) error {
+					// Validate the ports mapping
+					for mapping := range strings.SplitSeq(v, ";") {
+						ports := strings.Split(mapping, ":")
+						if len(ports) != 2 {
+							return fmt.Errorf("invalid ports mapping: %s", mapping)
+						}
+						proxyPort, err := strconv.Atoi(ports[0])
+						if err != nil || proxyPort < 1 || proxyPort > 65535 {
+							return fmt.Errorf("invalid proxy port: %s", ports[0])
+						}
+						targetPort, err := strconv.Atoi(ports[1])
+						if err != nil || targetPort < 1 || targetPort > 65535 {
+							return fmt.Errorf("invalid target port: %s", ports[1])
+						}
+						if proxyPort == targetPort {
+							return fmt.Errorf("proxy and target ports cannot be the same: %s", mapping)
+						}
+					}
+					return nil
+				},
 			},
 			&cli.IntFlag{
 				Name:    "session-timeout",
@@ -74,13 +97,13 @@ func main() {
 					sessionTimeout: cmd.Int("session-timeout"),
 				}
 
-				go initProxy(cfg, errChan)
+				go launchProxy(cfg, errChan)
 			}
 
-			// We don't expect to receive any errors from the channels, but if we do, we log and return early.
+			// Under normal circumstances, the main goroutine will block here
+			// until the server is stopped or an error occurs.
 			for err := range errChan {
 				if err != nil {
-					log.Errorf("Error: %v", err)
 					return err
 				}
 			}
@@ -93,13 +116,16 @@ func main() {
 	}
 }
 
-func initProxy(cfg proxyConfig, errChan chan error) {
+// launchProxy initializes the UDP proxy server with the given configuration.
+// It listens on the specified proxy host and port, and forwards traffic to the target host and port.
+// server.ListenAndServe blocks until the server is stopped or an error occurs.
+func launchProxy(cfg proxyConfig, errChan chan error) {
 	proxyPort, targetPort := cfg.portsMapping[0], cfg.portsMapping[1]
 
 	hostAddr := fmt.Sprintf("%s:%s", cfg.proxyHost, proxyPort)
 	proxyAddr := fmt.Sprintf("%s:%s", cfg.targetHost, targetPort)
 
-	c, err := udpproxy.New(
+	server, err := udpproxy.New(
 		hostAddr, proxyAddr,
 		udpproxy.WithSessionTimeout(time.Duration(cfg.sessionTimeout)*time.Minute))
 	if err != nil {
@@ -109,5 +135,5 @@ func initProxy(cfg proxyConfig, errChan chan error) {
 
 	log.Printf("q3rcon-proxy initialized: [proxy] (%s) [target] (%s)", hostAddr, proxyAddr)
 
-	errChan <- c.ListenAndServe()
+	errChan <- server.ListenAndServe()
 }

option.go

@@ -0,0 +1,22 @@
+package udpproxy
+
+import (
+	"time"
+
+	log "github.com/sirupsen/logrus"
+)
+
+// Option is a functional option type that allows us to configure the Client.
+type Option func(*Client)
+
+// WithSessionTimeout is a functional option to set the session timeout
+func WithSessionTimeout(timeout time.Duration) Option {
+	return func(c *Client) {
+		if timeout < time.Minute {
+			log.Warnf("cannot set stale session timeout to less than 1 minute.. defaulting to 20 minutes")
+			return
+		}
+
+		c.sessionTimeout = timeout
+	}
+}

udpproxy.go

@@ -7,21 +7,6 @@ import (
 	log "github.com/sirupsen/logrus"
 )
 
-// Option is a functional option type that allows us to configure the Client.
-type Option func(*Client)
-
-// WithSessionTimeout is a functional option to set the session timeout
-func WithSessionTimeout(timeout time.Duration) Option {
-	return func(c *Client) {
-		if timeout < time.Minute {
-			log.Warnf("cannot set stale session timeout to less than 1 minute.. defaulting to 20 minutes")
-			return
-		}
-
-		c.sessionTimeout = timeout
-	}
-}
-
 type Client struct {
 	laddr *net.UDPAddr
 	raddr *net.UDPAddr