Echo: Basic TCP echo server
Change-Id: I46e1f0e4d2733d14609efa68953e09b631cc28fb
diff --git a/apps/echo/go.mod b/apps/echo/go.mod
new file mode 100644
index 0000000..b958ea0
--- /dev/null
+++ b/apps/echo/go.mod
@@ -0,0 +1,3 @@
+module echo
+
+go 1.23.1
diff --git a/apps/echo/main.go b/apps/echo/main.go
new file mode 100644
index 0000000..9c46de6
--- /dev/null
+++ b/apps/echo/main.go
@@ -0,0 +1,74 @@
+package main
+
+import (
+ "flag"
+ "fmt"
+ "io"
+ "log"
+ "net"
+)
+
+var port = flag.Int("port", 8080, "port to listen on")
+
+const welcomeMessage = `
+ ____ ____ ____ ____
+ ||D ||||O ||||D ||||O ||
+ ||__||||__||||__||||__||
+ |/__\||/__\||/__\||/__\|
+
+Welcome to the Echo Server!
+`
+
+func main() {
+ flag.Parse()
+
+ // Listen on TCP port from flag
+ listener, err := net.Listen("tcp", fmt.Sprintf(":%d", *port))
+ if err != nil {
+ log.Fatalf("Failed to start server: %v", err)
+ }
+ defer listener.Close()
+ fmt.Printf("Echo server listening on :%d\n", *port)
+
+ for {
+ // Accept incoming connections
+ conn, err := listener.Accept()
+ if err != nil {
+ log.Printf("Failed to accept connection: %v", err)
+ continue
+ }
+ // Handle each connection in a separate goroutine
+ go func(c net.Conn) {
+ remoteAddr := c.RemoteAddr().String()
+ log.Printf("New connection from %s", remoteAddr)
+ if err := handleConnection(c); err != nil && err != io.EOF {
+ log.Printf("Error handling connection from %s: %v", remoteAddr, err)
+ }
+ log.Printf("Connection closed from %s", remoteAddr)
+ }(conn)
+ }
+}
+
+func handleConnection(conn net.Conn) error {
+ defer conn.Close()
+
+ // Send welcome message
+ if _, err := conn.Write([]byte(welcomeMessage)); err != nil {
+ return fmt.Errorf("sending welcome message: %w", err)
+ }
+
+ // Create a buffer for reading data
+ buffer := make([]byte, 1024)
+
+ for {
+ // Read incoming data
+ n, err := conn.Read(buffer)
+ if err != nil {
+ return err
+ }
+ // Echo the data back to the client
+ if _, err = conn.Write(buffer[:n]); err != nil {
+ return fmt.Errorf("writing to connection: %w", err)
+ }
+ }
+}
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