Add example/singleapp/unix/socket/01.basic

examples/singleapp/unix/socket/01.basic/.gitignore

@@ -0,0 +1 @@
+./bin

examples/singleapp/unix/socket/01.basic/Taskfile.yml

@@ -0,0 +1,31 @@
+# https://taskfile.dev
+
+version: '3'
+
+tasks:
+  default:
+    cmds:
+      - task: run
+  fmt:
+    cmds:
+      - goimports -w .
+  prepare:
+    cmds:
+      - mkdir -p bin
+  build:
+    deps: [ fmt ]
+    cmds:
+      - go build -o bin/server server/server.go
+      - go build -o bin/client client/client.go
+  run:
+    deps: [ build ]
+    cmds:
+      - ./bin/server &
+      - sleep 1
+      - ./bin/client
+      - sleep 1
+      - pgrep server && pkill server
+    ignore_error: true
+  clean:
+    cmds:
+      - rm -rf ./bin

examples/singleapp/unix/socket/01.basic/client/client.go

@@ -0,0 +1,81 @@
+//go:build linux
+
+package main
+
+import (
+	"log"
+	"net"
+
+	"golang.org/x/sys/unix"
+)
+
+func init() {
+	log.SetFlags(log.Lmicroseconds)
+}
+
+func main() {
+	if err := run(); err != nil {
+		log.Fatal(err)
+	}
+}
+
+func run() error {
+	var (
+		sfd int
+		err error
+	)
+
+	sfd, err = unix.Socket(unix.AF_INET, unix.SOCK_STREAM, unix.IPPROTO_TCP)
+	if err != nil {
+		return err
+	}
+	defer func() {
+		log.Println("[CLIENT] ソケットクローズ")
+		unix.Close(sfd)
+	}()
+
+	var (
+		ip   = net.ParseIP("127.0.0.1")
+		ipv4 [4]byte
+
+		sAddr unix.Sockaddr
+	)
+	copy(ipv4[:], ip.To4())
+
+	sAddr = &unix.SockaddrInet4{Port: 8888, Addr: ipv4}
+	err = unix.Connect(sfd, sAddr)
+	if err != nil {
+		return err
+	}
+
+	//
+	// Send
+	//
+	var (
+		buf = make([]byte, 2048)
+		msg = "helloworld"
+	)
+	copy(buf, []byte(msg))
+
+	err = unix.Send(sfd, buf[:len(msg)], 0)
+	if err != nil {
+		return err
+	}
+
+	//
+	// Recv
+	//
+	var (
+		n int
+	)
+	clear(buf)
+
+	n, err = unix.Read(sfd, buf)
+	if err != nil {
+		return err
+	}
+
+	log.Printf("[CLIENT] %s", buf[:n])
+
+	return nil
+}

examples/singleapp/unix/socket/01.basic/server/server.go

@@ -0,0 +1,136 @@
+//go:build linux
+
+package main
+
+import (
+	"errors"
+	"log"
+	"net"
+
+	"golang.org/x/sys/unix"
+)
+
+func init() {
+	log.SetFlags(log.Lmicroseconds)
+}
+
+func main() {
+	if err := run(); err != nil {
+		log.Fatal(err)
+	}
+}
+
+func run() error {
+	//
+	// Create
+	//
+	var (
+		sfd int
+		err error
+	)
+
+	sfd, err = unix.Socket(unix.AF_INET, unix.SOCK_STREAM, unix.IPPROTO_TCP)
+	if err != nil {
+		return err
+	}
+	defer func() {
+		log.Println("[SERVER] サーバーソケットクローズ")
+		unix.Close(sfd)
+	}()
+
+	//
+	// Bind and Listen
+	//
+	var (
+		ip   = net.ParseIP("127.0.0.1")
+		ipv4 [4]byte
+
+		sAddr   unix.Sockaddr
+		backLog = 2
+	)
+	copy(ipv4[:], ip.To4())
+
+	sAddr = &unix.SockaddrInet4{Port: 8888, Addr: ipv4}
+	err = unix.Bind(sfd, sAddr)
+	if err != nil {
+		return err
+	}
+
+	err = unix.Listen(sfd, backLog)
+	if err != nil {
+		return err
+	}
+
+	//
+	// Accept
+	//
+	var (
+		cfd   int
+		cAddr unix.Sockaddr
+	)
+
+	cfd, cAddr, err = unix.Accept(sfd)
+	if err != nil {
+		return err
+	}
+	defer func() {
+		log.Println("[SERVER] パケット送受信用ソケットクローズ")
+		unix.Close(cfd)
+	}()
+
+	cAddrInet4 := cAddr.(*unix.SockaddrInet4)
+	log.Printf("[SERVER] Connect from %v:%v", cAddrInet4.Addr, cAddrInet4.Port)
+
+	//
+	// Recv
+	//
+	var (
+		buf = make([]byte, 2048)
+		n   int
+	)
+
+	n, err = unix.Read(cfd, buf)
+	if err != nil {
+		return err
+	}
+
+	log.Printf("[SERVER] %s", string(buf[:n]))
+
+	//
+	// Send
+	//
+	var (
+		msg = "HELLOWORLD"
+	)
+
+	clear(buf)
+	copy(buf, []byte(msg))
+
+	err = unix.Send(cfd, buf[:len(msg)], 0)
+	if err != nil {
+		return err
+	}
+
+	//
+	// Disconnect detection
+	//
+LOOP:
+	for {
+		clear(buf)
+
+		n, err = unix.Read(cfd, buf)
+		switch {
+		case n == 0:
+			log.Println("[SERVER] 切断検知 (0 byte read)")
+			break LOOP
+		case err != nil:
+			var sysErr unix.Errno
+			if errors.As(err, &sysErr); sysErr == unix.ECONNRESET {
+				log.Printf("[SERVER] 切断検知 (%s)", sysErr)
+				break LOOP
+			}
+		}
+	}
+
+	return nil
+}