first

.gitlab-ci.yml

+stages:
+  - build
+  - deploy
+
+variables:
+  GIT_DEPTH: "1"
+  CONTAINER_TEST_IMAGE: $CI_REGISTRY_IMAGE:$CI_COMMIT_REF_SLUG
+  CONTAINER_RELEASE_IMAGE: $CI_REGISTRY_IMAGE:latest
+
+before_script:
+  - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
+
+build:
+  stage: build
+  tags: 
+    - docker
+  script:
+    - docker build --pull -t $CONTAINER_TEST_IMAGE .
+    - docker push $CONTAINER_TEST_IMAGE
+
+deploy_latest:
+  stage: deploy
+  tags: 
+    - docker
+  script:
+    - docker pull $CONTAINER_TEST_IMAGE
+    - docker tag $CONTAINER_TEST_IMAGE $CONTAINER_RELEASE_IMAGE
+    - docker push $CONTAINER_RELEASE_IMAGE
+  only:
+    - master
+
+deploy_tag:
+  stage: deploy
+  tags: 
+    - docker
+  variables:
+    CONTAINER_TAG_IMAGE: $CI_REGISTRY_IMAGE:$CI_COMMIT_TAG
+  script:
+    - docker pull $CONTAINER_TEST_IMAGE
+    - docker tag $CONTAINER_TEST_IMAGE $CONTAINER_TAG_IMAGE
+    - docker push $CONTAINER_TAG_IMAGE
+  only:
+    - tags

Dockerfile

+FROM golang as builder
+
+RUN go env -w GO111MODULE=auto \
+  && go env -w CGO_ENABLED=0 \
+  && go env -w GOPROXY=https://goproxy.cn,https://gocenter.io,https://goproxy.io,direct \
+  && go get golang.org/x/net/websocket
+
+WORKDIR /usr/src/app
+
+COPY ./main.go ./
+RUN go build -ldflags "-s -w -extldflags '-static'" -o maotama-server main.go
+
+FROM debian:buster-slim
+
+RUN apt update && \
+	apt -y install dnsutils && \
+	rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
+
+COPY ./entrypoint.sh /
+COPY --from=builder /usr/src/app/maotama-server /usr/bin/
+
+WORKDIR /data
+
+ENV TZ Asia/Shanghai
+
+ENTRYPOINT [ "/entrypoint.sh" ]
+CMD [ "/usr/bin/maotama-server" ]

entrypoint.sh

+#!/bin/bash
+export ADDRESS=$(dig whoami.cloudflare ch txt @1.0.0.1 +short | sed 's/\"//g')
+exec "$@"

main.go

+package main
+
+import (
+	"fmt"
+	"log"
+	"net"
+	"net/http"
+	"os"
+
+	"golang.org/x/net/websocket"
+)
+
+var IP = os.Getenv("ADDRESS")
+
+func transfer(local *net.UDPConn, remote *net.UDPConn, remotAddr *net.UDPAddr) {
+	buffer := make([]byte, 2048)
+	for {
+		length, _, _ := local.ReadFromUDP(buffer)
+		remote.WriteToUDP(buffer[:length], remotAddr)
+	}
+}
+func serverTransfer(client *net.UDPConn, remoteAddr *net.UDPAddr, channel chan []byte) {
+	for {
+		message := <-channel
+		client.WriteToUDP(message, remoteAddr)
+	}
+}
+func listenUDP(ws *websocket.Conn) {
+	server, err := net.ListenUDP("udp", nil)
+	if err != nil {
+		log.Println(err)
+		return
+	}
+	clients := make(map[string]chan []byte)
+
+	reply := fmt.Sprintf("LISTEN %s:%d", IP, server.LocalAddr().(*net.UDPAddr).Port)
+	ws.Write([]byte(reply))
+	for {
+		message := make([]byte, 2048)
+		length, clientAddr, _ := server.ReadFromUDP(message)
+		channel, ok := clients[clientAddr.String()]
+		if !ok {
+			client, err := net.ListenUDP("udp", nil)
+			if err != nil {
+				log.Println(err)
+				return
+			}
+			reply = fmt.Sprintf("CONNECT %s:%d", IP, client.LocalAddr().(*net.UDPAddr).Port)
+			ws.Write([]byte(reply))
+			_, remoteAddr, _ := client.ReadFromUDP(make([]byte, 2048))
+			reply = fmt.Sprintf("CONNECTED %s:%d", IP, client.LocalAddr().(*net.UDPAddr).Port)
+			ws.Write([]byte(reply))
+			client.WriteToUDP(message[:length], remoteAddr)
+			go transfer(client, server, clientAddr)
+			channel := make(chan []byte)
+			clients[clientAddr.String()] = channel
+			go serverTransfer(client, remoteAddr, channel)
+		} else {
+			channel <- message[:length]
+		}
+	}
+
+}
+func handler(ws *websocket.Conn) {
+	defer ws.Close()
+	go listenUDP(ws)
+
+	ws.Read(make([]byte, 1))
+	log.Println("Websocket disconnected")
+
+}
+func main() {
+	http.Handle("/", websocket.Handler(handler))
+	log.Println("Maotama server started on " + IP)
+	err := http.ListenAndServeTLS(":10800", "./cert/fullchain.pem",
+		"./cert/privkey.pem", nil)
+	if err != nil {
+		panic("ListenAndServe: " + err.Error())
+	}
+}