Implement IP echo

deploy.sh

@@ -0,0 +1 @@
+go build main && docker build -t echo-ip .

dockerfile

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+FROM golang:1.22.4-bullseye as base
+
+RUN adduser \
+	--disabled-password \
+	--gecos "" \
+	--home "/nonexistent" \
+	--shell "/sbin/nologin" \
+	--no-create-home \
+	--uid 65532 \
+	small-user
+
+WORKDIR $GOPATH/src/app/
+
+COPY . .
+
+RUN go mod download
+RUN go mod verify
+
+RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o /main .
+
+FROM scratch
+
+COPY --from=base /usr/share/zoneinfo /usr/share/zoneinfo
+COPY --from=base /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
+COPY --from=base /etc/passwd /etc/passwd
+COPY --from=base /etc/group /etc/group
+
+COPY --from=base /main .
+
+USER small-user:small-user
+
+CMD ["/main"]

main.go

@@ -0,0 +1,33 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"net/http"
+)
+
+var Error *log.Logger
+func init() {
+	log.SetFlags(log.Lmicroseconds | log.Lshortfile)
+	// logFile, err := os.Create("main.log")
+	// if err != nil {
+	// 	log.Printf("Error creating log file: %v", err)
+	// 	os.Exit(1)
+	// }
+	logger := io.MultiWriter(os.Stdout)
+	log.SetOutput(logger)
+
+	Error = log.New(io.MultiWriter(os.Stderr, os.Stdout),
+		fmt.Sprintf("%sERROR:%s ", "\033[0;101m", "\033[0m"),
+		log.Lmicroseconds|log.Lshortfile)
+}
+
+func main() {
+	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprintf(w, r.RemoteAddr)
+	})
+
+	http.ListenAndServe(":8080", nil)
+}