Case 2：使用镜像，部署失败 - 逻辑问题查日志定位

Dockerfile

# Use the official golang image to create a build artifact
FROM golang:1.13 as builder

# Create app directory
RUN mkdir /app

# Add file to /app/
ADD . /app/

# Build the binary
WORKDIR /app

RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o main .

# Run service on container startup
FROM alpine:latest

WORKDIR /app

COPY --from=builder /app/main .

CMD ["/app/main"]

fail.go

package main

import (
	"fmt"
	"log"
	"net/http"
	"os"
	"strconv"
)

func handler(w http.ResponseWriter, r *http.Request) {
	num1 := r.URL.Query().Get("num1")
	num2 := r.URL.Query().Get("num2")
	n1, _ := strconv.Atoi(num1)
	n2, _ := strconv.Atoi(num2)
	sum := n1 - n2 // this is show logic error !!!
	log.Print("Received a request.", "num1=", num1, " num2=", num2, " sum=", sum)
	fmt.Fprintf(w, "%s+%s=%d\n", num1, num2, sum)
}

func main() {

	log.Print("Server started.")

	http.HandleFunc("/add", handler)

	port := os.Getenv("PORT")
	if port == "" {
		port = "80"
	}

	log.Fatal(http.ListenAndServe(fmt.Sprintf(":%s", port), nil))
}