The simplest way to write Dockerfile!

1. choose a simple linux image

For example alpine, it's only about 5MB.

2. set timezone if necessary

RUN apk add --no-cache tzdata
ENV TZ America/New_York

3. multi-stage build

• the first stage to build the binary, ensure the binary is dev box independent
• use the binary in the first stage to build the final image

4. the simplest way to write Dockerfile

• first of all, install the tool goctl

GO111MODULE=on go get -u github.com/tal-tech/go-zero/tools/goctl

• in project greet, create a service called hello

goctl api new hello

• file structure listed below:

greet
  ├── go.mod
  ├── go.sum
  └── service
      └── hello
          ├── etc
          │   └── hello-api.yaml
          ├── hello.api
          ├── hello.go
          └── internal
              ├── config
              │   └── config.go
              ├── handler
              │   ├── hellohandler.go
              │   └── routes.go
              ├── logic
              │   └── hellologic.go
              ├── svc
              │   └── servicecontext.go
              └── types
                  └── types.go

• in dir hello, one shot to generate Dockerfile

goctl docker -go hello.go

• the content of Dockerfile like:

FROM golang:alpine AS builder

LABEL stage=gobuilder

ENV CGO_ENABLED 0
ENV GOOS linux

WORKDIR /build/zero

ADD go.mod .
ADD go.sum .
RUN go mod download
COPY . .
COPY service/hello/etc /app/etc
RUN go build -ldflags="-s -w" -o /app/hello service/hello/hello.go


FROM alpine

RUN apk update --no-cache && apk add --no-cache ca-certificates tzdata
ENV TZ America/New_York

WORKDIR /app
COPY --from=builder /app/hello /app/hello
COPY --from=builder /app/etc /app/etc

CMD ["./hello", "-f", "etc/hello-api.yaml"]

• in dir greet, build the final image

docker build -t hello:v1 -f service/hello/Dockerfile .

• check the image

hello v1 5455f2eaea6b 7 minutes ago 18.1MB

the image size is like 18MB.

• start the service

docker run --rm -it -p 8888:8888 hello:v1

• test the service

$ curl -i http://localhost:8888/from/you
HTTP/1.1 200 OK
Content-Type: application/json
Date: Thu, 10 Dec 2020 06:03:02 GMT
Content-Length: 14

{"message":""}

5. conclusion

goctl greatly simplifies the writing of Dockerfile. The generated Dockerfile is state-of-art and can be used directly. Also, you can customized the Dockerfile template in $HOME/.goctl/docker if necessary.

If it helps, welcome to star the project. 🤝

6. go-zero

https://github.com/tal-tech/go-zero/blob/master/readme-en.md