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

kevwan/dockerfile.md