Dockerfile is quite simple, first we need to pick the base image for build phase (only if you want to build inside docker, if you already have CI/CD that build it outside, you just need to copy the executable binary directly), put command of build steps, choose runtime image for run stage (popular one like ubuntu/debian have bunch of debugging tools, alpine/busybox for stripped one), copy the binary to that layer and done.
FROM golang:1.20 as build1
WORKDIR /app1
# if you don't use go mod vendor
#COPY go.mod .
#COPY go.sum .
#RUN go mod download
COPY . .
RUN CGO_ENABLED=0 GOOS=linux go build -o app1.exe
FROM busybox:latest
WORKDIR /
COPY --from=build1 /etc/ssl/certs /etc/ssl/certs
COPY --from=build1 /app1/app1.exe .
CMD ./app1.exe
then run the docker build and docker run command:
# build
docker build . -t app0
[+] Building 76.2s (15/15) FINISHED -- first time, without vendor
[+] Building 9.5s (12/12) FINISHED -- changing code, rebuild, with go mod vendor
# run
docker run -it app0
with nixpacks you just need to run this without having to create Dockerfile (as long there's main.go file):
# install nixpack
curl -sSL https://nixpacks.com/install.sh | bash
# build
nixpacks build . --name app1
[+] Building 315.7s (19/19) FINISHED -- first time build
[+] Building 37.2s (19/19) FINISHED -- changing code, rebuild
# run
docker run -it app1
With ko,
# install ko
go install github.com/google/ko@latest
# build
time ko build -L -t app2
CPU: 0.84s Real: 5.05s RAM: 151040KB
# run (have to do this since the image name is hashed)
docker run -it `docker image ls | grep app2 | cut -d ' ' -f 1`
How about container image size? Dockerfile with busybox only use 14.5MB, with ubuntu 82.4MB, debian 133MB, alpine 15.2MB, with nixpack it uses 99.2MB, and with ko it only took 11.5MB but it only support Go (and you cannot debug inside it, eg. for testing connectivity to 3rd party dependency using shell inside the container). So is it better to use nixpacks? I don't think so, both build speed and image size for this case is inferior compared to normal Dockerfile with busybox or ko.
