baseimage

minimal docker base image to build and deploy services and applications.

Three images provided:

1. go build image - umputun/baseimage:buildgo-latest. For build stage, includes go compiler and linters. Alpine based.
2. base application image umputun/baseimage:app-latest
3. scratch-based application image umputun/baseimage:scratch-latest

Go Build Image

Image umputun/baseimage:buildgo-latest and ghcr.io/umputun/baseimage/buildgo:latest intends to be used in multi-stage Dockefile to build go applications and services.

• Relatively small, based on the official golang:alpine image
• Enforces CGO_ENABLED=0
• With fully installed and ready to use golangci-lint
• Add useful packages for building and testing - testify, mockery and moq
• Includes goreleaser and statik
• With goveralls for easy integration with coverage services and provided coverage.sh script to report coverage.
• /script/version.sh script to make git-based version

Base Application Image

Image umputun/baseimage:app-latest and ghcr.io/umputun/baseimage/app:lastest designed as a lightweight, ready-to-use base for various services. It adds a few things to the regular alpine image.

• ENTRYPOINT /init.sh runs CMD via dumb-init
• Container command runs under app user with uid $APP_UID (default 1001)
• Optionally runs /srv/init.sh if provided by custom container
• Packages tzdata, curl, su-exec, ca-certificates and openssl pre-installed
• Adds the user app (uid=1001)
• By default enforces non-root execution of the command. Optional "/init-root.sh" can be used to run as root.

Run-time Customization

The container can be customized in runtime by setting environment from docker's command line or as a part of docker-compose.yml

• TIME_ZONE - set container's TZ, default "America/Chicago". For scratch-based TZ should be used instead
• APP_UID - UID of internal app user, default 1001

Example of multi-stage Dockerfile with baseimage:buildgo and baseimage:app

FROM umputun/baseimage:buildgo as build

WORKDIR /build
ADD . /build

RUN go test -mod=vendor ./...
RUN golangci-lint run --out-format=tab --tests=false ./...

RUN \
    revison=$(/script/git-rev.sh) && \
    echo "revision=${revison}" && \
    go build -mod=vendor -o app -ldflags "-X main.revision=$revison -s -w" .


FROM umputun/baseimage:app

COPY --from=build /build/app /srv/app

EXPOSE 8080
WORKDIR /srv

CMD ["/srv/app", "param1", "param2"]

It will make a container running "/srv/app" (with passed params) under 'app' user.

To customize both TIME_ZONE and UID - docker run -e TIME_ZONE=America/New_York -e APP_UID=2000 <image>

Base Scratch Image

Image umputun/baseimage:scratch-latest (or ghcr.io/umputun/baseimage/scratch) adds a few extras to the scratch (empty) image:

• zoneinfo to allow change the timezone of the running application
• SSL certificates (ca-certificates)
• /etc/passwd and /etc/groups with app user and group added (UID:1001, GID:1001)
• /nop program to wait forever and do nothing

Container sets user to app and working directory to /srv, no entrypoint set. In order to change time zone TZ env can be used.

The overall size of this image is about 1M only.