Containerize your first Go Lang App using Docker

Does size matter?

It does – in production. Most orchestration solutions involve a smoother transitions from one docker image to other. A simple up command, if downloading only ~10MB of file, obviously it will save few seconds – but not just that, what about limited size we have in our production servers? This normally leads to the regular cleanups which is usually a manual and tedious tasks. So, for a scalability point of view, a multi-stage build approach is preferred over usual.

The Multi stage build Approach

Most of the approaches are quite poor as it ends up with a large docker image. New approach involves having a two steps approach as following:

The Build:

You build Go in this system and use that to build your application. This will result in an insane size of docker image ~ from 200MB to 300MB

Copy Build

You copy the build from first step and this ensures size of final docker image is less. I bet you will have no more than 10MB image size.

Example:

# The Build
FROM golang:alpine AS the-build
ADD . /src
RUN cd /src && go build -o app

# Copy Build
FROM alpine
WORKDIR /app
COPY --from=the-build /src/app /app/
ENTRYPOINT ./app

Here you are naming the first step of the build as ‘the-build’ Docker supports a partial build on multi-build process. So if you would like to build till ‘the-build’ you can do it with:

docker build --target the-build -t github/go-app:latest

If you omit –target – you can build the whole system in a single command as following:

docker build -t github/go-app:latest
Containerize your first Go Lang App using Docker

2 thoughts on “Containerize your first Go Lang App using Docker

Leave a Reply

Your email address will not be published. Required fields are marked *

Scroll to top