Hi everybody! In this post, I’m going to explain how to create a Golang project with Docker. Video en español en mi canal.
This repository contains the code.
Requirements
Docker installed
Basic knowledge with docker
Docker compose installed
Structure project
The structure for this project is very simple.
app: Contains all the files of our application.
main.go: Application entry point.
Dockerfile: Dockerfile to build our image.
docker-compose.yml: File to help build our image more easily.
go.mod: File to track your project dependencies.
app
main.go
run.sh
go.mod
Dockerfile
docker-compose.yml
Dockerfile
ENV APP_ENV prod
ENV WORDIR_APP /usr/src
ENV BINARY_NAME main
ENV BINARY_PATH ${WORDIR_APP}/${BINARY_NAME}
WORKDIR ${WORDIR_APP}
COPY app/go.mod app/run.sh ./
RUN go mod download &&
go mod verify &&
go install github.com/cosmtrek/air@v1.51.0
WORKDIR ${WORDIR_APP}/app
COPY ./app .
RUN go build -v -o ${BINARY_PATH}
CMD [ «bash», «run.sh» ]
In this file we define image version FROM golang:1.22.3-bullseye. Then there are 4 environments.
APP_ENV: This environment is used to manage the mode in which our application is running. We use values like: (prod, develop, test).
WORDIR_APP: It is the location when we are working.
BINARY_NAME: This is the name of our application when it is finally built. You can use any name that you want.
BINARY_PATH: This is the full path of our binary when the application is built.
On line 11, we’re installing all dependencies in our project, and additionally, we add this library to enable live-reload functionality in our application.
I think that was the most important thing in Dockerfile.
go.mod
This file is to track dependencies in your project. You can check the basic tutorial.
go 1.22.3
module: The name of your package.
go: Golang version. In this case this version must be the same one that we use in our Dockerfile
run.sh
echo «=== Start app in (${APP_ENV}) ===»
env=${APP_ENV:-}
if [ «$env« = «prod» ]; then
# exucute binary
${BINARY_PATH}
else
air –build.cmd «go build -v -o ${BINARY_PATH}« –build.bin «${BINARY_PATH}«
fi
In this file, we have a conditional to execute a command depending on whether APP_ENV is prod or develop. If APP_ENV is prod, it executes the binary that we previously compiled in our Dockerfile. Otherwise, we execute the air command to use live reload in our app.
docker-compose.yml
services:
demogolang:
build: .
environment:
– APP_ENV=develop
volumes:
– ./app:/usr/src/app
Start app
To start our application we only have to execute the following command: docker compose up.
