Dev and Production Container for a go project
Dev Docker container
setup
mkdir src
cd src
export GOFLAGS=-mod=vendor
export GO111MODULE=on
go mod init github.com/vincepr/go-web-docker
- now we can use the following to download required ependencies in the /vendor/ folder instead of GOROOT-path.
- useful since we build them into our dev container
go mod tidy
go mod download
go mod vendor
go mod verify
creating the dockerfile (for production)
Dockerfile
# References the base image
FROM golang:1.20.2-bullseye
# installs bee tool globaly, used to live-reload our code during development
RUN go install github.com/beego/bee/v2@latest
# Env variables. used to configure the use of our vendor location for the GO modules
ENV GO111MODULE=on
ENV GOFLAGS=-mod=vendor
# creates a folder for the code and make it the active directory
ENV APP_HOME /go/src/mathapp
RUN mkdir -p "$APP_HOME"
WORKDIR "$APP_HOME"
# port of our port we work with
EXPOSE 8010
#uses the bee comand to start our application
CMD ["bee", "run"]
building the image
sudo docker build -t mathapp-development .
-t mathappsets the tag name for the new image, we can reference the image later as mathapp:latestto check and list images on the system
docker imageswe added (if not already existed) golang and mathapp images to the list
running the container
sudo docker run -it --rm -p 8888:8010 -v $PWD/src:/go/src/mathapp mathapp-development
- docker run to run a container
- -it flag to start the container in an interactive mode, tying it to the current shell
- --rm cleans out the container after it shuts down
- -p 8888:8010 flag allows the container to be accessed at port 8888 using the 8010 port inside the container
- -v $PWD/src:/go/src/mathapp makes the development files available inside and outside the container. Maping the src/ from the machine to the /go/src/mathapp in the container
- --name mathapp-instance would name the container so
- last mathapp just names the container
- access our app on:
http://localhost:8888/sum/4/5
to access our app
Docker in Production
- auto build after changes are pushed to the git repo
- auto run test
- create docker image if the above is sucessfull only, then push it to Docker Hub
setup
new dockerfile to create a self contained image, without external dependencies.
creating the dockerfile
Dockerfile.production
# 1st stage of the multistage build - to compile our binary (using semaphoreci instead of normal because of docker rates limites)
# builder is just our name for the stage
FROM registry.semaphoreci.com/golang:1.18 as builder
# create the application folder for the app and copies the source code.
ENV APP_HOME /go/src/mathapp
WORKDIR "$APP_HOME"
COPY src/ .
# download modules and build the binary
RUN go mod download
RUN go mod verify
RUN go build -o mathapp
# ----------------------------------------------------- #
# 2nd stage of the multistage build - the final container where we will run the services
FROM registry.semaphoreci.com/golang:1.18
# create a folder for the code and make it the active directory
ENV APP_HOME /go/src/mathapp
RUN mkdir -p "$APP_HOME"
WORKDIR "$APP_HOME"
# copy command to copy files into the image. --from lets copy from the previous "1st stage" named builder.
COPY src/conf/ conf/
COPY src/views/ views/
COPY --from=builder "$APP_HOME" /mathapp $APP_HOME
# what to look at and run app
EXPOSE 8010
CMD ["./mathapp"]
- build the deployment image:
sudo docker build -t mathapp-production -f Dockerfile.production . - run it:
sudo docker build run -it -p 8888:8010 mathapp-production - check mem/cpu usage with
sudo docker stats
Continous Integration (with Semaphore)
CI/CD
- Continous Integration CI and Continous Delivery CD
- Developers merge their changes to the main code branch many times per day (like Github-Actions automation)
- Each code merge triggers an automated build and test sequence
- Automated Testing neccessary to check that code is save to deploy