Containerize Go and SQLite with Docker

> Docker may be useful if an application has enormous reach and needs Google scale, but very few apps do. > I got sucked into the Docker hype some years ago and the demos worked well enough in isolation. > I pushed it on a small team that didn't need it. One of the biggest regrets of my career.

It sounds like (no offence) issues that containerization solved were missed and you had no dedicated operations/build-engineer guy on your team that could've explained/fixed these things for you and steer your infra in a right direction.

> I still feel bad about it. The company could have run on a couple $400 machines under a desk for years, but instead spent tens of thousands on AWS services it didn't need.

Does not sound like a docker issue. If you actually plan to run a money making business that your livelihood depends on, then running it under your desk is not something that you can reliably do even 10-15 years ago.

AWS is a money hog with a lot of things that are a distraction for a small project and it is easy to assume that their products are necessary to run your app effectively, but most often it is not. There is plenty of cloud providers that are not as expensive, and are much easier to manage compared to AWS.

> K8s is a total disaster for a small team working on a small project.

This is truly a YMMV thing. in my experience managed k8s for a small team can be a godsend for infra management after some level of complexity is reached, while self-hosted bare-metal k8s can utterly decimate the team. But again YMMV.

I am currently running several clusters of Nomad for different types of workloads each. CI, HPC, VM's, public facing services you name it. Containerization makes it all possible to run (mostly) single-handedly.

Testing locally, adding the "-linkmode external -extldflags '-static'" flags doesn't bring down the binary size. The heavy lifting is done by '-s -w'. It is a good idea to drop privileges even if there's a small attack surface.

At $work we use the following template. Sharing in case you find it interesting:

    FROM golang:1.17.1-alpine3.14 as builder
    RUN apk update && apk add ca-certificates curl git make tzdata
    RUN adduser -u 5003 --gecos '' --disabled-password --no-create-home mycompany
    COPY . /app
    WORKDIR /app
    RUN make build
    
    FROM scratch
    COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
    COPY --from=builder /app/bin/app-3 /bin/app-3
    COPY --from=builder /etc/passwd /etc/passwd
    USER mycompany
    CMD ["app-3"]

And a very simple makefile:

    help:
     @echo "Please use 'make ' where  is one of the following:"
     @echo "  test                 to run unit tests."
     @echo "  build                to build the app as a binary."
     @echo "  build-image          to build the app container."
     @echo "  run                  to run the app with go."
    
    run:
     go run -ldflags="$(govvv -flags -pkg) -w -s" ./cmd/app-3/main.go
    
    test:
     go test -v -coverpkg=./... -coverprofile=profile.cov ./...
     go tool cover -func profile.cov
     rm profile.cov
    
    build:
     CGO_ENABLED=0 go build -mod=readonly -a -ldflags="$(govvv -flags -pkg $(go list ./info)) -w -s -linkmode external -extldflags '-static'" -o ./bin/app-3 ./cmd/app-3/*
    
    build-image:
     docker build -t mycompanytown/app-3:latest .

I've worked with docker swarm extensively. I've managed it but also automated the deployment and implemented several features to ease deployment using the swarm API.

Swarm pros:

- Easy to setup

- Easy to run

- Relatively easy to debug

Swarm cons:

- Many problems persist for years. Some because of lack of resources, others because the problem is simply too hard.

- The community and automation around swarm is small

- Problems solved by third party tools, apps, etc. in kubernetes require in-house workarounds or solutions (e.g. there was an API to perform autoscaling, but we had to write the python app that will read data from prometheus and scale-in/out the deployment)

What I found it with Swarm is that it was extremely resilient. At some point the swarm cluster was running on AWS for ~2 years with minimal maintenance. That would have been impossible even for a managed EKS cluster for example. There are simply too many things that can go wrong.

> IME, Docker takes an enormous amount of focus away from the customer problem and moves it to the how to get this mess working problem.

This is the opposite in my experience: Docker lets me focus on the business problem by making deployment easier.

> You mostly just copy the binary into a slim image and you are done.

You don't need docker for that, just 'tar czf my-layer.tar.gz my-dir'. If you want a manifest file, you can get the digest using `sha256sum my-layer.tar.gz`.