Forem: Sam Atkins

Books I Want to Read in 2023

Sam Atkins — Tue, 03 Jan 2023 17:25:20 +0000

This year, like last year, I want to read some good software engineering books. These are the ones I currently have on my reading list:

Leading Snowflakes by Oren Ellenbogen
Modern Software Engineering by Dave Farley
Building Microservices: Designing Fine-grained Systems by Sam Newman
Machine Learning Engineering with Python by Andrew P. McMahon

Which books do you have on your reading list for 2023?

Go - how to create a JSON body with an array (slice) of maps?

Sam Atkins — Mon, 19 Apr 2021 19:12:59 +0000

I'm learning Go and am trying to build a JSON request body of this shape the name values are created dynamically based on a provided string. The JSON looks like this based on the input string "joan,john"

{
    "reviewers": [
        {"user": {"name": "joan"}},
        {"user": {"name": "john"}}
    ]
}

I've searched how to build a slice of maps and have put together the code below but am getting complier errors. Where are am I going wrong?

type HTTPRequestBody struct {
    Reviewers ReviewersArray `json:"reviewers,omitempty"`
}

type ReviewersArray struct {
    Rs []struct {
        Users User
    }
}

type User struct {
    User Name `json:"user`
}

type Name struct {
    Name string `json:"name`
}

func addReviewers(reviewers string) *ReviewersArray {
    reviewersSplit := strings.Split(reviewers, ",")
    rArray := &ReviewersArray{}
    for _, r := range reviewersSplit {
        u := &User{User: Name{Name: r}}
        // Error: cannot use u (variable of type *User) as struct{Users User} value in argument to append
        rArray.Rs = append(rArray.Rs, u)
    }
    return rArray
}

func main() {
    testReviewers := "joan,john"

    prReviewers := addReviewers(testReviewers)
    requestBody := &HTTPRequestBody{
        // Error: cannot use prReviewers (variable of type *ReviewersArray) as ReviewersArray value in struct literal
        Reviewers: prReviewers,
    }

    jsonData, _ := json.MarshalIndent(requestBody, "", "  ")
    fmt.Println(string(jsonData))
}

Docker Multi-Stage Builds

Sam Atkins — Sat, 06 Feb 2021 11:04:50 +0000

At work, we’re using Docker multi-stage builds to get smaller image sizes. I thought I’d try it out with a small learning project. The headline result is I reduced a Docker image from 305MB to 12.2MB.

# before
docker image ls
helloworldapi latest b24c966e9bgg 6 weeks ago 305MB

# after
docker image ls
helloworldapi latest f1f76e06146h 7 seconds ago 12.2MB

Multi-Stage Builds

How do multi-stage builds work? Every instruction i.e. line in a Dockerfile adds a layer to the image. A common practice was to have a development version of your Dockerfile which included everything you needed and a slimmed down version used for production. With multi-stage builds you don’t need to maintain two Dockerfiles. Instead you can use the syntax FROM ... AS <NAME> to name a stage, and then copy that named stage when you want want to use it. Only what is needed is brought across in this COPY and all the other layers are discarded. This results in smaller image sizes.

Here’s an example from the learning project I mentioned earlier. This is the Dockerfile before without using multi-stage. The image size was 305MB.

FROM golang:1.15.5-alpine
WORKDIR /app
COPY . .
RUN go mod download
RUN go build -o main .
CMD ["/app/main"]

This is the Dockerfile using a multi-stage, named as builder and used like this COPY --from=builder /app . i.e. copy the named stage into the /app directory.

FROM golang:1.15.5-alpine AS builder
WORKDIR /app
COPY main.go .
RUN go build -o main .

FROM alpine:latest
WORKDIR /app
COPY --from=builder /app .
CMD ["/app/main"]

As a result of using this multi-stage the image size is now 12.2MB.

Named Stages

Stages are not named by default and you can refer to each stage by an integer starting at 0 for the first FROM. So if the Dockerfile read FROM golang:1.15.5-alpine we could copy it across like this COPY --from=0 /app .. I prefer to use names as it makes it more obvious what is happening in the Dockerfile.

Target a Stage

How can you use multi-stage builds? When building an image you can target a stage. For example, a build stage named dev in a Dockerfile would be built like this:

docker build --target dev -t "${DOCKER_REGISTRY}"/${IMAGE_NAME}:"${IMAGE_TAG}-dev" .

The example above assumes variables are set for the Docker registry where the image is published, the image name and the image tag.

If the image is published then you can use this in Docker Compose:

service-name:
 image: $DOCKER_REGISTRY/$IMAGE_NAME:$IMAGE_TAG-dev

Alternatively, if the Dockerfile and source code are available on your local machine, you can target it like this:

service-name:
 build:
 context: path-to-service-name-source-code
 target: dev

3 Recommended Programming Books

Sam Atkins — Wed, 23 Jan 2019 09:21:12 +0000

As I reflect on 2018, there were three programming books I enjoyed reading and learned a lot from. I thought I would share my summary of each book.

The Pragmatic Programmer by Andrew Hunt and David Thomas

Recommended to me by my boss, this is a timeless guide to programming. Programming and technology moves fast, yet despite being written in 1999 this book is still relevant today. In my opinion, the fact this is the case shows just how important the principles the book teaches are. This book really helped me with understanding programming best practices and how I can build those best practices into my daily work. It's a reference to keep coming back to as I progress in my programming career.

Coders at Work by Peter Seibel

Another recommendation from my boss, this is a series of interviews with incredible programmers. It is interesting reading about the different approaches these programmers take to their work.

Of particular interest was reading the contrasting and complementary philosophies and approaches of Brendan Eich and Douglas Crockford when discussing developing the JavaScript language.

I also enjoyed reading about Brad Fitzpatrick and his incredible blend of programming skills and business/open source acumen with LiveJournal and Memcached as great examples of this.

And from a broader industry perspective a very topical and important theme, reading about Fran Allen's experience of the how the industry became male dominated and her views on the importance of increasing diversity.

The DevOps Handbook by Gene Kim, Jez Humble, Patrick Debois, John Willis

This was probably my favourite programming book I read last year. It's full title is The DevOps Handbook:: How to Create World-Class Agility, Reliability, and Security in Technology Organizations

My background, prior to switching careers, was in Supply Chain and Operations (in the manufacturing sense) including lean and process optimisation work. This book was a real eye opener, taking a manufacturing operational view to building software. The book explains how a DevOps culture looking at People, Process and Tools can drastically improve a software company's performance, in terms of speed to market and software resilience.

The insight that infrastructure as code is actually the most important aspect to use version control (rather than as I had previously assumed for development code) was a huge point but once digested makes sense. If you have an interest in DevOps and how teams work to build software, I highly recommend this book.

What's new in Python 3.7

Sam Atkins — Fri, 17 Aug 2018 13:41:30 +0000

This is an interesting summary of what's new in Python 3.7. I'm particularly excited about types and dataclasses, and breakpoint() should prove very handy too.

https://hackaday.com/2018/07/23/hands-on-with-python-3-7-whats-new-in-the-latest-release/