Rapidly building with Gleam

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# Rapidly building with **Gleam**

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## **Hi**

### *name -* Peter Saxton

### *@internets -* CrowdHailer

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![](./iindy.png)
[www.iindy.co](https://www.iindy.co/)

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![](./gleam-gathering.png)
[gleamgathering.com](https://gleamgathering.com/)

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![](./eyg.png)
[eyg.run](https://eyg.run/)

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## The original talk - **Good advice**

1. Focus on the need
2. Seek fast feedback
3. Be boring
4. Eliminate unnecessary components
--
![](./talks.png)

???

I was going to be talking about a lot that you have already heard.
So what I want to do is cover some principles and then speculate on the future.
Link to all the previous talks.

Do 10 x developers exist?
Do some projects take 10 times longer than expected

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## The new talk - **Wild opinions**

1. *Focus on the need*
2. *Seek fast feedback*
3. *Be boring*
4. *Eliminate unnecessary components*
5. Escape the turing tarpit with your sanity
6. Bash is worse than Gleam
7. Extending types over time and space

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# Focus on need
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> Building the right thing is more important building the thing right.

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![](./peter-drucker.jpg)

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> Management is doing things right; leadership is doing the right things.

> Efficiency is doing things right; effectiveness is doing the right things.

> There is nothing so useless as doing efficiently that which should not be done at all.

Peter Drucker

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![](/images/pebble-1.jpg)

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## Building the **right** thing

- What is the problem to be solved?
- Who has the problem?
- When and where does the problem affect them?

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## Building the **right** thing

- What is the problem to be solved? **I'm always curious how languages work**
- Who has the problem? **Me**
- When and where does the problem affect them? **Whenever I discuss language features**

???

EYG was for myself and to make sure I didn't get distracted it was called language

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It's hard to start writing a blog **and** learn Rust.

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## **Names** are important

- If you can't explain something do you understand it?
- If you can't name something can you explain it?
- Long names are fine.
- I talk to the AI "What's a better name for component in x Domain"

???
Iindy we have chats and chats and channels and channels

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## What you **measure** matters

Be very careful when:

- setting up code coverage tools
- tracking pull request statistics
- measuring productivity in general

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> Slow is smooth smooth is fast.

Not Peter Drucker

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![](./charlie.jpg)

If you don't know what you're doing, have a coffee

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# Seek fast feedback

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## Seek **faster** feedback

- Code reload
- Test quickly
- Deploy quickly
- Suffer real feedback

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![](./mist_reload.png)

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## Types vs Tests

![](./types-in-editor.png)

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## Default to **action**

> Plans are only good intentions unless they immediately degenerate into hard work.

Peter Drucker

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![](./pieter-levels.png)
[lexfridman.com/pieter-levels-transcript/](https://lexfridman.com/pieter-levels-transcript/)

???
You might not like this approach but remember what you've lost

He does this all with php that brings us to our next step

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# Be boring

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## Just use Postgres

https://www.amazingcto.com/postgres-for-everything/

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## Convention over configuration

```rs
pub fn handle(request, context) {
  let Request(method:, ..) = request
  case request.path_segments(request), method {
    [], http.Get -> wisp.redirect("/engine/flows")
    ["flows", ..rest], _ -> case rest, method {
      [], http.Get -> flows.index(context)
      ["new"], http.Get -> flows.new(context)
      [], http.Post -> flows.create(request, context)
      [id], http.Get -> flows.show(id, context)
      [id, "edit"], http.Get -> flows.edit(id, context)
      [id], http.Post -> flows.update(id, request, context)
      [id], http.Delete -> flows.delete(id, context)
      _, _ -> wisp.not_found()
    }
    _, _ -> wisp.not_found()
  }
}

```

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## Docker

- In local dev I run everything in docker
- In production my projects use docker-compose

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```sh
FROM ghcr.io/gleam-lang/gleam:v1.12.0-erlang-alpine 
RUN apk update \
# git for git dependencies of the project
# inotify-tools for code reloading in dev
# build-base for password hashing with argon
&& apk add git inotify-tools build-base

COPY ./ /opt

WORKDIR /opt
ENTRYPOINT ["gleam"]
CMD ["run"]
```

???

P.S. at iindy we use AWS and have accounts to isolate customer data an permissions

Just use docker
I use it for local dev, and I run docker compose in production

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## Manage secrets **one** way

Don't manage configuration at all

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*.development.env*
```sh
DOMAIN=localhost
OLLAMA_API_KEY=op://Development/Ollama/credential
POSTGRES_PASSWORD=NotSoSecret
```
*.production.env*
```sh
DOMAIN=localhost
OLLAMA_API_KEY=op://Production/Ollama/credential
POSTGRES_PASSWORD=op://Production/Postgres/credential
```
*$*
```sh
export OP_SERVICE_ACCOUNT_TOKEN=your-service-account-token
op inject -i .development.env -o .env
```

???
env variables take choices out of our code
IaC brings configuration back into our system

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## Eliminate ~~unnecessary~~ components

- eliminate boundaries
- eliminate tools
- eliminate concepts

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> I didn't have time to write you a short letter, so I wrote you a long one.

Not Mark Twain

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## Build a **Single** Application

- web app or a browser app?
- Lustre is great for browser apps

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## Use less **tech**

| Technical Requirement | Server A | Server B |
| -------- | ------- | ------- |
| HTTP server  | Nginx | erlang |
| Request processing | Ruby on Rails | erlang |
| Long-running requests | Go | erlang |
| Server-wide state | Redis | erlang |
| Persistable Data | Redis and MongoDB | erlang |
| Background jobs | Cron, Bash scripts | erlang |
| Service crash recovery | Upstart | erlang |

*From "Elixir in Action"*

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## Use less **concepts**

[All you need is data and functions](https://mckayla.blog/posts/all-you-need-is-data-and-functions.html)

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## But ...

> A Turing tarpit (or Turing tar-pit) is any programming language or computer interface that allows for flexibility in function but is difficult to learn and use because it offers little or no support for common tasks.

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# Escape the Turing tarpit

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# Escape the Turing tarpit*

`package.json`

*with your sanity

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## High **leverage** abstractions

- Garbage collection
- File systems
- Supervision trees
- Gleam's `use`
- Programming languages

High leverage abstractions are elegant.

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## Supervision trees

replace
- try/catch
- kubernetes

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## Gleam use

```rs
// result.gleam
pub fn try(result, fun) {
  case result {
    Ok(x) -> fun(x)
    Error(e) -> Error(e)
  }
}
```

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## Gleam use

```rs
fn foo() {
  result.try(httpc.send(req), fn(resp) {
    Ok(resp.body)
  })
}
```
```rs
fn foo() {
  use resp <- result.try(httpc.send(req))
  Ok(resp.body)
}
```

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![](./use-intro-1.png)

![](./use-intro-2.png)

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## Programming languages

- Are for humans
- A tool for organising thoughts

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### Powerful **platforms**

#### BEAM

- The best platform for highly concurrent systems
- Erlang/OTP is the DSL for the BEAM platform

#### Browsers
- The best platform for universal distribution
- JavaScript/DOM is the DSL for the Browser platform

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### Powerful **language**

#### Gleam
- A tool for thought.
- No syntactic niceties for processes or promises.
- Applicable to either platform.
- Validates your assumptions with type inference.

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## Glistix

![](./glistix.png)

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## Maximise leverage of **Gleam**
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### Benefits of a type system

![](../../2025-05-12/removing-fragility-with-eyg/noredink.png)

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### Benefits of a type system

What do types add to this Python program?

```py
print("Hello, World!")
```

Did you appreciate types the first day you were coding?

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What does a **type system** offer.

- Consistency based on some axioms.
- The axioms are the perimeter.
- The wider the perimeter of our axioms the more valuable the type system.

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### Web development

![](../../2025-05-12/removing-fragility-with-eyg/web-types.png)

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### Metaframeworks, Liveview

![](../../2025-05-12/removing-fragility-with-eyg/metaframework-types.png)

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### Web development

It's far more than a frontend/backend split

- Local development
- Build servers
- CI/CD
- codegen
- Backend/frontend
- Service workers
- Background queues
- Infra provisioning
- Database queries

How do you compose these components?

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# Bash is worse than Gleam

so is `make`.

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## The **unix** philosphy

- Write programs that do one thing and do it well.
- Write programs to work together.
- Write programs to handle text streams, because that is a universal interface.

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## The **unix** reality

![](../../2025-05-12/removing-fragility-with-eyg/unix-types.png)

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## It could be worse

![](../../2025-05-12/removing-fragility-with-eyg/kubernetes-types.png)

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### Powerful **platforms**

#### Linux

- A great platform for running multiple applications
- `.sh` is the DSL for the operating system

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```sh
wget .. \
&& cd .. \
&& echo .. >
```

Why not use **Gleam**

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![](./midas-readme.png)

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![](./midas-example.png)
https://github.com/CrowdHailer/gleamtours/blob/main/packages/gleamtours/src/gleamtours/dev.gleam

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![](./midas-share.png)
https://github.com/CrowdHailer/gleamweekly/blob/master/mailer/src/gleamweekly.gleam

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![](./midas-minimal.png)

We're stretching here. Can we do more?

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![](../../2025-05-12/removing-fragility-with-eyg/migration-types.png)

Not with Gleam. Maybe one day.

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## Thank you
P.S.
![](./gleam-gathering.png)
[gleamgathering.com](https://gleamgathering.com/)