write a config module

.env.sample

@@ -0,0 +1 @@
+export MQTT_PW=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

.gitignore

@@ -2,3 +2,5 @@
 *.ez
 /build
 erl_crash.dump
+
+.env

README.md

@@ -2,8 +2,6 @@
 
 This is a real-time, neighborhood-facing weather dashboard that streams sensory data from an MQTT broker (Home Assistant) to a web interface.
 
-Gleam code started created following [this guide](https://gleam.run/writing-gleam/).
-
 ## Tech Stack Overview
 - **Backend:** Gleam (Target: Erlang/OTP)
 - **Web Server:** Mist (HTTP & WebSockets)
@@ -11,6 +9,10 @@ Gleam code started created following [this guide](https://gleam.run/writing-glea
 - **Frontend:** SolidJS (Signals-based reactivity) + Tailwind CSS
 - **Infrastructure:** Nomad (Docker-based deployment)
 
+## Resources
+
+- https://learnxinyminutes.com/gleam/
+- [Getting started guide](https://gleam.run/writing-gleam/).
 
 ## Development
 

config.yml

@@ -0,0 +1,5 @@
+mqtt:
+  host: "192.168.1.11"
+  user: "homeassistant"
+  # password comes from env
+jwt_key: apuOQZyML+8PixmVDP4nXU4M # loaded from env on prod

gleam.toml

@@ -14,6 +14,9 @@ version = "1.0.0"
 
 [dependencies]
 gleam_stdlib = ">= 0.44.0 and < 2.0.0"
+simplifile = ">= 2.4.0 and < 3.0.0"
+glaml = ">= 3.0.2 and < 4.0.0"
+envoy = ">= 1.1.0 and < 2.0.0"
 
 [dev_dependencies]
 gleeunit = ">= 1.0.0 and < 2.0.0"

manifest.toml

@@ -2,10 +2,18 @@
 # You typically do not need to edit this file
 
 packages = [
+  { name = "envoy", version = "1.1.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "envoy", source = "hex", outer_checksum = "850DA9D29D2E5987735872A2B5C81035146D7FE19EFC486129E44440D03FD832" },
+  { name = "filepath", version = "1.1.2", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "filepath", source = "hex", outer_checksum = "B06A9AF0BF10E51401D64B98E4B627F1D2E48C154967DA7AF4D0914780A6D40A" },
+  { name = "glaml", version = "3.0.2", build_tools = ["gleam"], requirements = ["gleam_stdlib", "yamerl"], otp_app = "glaml", source = "hex", outer_checksum = "100CA23F526AB159712A3204D200969571FC43B193736B320C1400D410DEE7AD" },
   { name = "gleam_stdlib", version = "0.70.0", build_tools = ["gleam"], requirements = [], otp_app = "gleam_stdlib", source = "hex", outer_checksum = "86949BF5D1F0E4AC0AB5B06F235D8A5CC11A2DFC33BF22F752156ED61CA7D0FF" },
   { name = "gleeunit", version = "1.9.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleeunit", source = "hex", outer_checksum = "DA9553CE58B67924B3C631F96FE3370C49EB6D6DC6B384EC4862CC4AAA718F3C" },
+  { name = "simplifile", version = "2.4.0", build_tools = ["gleam"], requirements = ["filepath", "gleam_stdlib"], otp_app = "simplifile", source = "hex", outer_checksum = "7C18AFA4FED0B4CE1FA5B0B4BAC1FA1744427054EA993565F6F3F82E5453170D" },
+  { name = "yamerl", version = "0.10.0", build_tools = ["rebar3"], requirements = [], otp_app = "yamerl", source = "hex", outer_checksum = "346ADB2963F1051DC837A2364E4ACF6EB7D80097C0F53CBDC3046EC8EC4B4E6E" },
 ]
 
 [requirements]
+envoy = { version = ">= 1.1.0 and < 2.0.0" }
+glaml = { version = ">= 3.0.2 and < 4.0.0" }
 gleam_stdlib = { version = ">= 0.44.0 and < 2.0.0" }
 gleeunit = { version = ">= 1.0.0 and < 2.0.0" }
+simplifile = { version = ">= 2.4.0 and < 3.0.0" }

src/config.gleam

@@ -0,0 +1,78 @@
+import envoy
+import glaml
+import gleam/result
+import simplifile
+
+pub type Config {
+  Config(mqtt_host: String, mqtt_user: String, mqtt_pw: String, jwt_key: String)
+}
+
+fn load_file() -> Result(String, String) {
+  simplifile.read("config.yml")
+  |> result.map_error(fn(_) { "Failed to read config.yml" })
+}
+
+fn parse_yaml(contents: String) -> Result(glaml.Document, String) {
+  use docs <- result.try(
+    glaml.parse_string(contents)
+    |> result.map_error(fn(_) { "Failed to parse config.yml" }),
+  )
+
+  case docs {
+    [doc] -> Ok(doc)
+    _ -> Error("Expected exactly one YAML document in config.yml")
+  }
+}
+
+fn compile_config(doc: glaml.Document) -> Result(Config, String) {
+  let root = glaml.document_root(doc)
+
+  // Extract values from YAML
+  use mqtt_host_result <- result.try(
+    glaml.select_sugar(root, "mqtt.host")
+    |> result.map_error(fn(_) { "mqtt.host not found in config.yml" }),
+  )
+  use mqtt_user_result <- result.try(
+    glaml.select_sugar(root, "mqtt.user")
+    |> result.map_error(fn(_) { "mqtt.user not found in config.yml" }),
+  )
+  use jwt_key_result <- result.try(
+    glaml.select_sugar(root, "jwt_key")
+    |> result.map_error(fn(_) { "jwt_key not found in config.yml" }),
+  )
+
+  // Extract strings from nodes
+  case mqtt_host_result, mqtt_user_result, jwt_key_result {
+    glaml.NodeStr(host), glaml.NodeStr(user), glaml.NodeStr(key) -> {
+      let yaml_config =
+        Config(
+          mqtt_host: host,
+          mqtt_user: user,
+          mqtt_pw: "placeholder",
+          jwt_key: key,
+        )
+
+      // Override with env vars
+      let final_config =
+        Config(
+          mqtt_host: envoy.get("MQTT_HOST")
+            |> result.unwrap(yaml_config.mqtt_host),
+          mqtt_user: envoy.get("MQTT_USER")
+            |> result.unwrap(yaml_config.mqtt_user),
+          mqtt_pw: envoy.get("MQTT_PW")
+            |> result.unwrap(yaml_config.mqtt_pw),
+          jwt_key: envoy.get("JWT_KEY")
+            |> result.unwrap(yaml_config.jwt_key),
+        )
+
+      Ok(final_config)
+    }
+    _, _, _ -> Error("Config values must be strings in config.yml")
+  }
+}
+
+pub fn load_config() -> Result(Config, String) {
+  use file_content <- result.try(load_file())
+  use doc <- result.try(parse_yaml(file_content))
+  compile_config(doc)
+}

src/weather_portal.gleam

@@ -1,5 +1,17 @@
+import config
 import gleam/io
 
 pub fn main() -> Nil {
-  io.println("Hello from weather_portal!")
+  case config.load_config() {
+    Ok(cfg) -> {
+      io.println("Config loaded successfully!")
+      io.println("MQTT Host: " <> cfg.mqtt_host)
+      io.println("MQTT User: " <> cfg.mqtt_user)
+      io.println("MQTT PW: " <> cfg.mqtt_pw)
+      io.println("JWT Key: " <> cfg.jwt_key)
+    }
+    Error(err) -> {
+      io.println("Failed to load config: " <> err)
+    }
+  }
 }

tasks.txt

@@ -7,5 +7,6 @@ task: hookup a subdomain via reverse proxy
 
 -----------------------
 
+DONE task: write a config module
 DONE task: install gleam
 DONE task: get hello world working on local

weather_portal/.github/workflows/test.yml

@@ -1,23 +0,0 @@
-name: test
-
-on:
-  push:
-    branches:
-      - master
-      - main
-  pull_request:
-
-jobs:
-  test:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v6
-      - uses: erlef/setup-beam@v1
-        with:
-          otp-version: "28"
-          gleam-version: "1.15.2"
-          rebar3-version: "3"
-          # elixir-version: "1"
-      - run: gleam deps download
-      - run: gleam test
-      - run: gleam format --check src test

weather_portal/README.md

@@ -1,24 +0,0 @@
-# weather_portal
-
-[![Package Version](https://img.shields.io/hexpm/v/weather_portal)](https://hex.pm/packages/weather_portal)
-[![Hex Docs](https://img.shields.io/badge/hex-docs-ffaff3)](https://hexdocs.pm/weather_portal/)
-
-```sh
-gleam add weather_portal@1
-```
-```gleam
-import weather_portal
-
-pub fn main() -> Nil {
-  // TODO: An example of the project in use
-}
-```
-
-Further documentation can be found at <https://hexdocs.pm/weather_portal>.
-
-## Development
-
-```sh
-gleam run   # Run the project
-gleam test  # Run the tests
-```