jacobparry / weather_umbrella

WeatherUmbrella

Getting things running

I assume you already have the following installed:

• git installed and have cloned this repository.

• Homebrew (MacOS only)

• Clone this repo

• Install both the Homebrew and asdf package managers:

  • Install asdf-vm

    # on MacOS just run
    brew install asdf

• Install Elixir and erlang.

  • I chose to install elixir and erlang using asdf. I find it a relatively painless way to ensure a team is developing with the same erlang and elixir versions.

  • You can run this with elixir and erlang installed using brew, which you likely use, or you can install it via asdf.

  • Install Elixir and Erlang using brew.

    • brew install elixir

  • Using asdf-vm:

    • Install:

• take a moment to

  • read and learn more about the tool

    asdf plugin-add erlang
    asdf plugin-add elixir

  • in the terminal, navigate to the repo directory.

  • Install via asdf. This will install the versions in found in the .tool-versions file.

    asdf install

  • Set the versions of erlang and elixir to the current directory. Can set these globally if you want, but may conflict with a brew installed elixir

    asdf local erlang 24.2
    asdf local elixir 1.13.2-otp-24

  • Run asdf current to confirm that the correct versions are set for the repo.

• Once everything is set up and running:

  • Run mix test. The tests are all passing for me, as of right now. They'll probably fail for you because I noticed the values change, and I'm testing against the live API here. I know I know, shame on me. I should write the tests to use the mocks, but which I did do. It is split between live and mocked.

  • Inspect the logic, and tests that wrote

    • Main logic found. There are other files, but these contain most of the meat.

      • forecast.ex
      • location.ex
      • date_utils.ex
      • city_resolver.ex
      • weather_saver.ex

    • Tests are in the corresponding test files.

      • city_resolver_text.exs contains a test showing the proof of the technical assement, the average max temp for each of the 3 cities.

  • If you want, you can boot up the graphQL interface and play around with it. The functionality is limited because my schema is simple.

    • iex -S mix phx.server

    • http://localhost:4000/playground/graphiql

    • run the query to see the data of the proof.

    • I'd spend time here doing this."""

      {
        triCityDataSequencially {
          name
          averageMaxTemp
        }       
      }
      

      """

• Summary of work done:

  • Code structure

  • I created an umbrella with 4 different apps.

    • api

      • Set up an Absinthe Schema, defined a type, and created a resolver to return the data that was asked for in the proof.
      • This is where I think you should spend some time. The city_resolver.ex implements the async work.

    • db

      • I didn't do anything here. I originally had plans to do things with with the database, ecto, changesets, but I decided to stop before I ran way with it.

    • ui

      • Set up a graphQL interface for to run a simple query to return the data that was asked for in the proof.

    • weather

      • I spent most of my time here.
      • Set up a http client for MetaWeather.
      • Mocked it two different ways, one with Mox, another with Mimic because I wanted to try mimic. I've heard about it.
      • Created the logic for getting the average max temperature for a city based on a unique identifier and date, if desired

  • Future work:

    • Set up the DB with an ecto schema for the weather predictions.

      • The plan is to save the historical predictions, so that when asked for, I only need to hit MetaWeather if I don't have the historical data saved.

      • Set up a GenServer to poll MetaWeather about once a minute or so. I noticed in their docs that they said please don't hit them more than once a minute. I figured I'd be nice and rate limit myself.

      • Differentiate in the logic for when I need to query the db vs MetaWeather.

      • Flesh out Absinthe and GraphQL to allow more robust querying.

      • There is a bug in one of the genserver resolvers. For some reason, it is loading double data.