replacing ecto/postgres for erlang mnesia database

.gitignore

@@ -21,3 +21,6 @@ erl_crash.dump
 
 *.secret.exs
 mix.lock
+
+# all the Mnesia databases
+Mnesia*

README.md

@@ -1,19 +1,30 @@
 # Largo
 
-**TODO: Add description**
+Largo is a Slack Integration done in Elixir to store key/values in your Slack chat.
+
+## Dependencies
+You need to install Erlang and Elixir, we strongly recommend:
+http://elixir-lang.org/install.html
 
 ## Installation
 
-If [available in Hex](https://hex.pm/docs/publish), the package can be installed
-by adding `largo` to your list of dependencies in `mix.exs`:
+1. Install the dependencies:
+`mix deps.get`
+
+2. Copy your Slack API-KEY token in `api_token` under `config/dev.secret.exs`
+
+3. Create the Mnesia database
+`mix amnesia.create -d Database --disk`
 
-```elixir
-def deps do
-  [{:largo, "~> 0.1.0"}]
-end
-```
+4. Run the app!
+`iex -S mix`
 
-Documentation can be generated with [ExDoc](https://github.com/elixir-lang/ex_doc)
-and published on [HexDocs](https://hexdocs.pm). Once published, the docs can
-be found at [https://hexdocs.pm/largo](https://hexdocs.pm/largo).
+## Uses
+You can tag @largo bot in your Slack chat or just chat directly with it.
 
+- @largo guarda foo=bar
+- @largo trae foo
+- @largo guarda hora reunion=10:00 am
+- @largo trae todo
+- @largo borra foo
+- @largo trae todo

config/config.exs

@@ -2,16 +2,6 @@
 # and its dependencies with the aid of the Mix.Config module.
 use Mix.Config
 
-config :largo, Largo.Repo,
-  adapter: Ecto.Adapters.Postgres,
-  database: "largo",
-  username: "postgres",
-  password: "postgres",
-  hostname: "localhost",
-  port: 15432
-
-config :largo, ecto_repos: [Database.Repo]
-
 config :largo, default_message_parameters: %{
   as_user: true
 }

lib/database.ex

@@ -0,0 +1,31 @@
+use Amnesia
+
+defdatabase Database do
+  deftable Value
+
+  deftable Value, [{ :id, autoincrement }, :key, :value, :last_updater], type: :ordered_set, index: [:key] do
+    @type t :: %Value{id: non_neg_integer, key: String.t, value: String.t, last_updater: String.t}
+
+    # this is a helper function to add a message to the user, using write
+    # on the created records makes it write to the mnesia table
+    # def add_value(self, content) do
+    #   %Message{user_id: self.id, content: content} |> Message.write
+    # end
+
+    # # like above, but again with dirty operations, the bang methods are used
+    # # thorough amnesia to be the dirty counterparts of the bang-less functions
+    # def add_message!(self, content) do
+    #   %Message{user_id: self.id, content: content} |> Message.write!
+    # end
+
+    # # this is a helper to fetch all messages for the user
+    # def messages(self) do
+    #   Message.read(self.id)
+    # end
+
+    # # like above, but with dirty operations
+    # def messages!(self) do
+    #   Message.read!(self.id)
+    # end
+  end
+end

lib/largo/application.ex

@@ -9,7 +9,7 @@ defmodule Largo.Application do
     import Supervisor.Spec, warn: false
 
     # Define workers and child supervisors to be supervised
-    default_workers = [ supervisor(Largo.Repo, [])]
+    default_workers = []
 
     slack_workers = if Application.get_env(:largo, :enable_ws_client, true) do
       [worker(Slack.Bot, [Largo, [], Application.get_env(:slack, :api_token)])]

lib/largo/responders/memmory_responder.ex

@@ -1,7 +1,8 @@
 defmodule Largo.Responders.MemmoryResponder do
   @behaviour Largo.Responders.Responder
-  alias Largo.{Value, Repo}
-  import Ecto.Query
+  use Database
+  use Amnesia
+  alias Amnesia.Selection
 
   @matchers [
     {~r/Guard[aá]\s+(?<key>.+)[=:](?<value>.+)$/iu, :save},
@@ -35,42 +36,48 @@ defmodule Largo.Responders.MemmoryResponder do
 
   defp get(key) do
     key = clean_key(key)
-    case Ecto.Query.from(v in Value, where: v.key == ^key) |> Repo.one do
-      nil -> {:ok, build_colored_message("No encontré la clave #{key}", "warn")}
-      value -> {:ok, build_kv_message([{value.key, value.value}], "hmmmmmmm", "good")}
+    Amnesia.transaction do
+      case Value.read_at(key, :key) do
+        nil -> {:ok, build_colored_message("No encontré la clave #{key}", "warn")}
+        values -> {:ok, build_kv_message([{hd(values).key, hd(values).value}], "hmmmmmmm", "good")}
+      end
     end
   end
 
   defp delete(key) do
     key = clean_key(key)
-    case Ecto.Query.from(v in Value, where: v.key == ^key) |> Repo.one do
-      nil -> {:ok, build_colored_message("No encontré la clave #{key}", "warning")}
-      value ->
-        case Repo.delete(value) do
-          {:error, _} -> {:ok, build_colored_message("No pude borrar la clave #{key}", "danger")}
-          {:ok, value} -> {:ok, build_colored_message("Borré la clave #{value.key}. Último valor: #{value.value}", "good")}
+    Amnesia.transaction do
+      case Value.read_at(key, :key) do
+        nil -> {:ok, build_colored_message("No encontré la clave #{key}", "warning")}
+        values ->
+          case Value.delete(hd(values)) do
+            :error -> {:ok, build_colored_message("No pude borrar la clave #{key}", "danger")}
+            :ok -> {:ok, build_colored_message("Borré la clave #{hd(values).key}. Último valor: #{hd(values).value}", "good")}
+          end
         end
     end
   end
 
   defp list do
-    msg = Repo.all(Value)
-      |> Enum.map(&{&1.key, &1.value})
-      |> build_kv_message("*hmmmmm*", "good")
-    {:ok, msg}
+    Amnesia.transaction do
+      msg = Value.where(1 == 1) |> Amnesia.Selection.values
+        |> Enum.map(&{&1.key, &1.value})
+        |> build_kv_message("*hmmmmm*", "good")
+      {:ok, msg}
+    end
   end
 
   defp save(key, value) do
     key = clean_key(key)
-    case Repo.get_by(Value, key: key) do
-      nil ->
-        Value.changeset(%Value{}, %{key: key, value: String.trim(value)})
-        |> Repo.insert!
-        {:ok, build_colored_message("guardado...", "good")}
-      db_val ->
-        Value.changeset(db_val, %{value: String.trim(value)})
-        |> Repo.update!
-        {:ok, build_colored_message("actualizado...", "good")}
+    Amnesia.transaction do
+      case Value.read_at(key, :key) do
+        nil ->
+          %Value{key: key, value: String.trim(value)} |> Value.write
+          {:ok, build_colored_message("guardado...", "good")}
+        _ ->
+          %Value{value: String.trim(value)} |> Value.write
+          {:ok, build_colored_message("actualizado...", "good")}
+      end
     end
   end
 

mix.exs

@@ -29,8 +29,7 @@ defmodule Largo.Mixfile do
   #
   # Type "mix help deps" for more examples and options
   defp deps do
-    [{:ecto, "~> 2.0"},
-     {:postgrex, "~> 0.11"},
+    [{:amnesia, "~> 0.2.7"},
      {:slack, "~> 0.11.0"},
      {:poison, "~> 3.0"}]
   end