fix: Using Pockets to use DETS instead of ETS. #1

.gitignore

@@ -72,4 +72,5 @@ npm-debug.log
 /assets/node_modules/
 
 # Env files
-.env
+.env
+cache.dets

README.md

@@ -1114,8 +1114,11 @@ and can be employed to store large amounts of data
 Do note that since this engine is in-memory,
 **all data is lost when the process ends/server is shutdown**.
 
-There is an Elixir wrapper that makes it easy to use `ETS`.
-[`ets`](https://github.com/TheFirstAvenger/ets).
+There is an Elixir wrapper that makes it easy to use `ETS` and `DETS`, 
+where the latter is a disk-based variant of the former,
+where data is persisted on disk.
+We'll be using
+[`pockets`](https://github.com/fireproofsocks/pockets).
 
 Let's install it.
 
@@ -1124,7 +1127,7 @@ Add it to the `deps` section inside `mix.exs`.
 ```elixir
 def deps do
   [
-    {:ets, "~> 0.9.0"}
+    {:pockets, "~> 0.1.0"}
   ]
 end
 ```
@@ -1140,36 +1143,20 @@ For that, create a file in `lib/app/users.ex`.
 ```elixir
 defmodule UsersTable do
 
-  alias ETS.Set
+  alias Pockets
 
   @table :users_table
 
   def init do
-    Set.new(name: @table)
+    Pockets.new(@table, "cache.dets")
   end
 
   def list_users do
-    @table
-    |> Set.wrap_existing!()
-    |> Set.to_list()
+    Pockets.to_map(@table)
   end
 
-  def create_user(%{:stripe_id => stripe_id, :person_id => person_id}) do
-    @table
-    |> Set.wrap_existing!()
-    |> Set.put_new( {person_id, stripe_id, false})
-  end
-
-  def update_payment_status(%{:person_id => person_id, :status => new_status}) do
-
-    set = @table
-    |> Set.wrap_existing!()
-
-    {person_id, stripe_id, _status} = set
-      |> Set.get!(person_id)
-
-    set
-    |> Set.put({person_id, stripe_id, new_status})
+  def create_user(%{:stripe_id => stripe_id, :person_id => person_id, :status => status}) do
+    Pockets.put(@table, person_id, %{stripe_id: stripe_id, status: status})
   end
 
 end
@@ -1186,25 +1173,17 @@ All the functions being used are used
 according to the [`ets` wrapper documentation](https://github.com/TheFirstAvenger/ets).
 - the `init/0` function creates the table to store our users.
 - `list_users` returns the list of users.
-- `create_user/2` receives a `stripe_id` and `person_id`
+- `create_user/3` receives a `stripe_id`, `person_id` and `status` 
+(pertaining to whether the payment has been made or not)
 and creates a user object.
-By default, the `status` field is created with `false`.
-- `update_payment_status/1` receives a user object
-and updates accordingly.
 
 Let's make use of some of these functions.
-We want to setup the `ETS` table on the process startup.
+We want to setup the `DETS` table on the process startup.
 For this, we are going to initiate the table
 on the `start/1` function inside `lib/app/application.ex`.
 This functions is executed when the process is created,
 so it fits right our needs!
 
-Inside this function, add:
-
-```elixir
-# Creating ETS user table     
-{:ok, _set} = UsersTable.init()
-```
 
 Awesome!
 

lib/app/application.ex

@@ -22,8 +22,10 @@ defmodule App.Application do
       # {App.Worker, arg}
     ]
 
-    # Creating ETS user table
-    {:ok, _set} = UsersTable.init()
+    # Creating DETS user table
+    UsersTable.init()
+    #UsersTable.create_user(%{person_id: 1, stripe_id: 1, status: false})
+    #dbg(UsersTable.list_users())
 
     # See https://hexdocs.pm/elixir/Supervisor.html
     # for other strategies and supported options

lib/app/users.ex

@@ -1,35 +1,19 @@
 defmodule UsersTable do
 
-  alias ETS.Set
+  alias Pockets
 
   @table :users_table
 
   def init do
-    Set.new(name: @table)
+    Pockets.new(@table, "cache.dets")
   end
 
   def list_users do
-    @table
-    |> Set.wrap_existing!()
-    |> Set.to_list()
+    Pockets.to_map(@table)
   end
 
-  def create_user(%{:stripe_id => stripe_id, :person_id => person_id}) do
-    @table
-    |> Set.wrap_existing!()
-    |> Set.put_new( {person_id, stripe_id, false})
-  end
-
-  def update_payment_status(%{:person_id => person_id, :status => new_status}) do
-
-    set = @table
-    |> Set.wrap_existing!()
-
-    {person_id, stripe_id, _status} = set
-      |> Set.get!(person_id)
-
-    set
-    |> Set.put({person_id, stripe_id, new_status})
+  def create_user(%{:stripe_id => stripe_id, :person_id => person_id, :status => status}) do
+    Pockets.put(@table, person_id, %{stripe_id: stripe_id, status: status})
   end
 
 end

mix.exs

@@ -59,7 +59,7 @@ defmodule App.MixProject do
       {:stripity_stripe, "~> 2.17"},
 
       # Storage
-      {:ets, "~> 0.9.0"}
+      {:pockets, "~> 0.1.0"}
 
     ]
   end

mix.lock

@@ -43,6 +43,7 @@
   "plug": {:hex, :plug, "1.14.0", "ba4f558468f69cbd9f6b356d25443d0b796fbdc887e03fa89001384a9cac638f", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:plug_crypto, "~> 1.1.1 or ~> 1.2", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.3 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "bf020432c7d4feb7b3af16a0c2701455cbbbb95e5b6866132cb09eb0c29adc14"},
   "plug_cowboy": {:hex, :plug_cowboy, "2.6.0", "d1cf12ff96a1ca4f52207c5271a6c351a4733f413803488d75b70ccf44aebec2", [:mix], [{:cowboy, "~> 2.7", [hex: :cowboy, repo: "hexpm", optional: false]}, {:cowboy_telemetry, "~> 0.3", [hex: :cowboy_telemetry, repo: "hexpm", optional: false]}, {:plug, "~> 1.14", [hex: :plug, repo: "hexpm", optional: false]}], "hexpm", "073cf20b753ce6682ed72905cd62a2d4bd9bad1bf9f7feb02a1b8e525bd94fa6"},
   "plug_crypto": {:hex, :plug_crypto, "1.2.3", "8f77d13aeb32bfd9e654cb68f0af517b371fb34c56c9f2b58fe3df1235c1251a", [:mix], [], "hexpm", "b5672099c6ad5c202c45f5a403f21a3411247f164e4a8fab056e5cd8a290f4a2"},
+  "pockets": {:hex, :pockets, "0.1.0", "0841c02a4d9a3d2ecba9e027fdeaa94be7371a52b4b1ab62833675a7d7aa17f3", [:mix], [], "hexpm", "a026f6a73f9cac165113135aeea79b65650174eea65fb013406c2103290ecac0"},
   "postgrex": {:hex, :postgrex, "0.16.5", "fcc4035cc90e23933c5d69a9cd686e329469446ef7abba2cf70f08e2c4b69810", [:mix], [{:connection, "~> 1.1", [hex: :connection, repo: "hexpm", optional: false]}, {:db_connection, "~> 2.1", [hex: :db_connection, repo: "hexpm", optional: false]}, {:decimal, "~> 1.5 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:table, "~> 0.1.0", [hex: :table, repo: "hexpm", optional: true]}], "hexpm", "edead639dc6e882618c01d8fc891214c481ab9a3788dfe38dd5e37fd1d5fb2e8"},
   "ranch": {:hex, :ranch, "1.8.0", "8c7a100a139fd57f17327b6413e4167ac559fbc04ca7448e9be9057311597a1d", [:make, :rebar3], [], "hexpm", "49fbcfd3682fab1f5d109351b61257676da1a2fdbe295904176d5e521a2ddfe5"},
   "ssl_verify_fun": {:hex, :ssl_verify_fun, "1.1.6", "cf344f5692c82d2cd7554f5ec8fd961548d4fd09e7d22f5b62482e5aeaebd4b0", [:make, :mix, :rebar3], [], "hexpm", "bdb0d2471f453c88ff3908e7686f86f9be327d065cc1ec16fa4540197ea04680"},