data tracking by process implemented

README.md

@@ -75,7 +75,7 @@ defmodule MyApp.Version do
     field :recorded_at, :utc_datetime
 
     # custom fields
-    has_one :actor, MyApp.User
+    belongs_to :actor, MyApp.User
   end
 
   def changeset(struct, params \\ %{}) do
@@ -119,8 +119,6 @@ end
 
 ### Recording custom data
 
-**TBD: not implemented yet**
-
 If you want to track custom data such as the user id, you can simply pass a keyword list with that data
 to the `:ex_audit_custom` option in any Repo function:
 
@@ -151,6 +149,14 @@ in the plug tree.
 In some cases where it is not possible to call the Repo function from the conn process, you have to pass the 
 custom data manually via the options described above.
 
+Examples for data you might want to track additionally:
+
+ * User ID
+ * API Key ID 
+ * Message from the user describing what she changed
+
 ## More
 
-The documentation is at [https://hexdocs.pm/ex_audit](https://hexdocs.pm/ex_audit).
+The documentation is available at [https://hexdocs.pm/ex_audit](https://hexdocs.pm/ex_audit). **TBD: release documentation on hexdocs.pm**
+
+Check out [ZENNER IoT Solutions](https://zenner-iot.com/), makers of the [ELEMENT IoT platform](https://zenner-iot.com/iot-plattform).

example/version.ex

@@ -10,7 +10,7 @@ defmodule ExAudit.Test.Version do
     field :recorded_at, :utc_datetime
 
     # custom fields
-    has_one :actor, Test.User
+    belongs_to :actor, ExAudit.Test.User
   end
 
   def changeset(struct, params \\ %{}) do

lib/ex_audit.ex

@@ -1,4 +1,18 @@
 defmodule ExAudit do
+  use Application
+
+  @tracked_data_table :tracked_data_table
+
+  def start(_, _) do
+    import Supervisor.Spec
+
+    children = [
+      worker(ExAudit.CustomData, [])
+    ]
+
+    opts = opts = [strategy: :one_for_one, name: ExAudit.Supervisor]
+    Supervisor.start_link(children, opts)
+  end
   @moduledoc """
   # Configuration
 
@@ -15,6 +29,6 @@ defmodule ExAudit do
   end
 
   def track_pid(pid, data) do
-    # TODO
+    ExAudit.CustomData.track(pid, data)
   end
 end

lib/tracking/custom_data.ex

@@ -0,0 +1,44 @@
+defmodule ExAudit.CustomData do
+  use GenServer
+
+  def start_link() do
+    GenServer.start_link(__MODULE__, nil, name: __MODULE__)
+  end
+
+  def init(nil) do
+    ets = :ets.new(:track_by_pid, [:public])
+    {:ok, ets}
+  end
+
+  def track(pid, data) do
+    GenServer.call(__MODULE__, {:store, pid, data})
+  end
+
+  def handle_call({:store, pid, data}, _, ets) do
+    :ets.insert(ets, {pid, data})
+    Process.monitor(pid)
+    {:reply, :ok, ets}
+  end
+
+  def handle_call({:get, pid}, _, ets) do
+    case :ets.lookup(ets, pid) do
+      [] -> {:reply, [], ets}
+      list ->
+        values = Enum.flat_map(list, &elem(&1, 1))
+        {:reply, values, ets}
+    end
+  end
+
+  def get() do
+    GenServer.call(__MODULE__, {:get, self()})
+  end
+
+  def get(pid) do
+    GenServer.call(__MODULE__, {:get, pid})
+  end
+
+  def handle_info({:DOWN, _, :process, pid, _}, ets) do
+    :ets.delete(ets, pid)
+    {:noreply, ets}
+  end
+end

lib/tracking/tracking.ex

@@ -48,7 +48,13 @@ defmodule ExAudit.Tracking do
     changes = find_changes(action, changeset, resulting_struct)
 
     now = DateTime.utc_now
-    custom_fields = Keyword.get(opts, :ex_audit_custom, []) |> Enum.into(%{})
+    custom_fields_opts = 
+      Keyword.get(opts, :ex_audit_custom, [])
+      |> Enum.into(%{})
+    custom_fields_process = 
+      ExAudit.CustomData.get()
+      |> Enum.into(%{})
+    custom_fields = Map.merge(custom_fields_process, custom_fields_opts)
 
     changes = Enum.map(changes, fn change ->
       change = Map.put(change, :recorded_at, now)

mix.exs

@@ -26,6 +26,7 @@ defmodule ExAudit.Mixfile do
   # Run "mix help compile.app" to learn about applications.
   def application do
     [
+      mod: {ExAudit, []},
       extra_applications: [:logger]
     ]
   end

test/ex_audit_test.exs

@@ -4,7 +4,7 @@ defmodule ExAuditTest do
 
   import Ecto.Query
 
-  alias ExAudit.Test.{Repo, User, Version}
+  alias ExAudit.Test.{Repo, User, Version, BlogPost}
 
   test "should document lifecycle of an entity" do
     params = %{
@@ -53,4 +53,42 @@ defmodule ExAuditTest do
 
     assert length(versions) == 3
   end
+
+  test "should track custom data" do
+    user = Repo.insert!(User.changeset(%User{}, %{name: "Admin", email: "admin@example.com"}))
+
+    changeset = BlogPost.changeset(%BlogPost{}, %{
+      author_id: user.id,
+      title: "My First Post"
+    }) 
+
+    {:ok, blog_post} = Repo.insert(changeset, ex_audit_custom: [actor_id: user.id])
+
+    version = Repo.one(from v in Version,
+        where: v.entity_id == ^blog_post.id,
+        where: v.entity_schema == ^BlogPost,
+        where: v.action == ^:created)
+
+    assert version.actor_id == user.id
+  end
+
+  test "should track custom data from plugs or similar" do
+    user = Repo.insert!(User.changeset(%User{}, %{name: "Admin", email: "admin@example.com"}))
+
+    changeset = BlogPost.changeset(%BlogPost{}, %{
+      author_id: user.id,
+      title: "My Second Post"
+    }) 
+
+    ExAudit.track(actor_id: user.id)
+
+    {:ok, blog_post} = Repo.insert(changeset)
+
+    version = Repo.one(from v in Version,
+        where: v.entity_id == ^blog_post.id,
+        where: v.entity_schema == ^BlogPost,
+        where: v.action == ^:created)
+
+    assert version.actor_id == user.id
+  end
 end

test/test_helper.exs

@@ -1,3 +1,4 @@
+:ok = Application.ensure_started(:ex_audit)
 ExAudit.Test.Repo.start_link()
 Ecto.Adapters.SQL.Sandbox.mode(ExAudit.Test.Repo, :auto)