Add multi tenancy capabilities with ecto meta prefix

README.md

@@ -379,6 +379,58 @@ Bang functions assume the operation will always be successful, otherwise functio
   #     "updated_at" => "2016-09-15T22:00:59"},
   #   item_id: 1, item_type: "Post", originator_id: nil, originator: nil, meta: nil}
 ```
+
+## Working with multi tenancy
+
+Sometimes you have to deal with applications where you need multi tenancy capabilities,
+and you want to keep tracking of the versions of your data on different schemas (PostgreSQL)
+or databases (MySQL).
+
+You can use the [Ecto.Query prefix](https://hexdocs.pm/ecto/Ecto.Query.html#module-query-prefix)
+in order to switch between different schemas/databases for your own data, so
+you can specify in your changeset where to store your record. Example:
+
+```elixir
+tenant = "tenant_id"
+changeset = User.changeset(%User{}, %{first_name: "Izel", last_name: "Nakri"})
+
+changeset
+|> Ecto.Queryable.to_query()
+|> Map.put(:prefix, tenant)
+|> Repo.insert()
+```
+
+PaperTrail also allows you to store the `Version` entries generated by your activity in
+different schemas/databases by using the value of the element `:prefix` on the options
+of the functions. Example:
+
+```elixir
+tenant = "tenant_id"
+
+changeset =
+  User.changeset(%User{}, %{first_name: "Izel", last_name: "Nakri"})
+  |> Ecto.Queryable.to_query()
+  |> Map.put(:prefix, tenant)
+
+PaperTrail.insert(changeset, [prefix: tenant])
+```
+
+By doing this, you're storing the new `User` entry into the schema/database
+specified by the `:prefix` value (`tenant_id`). Notice that the `User`'s changeset it's sent
+with the `:prefix` already set properly, so PaperTrail **only will take care of the
+storage of the generated `Version` entry in the desired schema/database**, be sure
+to add this info to your changeset before the execution of the PaperTrail function.
+
+PaperTrail can get versions of records or models from different schemas/databases as well
+by using the value of the element `:prefix` on the options of the functions. Example:
+
+```elixir
+tenant = "tenant_id"
+id = 1
+
+PaperTrail.get_versions(User, id, [prefix: tenant])
+```
+
 ## Suggestions
 - PaperTrail.Version(s) order matter,
 - don't delete your paper_trail versions, instead you can merge them
@@ -392,6 +444,7 @@ Many thanks to:
 - [Jason Draper](https://github.com/drapergeek) - UUID primary keys feature
 - [Josh Taylor](https://github.com/joshuataylor) - Maintenance and new feature suggestions
 - [Mitchell Henke](https://github.com/mitchellhenke) - Fixed weird elixir compiler warnings
+- [Iván González](https://github.com/dreamingechoes) - Multi tenancy feature and some minor refactors
 - [Izel Nakri](https://github.com/izelnakri) - The Originator of this library. See what I did there ;)
 
 Additional thanks to:

example/test/company_test.exs

@@ -12,24 +12,23 @@ defmodule CompanyTest do
   end
 
   test "creating a company creates a company version with correct attributes" do
-    new_company = Company.changeset(%Company{}, %{
-      name: "Acme LLC", is_active: true, city: "Greenwich", people: []
-    })
-
-    {:ok, result} = PaperTrail.insert(new_company, origin: "test")
-
-    company_count = Repo.all(
-      from company in Company,
-      select: count(company.id)
-    )
+    {:ok, result} =
+      %Company{}
+      |> Company.changeset(%{name: "Acme LLC", is_active: true, city: "Greenwich", people: []})
+      |> PaperTrail.insert(origin: "test")
+
+    company_count =
+      from(company in Company, select: count(company.id))
+      |> Repo.all()
+    version_count =
+      from(version in PaperTrail.Version, select: count(version.id))
+      |> Repo.all()
+    first_company =
+      first(Company, :id)
+      |> preload(:people)
+      |> Repo.one()
 
     company = result[:model] |> Map.drop([:__meta__, :__struct__, :inserted_at, :updated_at, :id])
-
-    version_count = Repo.all(
-      from version in PaperTrail.Version,
-      select: count(version.id)
-    )
-
     version = result[:version] |> Map.drop([:__meta__, :__struct__, :inserted_at])
 
     assert company_count == [1]
@@ -50,7 +49,7 @@ defmodule CompanyTest do
     assert Map.drop(version, [:id]) == %{
       event: "insert",
       item_type: "Company",
-      item_id: Repo.one(first(Company, :id)).id,
+      item_id: first_company.id,
       item_changes: Map.drop(result[:model], [:__meta__, :__struct__, :people]),
       origin: "test",
       originator_id: nil,
@@ -59,27 +58,27 @@ defmodule CompanyTest do
   end
 
   test "updating a company creates a company version with correct item_changes" do
-    old_company = first(Company, :id) |> preload(:people) |> Repo.one
-    new_company = Company.changeset(old_company, %{
-      city: "Hong Kong",
-      website: "http://www.acme.com",
-      facebook: "acme.llc"
-    })
-
-    {:ok, result} = PaperTrail.update(new_company)
+    first_company =
+      first(Company, :id)
+      |> preload(:people)
+      |> Repo.one()
+
+    {:ok, result} =
+      first_company
+      |> Company.changeset(%{
+        city: "Hong Kong",
+        website: "http://www.acme.com",
+        facebook: "acme.llc"
+      }) |> PaperTrail.update()
 
-    company_count = Repo.all(
-      from company in Company,
-      select: count(company.id)
-    )
+    company_count =
+      from(company in Company, select: count(company.id))
+      |> Repo.all()
+    version_count =
+      from(version in PaperTrail.Version, select: count(version.id))
+      |> Repo.all()
 
     company = result[:model] |> Map.drop([:__meta__, :__struct__, :inserted_at, :updated_at, :id])
-
-    version_count = Repo.all(
-      from version in PaperTrail.Version,
-      select: count(version.id)
-    )
-
     version = result[:version] |> Map.drop([:__meta__, :__struct__, :inserted_at])
 
     assert company_count == [1]
@@ -100,7 +99,7 @@ defmodule CompanyTest do
     assert Map.drop(version, [:id]) == %{
       event: "update",
       item_type: "Company",
-      item_id: Repo.one(first(Company, :id)).id,
+      item_id: first_company.id,
       item_changes: %{city: "Hong Kong", website: "http://www.acme.com", facebook: "acme.llc"},
       origin: nil,
       originator_id: nil,
@@ -109,22 +108,23 @@ defmodule CompanyTest do
   end
 
   test "deleting a company creates a company version with correct attributes" do
-    company = first(Company, :id) |> preload(:people) |> Repo.one
-
-    {:ok, result} = PaperTrail.delete(company)
-
-    company_count = Repo.all(
-      from company in Company,
-      select: count(company.id)
-    )
+    company =
+      first(Company, :id)
+      |> preload(:people)
+      |> Repo.one()
+
+    {:ok, result} =
+      company
+      |> PaperTrail.delete()
+
+    company_count =
+      from(company in Company, select: count(company.id))
+      |> Repo.all()
+    version_count =
+      from(version in PaperTrail.Version, select: count(version.id))
+      |> Repo.all()
 
     company_ref = result[:model] |> Map.drop([:__meta__, :__struct__, :inserted_at, :updated_at, :id])
-
-    version_count = Repo.all(
-      from version in PaperTrail.Version,
-      select: count(version.id)
-    )
-
     version = result[:version] |> Map.drop([:__meta__, :__struct__, :inserted_at])
 
     assert company_count == [0]

example/test/multi_tenant_company_test.exs

@@ -0,0 +1,175 @@
+defmodule MultiTenantCompanyTest do
+  use ExUnit.Case
+  import Ecto.Query
+
+  setup_all do
+    MultiTenantHelper.setup_tenant(Repo)
+    :ok
+  end
+
+  test "[multi tenant] creating a company creates a company version with correct attributes" do
+    {:ok, result} =
+      %Company{}
+      |> Company.changeset(%{name: "Acme LLC", is_active: true, city: "Greenwich", people: []})
+      |> MultiTenantHelper.add_prefix_to_changeset()
+      |> PaperTrail.insert(origin: "test", prefix: MultiTenantHelper.tenant())
+
+    company_count =
+      from(company in Company, select: count(company.id))
+      |> MultiTenantHelper.add_prefix_to_query()
+      |> Repo.all()
+    version_count =
+      from(version in PaperTrail.Version, select: count(version.id))
+      |> MultiTenantHelper.add_prefix_to_query()
+      |> Repo.all()
+    first_company =
+      first(Company, :id)
+      |> preload(:people)
+      |> MultiTenantHelper.add_prefix_to_query()
+      |> Repo.one()
+
+    company = result[:model] |> Map.drop([:__meta__, :__struct__, :inserted_at, :updated_at, :id])
+    version = result[:version] |> Map.drop([:__meta__, :__struct__, :inserted_at])
+
+    assert company_count == [1]
+    assert version_count == [1]
+
+    assert company == %{
+      name: "Acme LLC",
+      is_active: true,
+      city: "Greenwich",
+      website: nil,
+      address: nil,
+      facebook: nil,
+      twitter: nil,
+      founded_in: nil,
+      people: []
+    }
+
+    assert Map.drop(version, [:id]) == %{
+      event: "insert",
+      item_type: "Company",
+      item_id: first_company.id,
+      item_changes: Map.drop(result[:model], [:__meta__, :__struct__, :people]),
+      origin: "test",
+      originator_id: nil,
+      meta: nil
+    }
+  end
+
+  test "[multi tenant] updating a company creates a company version with correct item_changes" do
+    first_company =
+      first(Company, :id)
+      |> preload(:people)
+      |> MultiTenantHelper.add_prefix_to_query()
+      |> Repo.one()
+
+    {:ok, result} =
+      first_company
+      |> Company.changeset(%{
+        city: "Hong Kong",
+        website: "http://www.acme.com",
+        facebook: "acme.llc"
+      })
+      |> MultiTenantHelper.add_prefix_to_changeset()
+      |> PaperTrail.update(prefix: MultiTenantHelper.tenant())
+
+    company_count =
+      from(company in Company, select: count(company.id))
+      |> MultiTenantHelper.add_prefix_to_query()
+      |> Repo.all()
+    version_count =
+      from(version in PaperTrail.Version, select: count(version.id))
+      |> MultiTenantHelper.add_prefix_to_query()
+      |> Repo.all()
+
+    company = result[:model] |> Map.drop([:__meta__, :__struct__, :inserted_at, :updated_at, :id])
+    version = result[:version] |> Map.drop([:__meta__, :__struct__, :inserted_at])
+
+    assert company_count == [1]
+    assert version_count == [2]
+
+    assert company == %{
+      name: "Acme LLC",
+      is_active: true,
+      city: "Hong Kong",
+      website: "http://www.acme.com",
+      address: nil,
+      facebook: "acme.llc",
+      twitter: nil,
+      founded_in: nil,
+      people: []
+    }
+
+    assert Map.drop(version, [:id]) == %{
+      event: "update",
+      item_type: "Company",
+      item_id: first_company.id,
+      item_changes: %{city: "Hong Kong", website: "http://www.acme.com", facebook: "acme.llc"},
+      origin: nil,
+      originator_id: nil,
+      meta: nil
+    }
+  end
+
+  test "[multi tenant] deleting a company creates a company version with correct attributes" do
+    company =
+      first(Company, :id)
+      |> preload(:people)
+      |> MultiTenantHelper.add_prefix_to_query()
+      |> Repo.one()
+
+    {:ok, result} =
+      company
+      |> PaperTrail.delete(prefix: MultiTenantHelper.tenant())
+
+    company_count =
+      from(company in Company, select: count(company.id))
+      |> MultiTenantHelper.add_prefix_to_query()
+      |> Repo.all()
+    version_count =
+      from(version in PaperTrail.Version, select: count(version.id))
+      |> MultiTenantHelper.add_prefix_to_query()
+      |> Repo.all()
+
+    company_ref = result[:model] |> Map.drop([:__meta__, :__struct__, :inserted_at, :updated_at, :id])
+    version = result[:version] |> Map.drop([:__meta__, :__struct__, :inserted_at])
+
+    assert company_count == [0]
+    assert version_count == [3]
+
+    assert company_ref == %{
+      name: "Acme LLC",
+      is_active: true,
+      city: "Hong Kong",
+      website: "http://www.acme.com",
+      address: nil,
+      facebook: "acme.llc",
+      twitter: nil,
+      founded_in: nil,
+      people: []
+    }
+
+    assert Map.drop(version, [:id]) == %{
+      event: "delete",
+      item_type: "Company",
+      item_id: company.id,
+      item_changes: %{
+        id: company.id,
+        inserted_at: company.inserted_at,
+        updated_at: company.updated_at,
+        name: "Acme LLC",
+        is_active: true,
+        website: "http://www.acme.com",
+        city: "Hong Kong",
+        address: nil,
+        facebook: "acme.llc",
+        twitter: nil,
+        founded_in: nil
+      },
+      origin: nil,
+      originator_id: nil,
+      meta: nil
+    }
+  end
+end