From 6f160bee4d90c3a9e5c96d2a30f01c915893dd2c Mon Sep 17 00:00:00 2001
From: Thomas Schmidleithner <tschmidleithner@users.noreply.github.com>
Date: Mon, 24 Aug 2020 00:54:48 +0200
Subject: [PATCH] Support schema prefixes (#91)

* Support schema prefixes

* Fix format

* Code review changes

* Remove prefix from comments and key_values migrations
---
 lib/scrivener/paginater/ecto/query.ex         | 13 ++++---
 priv/repo/migrations/04_create_schemas.exs    | 17 +++++++++
 priv/repo/migrations/05_create_users.exs      | 13 +++++++
 test/scrivener/paginator/ecto/prefix_test.exs | 36 +++++++++++++++++++
 test/support/user.ex                          |  7 ++++
 5 files changed, 82 insertions(+), 4 deletions(-)
 create mode 100644 priv/repo/migrations/04_create_schemas.exs
 create mode 100644 priv/repo/migrations/05_create_users.exs
 create mode 100644 test/scrivener/paginator/ecto/prefix_test.exs
 create mode 100644 test/support/user.ex

diff --git a/lib/scrivener/paginater/ecto/query.ex b/lib/scrivener/paginater/ecto/query.ex
index 313a6d6..f648e46 100644
--- a/lib/scrivener/paginater/ecto/query.ex
+++ b/lib/scrivener/paginater/ecto/query.ex
@@ -14,7 +14,9 @@ defimpl Scrivener.Paginater, for: Ecto.Query do
         options: options
       }) do
     total_entries =
-      Keyword.get_lazy(options, :total_entries, fn -> total_entries(query, repo, caller) end)
+      Keyword.get_lazy(options, :total_entries, fn ->
+        total_entries(query, repo, caller, options)
+      end)
 
     total_pages = total_pages(total_entries, page_size)
     allow_overflow_page_number = Keyword.get(options, :allow_overflow_page_number, false)
@@ -35,20 +37,23 @@ defimpl Scrivener.Paginater, for: Ecto.Query do
 
   defp entries(query, repo, page_number, _, page_size, caller, options) do
     offset = Keyword.get_lazy(options, :offset, fn -> page_size * (page_number - 1) end)
+    prefix = options[:prefix]
 
     query
     |> offset(^offset)
     |> limit(^page_size)
-    |> repo.all(caller: caller)
+    |> repo.all(caller: caller, prefix: prefix)
   end
 
-  defp total_entries(query, repo, caller) do
+  defp total_entries(query, repo, caller, options) do
+    prefix = options[:prefix]
+
     total_entries =
       query
       |> exclude(:preload)
       |> exclude(:order_by)
       |> aggregate()
-      |> repo.one(caller: caller)
+      |> repo.one(caller: caller, prefix: prefix)
 
     total_entries || 0
   end
diff --git a/priv/repo/migrations/04_create_schemas.exs b/priv/repo/migrations/04_create_schemas.exs
new file mode 100644
index 0000000..3f4de5e
--- /dev/null
+++ b/priv/repo/migrations/04_create_schemas.exs
@@ -0,0 +1,17 @@
+defmodule TestRepo.Migrations.CreateSchemas do
+  use Ecto.Migration
+
+  @prefixes ["tenant_1", "tenant_2"]
+
+  def up do
+    for prefix <- @prefixes do
+      execute "CREATE SCHEMA #{prefix}"
+    end
+  end
+
+  def down do
+    for prefix <- @prefixes do
+      execute "DROP SCHEMA #{prefix}"
+    end
+  end
+end
diff --git a/priv/repo/migrations/05_create_users.exs b/priv/repo/migrations/05_create_users.exs
new file mode 100644
index 0000000..b811c40
--- /dev/null
+++ b/priv/repo/migrations/05_create_users.exs
@@ -0,0 +1,13 @@
+defmodule TestRepo.Migrations.CreateUsers do
+  use Ecto.Migration
+
+  @prefixes ["tenant_1", "tenant_2"]
+
+  def change do
+    for prefix <- @prefixes do
+      create table(:users, prefix: prefix) do
+        add :email, :string
+      end
+    end
+  end
+end
diff --git a/test/scrivener/paginator/ecto/prefix_test.exs b/test/scrivener/paginator/ecto/prefix_test.exs
new file mode 100644
index 0000000..0b3bb9b
--- /dev/null
+++ b/test/scrivener/paginator/ecto/prefix_test.exs
@@ -0,0 +1,36 @@
+defmodule Scrivener.Paginator.Ecto.PrefixTest do
+  use Scrivener.Ecto.TestCase
+
+  alias Scrivener.Ecto.User
+
+  defp create_users(number, prefix) do
+    Enum.map(1..number, fn i ->
+      %User{email: "user_#{i}@#{prefix}.com"}
+      |> Scrivener.Ecto.Repo.insert!(prefix: prefix)
+    end)
+  end
+
+  @schema_tenant_1 "tenant_1"
+  @schema_tenant_2 "tenant_2"
+
+  describe "prefix" do
+    test "can specify prefix" do
+      create_users(6, @schema_tenant_1)
+      create_users(2, @schema_tenant_2)
+
+      page_tenant_1 = Scrivener.Ecto.Repo.paginate(User, options: [prefix: @schema_tenant_1])
+
+      assert page_tenant_1.page_size == 5
+      assert page_tenant_1.page_number == 1
+      assert page_tenant_1.total_entries == 6
+      assert page_tenant_1.total_pages == 2
+
+      page_tenant_2 = Scrivener.Ecto.Repo.paginate(User, options: [prefix: @schema_tenant_2])
+
+      assert page_tenant_2.page_size == 5
+      assert page_tenant_2.page_number == 1
+      assert page_tenant_2.total_entries == 2
+      assert page_tenant_2.total_pages == 1
+    end
+  end
+end
diff --git a/test/support/user.ex b/test/support/user.ex
new file mode 100644
index 0000000..3071e0d
--- /dev/null
+++ b/test/support/user.ex
@@ -0,0 +1,7 @@
+defmodule Scrivener.Ecto.User do
+  use Ecto.Schema
+
+  schema "users" do
+    field(:email, :string)
+  end
+end