From f01881e82a48b4177f943c73338d013010719040 Mon Sep 17 00:00:00 2001
From: Chris McCord <chris@chrismccord.com>
Date: Thu, 11 Jul 2019 16:33:20 -0400
Subject: [PATCH] Add federated test infrastructure

---
 test/federation/federation_test.exs |  43 ++++++
 test/support/cluster.ex             | 218 ++++++++++++++++++++++++++++
 2 files changed, 261 insertions(+)
 create mode 100644 test/federation/federation_test.exs
 create mode 100644 test/support/cluster.ex

diff --git a/test/federation/federation_test.exs b/test/federation/federation_test.exs
new file mode 100644
index 000000000..7400d2abc
--- /dev/null
+++ b/test/federation/federation_test.exs
@@ -0,0 +1,43 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2018 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Integration.FederationTest do
+  use Pleroma.DataCase
+
+  import Pleroma.Cluster
+
+  @federated1 :"federated1@127.0.0.1"
+
+  describe "federated cluster primitives" do
+    test "within/2 captures local bindings and executes block on remote node" do
+      captured_binding = :captured
+
+      result =
+        within @federated1 do
+          user = Pleroma.Factory.insert(:user)
+          {captured_binding, node(), user}
+        end
+
+      assert {:captured, @federated1, user} = result
+      refute Pleroma.User.get_by_id(user.id)
+      assert user.id == within(@federated1, do: Pleroma.User.get_by_id(user.id)).id
+    end
+
+    test "runs webserver on customized port" do
+      {nickname, url, url_404} =
+        within @federated1 do
+          import Pleroma.Web.Router.Helpers
+          user = Pleroma.Factory.insert(:user)
+          user_url = mastodon_api_url(Pleroma.Web.Endpoint, :user, user)
+          url_404 = mastodon_api_url(Pleroma.Web.Endpoint, :user, "not-exists")
+
+          {user.nickname, user_url, url_404}
+        end
+
+      assert {:ok, {{_, 200, _}, _headers, body}} = :httpc.request(~c"#{url}")
+      assert %{"acct" => ^nickname} = Jason.decode!(body)
+      assert {:ok, {{_, 404, _}, _headers, _body}} = :httpc.request(~c"#{url_404}")
+    end
+  end
+end
diff --git a/test/support/cluster.ex b/test/support/cluster.ex
new file mode 100644
index 000000000..deb37f361
--- /dev/null
+++ b/test/support/cluster.ex
@@ -0,0 +1,218 @@
+defmodule Pleroma.Cluster do
+  @moduledoc """
+  Facilities for managing a cluster of slave VM's for federated testing.
+
+  ## Spawning the federated cluster
+
+  `spawn_cluster/1` spawns a map of slave nodes that are started
+  within the running VM. During startup, the slave node is sent all configuration
+  from the parent node, as well as all code. After receiving configuration and
+  code, the slave then starts all applications currently running on the parent.
+  The configuration passed to `spawn_cluster/1` overrides any parent application
+  configuration for the provided OTP app and key. This is useful for customizing
+  the Ecto database, Phoenix webserver ports, etc.
+
+  For example, to start a single federated VM named ":federated1", with the
+  Pleroma Endpoint running on port 4123, and with a database named
+  "pleroma_test1", you would run:
+
+    endpoint_conf = Application.fetch_env!(:pleroma, Pleroma.Web.Endpoint)
+    repo_conf = Application.fetch_env!(:pleroma, Pleroma.Repo)
+
+    Pleroma.Cluster.spawn_cluster(%{
+      :"federated1@127.0.0.1" => [
+        {:pleroma, Pleroma.Repo, Keyword.merge(repo_conf, database: "pleroma_test1")},
+        {:pleroma, Pleroma.Web.Endpoint,
+        Keyword.merge(endpoint_conf, http: [port: 4011], url: [port: 4011], server: true)}
+      ]
+    })
+
+  *Note*: application configuration for a given key is not merged,
+  so any customization requires first fetching the existing values
+  and merging yourself by providing the merged configuration,
+  such as above with the endpoint config and repo config.
+
+  ## Executing code within a remote node
+
+  Use the `within/2` macro to execute code within the context of a remote
+  federated node. The code block captures all local variable bindings from
+  the parent's context and returns the result of the expression after executing
+  it on the remote node. For example:
+
+      import Pleroma.Cluster
+
+      parent_value = 123
+
+      result =
+        within :"federated1@127.0.0.1" do
+          {node(), parent_value}
+        end
+
+      assert result == {:"federated1@127.0.0.1, 123}
+
+  *Note*: while local bindings are captured and available within the block,
+  other parent contexts like required, aliased, or imported modules are not
+  in scope. Those will need to be reimported/aliases/required within the block
+  as `within/2` is a remote procedure call.
+  """
+
+  @extra_apps Pleroma.Mixfile.application()[:extra_applications]
+
+  @doc """
+  Spawns the default Pleroma federated cluster.
+
+  Values before may be customized as needed for the test suite.
+  """
+  def spawn_default_cluster do
+    endpoint_conf = Application.fetch_env!(:pleroma, Pleroma.Web.Endpoint)
+    repo_conf = Application.fetch_env!(:pleroma, Pleroma.Repo)
+
+    spawn_cluster(%{
+      :"federated1@127.0.0.1" => [
+        {:pleroma, Pleroma.Repo, Keyword.merge(repo_conf, database: "pleroma_test_federated1")},
+        {:pleroma, Pleroma.Web.Endpoint,
+         Keyword.merge(endpoint_conf, http: [port: 4011], url: [port: 4011], server: true)}
+      ],
+      :"federated2@127.0.0.1" => [
+        {:pleroma, Pleroma.Repo, Keyword.merge(repo_conf, database: "pleroma_test_federated2")},
+        {:pleroma, Pleroma.Web.Endpoint,
+         Keyword.merge(endpoint_conf, http: [port: 4012], url: [port: 4012], server: true)}
+      ]
+    })
+  end
+
+  @doc """
+  Spawns a configured map of federated nodes.
+
+  See `Pleroma.Cluster` module documentation for details.
+  """
+  def spawn_cluster(node_configs) do
+    # Turn node into a distributed node with the given long name
+    :net_kernel.start([:"primary@127.0.0.1"])
+
+    # Allow spawned nodes to fetch all code from this node
+    {:ok, _} = :erl_boot_server.start([])
+    allow_boot("127.0.0.1")
+
+    silence_logger_warnings(fn ->
+      node_configs
+      |> Enum.map(&Task.async(fn -> start_slave(&1) end))
+      |> Enum.map(&Task.await(&1, 60_000))
+    end)
+  end
+
+  @doc """
+  Executes block of code again remote node.
+
+  See `Pleroma.Cluster` module documentation for details.
+  """
+  defmacro within(node, do: block) do
+    quote do
+      rpc(unquote(node), unquote(__MODULE__), :eval_quoted, [
+        unquote(Macro.escape(block)),
+        binding()
+      ])
+    end
+  end
+
+  @doc false
+  def eval_quoted(block, binding) do
+    {result, _binding} = Code.eval_quoted(block, binding, __ENV__)
+    result
+  end
+
+  defp start_slave({node_host, override_configs}) do
+    log(node_host, "booting federated VM")
+    {:ok, node} = :slave.start(~c"127.0.0.1", node_name(node_host), vm_args())
+    add_code_paths(node)
+    load_apps_and_transfer_configuration(node, override_configs)
+    ensure_apps_started(node)
+    {:ok, node}
+  end
+
+  def rpc(node, module, function, args) do
+    :rpc.block_call(node, module, function, args)
+  end
+
+  defp vm_args do
+    ~c"-loader inet -hosts 127.0.0.1 -setcookie #{:erlang.get_cookie()}"
+  end
+
+  defp allow_boot(host) do
+    {:ok, ipv4} = :inet.parse_ipv4_address(~c"#{host}")
+    :ok = :erl_boot_server.add_slave(ipv4)
+  end
+
+  defp add_code_paths(node) do
+    rpc(node, :code, :add_paths, [:code.get_path()])
+  end
+
+  defp load_apps_and_transfer_configuration(node, override_configs) do
+    Enum.each(Application.loaded_applications(), fn {app_name, _, _} ->
+      app_name
+      |> Application.get_all_env()
+      |> Enum.each(fn {key, primary_config} ->
+        rpc(node, Application, :put_env, [app_name, key, primary_config, [persistent: true]])
+      end)
+    end)
+
+    Enum.each(override_configs, fn {app_name, key, val} ->
+      rpc(node, Application, :put_env, [app_name, key, val, [persistent: true]])
+    end)
+  end
+
+  defp log(node, msg), do: IO.puts("[#{node}] #{msg}")
+
+  defp ensure_apps_started(node) do
+    loaded_names = Enum.map(Application.loaded_applications(), fn {name, _, _} -> name end)
+    app_names = @extra_apps ++ (loaded_names -- @extra_apps)
+
+    rpc(node, Application, :ensure_all_started, [:mix])
+    rpc(node, Mix, :env, [Mix.env()])
+    rpc(node, __MODULE__, :prepare_database, [])
+
+    log(node, "starting application")
+
+    Enum.reduce(app_names, MapSet.new(), fn app, loaded ->
+      if Enum.member?(loaded, app) do
+        loaded
+      else
+        {:ok, started} = rpc(node, Application, :ensure_all_started, [app])
+        MapSet.union(loaded, MapSet.new(started))
+      end
+    end)
+  end
+
+  @doc false
+  def prepare_database do
+    log(node(), "preparing database")
+    repo_config = Application.get_env(:pleroma, Pleroma.Repo)
+    repo_config[:adapter].storage_down(repo_config)
+    repo_config[:adapter].storage_up(repo_config)
+
+    {:ok, _, _} =
+      Ecto.Migrator.with_repo(Pleroma.Repo, fn repo ->
+        Ecto.Migrator.run(repo, :up, log: false, all: true)
+      end)
+
+    Ecto.Adapters.SQL.Sandbox.mode(Pleroma.Repo, :manual)
+    {:ok, _} = Application.ensure_all_started(:ex_machina)
+  end
+
+  defp silence_logger_warnings(func) do
+    prev_level = Logger.level()
+    Logger.configure(level: :error)
+    res = func.()
+    Logger.configure(level: prev_level)
+
+    res
+  end
+
+  defp node_name(node_host) do
+    node_host
+    |> to_string()
+    |> String.split("@")
+    |> Enum.at(0)
+    |> String.to_atom()
+  end
+end