Add LiveView hook (#722)

Closes #484.

Author: whatyouhide

.formatter.exs

@@ -1,5 +1,5 @@
 [
-  import_deps: [:plug],
+  import_deps: [:plug, :phoenix, :phoenix_live_view],
   inputs: [
     "lib/**/*.ex",
     "config/*.exs",

.github/workflows/main.yml

@@ -31,8 +31,8 @@ jobs:
             otp: '25.3'
 
           # Oldest supported Elixir/Erlang pair.
-          - elixir: '1.11.4'
-            otp: '21.3'
+          - elixir: '1.13.4-otp-22'
+            otp: '22.3.4'
 
     steps:
     - name: Check out this repository

lib/sentry/live_view_hook.ex

@@ -0,0 +1,155 @@
+if Code.ensure_loaded?(Phoenix.LiveView) do
+  defmodule Sentry.LiveViewHook do
+    @moduledoc """
+    A module that provides a `Phoenix.LiveView` hook to add Sentry context and breadcrumbs.
+
+    *Available since v10.5.0.*
+
+    This module sets context and breadcrumbs for the live view process through
+    `Sentry.Context`. It sets things like:
+
+      * The request URL
+      * The user agent and user's IP address
+      * Breadcrumbs for events that happen within LiveView
+
+    To make this module work best, you'll need to fetch information from the LiveView's
+    WebSocket. You can do that when calling the `socket/3` macro in your Phoenix endpoint.
+    For example:
+
+        socket "/live", Phoenix.LiveView.Socket,
+          websocket: [connect_info: [:peer_data, :uri, :user_agent]]
+
+    ## Examples
+
+        defmodule MyApp.UserLive do
+          use Phoenix.LiveView
+
+          on_mount Sentry.LiveViewHook
+
+          # ...
+        end
+
+    You can do the same at the router level:
+
+        live_session :default, on_mounbt: Sentry.LiveViewHook do
+          scope "..." do
+            # ...
+          end
+        end
+
+    You can also set this in your `MyAppWeb` module, so that all LiveViews that
+    `use MyAppWeb, :live_view` will have this hook.
+    """
+
+    @moduledoc since: "10.5.0"
+
+    import Phoenix.LiveView, only: [attach_hook: 4, get_connect_info: 2]
+
+    alias Sentry.Context
+
+    require Logger
+
+    # See also:
+    # https://develop.sentry.dev/sdk/event-payloads/request/
+
+    @doc false
+    @spec on_mount(:default, map(), map(), struct()) :: {:cont, struct()}
+    def on_mount(:default, params, _session, socket), do: on_mount(params, socket)
+
+    ## Helpers
+
+    defp on_mount(params, %Phoenix.LiveView.Socket{} = socket) do
+      Context.set_extra_context(%{socket_id: socket.id})
+      Context.set_request_context(%{url: socket.host_uri})
+
+      Context.add_breadcrumb(%{
+        category: "web.live_view.mount",
+        message: "Mounted live view",
+        data: params
+      })
+
+      if uri = get_connect_info(socket, :uri) do
+        Context.set_request_context(%{url: URI.to_string(uri)})
+      end
+
+      if user_agent = get_connect_info(socket, :user_agent) do
+        Context.set_extra_context(%{user_agent: user_agent})
+      end
+
+      # :peer_data returns t:Plug.Conn.Adapter.peer_data/0.
+      # https://hexdocs.pm/plug/Plug.Conn.Adapter.html#t:peer_data/0
+      if ip_address = socket |> get_connect_info(:peer_data) |> get_safe_ip_address() do
+        Context.set_user_context(%{ip_address: ip_address})
+      end
+
+      socket
+      |> maybe_attach_hook_handle_params()
+      |> attach_hook(__MODULE__, :handle_event, &handle_event_hook/3)
+      |> attach_hook(__MODULE__, :handle_info, &handle_info_hook/2)
+    catch
+      # We must NEVER raise an error in a hook, as it will crash the LiveView process
+      # and we don't want Sentry to be responsible for that.
+      kind, reason ->
+        Logger.error(
+          "Sentry.LiveView.on_mount hook errored out: #{Exception.format(kind, reason)}",
+          event_source: :logger
+        )
+
+        {:cont, socket}
+    else
+      socket -> {:cont, socket}
+    end
+
+    defp handle_event_hook(event, params, socket) do
+      Context.add_breadcrumb(%{
+        category: "web.live_view.event",
+        message: inspect(event),
+        data: %{event: event, params: params}
+      })
+
+      {:cont, socket}
+    end
+
+    defp handle_info_hook(message, socket) do
+      Context.add_breadcrumb(%{
+        category: "web.live_view.info",
+        message: inspect(message, pretty: true)
+      })
+
+      {:cont, socket}
+    end
+
+    defp handle_params_hook(params, uri, socket) do
+      Context.set_extra_context(%{socket_id: socket.id})
+      Context.set_request_context(%{url: uri})
+
+      Context.add_breadcrumb(%{
+        category: "web.live_view.params",
+        message: "#{uri}",
+        data: %{params: params, uri: uri}
+      })
+
+      {:cont, socket}
+    end
+
+    defp maybe_attach_hook_handle_params(socket) do
+      case socket.parent_pid do
+        nil -> attach_hook(socket, __MODULE__, :handle_params, &handle_params_hook/3)
+        pid when is_pid(pid) -> socket
+      end
+    end
+
+    defp get_safe_ip_address(%{ip_address: ip} = _peer_data) do
+      case :inet.ntoa(ip) do
+        ip_address when is_list(ip_address) -> List.to_string(ip_address)
+        {:error, _reason} -> nil
+      end
+    catch
+      _kind, _reason -> nil
+    end
+
+    defp get_safe_ip_address(_peer_data) do
+      nil
+    end
+  end
+end

mix.exs

@@ -46,7 +46,7 @@ defmodule Sentry.Mixfile do
           "Upgrade Guides": [~r{^pages/upgrade}]
         ],
         groups_for_modules: [
-          "Plug and Phoenix": [Sentry.PlugCapture, Sentry.PlugContext],
+          "Plug and Phoenix": [Sentry.PlugCapture, Sentry.PlugContext, Sentry.LiveViewHook],
           Loggers: [Sentry.LoggerBackend, Sentry.LoggerHandler],
           "Data Structures": [Sentry.Attachment, Sentry.CheckIn],
           HTTP: [Sentry.HTTPClient, Sentry.HackneyClient],
@@ -91,6 +91,8 @@ defmodule Sentry.Mixfile do
       # Optional dependencies
       {:hackney, "~> 1.8", optional: true},
       {:jason, "~> 1.1", optional: true},
+      {:phoenix, "~> 1.6", optional: true},
+      {:phoenix_live_view, "~> 0.20", optional: true},
       {:plug, "~> 1.6", optional: true},
       {:telemetry, "~> 0.4 or ~> 1.0", optional: true},
 
@@ -99,27 +101,11 @@ defmodule Sentry.Mixfile do
       {:dialyxir, "~> 1.0", only: [:test, :dev], runtime: false},
       {:ex_doc, "~> 0.29.0", only: :dev},
       {:excoveralls, "~> 0.17.1", only: [:test]},
-      {:phoenix, "~> 1.5", only: [:test]},
-      {:phoenix_html, "~> 2.0", only: [:test]}
-    ] ++ maybe_oban_optional_dependency() ++ maybe_quantum_optional_dependency()
-  end
-
-  # TODO: Remove this once we drop support for Elixir < 1.13.
-  defp maybe_oban_optional_dependency do
-    if Version.match?(System.version(), "~> 1.13") do
-      [{:oban, "~> 2.17 and >= 2.17.6", only: [:test]}]
-    else
-      []
-    end
-  end
-
-  # TODO: Remove this once we drop support for Elixir < 1.12.
-  defp maybe_quantum_optional_dependency do
-    if Version.match?(System.version(), "~> 1.12") do
-      [{:quantum, "~> 3.0", only: [:test]}]
-    else
-      []
-    end
+      # Required by Phoenix.LiveView's testing
+      {:floki, ">= 0.30.0", only: :test},
+      {:oban, "~> 2.17 and >= 2.17.6", only: [:test]},
+      {:quantum, "~> 3.0", only: [:test]}
+    ]
   end
 
   defp package do