Handle Phoenix LiveView exceptions (#9)

* Handle LiveView exceptions

* LiveView dev script

* Crash on handle params

* Use latest Phoenix Playground commit

* Handle throws and exits

Author: crbelaus

lib/error_tracker/integrations/phoenix.ex

@@ -10,10 +10,18 @@ defmodule ErrorTracker.Integrations.Phoenix do
 
   alias ErrorTracker.Integrations.Plug, as: PlugIntegration
 
-  # https://hexdocs.pm/phoenix/Phoenix.Logger.html#module-instrumentation
   @events [
+    # https://hexdocs.pm/phoenix/Phoenix.Logger.html#module-instrumentation
     [:phoenix, :router_dispatch, :start],
-    [:phoenix, :router_dispatch, :exception]
+    [:phoenix, :router_dispatch, :exception],
+    # https://hexdocs.pm/phoenix_live_view/telemetry.html
+    [:phoenix, :live_view, :mount, :start],
+    [:phoenix, :live_view, :mount, :exception],
+    [:phoenix, :live_view, :handle_params, :start],
+    [:phoenix, :live_view, :handle_params, :exception],
+    [:phoenix, :live_view, :handle_event, :start],
+    [:phoenix, :live_view, :handle_event, :exception],
+    [:phoenix, :live_view, :render, :exception]
   ]
 
   def attach do
@@ -36,6 +44,30 @@ defmodule ErrorTracker.Integrations.Phoenix do
           {reason, kind, stack}
       end
 
-    PlugIntegration.report_error(metadata.conn, {reason, kind}, stack)
+    PlugIntegration.report_error(metadata.conn, {kind, reason}, stack)
+  end
+
+  def handle_event([:phoenix, :live_view, :mount, :start], _, metadata, :no_config) do
+    ErrorTracker.set_context(%{
+      "live_view.view" => metadata.socket.view
+    })
+  end
+
+  def handle_event([:phoenix, :live_view, :handle_params, :start], _, metadata, :no_config) do
+    ErrorTracker.set_context(%{
+      "live_view.uri" => metadata.uri,
+      "live_view.params" => metadata.params
+    })
+  end
+
+  def handle_event([:phoenix, :live_view, :handle_event, :start], _, metadata, :no_config) do
+    ErrorTracker.set_context(%{
+      "live_view.event" => metadata.event,
+      "live_view.event_params" => metadata.params
+    })
+  end
+
+  def handle_event([:phoenix, :live_view, _action, :exception], _, metadata, :no_config) do
+    ErrorTracker.report({metadata.kind, metadata.reason}, metadata.stacktrace)
   end
 end

live.exs

@@ -0,0 +1,89 @@
+Mix.install([
+  {:phoenix_playground, github: "phoenix-playground/phoenix_playground", ref: "ee6da0fc3b141f78b9f967ce71a4fb015c6764a6"},
+  {:error_tracker, path: "."}
+])
+
+# Set up the repository for the Error Tracker
+defmodule ErrorTrackerDev.Repo do
+  use Ecto.Repo, otp_app: :error_tracker, adapter: Ecto.Adapters.Postgres
+end
+
+Application.put_env(:error_tracker, :repo, ErrorTrackerDev.Repo)
+Application.put_env(:error_tracker, :application, :error_tracker_dev)
+Application.put_env(:error_tracker, :prefix, "private")
+Application.put_env(:error_tracker, ErrorTrackerDev.Repo, url: "ecto://postgres:postgres@127.0.0.1/error_tracker_dev")
+
+
+# This migration will set up the database structure
+defmodule Migration0 do
+  use Ecto.Migration
+
+  def up, do: ErrorTracker.Migrations.up(prefix: "private")
+  def down, do: ErrorTracker.Migrations.down(prefix: "private")
+end
+
+
+defmodule DemoLive do
+  use Phoenix.LiveView
+
+  def mount(params, _session, socket) do
+    if params["crash"] == "mount" do
+      raise "Crashing on mount"
+    end
+
+    {:ok, assign(socket, count: 0)}
+  end
+
+  def render(assigns) do
+    if assigns.count == 5 do
+      raise "Crash on render"
+    end
+
+    ~H"""
+    <span><%= @count %></span>
+    <button phx-click="inc">+</button>
+    <button phx-click="dec">-</button>
+    <button phx-click="error">Crash on handle_event</button>
+
+    <.link href="/?crash=mount">Crash on mount</.link>
+    <.link patch="/?crash=handle_params">Crash on handle_params</.link>
+
+    <style type="text/css">
+      body { padding: 1em; }
+    </style>
+    """
+  end
+
+
+  def handle_event("inc", _params, socket) do
+    {:noreply, assign(socket, count: socket.assigns.count + 1)}
+  end
+
+  def handle_event("dec", _params, socket) do
+    {:noreply, assign(socket, count: socket.assigns.count - 1)}
+  end
+
+  def handle_event("error", _params, _socket) do
+    raise "Crash on handle_event"
+  end
+
+  def handle_params(params, _uri, socket) do
+    if params["crash"] == "handle_params" do
+      raise "Crash on handle_params"
+    end
+    {:noreply, socket}
+  end
+end
+
+
+
+PhoenixPlayground.start(live: DemoLive, child_specs: [ErrorTrackerDev.Repo])
+
+
+# Create the database if it does not exist and run migrations if needed
+_ = Ecto.Adapters.Postgres.storage_up(ErrorTrackerDev.Repo.config())
+
+Ecto.Migrator.run(ErrorTrackerDev.Repo, [{0, Migration0}], :up,
+  all: true,
+  log_migrations_sql: :debug
+)