From e58d33243abbdb0caca7f1f2e77d52623ca33a56 Mon Sep 17 00:00:00 2001
From: Connor Rigby <connor@farmbot.io>
Date: Mon, 21 Oct 2019 13:46:07 -0700
Subject: [PATCH] Simplify telemetry systems

---
 farmbot_telemetry/lib/farmbot_telemetry.ex    | 200 ++++++++++++------
 .../lib/farmbot_telemetry/application.ex      |  19 +-
 .../lib/farmbot_telemetry/event_class.ex      |  14 --
 .../event_classes/amqp_event_class.ex         |  28 ---
 .../event_classes/dns_event_class.ex          |  22 --
 .../event_classes/http_event_class.ex         |  36 ----
 .../event_classes/network_event_class.ex      |  18 --
 .../lib/farmbot_telemetry/log_handler.ex      |   9 -
 .../test/farmbot_telemetry_test.exs           |  50 -----
 9 files changed, 131 insertions(+), 265 deletions(-)
 delete mode 100644 farmbot_telemetry/lib/farmbot_telemetry/event_class.ex
 delete mode 100644 farmbot_telemetry/lib/farmbot_telemetry/event_classes/amqp_event_class.ex
 delete mode 100644 farmbot_telemetry/lib/farmbot_telemetry/event_classes/dns_event_class.ex
 delete mode 100644 farmbot_telemetry/lib/farmbot_telemetry/event_classes/http_event_class.ex
 delete mode 100644 farmbot_telemetry/lib/farmbot_telemetry/event_classes/network_event_class.ex
 delete mode 100644 farmbot_telemetry/lib/farmbot_telemetry/log_handler.ex

diff --git a/farmbot_telemetry/lib/farmbot_telemetry.ex b/farmbot_telemetry/lib/farmbot_telemetry.ex
index 29e19ed9..eb51ab2b 100644
--- a/farmbot_telemetry/lib/farmbot_telemetry.ex
+++ b/farmbot_telemetry/lib/farmbot_telemetry.ex
@@ -1,94 +1,154 @@
 defmodule FarmbotTelemetry do
   @moduledoc """
-  Interface for farmbot system introspection
+  Interface for farmbot system introspection and metrics
   """
-  alias FarmbotTelemetry.EventClass
 
-  @typedoc "Module that implements the FarmbotTelemetry.EventClass behaviour"
-  @type class() :: module()
+  @typedoc "Classification of telemetry event"
+  @type class() :: event_class() | metric_class()
 
-  @typedoc "First argument to the handler"
-  @type event() :: nonempty_maybe_improper_list(class(), EventClass.type())
+  @typedoc "Event classes are events that have no measurable value"
+  @type event_class() :: atom()
 
-  @typedoc "Second argument to the handler"
-  @type data() :: %{
-          required(:action) => EventClass.action(),
+  @typedoc "Metric classes are events that have a measurable value"
+  @type metric_class() :: atom()
+
+  @typedoc "Type within an event"
+  @type event_type() :: atom()
+
+  @typedoc "Action withing a type"
+  @type event_action() :: atom()
+
+  @typedoc "Value of a metric event"
+  @type metric_value() :: term()
+
+  @typedoc """
+  1st arg passed to a `handler` if the type was an event
+      [:farmbot_telemetry, :event, t/event_class()]
+  """
+  @type event_class_path() :: [atom()]
+
+  @typedoc "2nd arg passed to a `handler` if the type was an event"
+  @type event_class_data() :: %{
+          required(:type) => event_type(),
+          required(:action) => event_action(),
           required(:timestamp) => DateTime.t()
         }
 
-  @type meta() :: map()
+  @typedoc """
+  1st arg passed to a `handler` if the type was a metric
+      [:farmbot_telemetry, :metric, t/metric_class()]
+  """
+  @type metric_class_path() :: [atom()]
 
-  @typedoc "Term that will be passed to the handler."
-  @type config() :: any()
+  @typedoc "2nd arg passed to a `handler` if the type was a metric"
+  @type metric_class_data() :: %{
+          required(:value) => metric_value(),
+          required(:timestamp) => DateTime.t()
+        }
 
-  @typedoc "Module that implements the "
-  @type handler() :: (event(), data(), meta(), config() -> any())
+  @typedoc "3rd arg passed to a `handler`"
+  @type meta() :: %{
+          required(:module) => module() | nil,
+          required(:file) => Path.t() | nil,
+          required(:line) => pos_integer() | nil,
+          required(:function) => {atom, 0 | pos_integer()} | nil
+        }
 
-  @typedoc "required options for FarmbotTelemetry"
-  @type opt() ::
-          {:class, class()}
-          | {:handler, handler()}
-          | {:config, config()}
+  @typedoc "4th arg passed to a `handler`"
+  @type config() :: term()
 
-  @typedoc false
-  @type opts :: [opts]
+  @typedoc "Function that handles telemetry data"
+  @type handler() ::
+          (event_class_path(), event_class_data(), meta(), config() -> any())
+          | (metric_class_path(), metric_class_data(), meta(), config() -> any())
 
-  @doc false
-  @spec child_spec(opts) :: Supervisor.child_spec()
-  def child_spec(opts) do
-    %{
-      id: opts[:class],
-      start: {__MODULE__, :attach, [opts]}
-    }
-  end
+  @doc "Execute a telemetry event"
+  defmacro event(class, type, action, meta \\ %{}) do
+    meta =
+      Map.merge(meta, %{
+        module: __ENV__.module,
+        file: __ENV__.file,
+        line: __ENV__.line,
+        function: __ENV__.function
+      })
 
-  @doc false
-  @spec attach(opts) :: GenServer.on_start()
-  def attach(opts) do
-    class = opts[:class]
-    handler_id = opts[:handler_id]
-    handler = opts[:handler]
-    config = opts[:config]
-
-    for {type, _actions} <- class.matrix() do
-      _ = :telemetry.attach(handler_id, [class, type], handler, config)
-    end
-
-    :ignore
-  end
-
-  @doc false
-  defmacro __using__(_opts) do
-    quote do
-      alias FarmbotTelemetry.{
-              AMQPEventClass,
-              DNSEventClass,
-              HTTPEventClass,
-              NetworkEventClass
-            },
-            warn: false
-
-      require FarmbotTelemetry
+    quote location: :keep do
+      :telemetry.execute(
+        [:farmbot_telemetry, :event, unquote(class)],
+        %{type: unquote(type), action: unquote(action), timestamp: DateTime.utc_now()},
+        unquote(Macro.escape(meta))
+      )
     end
   end
 
-  @doc "Execute a telemetry event. `type` and `action` will be validated"
-  def execute(class, type, action, meta \\ %{}) do
-    :telemetry.execute([class, type], %{action: action, timestamp: DateTime.utc_now()}, meta)
-    # quote location: :keep,
-    #       bind_quoted: [class: class, type: type, action: action, meta: Macro.escape(meta)] do
-    #   # unless {type, action} in class.matrix() do
-    #   #   raise """
-    #   #   #{type}.#{action} is unknown for #{class}
-    #   #   """
-    #   # end
+  @doc "Execute a telemetry metric"
+  defmacro metric(class, value, meta \\ %{}) do
+    meta =
+      Map.merge(meta, %{
+        module: __ENV__.module,
+        file: __ENV__.file,
+        line: __ENV__.line,
+        function: __ENV__.function
+      })
 
-    #   _ = FarmbotTelemetry.unsafe_execute(class, type, action, meta)
-    # end
+    quote location: :keep do
+      :telemetry.execute(
+        [:farmbot_telemetry, :metric, unquote(class)],
+        %{value: unquote(value), timestamp: DateTime.utc_now()},
+        unquote(Macro.escape(meta))
+      )
+    end
+  end
+
+  @doc "Attach a handler to an event"
+  @spec attach(String.t(), event_class_path() | metric_class_path(), handler(), config()) :: any()
+  def attach(handler_id, event, handler, config \\ []) do
+    :telemetry.attach(handler_id, event, handler, config)
+  end
+
+  @doc "Helper to attach the log handler to an event"
+  @spec attach_logger(event_class_path() | metric_class_path(), config()) :: any()
+  def attach_logger(event, config \\ [level: :info]) do
+    attach(
+      "logger.#{:erlang.phash2({node(), :erlang.now()})}",
+      event,
+      &FarmbotTelemetry.log_handler/4,
+      config
+    )
+  end
+
+  @doc "Helper to send a message to the current processes when a matching event is dispatched"
+  @spec attach_recv(event_class_path() | metric_class_path(), config()) :: any()
+  def attach_recv(event, config \\ [pid: self()]) do
+    attach(
+      "recv.#{:erlang.phash2({node(), :erlang.now()})}",
+      event,
+      &Kernel.send(&4[:pid], {&1, &2, &3, &4}),
+      config
+    )
   end
 
   @doc false
-  def unsafe_execute(class, type, action, meta \\ %{}) do
-    :telemetry.execute([class, type], %{action: action, timestamp: DateTime.utc_now()}, meta)
+  def log_handler(event, data, meta, config) do
+    msg =
+      case event do
+        [:farmbot_telemetry, :event, class] ->
+          %{type: type, action: action} = data
+          "#{class}.#{type}.#{action}"
+
+        [:farmbot_telemetry, :metric, class] ->
+          %{value: value} = data
+          "#{class}.#{value}=#{value}"
+      end
+
+    Logger.bare_log(config[:level] || :debug, msg, Map.to_list(meta))
   end
+
+  @doc "Helper to generate a path for event names"
+  @spec event_class(event_class()) :: event_class_path()
+  def event_class(class), do: [:farmbot_telemetry, :event, class]
+
+  @doc "Helper to generate a path for metric names"
+  @spec metric_class(metric_class()) :: metric_class_path()
+  def metric_class(class), do: [:farmbot_telemetry, :metric, class]
 end
diff --git a/farmbot_telemetry/lib/farmbot_telemetry/application.ex b/farmbot_telemetry/lib/farmbot_telemetry/application.ex
index 0af78b83..60eed28b 100644
--- a/farmbot_telemetry/lib/farmbot_telemetry/application.ex
+++ b/farmbot_telemetry/lib/farmbot_telemetry/application.ex
@@ -2,28 +2,11 @@ defmodule FarmbotTelemetry.Application do
   # See https://hexdocs.pm/elixir/Application.html
   # for more information on OTP Applications
   @moduledoc false
-  alias FarmbotTelemetry.LogHandler
-
-  alias FarmbotTelemetry.{
-    AMQPEventClass,
-    DNSEventClass,
-    HTTPEventClass,
-    NetworkEventClass
-  }
 
   use Application
 
   def start(_type, _args) do
-    children =
-      for class <- [AMQPEventClass, DNSEventClass, HTTPEventClass, NetworkEventClass] do
-        {FarmbotTelemetry,
-         [
-           class: class,
-           handler_id: "#{class}-LogHandler",
-           handler: &LogHandler.handle_event/4,
-           config: [level: :info]
-         ]}
-      end
+    children = []
 
     # See https://hexdocs.pm/elixir/Supervisor.html
     # for other strategies and supported options
diff --git a/farmbot_telemetry/lib/farmbot_telemetry/event_class.ex b/farmbot_telemetry/lib/farmbot_telemetry/event_class.ex
deleted file mode 100644
index 83f9fbe9..00000000
--- a/farmbot_telemetry/lib/farmbot_telemetry/event_class.ex
+++ /dev/null
@@ -1,14 +0,0 @@
-defprotocol FarmbotTelemetry.EventClass do
-  @moduledoc """
-  Classificaiton of a telemetry event
-  """
-
-  @typedoc "Type of event in relation to the class"
-  @type type() :: atom()
-
-  @typedoc "Action in relation to the type"
-  @type action() :: atom()
-
-  @doc "mapping of `type` to `action`"
-  @callback matrix() :: [{type(), action()}]
-end
diff --git a/farmbot_telemetry/lib/farmbot_telemetry/event_classes/amqp_event_class.ex b/farmbot_telemetry/lib/farmbot_telemetry/event_classes/amqp_event_class.ex
deleted file mode 100644
index f2ca9af0..00000000
--- a/farmbot_telemetry/lib/farmbot_telemetry/event_classes/amqp_event_class.ex
+++ /dev/null
@@ -1,28 +0,0 @@
-defmodule FarmbotTelemetry.AMQPEventClass do
-  @moduledoc """
-  Classification of events pertaining to amqp channels including:
-
-  * channel connections
-  * channel disconnects
-  * channel errors
-  """
-
-  @behaviour FarmbotTelemetry.EventClass
-
-  @impl FarmbotTelemetry.EventClass
-  def matrix() do
-    channel_list = [
-      :auto_sync,
-      :celery_script,
-      :bot_state,
-      :logs,
-      :nerves_hub
-    ]
-
-    [
-      channel_connect: channel_list,
-      channel_disconnect: channel_list,
-      channel_error: channel_list
-    ]
-  end
-end
diff --git a/farmbot_telemetry/lib/farmbot_telemetry/event_classes/dns_event_class.ex b/farmbot_telemetry/lib/farmbot_telemetry/event_classes/dns_event_class.ex
deleted file mode 100644
index 463c4358..00000000
--- a/farmbot_telemetry/lib/farmbot_telemetry/event_classes/dns_event_class.ex
+++ /dev/null
@@ -1,22 +0,0 @@
-defmodule FarmbotTelemetry.DNSEventClass do
-  @moduledoc """
-  Classification of events pertaining to dns resolution accross the various
-  networked systems in the application including:
-
-  * ntp
-  * Farmbot http token fetching
-  * Farmbot http rest interface
-  * Farmbot AMQP interface
-  """
-
-  @behaviour FarmbotTelemetry.EventClass
-
-  @impl FarmbotTelemetry.EventClass
-  def matrix(),
-    do: [
-      ntp: [:nxdomain],
-      http: [:nxdomain],
-      token: [:nxdomain],
-      amqp: [:nxdomain]
-    ]
-end
diff --git a/farmbot_telemetry/lib/farmbot_telemetry/event_classes/http_event_class.ex b/farmbot_telemetry/lib/farmbot_telemetry/event_classes/http_event_class.ex
deleted file mode 100644
index c5ba3439..00000000
--- a/farmbot_telemetry/lib/farmbot_telemetry/event_classes/http_event_class.ex
+++ /dev/null
@@ -1,36 +0,0 @@
-defmodule FarmbotTelemetry.HTTPEventClass do
-  @moduledoc """
-  Classification of events pertaining to the Farmbot REST interface including:
-
-  * sequences
-  * farm events
-  * regimens
-  * etc
-  """
-
-  @behaviour FarmbotTelemetry.EventClass
-
-  @impl FarmbotTelemetry.EventClass
-  def matrix() do
-    [
-      farm_events: [:http_error, :http_timeout],
-      farmware_installations: [:http_error, :http_timeout],
-      regimens: [:http_error, :http_timeout],
-      device: [:http_error, :http_timeout],
-      diagnostic_dumps: [:http_error, :http_timeout],
-      farm_events: [:http_error, :http_timeout],
-      farmware_envs: [:http_error, :http_timeout],
-      fbos_config: [:http_error, :http_timeout],
-      firmware_config: [:http_error, :http_timeout],
-      peripherals: [:http_error, :http_timeout],
-      pin_bindings: [:http_error, :http_timeout],
-      points: [:http_error, :http_timeout],
-      public_keys: [:http_error, :http_timeout],
-      sensor_readings: [:http_error, :http_timeout],
-      sensors: [:http_error, :http_timeout],
-      sequences: [:http_error, :http_timeout],
-      sync: [:http_error, :http_timeout],
-      tools: [:http_error, :http_timeout]
-    ]
-  end
-end
diff --git a/farmbot_telemetry/lib/farmbot_telemetry/event_classes/network_event_class.ex b/farmbot_telemetry/lib/farmbot_telemetry/event_classes/network_event_class.ex
deleted file mode 100644
index bd70e184..00000000
--- a/farmbot_telemetry/lib/farmbot_telemetry/event_classes/network_event_class.ex
+++ /dev/null
@@ -1,18 +0,0 @@
-defmodule FarmbotTelemetry.NetworkEventClass do
-  @moduledoc """
-  Classification of events pertaining to a network interface, not network
-  software errors. This includes:
-
-  * WiFi errors
-  * ip address configuration errors
-  """
-
-  @behaviour FarmbotTelemetry.EventClass
-
-  @impl FarmbotTelemetry.EventClass
-  def matrix(),
-    do: [
-      access_point: [:disconnect, :connect, :eap_error, :assosiate_error, :assosiate_timeout],
-      ip_address: [:dhcp_lease, :dhcp_renew, :dhcp_lease_fail, :dhcp_renew_fail]
-    ]
-end
diff --git a/farmbot_telemetry/lib/farmbot_telemetry/log_handler.ex b/farmbot_telemetry/lib/farmbot_telemetry/log_handler.ex
deleted file mode 100644
index e1e3c907..00000000
--- a/farmbot_telemetry/lib/farmbot_telemetry/log_handler.ex
+++ /dev/null
@@ -1,9 +0,0 @@
-defmodule FarmbotTelemetry.LogHandler do
-  @moduledoc false
-  require Logger
-
-  def handle_event([class, type], %{action: action, timestamp: _timestamp}, meta, config) do
-    message = "#{class}.#{type}.#{action}"
-    Logger.bare_log(config[:level], message, Map.to_list(meta))
-  end
-end
diff --git a/farmbot_telemetry/test/farmbot_telemetry_test.exs b/farmbot_telemetry/test/farmbot_telemetry_test.exs
index e0da2af8..1e87cd83 100644
--- a/farmbot_telemetry/test/farmbot_telemetry_test.exs
+++ b/farmbot_telemetry/test/farmbot_telemetry_test.exs
@@ -1,54 +1,4 @@
 defmodule FarmbotTelemetryTest do
   use ExUnit.Case
   doctest FarmbotTelemetry
-  use FarmbotTelemetry
-
-  defmodule TestHandler do
-    def handle_event([class, type], %{action: action}, meta, config) do
-      send(config[:test_pid], {class, type, action, meta, config})
-    end
-  end
-
-  describe "network" do
-    setup do
-      opts = [
-        class: NetworkEventClass,
-        handler_id: "#{inspect(self())}",
-        handler: &TestHandler.handle_event/4,
-        config: [test_pid: self()]
-      ]
-
-      :ignore = FarmbotTelemetry.attach(opts)
-      :ok
-    end
-
-    test "access_point.disconnect" do
-      FarmbotTelemetry.execute(NetworkEventClass, :access_point, :disconnect, %{ssid: "test"})
-      assert_receive {NetworkEventClass, :access_point, :disconnect, %{ssid: "test"}, _}
-    end
-
-    test "access_point.connect" do
-      FarmbotTelemetry.execute(NetworkEventClass, :access_point, :connect, %{ssid: "test"})
-      assert_receive {NetworkEventClass, :access_point, :connect, %{ssid: "test"}, _}
-    end
-
-    test "access_point.eap_error" do
-      FarmbotTelemetry.execute(NetworkEventClass, :access_point, :eap_error, %{ssid: "test"})
-      assert_receive {NetworkEventClass, :access_point, :eap_error, %{ssid: "test"}, _}
-    end
-
-    test "access_point.assosiate_error" do
-      FarmbotTelemetry.execute(NetworkEventClass, :access_point, :assosiate_error, %{ssid: "test"})
-
-      assert_receive {NetworkEventClass, :access_point, :assosiate_error, %{ssid: "test"}, _}
-    end
-
-    test "access_point.assosiate_timeout" do
-      FarmbotTelemetry.execute(NetworkEventClass, :access_point, :assosiate_timeout, %{
-        ssid: "test"
-      })
-
-      assert_receive {NetworkEventClass, :access_point, :assosiate_timeout, %{ssid: "test"}, _}
-    end
-  end
 end