Revert "Add per-host metrics (#7)" (#13)

This reverts commit ee24f71.
TheRealReal · Jun 13, 2023 · e755b0f · e755b0f
1 parent ee24f71
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,18 +1,11 @@
 # Changelog
-
 All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## In development
-
-- Added per-host telemetry metrics (https://github.com/TheRealReal/hackney_telemetry/pull/7)
-
 ## [0.1.2] - 2022-09-19
-
 ### Changed
-
 - Update docs
 - Build docs with ex_doc
 - Update specs to successfully run Dialyzer
@@ -21,16 +14,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [0.1.1] - 2021-12-10
 
 ### Changed
-
 Minor update.
 
 ### Fixed
-
 - Fix histogram values shift for `in_use_count` and `free_count metrics`
 
 ## [0.1.0] - 2021-12-08
 
 ## Added
-
 - First version!
 - Metrics collector for hackney global and pool metrics
diff --git a/README.md b/README.md
@@ -18,22 +18,16 @@ so we need to transform the metrics data before reporting it.
 
 The following metrics are exported by this library to telemetry.
 
-| Metric                         | Tags | Meaning                                               |
-| ------------------------------ | ---- | ----------------------------------------------------- |
-| `hackney.nb_requests`          | -    | Current number of requests                            |
-| `hackney.finished_requests`    | -    | Total number of finished requests                     |
-| `hackney.total_requests`       | -    | Total number of requests                              |
-| `hackney_pool.free_count`      | pool | Number of free sockets in a connection pool           |
-| `hackney_pool.in_use_count`    | pool | Number of busy sockets in a connection pool           |
-| `hackney_pool.no_socket`       | pool | Count of new connections                              |
-| `hackney_pool.queue_count`     | pool | Number of requests waiting for a connection in a pool |
-| `hackney_pool.take_rate`       | pool | Rate at which a connection is retrieved from the pool |
-| `hackney_host.nb_requests`     | host | Number of running requests per host                   |
-| `hackney_host.request_time`    | host | Request time per host                                 |
-| `hackney_host.connect_time`    | host | Connect time per host                                 |
-| `hackney_host.response_time`   | host | Response time per host                                |
-| `hackney_host.connect_timeout` | host | Number of connect timeout per host                    |
-| `hackney_host.connect_error`   | host | Number of timeout errors per host                     |
+| Metric                      | Tags | Meaning                                               |
+| --------------------------- | ---- | ----------------------------------------------------- |
+| `hackney.nb_requests`       | -    | Current number of requests                            |
+| `hackney.finished_requests` | -    | Total number of finished requests                     |
+| `hackney.total_requests`    | -    | Total number of requests                              |
+| `hackney_pool.free_count`   | pool | Number of free sockets in a connection pool           |
+| `hackney_pool.in_use_count` | pool | Number of busy sockets in a connection pool           |
+| `hackney_pool.no_socket`    | pool | Count of new connections                              |
+| `hackney_pool.queue_count`  | pool | Number of requests waiting for a connection in a pool |
+| `hackney_pool.take_rate`    | pool | Rate at which a connection is retrieved from the pool |
 
 This module implements all the callbacks required by `hackney_metrics` but it does
 not support host metrics.
@@ -132,13 +126,7 @@ defmodule YourApplcation.Telemetry do
     last_value("hackney_pool.in_use_count", tags: [:pool]),
     last_value("hackney_pool.no_socket", tags: [:pool]),
     last_value("hackney_pool.queue_count", tags: [:pool]),
-    last_value("hackney_pool.take_rate", tags: [:pool]),
-    last_value("hackney_host.nb_requests", tags: [:host]),
-    last_value("hackney_host.request_time", tags: [:host]),
-    last_value("hackney_host.connect_time", tags: [:host]),
-    last_value("hackney_host.response_time", tags: [:host]),
-    last_value("hackney_host.connect_timeout", tags: [:host]),
-    last_value("hackney_host.connect_error", tags: [:host])
+    last_value("hackney_pool.take_rate", tags: [:pool])
   ]
   end
 end
@@ -172,7 +160,7 @@ rebar3 steamroll
 
 ## Code of Conduct
 
-This project Contributor Covenant version 2.1. Check [CODE_OF_CONDUCT.md](CODE_OF_CONDUCT.md) file for more information.
+This project  Contributor Covenant version 2.1. Check [CODE_OF_CONDUCT.md](CODE_OF_CONDUCT.md) file for more information.
 
 ## License
 

diff --git a/include/hackney_telemetry_worker.hrl b/include/hackney_telemetry_worker.hrl
@@ -1,7 +1,7 @@
 -record(
   worker_state,
   {
-    value :: map(),
+    value :: any(),
     report_interval :: non_neg_integer(),
     telemetry_settings :: {[atom(), ...], atom(), map()}
   }

diff --git a/src/hackney_telemetry_sup.erl b/src/hackney_telemetry_sup.erl
@@ -17,17 +17,14 @@
 
 start_link() -> supervisor:start_link({local, ?SERVER}, ?MODULE, []).
 
--define(PER_HOST, [nb_requests, request_time, connect_time, response_time, connect_timeout, connect_error]).
-
 init([]) ->
   SupFlags = #{strategy => one_for_one, intensity => 0, period => 1},
   ChildSpecs =
     [
-      hackney_telemetry_worker:child_spec([{metric, [hackney, Sub]}])
-     || Sub <- [nb_requests, total_requests, finished_requests]]
-        ++ [
-      hackney_telemetry_worker:child_spec([{metric, [hackney_host, Sub]}])
-     || Sub <- ?PER_HOST],
+      hackney_telemetry_worker:child_spec([{metric, [hackney, nb_requests]}]),
+      hackney_telemetry_worker:child_spec([{metric, [hackney, total_requests]}]),
+      hackney_telemetry_worker:child_spec([{metric, [hackney, finished_requests]}])
+    ],
   {ok, {SupFlags, ChildSpecs}}.
 
 %%% @doc Start worker for the given metric under this supervisor.

diff --git a/src/hackney_telemetry_worker.erl b/src/hackney_telemetry_worker.erl
@@ -58,17 +58,14 @@ child_spec(Args) ->
 %% @doc Return name of the worker process
 
 -spec worker_name(hackney_metric()) -> {global, {atom(), hackney_metric()}}.
-worker_name([hackney, Host, Key]) when is_list(Host) ->
-    worker_name([hackney_host, Key]);
-
 worker_name(Metric) -> {global, {node(), Metric}}.
 
 %% @doc Update metric
 
 -spec update(hackney_metric(), any(), transform_fun()) -> ok.
 update(Metric, EventValue, TransformFun) ->
   ProcessName = worker_name(Metric),
-  gen_server:cast(ProcessName, {update_event, Metric, EventValue, TransformFun}).
+  gen_server:cast(ProcessName, {update_event, EventValue, TransformFun}).
 
 %% @doc Start server
 
@@ -84,7 +81,7 @@ init(Args) ->
     {ok, TelemetrySettings} ->
       State =
         #worker_state{
-          value = #{},
+          value = 0,
           report_interval = fetch_report_interval(Args),
           telemetry_settings = TelemetrySettings
         },
@@ -100,8 +97,6 @@ telemetry_settings(Args) ->
   case Metric of
     [hackney, MeasurementKey] -> {ok, {[hackney], MeasurementKey, #{}}};
 
-    [hackney_host, MeasurementKey] -> {ok, {[hackney_host], MeasurementKey, #{}}};
-
     [hackney_pool, PoolName, MeasurementKey] ->
       {ok, {[hackney_pool], MeasurementKey, #{pool => PoolName}}};
 
@@ -114,29 +109,21 @@ handle_call(_Message, _From, State) -> {reply, ok, State}.
 
 %% @doc Handle update event
 
-handle_cast({update_event, Metric, EventValue, TransformFun}, State) ->
-  MetadataKey = metadata_key(Metric),
-  OldValue = maps:get(MetadataKey, State#worker_state.value, 0),
-  NewValue = TransformFun(OldValue, EventValue),
-
-  UpdatedState = State#worker_state{value = maps:put(MetadataKey, NewValue, State#worker_state.value)},
+handle_cast({update_event, EventValue, TransformFun}, State) ->
+  NewValue = TransformFun(State#worker_state.value, EventValue),
+  UpdatedState = State#worker_state{value = NewValue},
   if
-    UpdatedState#worker_state.report_interval == 0 ->
-      {noreply, report(UpdatedState)};
-    true ->
-      {noreply, UpdatedState}
-  end.
-
-metadata_key([hackney, Host, _]) when is_list(Host) -> #{host => Host};
-metadata_key([hackney_pool, Pool, _]) -> #{pool => Pool};
-metadata_key(_Metric) -> #{}.
+    UpdatedState#worker_state.report_interval == 0 -> report(UpdatedState);
+    true -> ok
+  end,
+  {noreply, UpdatedState}.
 
 %% @doc Handle report events
 
 handle_info(report, State) ->
-  State1 = report(State),
-  maybe_schedule_report(State1),
-  {noreply, State1}.
+  report(State),
+  maybe_schedule_report(State),
+  {noreply, State}.
 
 %% @doc gen_server terminate callback
 
@@ -151,11 +138,9 @@ code_change(_OldVersion, State, _Extra) -> {ok, State}.
 -spec report(#worker_state{}) -> ok.
 report(State) ->
   {Metric, MeasurementKey, Metadata} = State#worker_state.telemetry_settings,
-  [begin
-     Measurement = #{MeasurementKey => Value},
-     telemetry:execute(Metric, Measurement, maps:merge(ExtraMetadata, Metadata))
-   end || {ExtraMetadata, Value} <- maps:to_list(State#worker_state.value)],
-  State#worker_state{value = #{}}.
+  Measurement = #{MeasurementKey => State#worker_state.value},
+  telemetry:execute(Metric, Measurement, Metadata),
+  ok.
 
 %% @doc Report events to telemetry.
 %%