Add allocations to template renderer subscription

This PR adds the allocations to the instrumentation for template and
partial rendering.

Before:

```
  Rendering posts/new.html.erb within layouts/application
  Rendered posts/_form.html.erb (9.7ms)
  Rendered posts/new.html.erb within layouts/application (10.9ms)
Completed 200 OK in 902ms (Views: 890.8ms | ActiveRecord: 0.8ms)
```

After:

```
  Rendering posts/new.html.erb within layouts/application
  Rendered posts/_form.html.erb (Duration: 7.1ms | Allocations: 6004)
  Rendered posts/new.html.erb within layouts/application (Duration: 8.3ms | Allocations: 6654)
Completed 200 OK in 858ms (Views: 848.4ms | ActiveRecord: 0.4ms | Allocations: 1539564)
```

5 files changed, 27 insertions, 12 deletions

diff --git a/actionpack/lib/action_controller/log_subscriber.rb b/actionpack/lib/action_controller/log_subscriber.rb
index 6de1fb2c19..afbd38e7fe 100644
--- a/actionpack/lib/action_controller/log_subscriber.rb
+++ b/actionpack/lib/action_controller/log_subscriber.rb
@@ -18,14 +18,17 @@ module ActionController
 
     def process_action(event)
       info do
-        payload   = event.payload
+        payload = event.payload
         additions = ActionController::Base.log_process_action(payload)
-
         status = payload[:status]
+
         if status.nil? && payload[:exception].present?
           exception_class_name = payload[:exception].first
           status = ActionDispatch::ExceptionWrapper.status_code_for_exception(exception_class_name)
         end
+
+        additions << "Allocations: #{event.allocations}"
+
         message = +"Completed #{status} #{Rack::Utils::HTTP_STATUS_CODES[status]} in #{event.duration.round}ms"
         message << " (#{additions.join(" | ")})" unless additions.empty?
         message << "\n\n" if defined?(Rails.env) && Rails.env.development?
diff --git a/actionview/CHANGELOG.md b/actionview/CHANGELOG.md
index 252fce6472..fd8bae0cdf 100644
--- a/actionview/CHANGELOG.md
+++ b/actionview/CHANGELOG.md
@@ -1,3 +1,15 @@
+*   Add allocations to template rendering instrumentation.
+
+    Adds the allocations for template and partial rendering to the server output on render.
+
+    ```
+      Rendered posts/_form.html.erb (Duration: 7.1ms | Allocations: 6004)
+      Rendered posts/new.html.erb within layouts/application (Duration: 8.3ms | Allocations: 6654)
+    Completed 200 OK in 858ms (Views: 848.4ms | ActiveRecord: 0.4ms | Allocations: 1539564)
+    ```
+
+    *Eileen M. Uchitelle*, *Aaron Patterson*
+
 *   Respect the `only_path` option passed to `url_for` when the options are passed in as an array
     
     Fixes #33237.
diff --git a/actionview/lib/action_view/log_subscriber.rb b/actionview/lib/action_view/log_subscriber.rb
index db07b9d7fb..227f025385 100644
--- a/actionview/lib/action_view/log_subscriber.rb
+++ b/actionview/lib/action_view/log_subscriber.rb
@@ -18,7 +18,7 @@ module ActionView
       info do
         message = +"  Rendered #{from_rails_root(event.payload[:identifier])}"
         message << " within #{from_rails_root(event.payload[:layout])}" if event.payload[:layout]
-        message << " (#{event.duration.round(1)}ms)"
+        message << " (Duration: #{event.duration.round(1)}ms | Allocations: #{event.allocations})"
       end
     end
 
@@ -26,7 +26,7 @@ module ActionView
       info do
         message = +"  Rendered #{from_rails_root(event.payload[:identifier])}"
         message << " within #{from_rails_root(event.payload[:layout])}" if event.payload[:layout]
-        message << " (#{event.duration.round(1)}ms)"
+        message << " (Duration: #{event.duration.round(1)}ms | Allocations: #{event.allocations})"
         message << " #{cache_message(event.payload)}" unless event.payload[:cache_hit].nil?
         message
       end
@@ -37,7 +37,7 @@ module ActionView
 
       info do
         "  Rendered collection of #{from_rails_root(identifier)}" \
-        " #{render_count(event.payload)} (#{event.duration.round(1)}ms)"
+        " #{render_count(event.payload)} (Duration: #{event.duration.round(1)}ms | Allocations: #{event.allocations})"
       end
     end
 
diff --git a/actionview/test/activerecord/controller_runtime_test.rb b/actionview/test/activerecord/controller_runtime_test.rb
index 7cbd3aaf89..563044f11e 100644
--- a/actionview/test/activerecord/controller_runtime_test.rb
+++ b/actionview/test/activerecord/controller_runtime_test.rb
@@ -68,7 +68,7 @@ class ControllerRuntimeLogSubscriberTest < ActionController::TestCase
     wait
 
     assert_equal 2, @logger.logged(:info).size
-    assert_match(/\(Views: [\d.]+ms \| ActiveRecord: [\d.]+ms\)/, @logger.logged(:info)[1])
+    assert_match(/\(Views: [\d.]+ms \| ActiveRecord: [\d.]+ms \| Allocations: [\d.]+\)/, @logger.logged(:info)[1])
   end
 
   def test_runtime_reset_before_requests
@@ -77,20 +77,20 @@ class ControllerRuntimeLogSubscriberTest < ActionController::TestCase
     wait
 
     assert_equal 2, @logger.logged(:info).size
-    assert_match(/\(Views: [\d.]+ms \| ActiveRecord: 0\.0ms\)/, @logger.logged(:info)[1])
+    assert_match(/\(Views: [\d.]+ms \| ActiveRecord: [\d.]+ms \| Allocations: [\d.]+\)/, @logger.logged(:info)[1])
   end
 
   def test_log_with_active_record_when_post
     post :create
     wait
-    assert_match(/ActiveRecord: ([1-9][\d.]+)ms\)/, @logger.logged(:info)[2])
+    assert_match(/ActiveRecord: ([1-9][\d.]+)ms \| Allocations: [\d.]+\)/, @logger.logged(:info)[2])
   end
 
   def test_log_with_active_record_when_redirecting
     get :redirect
     wait
     assert_equal 3, @logger.logged(:info).size
-    assert_match(/\(ActiveRecord: [\d.]+ms\)/, @logger.logged(:info)[2])
+    assert_match(/\(ActiveRecord: [\d.]+ms \| Allocations: [\d.]+\)/, @logger.logged(:info)[2])
   end
 
   def test_include_time_query_time_after_rendering
@@ -98,6 +98,6 @@ class ControllerRuntimeLogSubscriberTest < ActionController::TestCase
     wait
 
     assert_equal 2, @logger.logged(:info).size
-    assert_match(/\(Views: [\d.]+ms \| ActiveRecord: ([1-9][\d.]+)ms\)/, @logger.logged(:info)[1])
+    assert_match(/\(Views: [\d.]+ms \| ActiveRecord: ([1-9][\d.]+)ms \| Allocations: [\d.]+\)/, @logger.logged(:info)[1])
   end
 end
diff --git a/actionview/test/template/log_subscriber_test.rb b/actionview/test/template/log_subscriber_test.rb
index 7f4fd25573..9fcf80bb24 100644
--- a/actionview/test/template/log_subscriber_test.rb
+++ b/actionview/test/template/log_subscriber_test.rb
@@ -129,14 +129,14 @@ class AVLogSubscriberTest < ActiveSupport::TestCase
       wait
       *, cached_inner, uncached_outer = @logger.logged(:info)
       assert_match(/Rendered test\/_cached_customer\.erb (.*) \[cache miss\]/, cached_inner)
-      assert_match(/Rendered test\/_nested_cached_customer\.erb \(.*?ms\)$/, uncached_outer)
+      assert_match(/Rendered test\/_nested_cached_customer\.erb \(Duration: .*?ms \| Allocations: .*?\)$/, uncached_outer)
 
       # Second render hits the cache for the _cached_customer partial. Outer template's log shouldn't be affected.
       @view.render(partial: "test/nested_cached_customer", locals: { cached_customer: Customer.new("Stan") })
       wait
       *, cached_inner, uncached_outer = @logger.logged(:info)
       assert_match(/Rendered test\/_cached_customer\.erb (.*) \[cache hit\]/, cached_inner)
-      assert_match(/Rendered test\/_nested_cached_customer\.erb \(.*?ms\)$/, uncached_outer)
+      assert_match(/Rendered test\/_nested_cached_customer\.erb \(Duration: .*?ms \| Allocations: .*?\)$/, uncached_outer)
     end
   end