Convert RateLimit-Reset format to Unix time

Issue https://gitlab.com/gitlab-com/gl-infra/scalability/-/issues/795

lib/gitlab/rack_attack.rb

@@ -49,9 +49,9 @@ module Gitlab
     # reset. This is a standardized HTTP header:
     # https://tools.ietf.org/html/rfc7231#page-69
     #
-    # - RateLimit-Reset: Similar to Retry-After.
+    # - RateLimit-Reset: the point of time that the quest quota is reset, in Unix time
     #
-    # - RateLimit-ResetTime: the point of time that the quest quota is reset.
+    # - RateLimit-ResetTime: the point of time that the quest quota is reset, in HTTP date format
     def self.throttled_response_headers(matched, match_data)
       # Match data example:
       # {:discriminator=>"127.0.0.1", :count=>12, :period=>60 seconds, :limit=>1, :epoch_time=>1609833930}
@@ -62,14 +62,14 @@ module Gitlab
       observed = match_data[:count]
       now = match_data[:epoch_time]
       retry_after = period - (now % period)
-      reset_time = now + (period - now % period)
+      reset_time = Time.at(now + (period - now % period)) # rubocop:disable Rails/TimeZone
       {
         'RateLimit-Name' => matched.to_s,
         'RateLimit-Limit' => rounded_limit.to_s,
         'RateLimit-Observed' => observed.to_s,
         'RateLimit-Remaining' => (limit > observed ? limit - observed : 0).to_s,
-        'RateLimit-Reset' => retry_after.to_s,
-        'RateLimit-ResetTime' => Time.at(reset_time).httpdate,
+        'RateLimit-Reset' => reset_time.to_i.to_s,
+        'RateLimit-ResetTime' => reset_time.httpdate,
         'Retry-After' => retry_after.to_s
       }
     end

spec/lib/gitlab/rack_attack_spec.rb

@@ -116,7 +116,7 @@ RSpec.describe Gitlab::RackAttack, :aggregate_failures do
             'RateLimit-Limit' => '60',
             'RateLimit-Observed' => '3700',
             'RateLimit-Remaining' => '0',
-            'RateLimit-Reset' => '1830',
+            'RateLimit-Reset' => '1609844400', # Time.utc(2021, 1, 5, 11, 0, 0).to_i.to_s
             'RateLimit-ResetTime' => 'Tue, 05 Jan 2021 11:00:00 GMT',
             'Retry-After' => '1830'
           }
@@ -135,7 +135,7 @@ RSpec.describe Gitlab::RackAttack, :aggregate_failures do
             'RateLimit-Limit' => '60',
             'RateLimit-Observed' => '3700',
             'RateLimit-Remaining' => '0',
-            'RateLimit-Reset' => '1',
+            'RateLimit-Reset' => '1609844400', # Time.utc(2021, 1, 5, 11, 0, 0).to_i.to_s
             'RateLimit-ResetTime' => 'Tue, 05 Jan 2021 11:00:00 GMT',
             'Retry-After' => '1'
           }
@@ -154,7 +154,7 @@ RSpec.describe Gitlab::RackAttack, :aggregate_failures do
             'RateLimit-Limit' => '60',
             'RateLimit-Observed' => '3700',
             'RateLimit-Remaining' => '0',
-            'RateLimit-Reset' => '3600',
+            'RateLimit-Reset' => '1609844400', # Time.utc(2021, 1, 5, 11, 0, 0).to_i.to_s
             'RateLimit-ResetTime' => 'Tue, 05 Jan 2021 11:00:00 GMT',
             'Retry-After' => '3600'
           }
@@ -173,7 +173,7 @@ RSpec.describe Gitlab::RackAttack, :aggregate_failures do
             'RateLimit-Limit' => '60',
             'RateLimit-Observed' => '3700',
             'RateLimit-Remaining' => '0',
-            'RateLimit-Reset' => '1800',
+            'RateLimit-Reset' => '1609891200', # Time.utc(2021, 1, 6, 0, 0, 0).to_i.to_s
             'RateLimit-ResetTime' => 'Wed, 06 Jan 2021 00:00:00 GMT', # Next day
             'Retry-After' => '1800'
           }
@@ -192,7 +192,7 @@ RSpec.describe Gitlab::RackAttack, :aggregate_failures do
             'RateLimit-Limit' => '57', # 56.66 requests per minute
             'RateLimit-Observed' => '3700',
             'RateLimit-Remaining' => '0',
-            'RateLimit-Reset' => '1800',
+            'RateLimit-Reset' => '1609844400', # Time.utc(2021, 1, 5, 11, 0, 0).to_i.to_s
             'RateLimit-ResetTime' => 'Tue, 05 Jan 2021 11:00:00 GMT',
             'Retry-After' => '1800'
           }
@@ -211,7 +211,7 @@ RSpec.describe Gitlab::RackAttack, :aggregate_failures do
             'RateLimit-Limit' => '62', # 61.66 requests per minute
             'RateLimit-Observed' => '3700',
             'RateLimit-Remaining' => '0',
-            'RateLimit-Reset' => '1800',
+            'RateLimit-Reset' => '1609844400', # Time.utc(2021, 1, 5, 11, 0, 0).to_i.to_s
             'RateLimit-ResetTime' => 'Tue, 05 Jan 2021 11:00:00 GMT',
             'Retry-After' => '1800'
           }
@@ -230,7 +230,7 @@ RSpec.describe Gitlab::RackAttack, :aggregate_failures do
             'RateLimit-Limit' => '1', # 0.9833 requests per minute
             'RateLimit-Observed' => '3700',
             'RateLimit-Remaining' => '0',
-            'RateLimit-Reset' => '1800',
+            'RateLimit-Reset' => '1609844400', # Time.utc(2021, 1, 5, 11, 0, 0).to_i.to_s
             'RateLimit-ResetTime' => 'Tue, 05 Jan 2021 11:00:00 GMT',
             'Retry-After' => '1800'
           }
@@ -249,7 +249,7 @@ RSpec.describe Gitlab::RackAttack, :aggregate_failures do
             'RateLimit-Limit' => '2', # 1.016 requests per minute
             'RateLimit-Observed' => '3700',
             'RateLimit-Remaining' => '0',
-            'RateLimit-Reset' => '1800',
+            'RateLimit-Reset' => '1609844400', # Time.utc(2021, 1, 5, 11, 0, 0).to_i.to_s
             'RateLimit-ResetTime' => 'Tue, 05 Jan 2021 11:00:00 GMT',
             'Retry-After' => '1800'
           }
@@ -268,7 +268,7 @@ RSpec.describe Gitlab::RackAttack, :aggregate_failures do
             'RateLimit-Limit' => '40',
             'RateLimit-Observed' => '3700',
             'RateLimit-Remaining' => '0',
-            'RateLimit-Reset' => '15',
+            'RateLimit-Reset' => '1609842615', # Time.utc(2021, 1, 5, 10, 30, 15).to_i.to_s
             'RateLimit-ResetTime' => 'Tue, 05 Jan 2021 10:30:15 GMT',
             'Retry-After' => '15'
           }
@@ -287,7 +287,7 @@ RSpec.describe Gitlab::RackAttack, :aggregate_failures do
             'RateLimit-Limit' => '23',
             'RateLimit-Observed' => '3700',
             'RateLimit-Remaining' => '0',
-            'RateLimit-Reset' => '27',
+            'RateLimit-Reset' => '1609842627', # Time.utc(2021, 1, 5, 10, 30, 27).to_i.to_s
             'RateLimit-ResetTime' => 'Tue, 05 Jan 2021 10:30:27 GMT',
             'Retry-After' => '27'
           }

spec/support/helpers/rack_attack_spec_helpers.rb

@@ -36,9 +36,12 @@ module RackAttackSpecHelpers
       'RateLimit-Name' => a_string_matching(/^throttle_.*$/),
       'RateLimit-Observed' => a_string_matching(/^\d+$/),
       'RateLimit-Remaining' => a_string_matching(/^\d+$/),
-      'RateLimit-Reset' => a_string_matching(/^\d+$/),
       'Retry-After' => a_string_matching(/^\d+$/)
     )
+    expect(response).to have_header('RateLimit-Reset')
+    expect do
+      DateTime.strptime(response.headers['RateLimit-Reset'], '%s')
+    end.not_to raise_error
     expect(response).to have_header('RateLimit-ResetTime')
     expect do
       Time.httpdate(response.headers['RateLimit-ResetTime'])