Retry once on Zlib::BufError

Shopify · Jan 16, 2024 · 79f06d0 · 79f06d0
1 parent f6c7e3b
commit 79f06d0
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Showing 3 changed files with 32 additions and 3 deletions.
diff --git a/lib/response_bank.rb b/lib/response_bank.rb
@@ -33,7 +33,20 @@ def read_from_backing_cache_store(_env, cache_key, backing_cache_store: cache_st
     def compress(content, encoding = "br")
       case encoding
       when 'gzip'
-        Zlib.gzip(content, level: Zlib::BEST_COMPRESSION)
+        attempts = 0
+
+        begin
+          Zlib.gzip(content, level: Zlib::BEST_COMPRESSION)
+        rescue Zlib::BufError
+          # We get sporadic Zlib::BufError, so we retry once (https://github.com/ruby/zlib/issues/49)
+          attempts += 1
+
+          if attempts <= 1
+            retry
+          else
+            raise
+          end
+        end
       when 'br'
         Brotli.deflate(content, mode: :text, quality: 7)
       else

diff --git a/test/response_bank_test.rb b/test/response_bank_test.rb
@@ -67,4 +67,20 @@ def test_cache_key_for_datetime
   def test_cache_key_for_date
     assert_equal("2020-01-01", ResponseBank.cache_key_for(Date.new(2020, 1, 1)))
   end
+
+  def test_compress_retries_once_on_zlib_buferror
+    content = 'mycontent'
+    compressed_content = Zlib.gzip(content, level: Zlib::BEST_COMPRESSION)
+    Zlib.stubs(:gzip).raises(Zlib::BufError).then.returns(compressed_content)
+
+    assert_equal(compressed_content, ResponseBank.compress(content, "gzip"))
+  end
+
+  def test_compress_retries_once_on_zlib_buferror_and_raises_if_it_happens_again
+    Zlib.stubs(:gzip).raises(Zlib::BufError)
+
+    assert_raises(Zlib::BufError) do
+      ResponseBank.compress("mycontent", "gzip")
+    end
+  end
 end
diff --git a/test/response_cache_handler_test.rb b/test/response_cache_handler_test.rb
@@ -125,7 +125,7 @@ def test_server_cache_hit_but_empty_body
     _status, _headers, _body, _timestamp = empty_page
     ResponseBank.expects(:decompress).never
 
-    status, headers, body = handler.run!
+    status, headers, _body = handler.run!
 
     assert_equal(_status, status)
     assert_equal(_headers['Content-Type'], headers["Content-Type"])
@@ -143,7 +143,7 @@ def test_server_cache_hit_support_gzip
 
     ResponseBank.expects(:decompress).returns(_body).once
 
-    status, headers, body = handler.run!
+    status, headers, _body = handler.run!
 
     assert_equal(_status, status)
     assert_equal(_headers['Content-Type'], headers["Content-Type"])