fsync file writes

nebhale · nebhale · commit f89e01ac85de · 2013-10-03T11:20:59.000+01:00
This change ensures that all file writes are fsync'd.  This is in an
attempt to address some issues we're seeing with corrupted files
shortly after they are written.

[#58149152]
diff --git a/lib/java_buildpack/container/play.rb b/lib/java_buildpack/container/play.rb
@@ -116,7 +116,12 @@ def start_script_relative(play_root)
     def update_file(file_name, pattern, replacement)
       content = File.open(file_name, 'r') { |file| file.read }
       result = content.gsub! pattern, replacement
-      File.open(file_name, 'w') { |file| file.write content }
+
+      File.open(file_name, 'w') do |file|
+        file.write content
+        file.fsync
+      end
+
       result
     end
 
diff --git a/lib/java_buildpack/framework/spring_auto_reconfiguration.rb b/lib/java_buildpack/framework/spring_auto_reconfiguration.rb
@@ -70,7 +70,11 @@ def modify_web_xml
         modifier.augment_root_context
         modifier.augment_servlet_contexts
 
-        File.open(web_xml, 'w') { |file| file.write(modifier.to_s) }
+        File.open(web_xml, 'w') do |file|
+          file.write(modifier.to_s)
+          file.fsync
+        end
+
         @logger.debug { "  Modified web.xml: #{File.read web_xml}" }
       end
     end
diff --git a/lib/java_buildpack/jre/openjdk.rb b/lib/java_buildpack/jre/openjdk.rb
@@ -95,6 +95,7 @@ def copy_killjava_script
       FileUtils.mkdir_p diagnostic_dir
       File.open(File.join(diagnostic_dir, KILLJAVA_FILE_NAME), 'w', 0755) do |file|
         file.write updated_content
+        file.fsync
       end
     end
 
diff --git a/lib/java_buildpack/util/download_cache.rb b/lib/java_buildpack/util/download_cache.rb
@@ -222,6 +222,7 @@ def persist_header(response, header, filename)
       unless response[header].nil?
         File.open(filename, File::CREAT | File::WRONLY) do |file|
           file.write(response[header])
+          file.fsync
         end
       end
     end
diff --git a/resources/openjdk/diagnostics/killjava b/resources/openjdk/diagnostics/killjava
@@ -31,6 +31,7 @@ module Kill
     File.open(log_file_name, 'a') do |log_file|
       log_file.sync = true
       log_file.write "#{log_data} @ #{Kill.time_in_millis}\n"
+      log_file.fsync
     end
   end
 
diff --git a/spec/java_buildpack/repository/repository_index_spec.rb b/spec/java_buildpack/repository/repository_index_spec.rb
@@ -97,7 +97,10 @@ def with_buildpack_cache(directory)
 
     def touch(root, extension, content = '')
       file = File.join(root, "http:%2F%2Ffoo.com%2Ftest.txt%2F.#{extension}")
-      File.open(file, 'w') { |f| f.write(content) }
+      File.open(file, 'w') do |f|
+        f.write(content)
+        f.fsync
+      end
       file
     end
 
