fluent-plugin-add, a plugin for Fluentd Installation gem install fluent-plugin-add Configration AddOutput <match test.**> @type add add_tag_prefix debug uuid true # optional <pair> hoge moge hogehoge mogemoge </pair> </match> Assuming following inputs are coming: test.aa: {"json":"dayo"} then output becomes as belows debug.test.aa: {"json":"dayo", "hoge":"moge","hogehoge":"mogemoge","uuid":"427037E7-235B-4F6C-9975-15AAC75E56C5"} AddFilter <filter test.**> @type add uuid true # optional <pair> hoge moge hogehoge mogemoge </pair> </filter> Assuming following inputs are coming: test.aa: {"json":"dayo"} then output bocomes as belows debug.test.aa: {"json":"dayo", "hoge":"moge","hogehoge":"mogemoge","uuid":"427037E7-235B-4F6C-9975-15AAC75E56C5"} Contributing Fork it Create your feature branch (git checkout -b my-new-feature) Commit your changes (git commit -am 'Add some feature') Push to the branch (git push origin my-new-feature) Create new Pull Request Copyright Copyright (c) 2013 yu-yamada