fluent-plugin-docker_metadata_filter, a plugin for Fluentd

Circle CI Code Climate Test Coverage


gem install fluent-plugin-


  type tail
  path /var/lib/docker/containers/*/*-json.log
  pos_file fluentd-docker.pos
  time_format %Y-%m-%dT%H:%M:%S
  tag docker.*
  format json
  read_from_head true

<filter docker.var.lib.docker.containers.*.*.log>
  type docker_metadata

<match **>
  type stdout

Docker logs in JSON format. Log files are normally in /var/lib/docker/containers/*/*-json.log, depending on what your Docker data directory is.

Assuming following inputs are coming from a log file: df14e0d5ae4c07284fa636d739c8fc2e6b52bc344658de7d3f08c36a2e804115-json.log:

  "log": "2015/05/05 19:54:41 \n",
  "stream": "stderr",
  "time": "2015-05-05T19:54:41.240447294Z"

Then output becomes as belows

  "log": "2015/05/05 19:54:41 \n",
  "stream": "stderr",
  "docker": {
    "id": "df14e0d5ae4c07284fa636d739c8fc2e6b52bc344658de7d3f08c36a2e804115",
    "name": "k8s_fabric8-console-container.efbd6e64_fabric8-console-controller-9knhj_default_8ae2f621-f360-11e4-8d12-54ee7527188d_7ec9aa3e",
    "container_hostname": "fabric8-console-controller-9knhj",
    "image": "fabric8/hawtio-kubernetes:latest",
    "image_id": "b2bd1a24a68356b2f30128e6e28e672c1ef92df0d9ec01ec0c7faea5d77d2303",
    "labels": {}

Running Tests

bundle install
bundle exec rake test


  1. Fork it
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Update and verify tests are successful (See Running Tests)
  6. Create new Pull Request

Copyright (c) 2015 jimmidyson