class Fluent::Plugin::MesosphereFilter

Parses Marathon and Chronos data from docker to make fluentd logs more useful.

Public Instance Methods

configure(conf) click to toggle source

Get the configuration for the plugin

Calls superclass method
# File lib/fluent/plugin/filter_mesosphere_filter.rb, line 45
def configure(conf)
  super

  @cache_ttl = :none if @cache_ttl < 0

  @cache = LruRedux::TTL::ThreadSafeCache.new(@cache_size, @cache_ttl)

  @chronos_task_regex_compiled = Regexp.compile(@cronos_task_regex)

  @marathon_app_regex_compiled = Regexp.compile(@marathon_app_regex)
end
filter_stream(tag, es) click to toggle source

Gets the log event stream and moifies it. This is where the plugin hooks into the fluentd envent stream.

# File lib/fluent/plugin/filter_mesosphere_filter.rb, line 59
def filter_stream(tag, es)
  new_es = Fluent::MultiEventStream.new
  container_id = ''

  container_id = get_container_id_from_tag(tag) if get_container_id_tag

  es.each do |time, record|
    container_id =
      get_container_id_from_record(record) if container_id.empty?
    next unless container_id
    new_es.add(time, modify_record(record, get_mesos_data(container_id)))
  end
  new_es
end
get_container_id_from_record(record) click to toggle source

If the user has configured container_id_attr the container id can be gathered from the record if it has been inserted there. If no container_id can be found, the record is not processed.

Attributes::

  • record - The record that is being transformed by the filter

Returns:

  • A docker container id

# File lib/fluent/plugin/filter_mesosphere_filter.rb, line 157
def get_container_id_from_record(record)
  record[@container_id_attr]
end
get_container_id_from_tag(tag) click to toggle source

Gets the container id from the last element in the tag. If the user has configured container_id_attr the container id can be gathered from the record if it has been inserted there.

Attributes:

  • tag - The tag of the log being processed

Returns:

  • A docker container id

# File lib/fluent/plugin/filter_mesosphere_filter.rb, line 145
def get_container_id_from_tag(tag)
  tag.split('.').last
end
get_container_metadata(id) click to toggle source

Goes out to docker to get environment variables for a container. Then we parse the environment varibles looking for known Marathon and Chronos environment variables

Attributes:

  • id - The id of the container to look at for mesosphere metadata.

Returns:

  • A hash that describes a mesos task gathered from the Docker API

# File lib/fluent/plugin/filter_mesosphere_filter.rb, line 110
def get_container_metadata(id)
  task_data = {}
  container = Docker::Container.get(id)
  if container
    environment = container.json['Config']['Env']
    environment.each do |env|
      # Chronos puts task_id in lowercase, and Marathon does it with
      # uppercase
      if env =~ /MESOS_TASK_ID/i
        task_data['mesos_task_id'] = parse_env(env)
      elsif env.include? 'MARATHON_APP_ID'
        match_data = parse_env(env).match(@marathon_app_regex_compiled)
        task_data['mesos_framework'] = 'marathon'
        task_data['app'] = match_data['app'] if match_data
      elsif env.include? 'CHRONOS_JOB_NAME'
        match_data = parse_env(env).match(@chronos_task_regex_compiled)
        task_data['mesos_framework'] = 'chronos'
        task_data['app'] = match_data['app'] if match_data
        task_data['chronos_task_type'] = match_data['task_type'] if match_data && match_data.names.include?('task_type')
      elsif @namespace_env_var && env.include?(@namespace_env_var)
        task_data['namespace'] = parse_env(env)
      end
    end
  end
  task_data
end
get_mesos_data(container_id) click to toggle source

Gets the mesos data about a container from the cache or calls the Docker api to retrieve the data about the container and store it in the cache.

Attributes:

  • container_id - The container_id where the log record originated from.

Returns:

  • A hash of data that describes a mesos task

# File lib/fluent/plugin/filter_mesosphere_filter.rb, line 96
def get_mesos_data(container_id)
  @cache.getset(container_id) do
    get_container_metadata(container_id)
  end
end
merge_json_log(record) click to toggle source

Look at the log value and if it is valid json then we will parse the json and merge it into the log record. If a namespace is present then the log record is placed under that key.

Attributes:

  • record - The record we are transforming in the fluentd event stream.

Examples

# Docker captures stdout and passes it in the 'log' record attribute. # We try to discover is the value of 'log' is json, if it is then we # will parse the json and add the keys and values to the record.

Returns:

  • A record hash that has json log data merged into the record

# File lib/fluent/plugin/filter_mesosphere_filter.rb, line 184
def merge_json_log(record)
  if record.key?('log')
    log = record['log'].strip
    namespace = record['namespace']
    if log[0].eql?('{') && log[-1].eql?('}')
      begin
        log_json = Oj.load(log)
        if namespace
          record[namespace] = log_json
        else
          record = log_json.merge(record)
        end
      rescue Oj::ParseError
      end
    end
  end
  record
end
modify_record(record, mesos_data) click to toggle source

Injects the meso framework data into the record and also merges the json log if that configuration is enabled.

Attributes:

  • record - The log record being processed

  • mesos_data - The mesos data retrived from the docker container

Returns:

  • A record hash that has mesos data and optinally log data added

# File lib/fluent/plugin/filter_mesosphere_filter.rb, line 83
def modify_record(record, mesos_data)
  modified_record = record.merge(mesos_data)
  modified_record = merge_json_log(modified_record) if @merge_json_log
  modified_record
end
parse_env(env) click to toggle source

Split the env var on = and return the value

Attributes:

  • env - The docker environment variable to parse to get the value.

Examples

# For the env value MARATHON_APP_ID the actual string value given to us # by docker is 'MARATHON_APP_ID=some-app'. We want to return 'some-app'.

Returns:

  • The value of an environment varaible

# File lib/fluent/plugin/filter_mesosphere_filter.rb, line 169
def parse_env(env)
  env.split('=').last
end