Class: Fluent::MesosphereFilter

Inherits:
Filter
  • Object
show all
Defined in:
lib/fluent/plugin/mesosphere.rb

Overview

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

Instance Method Summary collapse

Constructor Details

#initializeMesosphereFilter

Returns a new instance of MesosphereFilter.


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# File 'lib/fluent/plugin/mesosphere.rb', line 34

def initialize
  super
end

Instance Method Details

#configure(conf) ⇒ Object

Get the configuration for the plugin


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# File 'lib/fluent/plugin/mesosphere.rb', line 39

def configure(conf)
  super

  require 'docker-api'
  require 'lru_redux'
  require 'oj'

  @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_regex = '\/(?<app>[a-z0-9]([-a-z0-9_]*[a-z0-9_]))'
  @marathon_app_regex_compiled = Regexp.compile(marathon_regex)
end

#filter_stream(tag, es) ⇒ Object

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


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# File 'lib/fluent/plugin/mesosphere.rb', line 58

def filter_stream(tag, es)
  new_es = 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) ⇒ Object

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


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# File 'lib/fluent/plugin/mesosphere.rb', line 154

def get_container_id_from_record(record)
  record[@container_id_attr]
end

#get_container_id_from_tag(tag) ⇒ Object

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


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# File 'lib/fluent/plugin/mesosphere.rb', line 142

def get_container_id_from_tag(tag)
  tag.split('.').last
end

#get_container_metadata(id) ⇒ Object

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


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# File 'lib/fluent/plugin/mesosphere.rb', line 109

def (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
      end
    end
  end
  task_data
end

#get_mesos_data(container_id) ⇒ Object

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


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# File 'lib/fluent/plugin/mesosphere.rb', line 95

def get_mesos_data(container_id)
  @cache.getset(container_id) do
    (container_id)
  end
end

#merge_json_log(record) ⇒ Object

Look at the log value and if it is valid json then we will parse the json and merge it into the log record.

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


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# File 'lib/fluent/plugin/mesosphere.rb', line 180

def merge_json_log(record)
  if record.key?('log')
    log = record['log'].strip
    if log[0].eql?('{') && log[-1].eql?('}')
      begin
        record = Oj.load(log).merge(record)
      rescue Oj::ParseError
      end
    end
  end
  record
end

#modify_record(record, mesos_data) ⇒ Object

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


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# File 'lib/fluent/plugin/mesosphere.rb', line 82

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) ⇒ Object

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


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# File 'lib/fluent/plugin/mesosphere.rb', line 166

def parse_env(env)
  env.split('=').last
end