Module: KubernetesMetadata::WatchNamespaces

Includes:
Common
Included in:
Fluent::Plugin::KubernetesMetadataFilter
Defined in:
lib/fluent/plugin/kubernetes_metadata_watch_namespaces.rb

Instance Method Summary collapse

Methods included from Common

#match_annotations, #parse_namespace_metadata, #parse_pod_metadata, #syms_to_strs

Instance Method Details

#get_namespaces_and_start_watcher ⇒ Object

List all namespaces, record the resourceVersion and return a watcher starting from that resourceVersion.



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# File 'lib/fluent/plugin/kubernetes_metadata_watch_namespaces.rb', line 91

def get_namespaces_and_start_watcher
  options = {
    resource_version: '0' # Fetch from API server cache instead of etcd quorum read
  }
  namespaces = @client.get_namespaces(options)
  namespaces[:items].each do |namespace|
    cache_key = namespace[:metadata][:uid]
    @namespace_cache[cache_key] = parse_namespace_metadata(namespace)
    @stats.bump(:namespace_cache_host_updates)
  end

  # continue watching from most recent resourceVersion
  options[:resource_version] = namespaces[:metadata][:resourceVersion]

  watcher = @client.watch_namespaces(options)
  reset_namespace_watch_retry_stats
  watcher
end

#process_namespace_watcher_notices(watcher) ⇒ Object

Process a watcher notice and potentially raise an exception.



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# File 'lib/fluent/plugin/kubernetes_metadata_watch_namespaces.rb', line 118

def process_namespace_watcher_notices(watcher)
  watcher.each do |notice|
    case notice[:type]
    when 'MODIFIED'
      reset_namespace_watch_retry_stats
      cache_key = notice[:object][:metadata][:uid]
      cached    = @namespace_cache[cache_key]
      if cached
        @namespace_cache[cache_key] = parse_namespace_metadata(notice[:object])
        @stats.bump(:namespace_cache_watch_updates)
      else
        @stats.bump(:namespace_cache_watch_misses)
      end
    when 'DELETED'
      reset_namespace_watch_retry_stats
      # ignore and let age out for cases where
      # deleted but still processing logs
      @stats.bump(:namespace_cache_watch_deletes_ignored)
    when 'ERROR'
      if notice[:object] && notice[:object][:code] == 410
        @stats.bump(:namespace_watch_gone_notices)
        raise GoneError
      else
        @stats.bump(:namespace_watch_error_type_notices)
        message = notice[:object][:message] if notice[:object] && notice[:object][:message]
        raise "Error while watching namespaces: #{message}"
      end
    else
      reset_namespace_watch_retry_stats
      # Don't pay attention to creations, since the created namespace may not
      # be used by any namespace on this node.
      @stats.bump(:namespace_cache_watch_ignored)
    end
  end
end

#reset_namespace_watch_retry_stats ⇒ Object

Reset namespace watch retry count and backoff interval as there is a successful watch notice.



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# File 'lib/fluent/plugin/kubernetes_metadata_watch_namespaces.rb', line 112

def reset_namespace_watch_retry_stats
  Thread.current[:namespace_watch_retry_count] = 0
  Thread.current[:namespace_watch_retry_backoff_interval] = @watch_retry_interval
end

#set_up_namespace_thread ⇒ Object 



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# File 'lib/fluent/plugin/kubernetes_metadata_watch_namespaces.rb', line 28

def set_up_namespace_thread
  # Any failures / exceptions in the initial setup should raise
  # Fluent:ConfigError, so that users can inspect potential errors in
  # the configuration.
  namespace_watcher = start_namespace_watch
  Thread.current[:namespace_watch_retry_backoff_interval] = @watch_retry_interval
  Thread.current[:namespace_watch_retry_count] = 0

  # Any failures / exceptions in the followup watcher notice
  # processing will be swallowed and retried. These failures /
  # exceptions could be caused by Kubernetes API being temporarily
  # down. We assume the configuration is correct at this point.
  loop do
    namespace_watcher ||= get_namespaces_and_start_watcher
    process_namespace_watcher_notices(namespace_watcher)
  rescue GoneError => e
    # Expected error. Quietly go back through the loop in order to
    # start watching from the latest resource versions
    @stats.bump(:namespace_watch_gone_errors)
    log.info('410 Gone encountered. Restarting namespace watch to reset resource versions.', e)
    namespace_watcher = nil
  rescue StandardError => e
    @stats.bump(:namespace_watch_failures)
    if Thread.current[:namespace_watch_retry_count] < @watch_retry_max_times
      # Instead of raising exceptions and crashing Fluentd, swallow
      # the exception and reset the watcher.
      log.info(
        'Exception encountered parsing namespace watch event. ' \
        'The connection might have been closed. Sleeping for ' \
        "#{Thread.current[:namespace_watch_retry_backoff_interval]} " \
        'seconds and resetting the namespace watcher.', e
      )
      sleep(Thread.current[:namespace_watch_retry_backoff_interval])
      Thread.current[:namespace_watch_retry_count] += 1
      Thread.current[:namespace_watch_retry_backoff_interval] *= @watch_retry_exponential_backoff_base
      namespace_watcher = nil
    else
      # Since retries failed for many times, log as errors instead
      # of info and raise exceptions and trigger Fluentd to restart.
      message =
        'Exception encountered parsing namespace watch event. The ' \
        'connection might have been closed. Retried ' \
        "#{@watch_retry_max_times} times yet still failing. Restarting."
      log.error(message, e)
      raise Fluent::UnrecoverableError, message
    end
  end
end

#start_namespace_watch ⇒ Object 



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# File 'lib/fluent/plugin/kubernetes_metadata_watch_namespaces.rb', line 77

def start_namespace_watch
  get_namespaces_and_start_watcher
rescue StandardError => e
  message = 'start_namespace_watch: Exception encountered setting up ' \
            "namespace watch from Kubernetes API #{@apiVersion} endpoint " \
            "#{@kubernetes_url}: #{e.message}"
  message += " (#{e.response})" if e.respond_to?(:response)
  log.debug(message)

  raise Fluent::ConfigError, message
end