Class: LogStash::Outputs::ElasticSearch::HttpClient::Pool

Inherits:
Object
  • Object
show all
Defined in:
lib/logstash/outputs/elasticsearch/http_client/pool.rb

Defined Under Namespace

Classes: BadResponseCodeError, HostUnreachableError, NoConnectionAvailableError

Constant Summary collapse

ROOT_URI_PATH = 
'/'.freeze
LICENSE_PATH = 
'/_license'.freeze
VERSION_6_TO_7 = 
::Gem::Requirement.new([">= 6.0.0", "< 7.0.0"])
VERSION_7_TO_7_14 = 
::Gem::Requirement.new([">= 7.0.0", "< 7.14.0"])
DEFAULT_OPTIONS = 
{
  :healthcheck_path => ROOT_URI_PATH,
  :sniffing_path => "/_nodes/http",
  :bulk_path => "/_bulk",
  :scheme => 'http',
  :resurrect_delay => 5,
  :sniffing => false,
  :sniffer_delay => 10,
}.freeze
ES1_SNIFF_RE_URL = 
/\[([^\/]*)?\/?([^:]*):([0-9]+)\]/
ES2_AND_ABOVE_SNIFF_RE_URL = 
/([^\/]*)?\/?([^:]*):([0-9]+)/

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(logger, adapter, initial_urls = [], options = {}) ⇒ Pool

Returns a new instance of Pool.

Raises:

  • (ArgumentError) 


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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 53

def initialize(logger, adapter, initial_urls=[], options={})
  @logger = logger
  @adapter = adapter
  @metric = options[:metric]
  @initial_urls = initial_urls
  
  raise ArgumentError, "No URL Normalizer specified!" unless options[:url_normalizer]
  @url_normalizer = options[:url_normalizer]
  DEFAULT_OPTIONS.merge(options).tap do |merged|
    @bulk_path = merged[:bulk_path]
    @sniffing_path = merged[:sniffing_path]
    @healthcheck_path = merged[:healthcheck_path]
    @resurrect_delay = merged[:resurrect_delay]
    @sniffing = merged[:sniffing]
    @sniffer_delay = merged[:sniffer_delay]
  end

  # Used for all concurrent operations in this class
  @state_mutex = Mutex.new

  # Holds metadata about all URLs
  @url_info = {}
  @stopping = false

  @license_checker = options[:license_checker] || LogStash::PluginMixins::ElasticSearch::NoopLicenseChecker::INSTANCE

  @last_es_version = Concurrent::AtomicReference.new
end

Instance Attribute Details

#adapter ⇒ Object (readonly)

Returns the value of attribute adapter.



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 34

def adapter
  @adapter
end

#bulk_path ⇒ Object (readonly)

Returns the value of attribute bulk_path.



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 34

def bulk_path
  @bulk_path
end

#healthcheck_path ⇒ Object (readonly)

Returns the value of attribute healthcheck_path.



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 34

def healthcheck_path
  @healthcheck_path
end

#license_checker ⇒ Object (readonly)

license_checker is used by the pool specs



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 35

def license_checker
  @license_checker
end

#logger ⇒ Object (readonly)

Returns the value of attribute logger.



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 34

def logger
  @logger
end

#resurrect_delay ⇒ Object (readonly)

Returns the value of attribute resurrect_delay.



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 34

def resurrect_delay
  @resurrect_delay
end

#sniffer_delay ⇒ Object (readonly)

Returns the value of attribute sniffer_delay.



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 34

def sniffer_delay
  @sniffer_delay
end

#sniffing ⇒ Object (readonly)

Returns the value of attribute sniffing.



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 34

def sniffing
  @sniffing
end

#sniffing_path ⇒ Object (readonly)

Returns the value of attribute sniffing_path.



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 34

def sniffing_path
  @sniffing_path
end

Instance Method Details

#add_url(url) ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 381

def add_url(url)
  @url_info[url] ||= empty_url_meta
end

#address_str_to_uri(addr_str) ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 198

def address_str_to_uri(addr_str)
  matches = addr_str.match(ES1_SNIFF_RE_URL) || addr_str.match(ES2_AND_ABOVE_SNIFF_RE_URL)
  if matches
    host = matches[1].empty? ? matches[2] : matches[1]
    ::LogStash::Util::SafeURI.new("#{host}:#{matches[3]}")
  end
end

#alive_urls_count ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 119

def alive_urls_count
  @state_mutex.synchronize { @url_info.values.select {|v| v[:state] == :alive }.count }
end

#check_sniff ⇒ Object

Sniffs and returns the results. Does not update internal URLs!



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 173

def check_sniff
  _, url_meta, resp = perform_request(:get, @sniffing_path)
  @metric.increment(:sniff_requests)
  parsed = LogStash::Json.load(resp.body)
  nodes = parsed['nodes']
  if !nodes || nodes.empty?
    @logger.warn("Sniff returned no nodes! Will not update hosts.")
    return nil
  else
    sniff(nodes)
  end
end

#close ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 92

def close
  @state_mutex.synchronize { @stopping = true }

  logger.debug  "Stopping sniffer"
  stop_sniffer

  logger.debug  "Stopping resurrectionist"
  stop_resurrectionist

  logger.debug  "Waiting for in use manticore connections"
  wait_for_in_use_connections

  logger.debug("Closing adapter #{@adapter}")
  @adapter.close
end

#elasticsearch?(url) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 267

def elasticsearch?(url)
  begin
    response = perform_request_to_url(url, :get, ROOT_URI_PATH)
  rescue ::LogStash::Outputs::ElasticSearch::HttpClient::Pool::BadResponseCodeError => e
    return false if response.code == 401 || response.code == 403
    raise e
  end

  version_info = LogStash::Json.load(response.body)
  return false if version_info['version'].nil?

  version = ::Gem::Version.new(version_info["version"]['number'])
  return false if version < ::Gem::Version.new('6.0.0')

  if VERSION_6_TO_7.satisfied_by?(version)
    return valid_tagline?(version_info)
  elsif VERSION_7_TO_7_14.satisfied_by?(version)
    build_flavor = version_info["version"]['build_flavor']
    return false if build_flavor.nil? || build_flavor != 'default' || !valid_tagline?(version_info)
  else
    # case >= 7.14
    lower_headers = response.headers.transform_keys {|key| key.to_s.downcase }
    product_header = lower_headers['x-elastic-product']
    return false if product_header != 'Elasticsearch'
  end
  return true
rescue => e
  logger.error("Unable to retrieve Elasticsearch version", url: url.sanitized.to_s, exception: e.class, message: e.message)
  false
end

#empty_url_meta ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 389

def empty_url_meta
  {
    :in_use => 0,
    :state => :unknown
  }
end

#get_connection ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 435

def get_connection
  @state_mutex.synchronize do
    # The goal here is to pick a random connection from the least-in-use connections
    # We want some randomness so that we don't hit the same node over and over, but
    # we also want more 'fair' behavior in the event of high concurrency
    eligible_set = nil
    lowest_value_seen = nil
    @url_info.each do |url,meta|
      meta_in_use = meta[:in_use]
      next if meta[:state] == :dead

      if lowest_value_seen.nil? || meta_in_use < lowest_value_seen
        lowest_value_seen = meta_in_use
        eligible_set = [[url, meta]]
      elsif lowest_value_seen == meta_in_use
        eligible_set << [url, meta]
      end
    end

    return nil if eligible_set.nil?

    pick, pick_meta = eligible_set.sample
    pick_meta[:in_use] += 1

    [pick, pick_meta]
  end
end

#get_es_version(url) ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 470

def get_es_version(url)
  request = perform_request_to_url(url, :get, ROOT_URI_PATH)
  LogStash::Json.load(request.body)["version"]["number"] # e.g. "7.10.0"
end

#get_license(url) ⇒ Hash

Retrieve ES node license information

Parameters:

  • url (LogStash::Util::SafeURI) —

    ES node URL

Returns:

  • (Hash) —

    deserialized license document or empty Hash upon any error



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 225

def get_license(url)
  response = perform_request_to_url(url, :get, LICENSE_PATH)
  LogStash::Json.load(response.body)
rescue => e
  logger.error("Unable to get license information", url: url.sanitized.to_s, exception: e.class, message: e.message)
  {}
end

#health_check_request(url) ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 233

def health_check_request(url)
  logger.debug("Running health check to see if an ES connection is working", url: url.sanitized.to_s, path: @healthcheck_path)
  perform_request_to_url(url, :head, @healthcheck_path)
end

#healthcheck!(register_phase = true) ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 238

def healthcheck!(register_phase = true)
  # Try to keep locking granularity low such that we don't affect IO...
  @state_mutex.synchronize { @url_info.select {|url,meta| meta[:state] != :alive } }.each do |url,meta|
    begin
      health_check_request(url)

      # when called from resurrectionist skip the product check done during register phase
      if register_phase
        if !elasticsearch?(url)
          raise LogStash::ConfigurationError, "Could not connect to a compatible version of Elasticsearch"
        end
      end
      # If no exception was raised it must have succeeded!
      logger.warn("Restored connection to ES instance", url: url.sanitized.to_s)
      # We reconnected to this node, check its ES version
      es_version = get_es_version(url)
      @state_mutex.synchronize do
        meta[:version] = es_version
        set_last_es_version(es_version, url)

        alive = @license_checker.appropriate_license?(self, url)
        meta[:state] = alive ? :alive : :dead
      end
    rescue HostUnreachableError, BadResponseCodeError => e
      logger.warn("Attempted to resurrect connection to dead ES instance, but got an error", url: url.sanitized.to_s, exception: e.class, message: e.message)
    end
  end
end

#in_use_connections ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 115

def in_use_connections
  @state_mutex.synchronize { @url_info.values.select {|v| v[:in_use] > 0 } }
end

#last_es_version ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 475

def last_es_version
  @last_es_version.get
end

#major_version(version_string) ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 186

def major_version(version_string)
  version_string.split('.').first.to_i
end

#mark_dead(url, error) ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 415

def mark_dead(url, error)
  @state_mutex.synchronize do
    meta = @url_info[url]
    # In case a sniff happened removing the metadata just before there's nothing to mark
    # This is an extreme edge case, but it can happen!
    return unless meta
    logger.warn("Marking url as dead. Last error: [#{error.class}] #{error.message}",
                :url => url, :error_message => error.message, :error_class => error.class.name)
    meta[:state] = :dead
    meta[:last_error] = error
    meta[:last_errored_at] = Time.now
  end
end

#maximum_seen_major_version ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 479

def maximum_seen_major_version
  @state_mutex.synchronize { @maximum_seen_major_version }
end

#normalize_url(uri) ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 331

def normalize_url(uri)
  u = @url_normalizer.call(uri)
  if !u.is_a?(::LogStash::Util::SafeURI)
    raise "URL Normalizer returned a '#{u.class}' rather than a SafeURI! This shouldn't happen!"
  end
  u
end

#perform_request(method, path, params = {}, body = nil) ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 311

def perform_request(method, path, params={}, body=nil)
  with_connection do |url, url_meta|
    resp = perform_request_to_url(url, method, path, params, body)
    [url, url_meta, resp]
  end
end

#perform_request_to_url(url, method, path, params = {}, body = nil) ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 325

def perform_request_to_url(url, method, path, params={}, body=nil)
  res = @adapter.perform_request(url, method, path, params, body)
rescue *@adapter.host_unreachable_exceptions => e
  raise HostUnreachableError.new(e, url), "Could not reach host #{e.class}: #{e.message}"
end

#remove_url(url) ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 385

def remove_url(url)
  @url_info.delete(url)
end

#resurrectionist_alive? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 307

def resurrectionist_alive?
  @resurrectionist ? @resurrectionist.alive? : nil
end

#return_connection(url) ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 463

def return_connection(url)
  @state_mutex.synchronize do
    info = @url_info[url]
    info[:in_use] -= 1 if info # Guard against the condition where the connection has already been deleted
  end
end

#size ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 377

def size
  @state_mutex.synchronize { @url_info.size }
end

#sniff(nodes) ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 190

def sniff(nodes)
  nodes.map do |id,info|
    # Skip master-only nodes
    next if info["roles"] && info["roles"] == ["master"]
    address_str_to_uri(info["http"]["publish_address"]) if info["http"]
  end.compact
end

#sniff! ⇒ Object

Sniffs the cluster then updates the internal URLs



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 166

def sniff!
  update_urls(check_sniff)
end

#sniffer_alive? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 210

def sniffer_alive?
  @sniffer ? @sniffer.alive? : nil
end

#start ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 82

def start
  update_initial_urls
  start_resurrectionist
  start_sniffer if @sniffing
end

#start_resurrectionist ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 214

def start_resurrectionist
  @resurrectionist = Thread.new do
    until_stopped("resurrection", @resurrect_delay) do
      healthcheck!(false)
    end
  end
end

#start_sniffer ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 152

def start_sniffer
  @sniffer = Thread.new do
    until_stopped("sniffing", sniffer_delay) do
      begin
        sniff!
      rescue NoConnectionAvailableError => e
        @state_mutex.synchronize { # Synchronize around @url_info
          logger.warn("Elasticsearch output attempted to sniff for new connections but cannot. No living connections are detected. Pool contains the following current URLs", :url_info => @url_info) }
      end
    end
  end
end

#stop_resurrectionist ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 303

def stop_resurrectionist
  @resurrectionist.join if @resurrectionist
end

#stop_sniffer ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 206

def stop_sniffer
  @sniffer.join if @sniffer
end

#until_stopped(task_name, delay) ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 131

def until_stopped(task_name, delay)
  last_done = Time.now
  until @state_mutex.synchronize { @stopping }
    begin
      now = Time.now
      if (now - last_done) >= delay
        last_done = now
        yield
      end
      sleep 1
    rescue => e
      logger.warn(
        "Error while performing #{task_name}",
        :error_message => e.message,
        :class => e.class.name,
        :backtrace => e.backtrace
        )
    end
  end
end

#update_initial_urls ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 88

def update_initial_urls
  update_urls(@initial_urls)
end

#update_urls(new_urls) ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 339

def update_urls(new_urls)
  return if new_urls.nil?
  
  # Normalize URLs
  new_urls = new_urls.map(&method(:normalize_url))

  # Used for logging nicely
  state_changes = {:removed => [], :added => []}
  @state_mutex.synchronize do
    # Add new connections
    new_urls.each do |url|
      # URI objects don't have real hash equality! So, since this isn't perf sensitive we do a linear scan
      unless @url_info.keys.include?(url)
        state_changes[:added] << url
        add_url(url)
      end
    end

    # Delete connections not in the new list
    @url_info.each do |url,_|
      unless new_urls.include?(url)
        state_changes[:removed] << url
        remove_url(url)
      end
    end
  end

  if state_changes[:removed].size > 0 || state_changes[:added].size > 0
    logger.info? && logger.info("Elasticsearch pool URLs updated", :changes => state_changes)
  end
  
  # Run an inline healthcheck anytime URLs are updated
  # This guarantees that during startup / post-startup
  # sniffing we don't have idle periods waiting for the
  # periodic sniffer to allow new hosts to come online
  healthcheck! 
end

#url_info ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 123

def url_info
  @state_mutex.synchronize { @url_info }
end

#url_meta(url) ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 429

def url_meta(url)
  @state_mutex.synchronize do
    @url_info[url]
  end
end

#urls ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 127

def urls
  url_info.keys
end

#valid_tagline?(version_info) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 298

def valid_tagline?(version_info)
  tagline = version_info['tagline']
  tagline == "You Know, for Search"
end

#wait_for_in_use_connections ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 108

def wait_for_in_use_connections
  until in_use_connections.empty?
    logger.info "Blocked on shutdown to in use connections #{@state_mutex.synchronize {@url_info}}"
    sleep 1
  end
end

#with_connection ⇒ Object 



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# File 'lib/logstash/outputs/elasticsearch/http_client/pool.rb', line 396

def with_connection
  url, url_meta = get_connection

  # Custom error class used here so that users may retry attempts if they receive this error
  # should they choose to
  raise NoConnectionAvailableError, "No Available connections" unless url
  yield url, url_meta
rescue HostUnreachableError => e
  # Mark the connection as dead here since this is likely not transient
  mark_dead(url, e)
  raise e
rescue BadResponseCodeError => e
  # These aren't discarded from the pool because these are often very transient
  # errors
  raise e
ensure
  return_connection(url)
end