Class: Scalyr::Common::Client::ClientSession

Inherits:
Object
  • Object
show all
Defined in:
lib/scalyr/common/client.rb

Overview

Encapsulates the connection between the agent and the Scalyr server, thus shielding the implementation (which may create a new connection for every post or use a persistent connection)

Instance Method Summary collapse

Constructor Details

#initialize(logger, add_events_uri, compression_type, compression_level, ssl_verify_peer, ssl_ca_bundle_path, append_builtin_cert, record_stats_for_status, flush_quantile_estimates_on_status_send, connect_timeout, socket_timeout, request_timeout, pool_max, pool_max_per_route) ⇒ ClientSession

Returns a new instance of ClientSession.



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# File 'lib/scalyr/common/client.rb', line 59

def initialize(logger, add_events_uri, compression_type, compression_level,
               ssl_verify_peer, ssl_ca_bundle_path, append_builtin_cert,
               record_stats_for_status, flush_quantile_estimates_on_status_send,
               connect_timeout, socket_timeout, request_timeout, pool_max, pool_max_per_route)
  @logger = logger
  @add_events_uri = add_events_uri  # typically /addEvents
  @compression_type = compression_type
  @compression_level = compression_level
  @ssl_verify_peer = ssl_verify_peer
  @ssl_ca_bundle_path = ssl_ca_bundle_path
  @append_builtin_cert = append_builtin_cert
  @record_stats_for_status = record_stats_for_status
  @flush_quantile_estimates_on_status_send = flush_quantile_estimates_on_status_send
  @connect_timeout = connect_timeout
  @socket_timeout = socket_timeout
  @request_timeout = request_timeout
  @pool_max = pool_max
  @pool_max_per_route = pool_max_per_route

  # A cert to use by default to avoid issues caused by the OpenSSL library not validating certs according to standard
  @cert_string = CA_CERT_STRING

  # Request statistics are accumulated across multiple threads and must be accessed through a mutex
  @stats_lock = Mutex.new
  @latency_stats = get_new_latency_stats
  @stats = {
      :total_requests_sent => 0, # The total number of RPC requests sent.
      :total_requests_failed => 0, # The total number of RPC requests that failed.
      :total_request_bytes_sent => 0, # The total number of bytes sent over the network.
      :total_compressed_request_bytes_sent => 0,  # The total number of compressed bytes sent over the network
      :total_response_bytes_received => 0,  # The total number of bytes received.
      :total_request_latency_secs => 0, #  The total number of secs spent waiting for a responses (so average latency
      # can be calculated by dividing this number by @total_requests_sent).
      # This includes connection establishment time.
      :total_serialization_duration_secs => 0, # The total duration (in seconds) it took to serialize (JSON dumos) all the request bodies.
      # You can calculate avg compression duration by diving this value with total_requests_sent
      :total_compression_duration_secs => 0, # The total duration (in seconds) it took to compress all the request bodies.
      # You can calculate avg compression duration by diving this value with total_requests_sent
      :compression_type => @compression_type,
      :compression_level => @compression_level,
  }
end

Instance Method Details

#client ⇒ Object 



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# File 'lib/scalyr/common/client.rb', line 164

def client
  @client ||= Manticore::Client.new(client_config)
end

#client_config ⇒ Object

def initialize



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# File 'lib/scalyr/common/client.rb', line 102

def client_config
  # TODO: Eventually expose some more of these as config options, though nothing here really needs tuning normally
  # besides SSL
  c = {
    connect_timeout: @connect_timeout,
    socket_timeout: @socket_timeout,
    request_timeout: @request_timeout,
    follow_redirects: true,
    automatic_retries: 1,
    retry_non_idempotent: false,
    check_connection_timeout: 200,
    pool_max: @pool_max,
    pool_max_per_route: @pool_max_per_route,
    cookies: true,
    keepalive: true,
    ssl: {}
  }

  # verify peers to prevent potential MITM attacks
  if @ssl_verify_peer
    c[:ssl][:verify] = :strict

    if not @append_builtin_cert
      # System CA bundle is used, no need to copy it over and append our bundled CA cert
      @logger.info("Using CA bundle from #{@ssl_ca_bundle_path} to validate the server side certificate")
      @ca_cert_path = @ssl_ca_bundle_path

      if not File.file?(@ssl_ca_bundle_path)
        # TODO: For now we don't throw to keep code backward compatible. In the future in case
        # file doesn't exist, we should throw instead of write empty CA cert file and pass that 
        # to Manticore which will eventually fail and throw on cert validation
        #raise Errno::ENOENT.new("ssl_ca_bundle_path config option to an invalid file path which doesn't exist - #{@ssl_ca_bundle_path}")
        @ca_cert = Tempfile.new("ca_cert")
        @ca_cert_path = @ca_cert.path
      end
    else
      @ca_cert = Tempfile.new("ca_cert")

      if File.file?(@ssl_ca_bundle_path)
        @ca_cert.write(File.read(@ssl_ca_bundle_path))
        @ca_cert.flush
      else
        @logger.warn("CA bundle (#{@ssl_ca_bundle_path}) doesn't exist, using only bundled CA certificates")
      end

      open(@ca_cert.path, "a") do |f|
        f.puts @cert_string
      end

      @ca_cert.flush
      @ca_cert_path = @ca_cert.path

      @logger.info("Using CA bundle from #{@ssl_ca_bundle_path} combined with bundled certificates to validate the server side certificate (#{@ca_cert_path})")
    end
    c[:ssl][:ca_file] = @ca_cert_path
  else
    c[:ssl][:verify] = :disable
  end

  c
end

#close ⇒ Object 



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# File 'lib/scalyr/common/client.rb', line 261

def close
  @client.close if @client
end

#get_new_latency_stats ⇒ Object

Convenience method to create a fresh quantile estimator



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# File 'lib/scalyr/common/client.rb', line 169

def get_new_latency_stats
  return {
    # The total number of HTTP connections successfully created.
    :serialization_duration_secs => Quantile::Estimator.new, # The duration (in seconds) it took to serialize (JSON dumos) all the request bodies.
    :compression_duration_secs => Quantile::Estimator.new, # The duration (in seconds) it took to compress all the request bodies.
    :request_latency_secs => Quantile::Estimator.new, #  Secs spent waiting for a responses. This includes connection establishment time.
    :bytes_sent => Quantile::Estimator.new  # The number of bytes sent over the network. Batch size with a bit more overhead.
  }
end

#get_stats ⇒ Object

Get a clone of current statistics hash and calculate percentiles



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# File 'lib/scalyr/common/client.rb', line 180

def get_stats
  @stats_lock.synchronize do
    current_stats = @stats.clone

    current_stats[:request_latency_p50] = @latency_stats[:request_latency_secs].query(0.5)
    current_stats[:request_latency_p90] = @latency_stats[:request_latency_secs].query(0.9)
    current_stats[:request_latency_p99] = @latency_stats[:request_latency_secs].query(0.99)
    current_stats[:serialization_duration_secs_p50] = @latency_stats[:serialization_duration_secs].query(0.5)
    current_stats[:serialization_duration_secs_p90] = @latency_stats[:serialization_duration_secs].query(0.9)
    current_stats[:serialization_duration_secs_p99] = @latency_stats[:serialization_duration_secs].query(0.99)
    current_stats[:compression_duration_secs_p50] = @latency_stats[:compression_duration_secs].query(0.5)
    current_stats[:compression_duration_secs_p90] = @latency_stats[:compression_duration_secs].query(0.9)
    current_stats[:compression_duration_secs_p99] = @latency_stats[:compression_duration_secs].query(0.99)
    current_stats[:bytes_sent_p50] = @latency_stats[:bytes_sent].query(0.5)
    current_stats[:bytes_sent_p90] = @latency_stats[:bytes_sent].query(0.9)
    current_stats[:bytes_sent_p99] = @latency_stats[:bytes_sent].query(0.99)

    if @flush_quantile_estimates_on_status_send
      @logger.debug "Recreating / reseting quantile estimator classes for plugin metrics"
      @latency_stats = get_new_latency_stats
    end
    current_stats
  end
end

#post_add_events(body, is_status, body_serialization_duration = 0) ⇒ Object

Upload data to Scalyr. Assumes that the body size complies with Scalyr limits



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# File 'lib/scalyr/common/client.rb', line 216

def post_add_events(body, is_status, body_serialization_duration = 0)
  post_body, post_headers, compression_duration = prepare_post_object @add_events_uri.path, body
  fail_count = 1  # putative assume failure
  start_time = Time.now
  uncompressed_bytes_sent = 0
  compressed_bytes_sent = 0
  bytes_received = 0
  begin
    response = client.send(:post, @add_events_uri, body: post_body, headers: post_headers)
    handle_response(response)

    fail_count -= 1  # success means we negate the putative failure
    uncompressed_bytes_sent = (body.bytesize + @add_events_uri.path.bytesize)
    compressed_bytes_sent = (post_body.bytesize + @add_events_uri.path.bytesize)
    bytes_received = response.body.bytesize  # echee: double check
      # echee TODO add more statistics

  rescue Manticore::ManticoreException => e
    # The underlying persistent-connection library automatically retries when there are network-related errors.
    # Eventually, it will give up and raise this generic error, at which time, we convert it to a ClientError
    raise ClientError.new(e.message, @add_events_uri, e.class.name)

  ensure
    if @record_stats_for_status or !is_status
      @stats_lock.synchronize do
        @stats[:total_requests_sent] += 1
        @stats[:total_requests_failed] += fail_count
        @stats[:total_request_bytes_sent] += uncompressed_bytes_sent
        @stats[:total_compressed_request_bytes_sent] += compressed_bytes_sent
        @stats[:total_response_bytes_received] += bytes_received
        @stats[:total_serialization_duration_secs] += body_serialization_duration
        @stats[:total_compression_duration_secs] += compression_duration
        end_time = Time.now
        @stats[:total_request_latency_secs] += (end_time - start_time)
        @latency_stats[:request_latency_secs].observe(end_time - start_time)
        @latency_stats[:serialization_duration_secs].observe(body_serialization_duration)
        @latency_stats[:compression_duration_secs].observe(compression_duration)
        @latency_stats[:bytes_sent].observe(uncompressed_bytes_sent)
      end
    end
  end
end

#send_ping(body) ⇒ Object

Send “ping” request to the API. This is mostly used to test the connecting with Scalyr API and verify that the API key is valid.



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# File 'lib/scalyr/common/client.rb', line 207

def send_ping(body)
  post_body, post_headers, compression_duration = prepare_post_object @add_events_uri.path, body
  response = client.send(:post, @add_events_uri, body: post_body, headers: post_headers)
  handle_response(response)

  response
end