Module: ZipkinQuery::Client

Defined in:
lib/zipkin-query.rb

Constant Summary collapse

NODE_PATH =

The node location in zookeeper that stores the cassandra location

"/twitter/service/zipkin/query"

Class Method Summary collapse

Class Method Details

.get_query_service(zk_host, zk_port, opts = {}) ⇒ Object 



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# File 'lib/zipkin-query.rb', line 75

def self.get_query_service(zk_host, zk_port, opts={})
  # Takes either:
  # - ZooKeeper config options that map to a Zipkin Query server set OR
  # - Direct host/port of a Query daemon

  if opts[:skip_zookeeper]
    return [ opts[:zipkin_query_host], opts[:zipkin_query_port] ]
  end

  node_path = opts[:node_path] || NODE_PATH

  # TODO: throw error if it fails
  zk = Zookeeper.new("#{zk_host}:#{zk_port}")

  begin
    # TODO: handle errors here
    children = zk.get_children(:path => node_path)
    node_key = children[:children][0]

    # TODO: throw errors
    node = zk.get(:path => "#{node_path}/#{node_key}")
  ensure
    zk.close() if zk
  end

  # Deserialize the result
  d = Thrift::Deserializer.new
  si = d.deserialize(Twitter::Thrift::ServiceInstance.new, node[:data])

  # Return the host and port
  [si.serviceEndpoint.host, si.serviceEndpoint.port]
end

.with_transport(opts = {}) ⇒ Object 



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# File 'lib/zipkin-query.rb', line 29

def self.with_transport(opts = {})
  # Open a connection to a thrift server, do something, and close the connection

  begin

    if opts[:use_local_server]
      # If we're running local (development mode) return a set value
      host = "localhost"
      port = 9149

      # Create the connection to the local b3 query_daemon which uses different
      # transport mechanism
      socket = Thrift::Socket.new(host, port)
      transport = Thrift::BufferedTransport.new(socket)
    else
      # Get the host and port of the location of the query service from zookeeper
      zk_host = opts[:zk_host] || "localhost"
      zk_port = opts[:zk_port] || 2181

      host, port = Client::get_query_service(zk_host, zk_port, opts)

      # Create the connection to the b3 query_daemon
      socket = Thrift::Socket.new(host, port)
      buffered_tp = Thrift::BufferedTransport.new(socket)
      transport = Thrift::FramedTransport.new(buffered_tp)
    end

    protocol = Thrift::BinaryProtocol.new(transport)
    client = ThriftClient.new(Zipkin::ZipkinQuery::Client, host + ':' + port.to_s, :retries => 0, :timeout => 60)

    # set up tracing for the client we use to talk to the query daemon
    client_id = FinagleThrift::ClientId.new(:name => "zipkin.prod")
    FinagleThrift.enable_tracing!(client, client_id, "zipkin")

    begin
      transport.open
      yield(client)
    ensure
      transport.close
    end
  rescue ZookeeperExceptions::ZookeeperException::ConnectionClosed => ze
    "Could not connect to zookeeper at #{opts[:zk_host]}:#{opts[:zk_port]}"
  end

end