Class: KafkaETLBase::Base

Inherits:
Object
  • Object
show all
Defined in:
lib/kafka_etl_base/base.rb

Instance Method Summary collapse

Constructor Details

#initialize(zookeeper, kafka_brokers, kafka_topic, opts = {}) ⇒ Base

Returns a new instance of Base.



10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
 
# File 'lib/kafka_etl_base/base.rb', line 10

def initialize(zookeeper, kafka_brokers, kafka_topic, opts={})
  
  @num_threads = opts[:num_threads] ? opts[:num_threads] : 2 
  @max_fetch_bytes = opts[:max_fetch_bytes] ? opts[:max_fetch_bytes] : 5_000_000
  @min_fetch_bytes = opts[:min_fetch_bytes] ? opts[:min_fetch_bytes] : 0
  @kafka_client_id = opts[:kafka_client_id] ? opts[:kafka_client_id] : "my_consumer"
  @kafka_part_num = opts[:kafka_topic_part_num] ? opts[:kafka_topic_part_num] : 2
  
  @zookeeper = zookeeper
  @kafka_brokers = kafka_brokers
  @kafka_topic = kafka_topic
  
  $log = Logger.new(STDOUT) if $log.nil?

  $log.debug("zookeeper: #{@zookeeper}")
  $log.debug("kafka_brokers: #{@kafka_brokers}")
  $log.debug("kafka_topic: #{@kafka_topic}")
  $log.debug("kafka_client_id: #{@kafka_client_id}")
  
  @partition_shuffle = true
  
  @mutex = Mutex.new
  
  @total_procs = 0
end

Instance Method Details

#proccess_thread(zk, part_no) ⇒ Object 



107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
 
# File 'lib/kafka_etl_base/base.rb', line 107

def proccess_thread(zk, part_no)
  zk_part_node = "/part_offset_#{part_no}"
  
  num_cur_part_procs = 0
  
  if ! zk.exists?(zk_part_node)
    zk.create(zk_part_node, "0")
  end
  
  offset = nil
  begin
    value, stat = zk.get(zk_part_node)
    offset = value.to_i
    if offset == 0
      part_offset = :earliest_offset
      #part_offset = :latest_offset
    else
      part_offset = offset
    end
  rescue ZK::Exceptions::NoNode => e
    part_offset = :earliest_offset
    #part_offset = :latest_offset
  end
  $log.debug "part: #{part_no}, offset: #{part_offset}"
  
  cons = Poseidon::PartitionConsumer.consumer_for_partition(@kafka_client_id,
                                                            @kafka_brokers,
                                                            @kafka_topic,
                                                            part_no,
                                                            part_offset,
                                                            :max_wait_ms => 0,
                                                            :max_bytes => @max_fetch_bytes,
                                                            :min_bytes => @min_fetch_bytes
                                                           )
  begin
    num_cur_part_procs += process_messages(cons, part_no)
    
    next_offset = cons.next_offset
    last_offset = cons.highwater_mark
    $log.info "part: #{part_no}, next_offset: #{next_offset}, last_offset: #{last_offset},  proc: #{num_cur_part_procs}"
    @mutex.synchronize do
      @total_procs += num_cur_part_procs
    end
    # set next offset to zookeper
    zk.set(zk_part_node, next_offset.to_s) if next_offset >= offset
    return last_offset - next_offset
  rescue Poseidon::Connection::ConnectionFailedError
    $log.error "kafka connection failed"
    return 0
  rescue BackendError
    $log.debug "backend error"
    return 0
  ensure
    cons.close if ! cons.nil?
  end
rescue Poseidon::Errors::OffsetOutOfRange => e
  zk.set(zk_part_node, "0")
  $log.error e.inspect
  return 0
rescue Poseidon::Errors::NotLeaderForPartition, Poseidon::Errors::UnableToFetchMetadata => e
  $log.error e.inspect
  return 0
end

#process ⇒ Object 



36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
 
# File 'lib/kafka_etl_base/base.rb', line 36

def process()
  
  @total_procs = 0
  
  zk = ZK.new(@zookeeper)
  begin
    #zk.create("/", ignore: :node_exists)
    if zk.exists?("/stop_etl")
      $log.info("zk: /stop_etl exist.")
      $log.info("stop message processing.")
      return
    end
  ensure
    zk.close!
  end
  
  seq = [ * 0 ... @kafka_part_num ]
  seq.shuffle! if @partition_shuffle == true
  
  r = Parallel.each(seq, :in_threads => @num_threads) do |part_no|
    zk_th = nil
    begin
      zk_th = ZK.new(@zookeeper)
      zk_lock = "lock_hdfs_part_#{part_no}"
      locker = zk_th.locker(zk_lock)
      begin
        if locker.lock!
          remain = proccess_thread(zk_th, part_no)
        else
          $log.info("part: #{part_no} is already locked skip")
        end
      ensure
        begin
          locker.unlock!
        rescue => e
          $log.error(e.inspect)
          $log.error(e.backtrace)
        end
      end
    rescue ZK::Exceptions::ConnectionLoss => e
      $log.error(e.inspect)
      $log.error(e.backtrace)
    ensure
      begin
        zk_th.close! if ! zk_th.nil?
      rescue
      end
    end
  end
  $log.info "total procs: #{@total_procs}"
end

#process_messages(cons, part_no) ⇒ Object 



171
172
173
174
175
176
177
178
179
 
# File 'lib/kafka_etl_base/base.rb', line 171

def process_messages(cons, part_no)
  messages = cons.fetch
  messages.each do |m|
    key = m.key
    val = m.value
    puts "part: #{part_no}, key: #{key}, val: #{val}"
  end
  messages.size
end

#process_partition(part_no) ⇒ Object 



88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
 
# File 'lib/kafka_etl_base/base.rb', line 88

def process_partition(part_no)
  zk = ZK.new(@zookeeper)
  begin
    zk_lock = "lock_hdfs_part_#{part_no}"
    locker = zk.locker(zk_lock)
    begin
      if locker.lock!
        remain = proccess_thread(zk, part_no)
      else
        $log.info("part: #{part_no} is already locked skip")
      end
    ensure
      locker.unlock!
    end
  ensure
    zk.close
  end
end