|
1
|
|
|
""" |
|
2
|
|
|
A worker handles the connection to both, Kafka and InfluxDB and handles encoding in between. |
|
3
|
|
|
""" |
|
4
|
|
|
import logging |
|
5
|
|
|
import time |
|
6
|
|
|
from requests.exceptions import ConnectionError |
|
7
|
|
|
from influxdb.exceptions import InfluxDBServerError, InfluxDBClientError |
|
8
|
|
|
from kafka_influxdb.encoder.errors import EncoderError |
|
9
|
|
|
|
|
10
|
|
|
|
|
11
|
|
|
class Worker(object): |
|
12
|
|
|
""" |
|
13
|
|
|
Implementation of worker class that handles Kafka and InfluxDB |
|
14
|
|
|
connections and manages message encoding. |
|
15
|
|
|
""" |
|
16
|
|
|
|
|
17
|
|
|
def __init__(self, reader, encoder, writer, config): |
|
18
|
|
|
""" |
|
19
|
|
|
Setup |
|
20
|
|
|
""" |
|
21
|
|
|
self.config = config |
|
22
|
|
|
self.reader = reader |
|
23
|
|
|
self.encoder = encoder |
|
24
|
|
|
self.writer = writer |
|
25
|
|
|
self.buffer = [] |
|
26
|
|
|
|
|
27
|
|
|
# Field for time measurement |
|
28
|
|
|
self.start_time = None |
|
29
|
|
|
self.last_flush_time = None |
|
30
|
|
|
self.db_create_delay = 1 |
|
31
|
|
|
|
|
32
|
|
|
def consume(self): |
|
33
|
|
|
""" |
|
34
|
|
|
Run loop. Consume messages from reader, convert it to the |
|
35
|
|
|
output format using encoder and write to output with writer |
|
36
|
|
|
""" |
|
37
|
|
|
self.init_database() |
|
38
|
|
|
|
|
39
|
|
|
logging.info("Listening for messages on Kafka topic %s...", |
|
40
|
|
|
self.config.kafka_topic) |
|
41
|
|
|
self.start_time = self.last_flush_time = time.time() |
|
42
|
|
|
while True: |
|
43
|
|
|
try: |
|
44
|
|
|
for index, raw_message in enumerate(self.reader.read(), 1): |
|
45
|
|
|
if raw_message: |
|
46
|
|
|
self.buffer.extend(self.encoder.encode(raw_message)) |
|
47
|
|
|
if index % self.config.buffer_size == 0: |
|
48
|
|
|
self.flush() |
|
49
|
|
|
elif (self.config.buffer_timeout and len(self.buffer) > 0 and |
|
50
|
|
|
(time.time() - self.last_flush_time) >= self.config.buffer_timeout): |
|
51
|
|
|
logging.debug("Buffer timeout %ss. Flushing remaining %s messages from buffer.", |
|
52
|
|
|
self.config.buffer_timeout, len(self.buffer)) |
|
53
|
|
|
self.flush() |
|
54
|
|
|
except EncoderError: |
|
55
|
|
|
logging.error("Encoder error. Trying to reconnect to %s:%s", |
|
56
|
|
|
self.config.kafka_host, self.config.kafka_port) |
|
57
|
|
|
logging.debug("Sleeping for %d ms before reconnect", |
|
58
|
|
|
self.config.reconnect_wait_time_ms) |
|
59
|
|
|
time.sleep(self.config.reconnect_wait_time_ms / 1000.0) |
|
60
|
|
|
except KeyboardInterrupt: |
|
61
|
|
|
logging.info( |
|
62
|
|
|
"Shutdown. Flushing remaining messages from buffer.") |
|
63
|
|
|
self.flush() |
|
64
|
|
|
break |
|
65
|
|
|
except SystemExit: |
|
66
|
|
|
break |
|
67
|
|
|
|
|
68
|
|
|
def init_database(self): |
|
69
|
|
|
""" |
|
70
|
|
|
Initialize the InfluxDB database if it is not already there |
|
71
|
|
|
""" |
|
72
|
|
|
try: |
|
73
|
|
|
logging.info("Creating InfluxDB database if not exists: %s", |
|
74
|
|
|
self.config.influxdb_dbname) |
|
75
|
|
|
self.writer.create_database(self.config.influxdb_dbname) |
|
76
|
|
|
except ConnectionError as error: |
|
77
|
|
|
logging.error( |
|
78
|
|
|
"Connection error while trying to create InfluxDB database: %s. Waiting for retry...", error) |
|
79
|
|
|
time.sleep(self.db_create_delay) |
|
80
|
|
|
self.init_database() |
|
81
|
|
|
except (InfluxDBServerError, InfluxDBClientError) as error: |
|
82
|
|
|
logging.warning( |
|
83
|
|
|
"Could not create InfluxDB database. Assuming it already exists: %s", error) |
|
84
|
|
|
|
|
85
|
|
|
def flush(self): |
|
86
|
|
|
""" |
|
87
|
|
|
Flush values with writer |
|
88
|
|
|
""" |
|
89
|
|
|
if not self.buffer: |
|
90
|
|
|
# Don't do anything when buffer empty |
|
91
|
|
|
return |
|
92
|
|
|
try: |
|
93
|
|
|
self.last_flush_time = time.time() |
|
94
|
|
|
self.writer.write(self.buffer) |
|
95
|
|
|
if self.config.statistics: |
|
96
|
|
|
self.show_statistics() |
|
97
|
|
|
except (InfluxDBServerError, InfluxDBClientError) as influx_error: |
|
98
|
|
|
logging.error("Error while writing to InfluxDB: %s", influx_error) |
|
99
|
|
|
finally: |
|
100
|
|
|
self.buffer = [] |
|
101
|
|
|
|
|
102
|
|
|
def show_statistics(self): |
|
103
|
|
|
""" |
|
104
|
|
|
Print performance metrics to stdout |
|
105
|
|
|
""" |
|
106
|
|
|
delta = time.time() - self.start_time |
|
107
|
|
|
msg_per_sec = self.config.buffer_size / delta |
|
108
|
|
|
print("Flushing output buffer. {0:.2f} messages/s".format(msg_per_sec)) |
|
109
|
|
|
# Reset timer |
|
110
|
|
|
self.start_time = time.time() |
|
111
|
|
|
|
|
112
|
|
|
def set_reader(self, reader): |
|
113
|
|
|
self.reader = reader |
|
114
|
|
|
|
|
115
|
|
|
def get_reader(self): |
|
116
|
|
|
return self.reader |
|
117
|
|
|
|
|
118
|
|
|
def set_writer(self, writer): |
|
119
|
|
|
self.writer = writer |
|
120
|
|
|
|
|
121
|
|
|
def get_writer(self): |
|
122
|
|
|
return self.writer |
|
123
|
|
|
|
|
124
|
|
|
def get_buffer(self): |
|
125
|
|
|
return self.buffer |
|
126
|
|
|
|
|
127
|
|
|
def get_config(self): |
|
128
|
|
|
return self.config |
|
129
|
|
|
|
mre /
kafka-influxdb
