1시간마다 모든 공지를 불러 {"TITLE": "제목", "DATE": "올린 날", "LINK": "http 주소", "WRITER": "글쓴이"}를 json 형태로 저장한다.

이 json 파일이나 새로운 공지가 있으면 기존 json과 비교해서 새로운 데이터를 Consumer로 보내고, Consumer는 새로운 데이터를 받으면, Slack API를 이용해, "#아주대" 채널에 공지를 올려준다.

마지막 파싱 시간도 기록해 종료 후 다시 불러도 1시간이 지나지 않으면 파싱하지 않는다.

결과)
Last parsing: 1972-12-01 07:00:00
Trying to parse new posts...
Sending a new post...: 12179
...

Last parsing: 2020-12-04 19:11:42.839219
Trying to parse new posts...
No new posts yet...
Resting 1 hour...
...
Last parsing: 2020-12-06 11:55:35.386262
Wait for 3494 seconds to sync new posts.

this producer reads all messages from "#general", in every 5 seconds (this will cause ratelimited)

and if messages contain a word "bug", it will automatically sends "USERNAME" and "MESSAGE" to Kafka consumer.

And the consumer will leave a message in "#kafka" channel saying "USER found a bug ..."

modified version of an official confluent example.

topic id: SLACK-KAFKA

this will automatically posts a message to your specified channel in Slack, if someone leaves a bad review

(for now, you can just send a json data to test from CLI, see the README file.)

Create a topic named "twitter-tweets" with below command,

kafka-topics --zookeeper localhost:2181 --create --topic twitter-tweets --partitions 6 --replication-factor 1

and run this application.

Next we will build kafka producer to send tweets to kafka.

https://github.com/twitter/hbc

In this example, we read "first-topic", in partition 0, from offset 5 until offset becomes 10.

[main] INFO csw.kafka.study.lesson2.ConsumerDemoAssignSeek - Key: null, Value: five
[main] INFO csw.kafka.study.lesson2.ConsumerDemoAssignSeek - Partition:  0, Offset: 5
[main] INFO csw.kafka.study.lesson2.ConsumerDemoAssignSeek - Key: null, Value: Hello World!
[main] INFO csw.kafka.study.lesson2.ConsumerDemoAssignSeek - Partition:  0, Offset: 6
[main] INFO csw.kafka.study.lesson2.ConsumerDemoAssignSeek - Key: id_1, Value: Hello 1
[main] INFO csw.kafka.study.lesson2.ConsumerDemoAssignSeek - Partition:  0, Offset: 7
[main] INFO csw.kafka.study.lesson2.ConsumerDemoAssignSeek - Key: id_3, Value: Hello 3
[main] INFO csw.kafka.study.lesson2.ConsumerDemoAssignSeek - Partition:  0, Offset: 8
[main] INFO csw.kafka.study.lesson2.ConsumerDemoAssignSeek - Key: key_1, Value: world
[main] INFO csw.kafka.study.lesson2.ConsumerDemoAssignSeek - Partition:  0, Offset: 9
[main] INFO csw.kafka.study.lesson2.ConsumerDemoAssignSeek - Exiting...

+ python config updates for consumers

+ README updates

it reads all datas in three partitions from a topic named "first-topic".

I sent datas in String, like "hello world".

At line 34, we added key parameter.

Whenever we use same key when sending a data, same key always use same partition.

i.e)
i = 0, key = "truck_1" -> partition_0
i = 1, key = "truck_1" -> partition_0
...

for example,

whenever we send a data, this callback function will execute.

새 메타데이터
Topic: first-topic
Partition: 2
Offset: 13
Timestamp: 1606555474565

Send "Hello World!" string to topic named "first-topic".

Producer sends a data to Consumer asynchronous, so we have to flush to see results right away.

Execute below command to see "Hello World!"

>> kafka-console-consumer --bootstrap-server localhost:9092 --topic first-topic --group group-one