Send database table (rows filtered by criteria) to Kafka

Every second by the scheduler in one transaction

1. Lock rows in database table by criteria (to concurrency with another instance of microservices)
2. Select rows
3. Convert rows to messages
4. Send messages to Kafka
5. Update selected rows in database table
6. Unlock rows

Used Simple Moving Average (SMA) for adjust the amount of rows selected from database

Core in GetTradeRsProcessor.java

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• Execute postgresql.sql instance to create database table
• Run DataGenerator.java to fill table by test data before execution
• Build mvn clean install
• Run 1st instance ./run.sh
• Run 2nd instance ./run2.sh
• To monitoring process, execute

select count(*) from sample.trade t where t.sent = true;

Test data like this:

INSERT INTO sample.trade (id, client_id, exchange, ticker, price, amount, date, status, sent) 
VALUES (13784, 29321, 'NASDAQ', 'AAPL', 246.31, 28, '2020-09-25 17:22:28.931+00', 'COMPLETED', false);
INSERT INTO sample.trade (id, client_id, exchange, ticker, price, amount, date, status, sent) 
VALUES (13785, 43001, 'NYSE', 'DIS', 226.14, 2, '2020-09-25 17:22:28.931+00', 'CANCELLED', false);
INSERT INTO sample.trade (id, client_id, exchange, ticker, price, amount, date, status, sent) 
VALUES (13786, 14295, 'NASDAQ', 'MSFT', 290.8, 97, '2020-09-25 17:22:28.931+00', 'CANCELLED', false);

• http://localhost:8081/actuator/health
• http://localhost:8081/actuator/info

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1. Run Zookeeper bin/zookeeper-server-start.sh config/zookeeper.properties
2. Run Kafka bin/kafka-server-start.sh config/server.properties
3. See Topics bin/kafka-topics.sh --list --bootstrap-server localhost:9092