data_transformer

This program takes JSON records from AWS SQS Queue, masks device_id and ip fields, and writes user login data into PostgreSQL database.

1. In order to create and fill the AWS SQS Queue, stand up PostgreSQL database please follow steps from README_input_output.md file to execute docker-compose.yml .

2. Reading data from AWS SQS Queue, transforming and writing it into PostgreSQL database could be accomplished by creating and running data_transformer-1.0-SNAPSHOT.jar:

   1. Install JDK (version 17 or later): https://docs.oracle.com/en/java/javase/18/install/overview-jdk-installation.html#GUID-8677A77F-231A-40F7-98B9-1FD0B48C346A

   2. Install maven (3.8.4 or later): https://maven.apache.org/install.html

   3. In terminal, switch to the data_transformer directory:

      cd PATH_TO_DIRECTORY/data_manipulation/data_transformer
      

   4. Create .jar file using maven (target directory would appear in data_transformer):

      mvn package
      

   5. Execute data_transformer-1.0-SNAPSHOT.jar (located in PATH_TO_DIRECTORY/data_manipulation/data_transformer/target)

      java -jar target/data_transformer-1.0-SNAPSHOT.jar
      

      The terminal output should be like this:

      Database opened successfully.
      Data transferred successfully.
      

Here is the list of improvements that should be implemented in the future:

1. Rewrite the logic of the program in a way that it can process a generalized message with an arbitrary JSON message body.
2. Add an event listener that would retrieve messages from an AWS Queue, if new messages were added after the initial scan of the Queue.
3. Implement DTO (Data Transfer Object) pattern.
4. Adding additional precautions for securing a PostgreSQL database. I added parameterized statements to prevent SQL injection and masked required fields. However, I think that the user_id field should be also masked.