Bank Application in Go with Gin, Docker and K8S

Technologies and concepts applied

• Go 1.22.3
  • golang-migrate
  • sqlc
• Gin
• PostgreSQL
• gRPC
• Rest API
• Protocol Buffers
• Postman
• Evans
• Table Plus
• Docker
• Kubernetes
• AWS / Azure

Database Design Tools and Management

Diagrams

Accounts Table

• id bigserial [pk]

• bigserial should be used if you anticipate the use of more than $2^31$ identifiers over the lifetime of the table.
• owner varchar
  • The name of the owner of the account
• balance bigint
  • It is used to facilitate the process, but in real life, some currencies use decimal types
• currency varchar
  • Label for the currency type (e.g. Dollar, Euro, Real, etc)
• created_at timestamptz
  • timestamptz stands for “timestamp with time zone”.
  • Stores Date and Time: It records both the date and the time.
  • Includes Time Zone Information: It is timezone-aware, meaning it stores the timestamp in UTC (Coordinated Universal Time) and displays it in the session’s time zone.
  • Automatic Time Zone Adjustment: When you insert a timestamp with a time zone into a timestamptz column, PostgreSQL converts it to UTC for storage. When you retrieve the value, it is converted back to the session’s time zone.

Benefits of Using ‘timestamptz’

1. Time Zone Awareness:

• Ensures that timestamps are consistent globally. Regardless of where the data is inserted or queried from, the ‘timestamptz’ type helps maintain a consistent and accurate time record.

2. Avoids Ambiguities:

• Handles daylight saving time changes and other time zone-related issues, avoiding the common pitfalls of time zone differences.

3. Convenience:

• Automatically converts timestamps to the appropriate time zone when displaying to users, which can simplify handling date and time data in applications.

Important Notes

Session Time Zone: The displayed time zone can be affected by the session’s time zone setting. You can set the session’s time zone using -e TZ=Timezone:

docker run --name postgres \
  -e POSTGRES_USER=[user] \
  -e POSTGRES_PASSWORD=[password] \
  -e TZ=America/Sao_Paulo \
  -p 5432:5432 \
  -d postgres:16.3-alpine3.19

• Comparison and Arithmetic:
• ‘timestamptz’ allows direct comparison and arithmetic operations on timestamps, which can be very useful for queries involving time ranges, differences, etc.