Implement [Database Template] [MySQL] [PostgreSQL] [SQLite] Close Database Connection

[H0llyW00dzZ]

By submitting this pull request, I confirm that my contribution is made under the terms of the MIT license.

Problem/Feature

By implementing this Close Database Connection, it can be useful in scenarios such as graceful shutdown, for example, in Kubernetes (k8s).

Description of Changes:

• [+] feat(mysql.tmpl): add Close() method to Service interface and its implementation
• [+] docs(mysql.tmpl): add comments for Service interface and its methods

Note: By using the "log.Printf" method, it is more concise and idiomatic Go.

Checklist

• I have self-reviewed the changes being requested
• I have updated the documentation (if applicable)

[briancbarrow]

wouldn't we want to try to close before logging? What happens if s.db.Close returns an error? Will it still have disconnected?

[H0llyW00dzZ]

wouldn't we want to try to close before logging? What happens if s.db.Close returns an error? Will it still have disconnected?

The log.Printf("Disconnected from database: %s", dbname) statement is useful when used with goroutines, such as for asynchronously starting and shutting down the server. However, it's recommended to handle the error returned by s.db.Close before logging the disconnection message. This way, you can ensure that the database connection is properly closed, even if an error occurs during the process. If s.db.Close returns an error, it doesn't necessarily mean that the connection has been successfully disconnected.

[H0llyW00dzZ]

@briancbarrow example how it work its like this

$ go run cmd/api/main.go
2024/04/04 20:52:02 [H0llyW00dzZ Firewall] [INFO] Connected to database: defaultdb
2024/04/04 20:52:04 [H0llyW00dzZ] [INFO] Starting server on :8080

 ┌───────────────────────────────────────────────────┐ 
 │                    H0llyW00dzZ                    │ 
 │                   Fiber v2.52.4                   │ 
 │               http://127.0.0.1:8080               │ 
 │       (bound on host 0.0.0.0 and port 8080)       │ 
 │                                                   │ 
 │ Handlers ............ 537 Processes ........... 1 │ 
 │ Prefork ....... Disabled  PID ............. 15836 │ 
 └───────────────────────────────────────────────────┘ 

2024/04/04 20:52:12 [H0llyW00dzZ] [INFO] Shutting down server... reason: interrupt
2024/04/04 20:52:12 [H0llyW00dzZ] [INFO] Disconnected from database: defaultdb
2024/04/04 20:52:12 [H0llyW00dzZ] [INFO] Database connection closed.
2024/04/04 20:52:17 [H0llyW00dzZ] [INFO] Server exiting

[H0llyW00dzZ]

That My Fiber application is fully managed by goroutines running in parallel.

[briancbarrow]

Hey @H0llyW00dzZ, another good idea but we'd need the changes in all the db files, not just MySQL.

[H0llyW00dzZ]

Hey @H0llyW00dzZ, another good idea but we'd need the changes in all the db files, not just MySQL.

@briancbarrow, have to test later one by one for other database

[briancbarrow]

Hey @H0llyW00dzZ, another good idea but we'd need the changes in all the db files, not just MySQL.

@briancbarrow, have to test later one by one for other database

I'm going to move this PR into draft until the other databases have been supported. Ping me again when it is ready.

[H0llyW00dzZ]

Hey @H0llyW00dzZ, another good idea but we'd need the changes in all the db files, not just MySQL.

@briancbarrow, have to test later one by one for other database

I'm going to move this PR into draft until the other databases have been supported. Ping me again when it is ready.

I think any database driver supported database/sql it supported to call this Close()

[briancbarrow]

Hey @H0llyW00dzZ, another good idea but we'd need the changes in all the db files, not just MySQL.

@briancbarrow, have to test later one by one for other database

I'm going to move this PR into draft until the other databases have been supported. Ping me again when it is ready.

I think any database driver supported database/sql it supported to call this Close()

Have you tested this that it works with the other databases?

[H0llyW00dzZ]

Hey @H0llyW00dzZ, another good idea but we'd need the changes in all the db files, not just MySQL.

@briancbarrow, have to test later one by one for other database

I'm going to move this PR into draft until the other databases have been supported. Ping me again when it is ready.

I think any database driver supported database/sql it supported to call this Close()

Have you tested this that it works with the other databases?

currently only Redis and MySQL, was implemented this as well for Redis and MySQL

[H0llyW00dzZ]

@briancbarrow Anyway, it's possible to close the connection for any database supported by the standard library's . So, I think I'm going to implement this for MySQL, PostgreSQL, and SQLite.

[H0llyW00dzZ]

@briancbarrow Done, by the way. Only Redis and MongoDB are left, and they must be implemented independently because they are not supported by the standard library's.

[H0llyW00dzZ]

Note

Also note that this is pretty useful when used for restarting or shutting down, because if the server or service is shut down or restarted without closing the connection, the connection will remain open and could lead to potential deadlocks/hangs for the database (e.g., MySQL, PostgreSQL, SQLite).