NotionKeeper

This project extends the jckleiner/notion-backup project by patching a couple of bugs and incorporating a scheduler to the Docker image so that the backups can be scheduled. This is achieved using a cron which scheduling is based on an .env value. An updated .env.dist file is provided with the original project's variables (see README -> Set Credentials) plus a couple of custom more. A compose.yaml is included too, to ease up the configuration of the container.

Configure the service

Follow the instructions at README -> Set Credentials and add:

• BACKUP_PATH to set where do you want your backup files to be stored
• SCHEDULING_CONFIG to set the scheduling interval. Check out this link for more information on the format

Backup retention

After each backup is created, a retention policy is applied to the local backup directory to automatically delete old files. Each rule operates on a non-overlapping time window and preserves the oldest available backups within that window, maximising temporal coverage.

Environment variable	Default	Description
RETENTION_KEEP_LAST	5	Always keep the N most recent backups, regardless of age
RETENTION_KEEP_LAST_DAY	1	Keep the N oldest backups from the last 24 hours
RETENTION_KEEP_LAST_WEEK	3	Keep the N oldest backups from the 1–7 day range
RETENTION_KEEP_LAST_MONTH	8	Keep the N oldest backups from the 7–30 day range
RETENTION_KEEP_LAST_YEAR	12	Keep the N oldest backups from the 30–365 day range

A file is deleted only if it is not selected by any rule. Set a variable to 0 to disable that rule.

Example outcome with daily backups after one year (default values):

• Most recent 5 — unconditional, always available
• ~23 h ago — oldest from the last day window
• ~4, 5, 6 days ago — oldest 3 from the last week window
• ~22–29 days ago — oldest 8 from the last month window
• ~353–364 days ago — oldest 12 from the last year window

Testing

Tests are written with JUnit 5, Mockito, and AssertJ. Run them locally with:

mvn test

Tests run automatically on every push and pull request via the Test GitHub Actions workflow.

What is tested

BackupRetentionManager is covered by unit tests that exercise every retention rule in isolation as well as combined:

Test scenario	What it verifies
Empty / non-existent directory	No crash, no side-effects
Non-backup files present	Files that don't match the backup pattern are never deleted
All rules disabled (0)	Every backup file is deleted
RETENTION_KEEP_LAST	Keeps the N most recent files unconditionally; deletes the rest
keepLast on a very old file	Even a file older than a year is kept if it is among the N most recent
RETENTION_KEEP_LAST_DAY	Keeps the N oldest files from the (now-1d, now] window
RETENTION_KEEP_LAST_WEEK	Exclusive window (now-7d, now-1d] — day-window files are not counted
RETENTION_KEEP_LAST_MONTH	Exclusive window (now-30d, now-7d] — week-window files are not counted
RETENTION_KEEP_LAST_YEAR	Exclusive window (now-365d, now-30d] — month-window files are not counted
Files older than 365 days	Deleted unless saved by keepLast
Invalid env var value	Falls back to the default for that rule
Negative env var value	Falls back to the default for that rule
All rules combined	Each window contributes distinct files; file outside every window is deleted

Code style

This project uses Checkstyle to enforce a consistent code style. The rules are defined in checkstyle.xml and cover:

• No wildcard or unused imports
• Standard Java naming conventions (types, constants, methods, variables)
• All control structures must use braces
• No empty catch blocks (unless the variable is named expected or ignore)
• One statement per line
• Miscellaneous best-practice rules (StringLiteralEquality, SimplifyBooleanReturn, FallThrough, …)

Checkstyle runs automatically on every push and pull request via the Lint GitHub Actions workflow. It also runs locally as part of the Maven build during the validate phase, so any violation will fail mvn install too:

mvn checkstyle:check

Run the service

Just start the service with docker compose and you are good to go:

docker compose up -d