Update README and create healthcheck for container image.

Dockerfile

@@ -19,4 +19,6 @@ COPY backup_incremental.sh /scripts/backup_incremental.sh
 COPY entrypoint.sh /entrypoint.sh
 RUN chmod +x /scripts/*.sh /entrypoint.sh
 
+HEALTHCHECK --interval=1m --timeout=10s --start-period=1m --retries=3 CMD pgrep crond >/dev/null && [ -d /backups ] && [ -w /backups ]
+
 ENTRYPOINT ["/entrypoint.sh"]

README.md

@@ -1,2 +1,110 @@
 # docker-postgres-backup
-Simple containerized solution for backing up a PostgreSQL database.
+
+A simple, containerized solution for automated full and incremental backups of a PostgreSQL database, with retention policies and optional incremental backup scheduling.
+
+## Features
+
+- **Full Backups:** Scheduled `pg_dump` backups of your PostgreSQL database, compressed and stored in `/backups/full`.
+- **Incremental Backups:** Optionally archive PostgreSQL WAL files for point-in-time recovery, stored in `/backups/incremental`.
+- **Retention Policies:** Automatically remove old backups based on configurable retention periods.
+- **Configurable Scheduling:** Use environment variables to control backup intervals via cron.
+- **Easy Integration:** Designed to run as a Docker container, with minimal configuration.
+- **Customizable:** Enable or disable incremental backups with a single environment variable.
+
+## Usage
+
+### Environment Variables
+
+| Variable                      | Description                                              | Default                |
+|-------------------------------|----------------------------------------------------------|------------------------|
+| `POSTGRES_HOST`               | PostgreSQL host                                          | (required)             |
+| `POSTGRES_PORT`               | PostgreSQL port                                          | (required)             |
+| `POSTGRES_USER`               | PostgreSQL user                                          | (required)             |
+| `POSTGRES_DB`                 | PostgreSQL database name                                 | (required)             |
+| `PGPASSWORD_FILE`             | Path to file containing the PostgreSQL password          | (required)             |
+| `ENABLE_INCREMENTAL`          | Enable incremental (WAL) backups (`true`/`false`)        | `true`                 |
+| `BACKUP_NAME`                 | Name for the backup file                                 | `backup`               |
+| `RETENTION_FULL_DAYS`         | Days to keep full backups                                | `7`                    |
+| `RETENTION_INC_DAYS`          | Days to keep incremental backups                         | `3`                    |
+| `BACKUP_FULL_INTERVAL`        | Cron schedule for full backups                           | `0 2 * * 0`            |
+| `BACKUP_INCREMENTAL_INTERVAL` | Cron schedule for incremental backups                    | `0 */6 * * *`          |
+
+### Volumes
+
+- `/backups` — Where backups are stored (mount this to persist backups)
+- `/wal_archive` — Directory where PostgreSQL archives WAL files (mount this for incremental backups)
+
+### Docker Run Example
+
+```sh
+docker run -d \
+  -e POSTGRES_HOST=db \
+  -e POSTGRES_PORT=5432 \
+  -e POSTGRES_USER=postgres \
+  -e POSTGRES_DB=mydb \
+  -e PGPASSWORD_FILE=/run/secrets/pgpassword \
+  -e RETENTION_FULL_DAYS=7 \
+  -e RETENTION_INC_DAYS=3 \
+  -e ENABLE_INCREMENTAL=true \
+  -v /host/backups:/backups \
+  -v /host/wal_archive:/wal_archive \
+  --name pg-backup \
+  fridwin/postgres-backup
+```
+
+### Docker Compose Example
+
+```yaml
+services:
+  postgres-backup:
+    image: fridwin/postgres-backup
+    container_name: postgres-backup
+    user: "my_uid:my_gid" # Suggested, not required
+    environment:
+      - TZ=${TIME_ZONE}
+      - POSTGRES_HOST=db
+      - POSTGRES_PORT=5432
+      - POSTGRES_USER=postgres
+      - POSTGRES_DB=mydb
+      - PGPASSWORD_FILE=/run/secrets/pgpassword
+      - RETENTION_FULL_DAYS=7
+      - RETENTION_INC_DAYS=3
+      - ENABLE_INCREMENTAL=true
+    volumes:
+      - /host/backups:/backups
+      - /host/wal_archive:/wal_archive
+    restart: unless-stopped
+```
+
+### PostgreSQL WAL Archiving
+
+To use incremental backups, configure your PostgreSQL server to archive WAL files to the `/wal_archive` directory (mounted into the container). Example `postgresql.conf` settings:
+
+```
+archive_mode = on
+archive_command = 'cp %p /wal_archive/%f'
+```
+
+### Restore
+
+__TODO: Better examples for restore process. Possible commands that can be run with container as one-time execution for restore.__
+- **Full backup:** Unzip and restore with `pg_restore` or `psql`.
+- **Incremental backup:** Use full backup plus WAL files for point-in-time recovery.
+
+
+### Healthcheck
+
+The container includes a healthcheck that verifies:
+
+1. Cron is running
+2. The last backup completed successfully
+3. Optionally, the last backup is recent (if `MAX_AGE` is set)
+
+```yaml
+HEALTHCHECK --interval=5m --timeout=10s --start-period=1m CMD /healthcheck.sh
+```
+
+---
+## License
+
+MIT License © 2025 Scott Fridlund