🐘 Paagan

paagan is a lightweight CLI tool to manage multiple PostgreSQL versions and instances locally using Docker.

The primary motivation for this project is to have a developer experience similar to CloudNativePG (CNPG) but running locally on a development machine. It simplifies tasks like running specific PostgreSQL versions, managing multiple isolated databases, and performing Point-In-Time Recovery (PITR) through forking.

Features

• Multi-Version Support: Run any PostgreSQL version (including 15, 16, 17, and the new 18+ structure).
• Isolation: Each instance gets its own data, WAL archive, and backup directories.
• Dynamic Port Management: Automatically assigns and remembers unused ports for each instance.
• Local PITR: Fork an existing database to a new instance at a specific point in time.
• Cloud-Native Logic: Mimics production-grade database management patterns (WAL archiving, base backups).
• Portable: Automatically handles UID/GID mapping to ensure Docker has correct permissions on your local filesystem.

Installation

Ensure you have Rust and Docker installed.

cargo build --release
cp target/release/paagan /usr/local/bin/ # or wherever you want it

Note: Ensure your DOCKER_HOST is correctly set if you are using Colima or a non-standard Docker socket.

Directory Structure

All configuration and data are stored in ~/.paagan:

• instances.json: Metadata for all managed instances.
• instances/<name>/data: PostgreSQL data directory.
• instances/<name>/archive: WAL archive directory.
• instances/<name>/backups: Base backups used for forking.

Commands

list

Lists all database containers managed by paagan along with their versions, ports, and current Docker status.

paagan list

create

Creates a new PostgreSQL instance. It pulls the required image, sets up the directory structure, and starts the container.

paagan create --version 18-alpine my-db

start / stop

Starts or stops an existing database instance. start will recreate the container if it was manually removed, ensuring your data is always accessible.

paagan stop my-db
paagan start my-db

psql

Opens an interactive psql session to the specified instance.

paagan psql my-db

show

Shows detailed information about an instance, including the connection string and data directory paths.

paagan show my-db

fork

Creates a new instance from an existing one. If --at is provided, it performs a Point-In-Time Recovery (PITR).

# Direct fork
paagan fork source-db forked-db

# Fork to a specific timestamp (PITR)
paagan fork --at "2026-03-10 14:30:00+00" source-db recovery-db

delete

Removes the database instance, its Docker container, and all associated data on disk.

paagan delete my-db

How Forking Works (The CNPG way)

1. paagan triggers a pg_basebackup on the source instance.
2. It ensures all pending WAL logs are archived.
3. It extracts the backup into the new instance's data directory.
4. It configures a restore_command to pull logs from the source's archive.
5. If a timestamp is provided, it sets recovery_target_time.
6. The new instance starts in recovery mode, reaches the target, promotes itself, and becomes a standalone database.