# systemg
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# Systemg - A Lightweight Process Manager
Systemg is a **simple, fast, and dependency-free process manager** written in Rust.
It aims to provide **a minimal alternative to systemd** and other heavyweight service managers, focusing on **ease of use**, **clarity**, and **performance**.
## Why Systemg?
Traditional process managers like **systemd** are complex, heavy, and introduce unnecessary dependencies.
Systemg offers a **lightweight**, **configuration-driven** solution that's **easy to set up and maintain**.
## Features
- **Declarative YAML Configuration** - Define services, dependencies, and restart policies easily.
- **Automatic Process Monitoring** - Restart crashed services based on custom policies.
- **Dependency-Aware Startup** - Honour `depends_on` chains, skip unhealthy dependencies, and cascade stop dependents on failure.
- **Environment Variable Support** - Load variables from `.env` files and per-service configurations.
- **Minimal & Fast** - Built with Rust, designed for performance and low resource usage.
- **No Root Required** - Unlike systemd, it doesn't take over PID 1.
---
## Comparison vs Alternatives
| **Lightweight** | Yes | No (Heavy) | No (Python) | No (Containers) |
| **No Dependencies**| Yes | No (DBus, etc.) | No (Python) | No (Docker) |
| **Simple Config** | YAML | Complex Units | INI | YAML |
| **Process Monitoring** | Yes | Yes | Yes | Yes |
| **PID 1 Required?**| No | Yes | No | No |
| **Handles Dependencies?** | Yes | Yes | No | Yes |
---
## Getting Started
### Installation
Install the system binary:
```sh
Install systemg using cargo:
```sh
cargo install sysg
```
Or download the pre-built binary from the releases page.
### Basic Commands
The `sysg` command-line interface provides several subcommands for managing processes.
#### Start
Start the process manager with the given configuration:
```sh
# Start with default configuration file (systemg.yaml)
sysg start
# Start with a specific configuration file
sysg start --config systemg.yaml
# Start the long-lived supervisor (persists after you log out)
sysg start --config systemg.yaml --daemonize
# Subsequent commands talk to the supervisor without re-spawning it
sysg status
# Override logging verbosity for the current run (works with every subcommand; names or 0-5)
sysg start --log-level debug
sysg start --log-level 4
```
When the supervisor is running it remains active in the background, holding service
processes in the same process group so `sysg stop`, `sysg restart`, `sysg status`,
and `sysg logs` can coordinate them even after you disconnect from the shell that
started them.
#### Stop
Stop the process manager or a specific service:
```sh
# Stop the supervisor and every managed service
sysg stop
# Stop a specific service
sysg stop --service myapp
```
#### Restart
Restart the process manager:
```sh
# Restart all services managed by the supervisor
sysg restart
# Restart with a different configuration
sysg restart --config new-config.yaml
```
#### Status
Check the status of running services:
```sh
# Show status of all services
sysg status
# Show status of a specific service
sysg status --service webserver
```
#### Logs
View logs for a specific service:
```sh
# View the last 50 lines of logs for all services
sysg logs
# View logs for a specific service
sysg logs api-service
# View a custom number of log lines
sysg logs database --lines 100
```
### Dependency handling
Declare service relationships with the `depends_on` field to coordinate startup order and health checks. Systemg will:
- start services in a topologically sorted order so each dependency is running or has exited successfully before its dependents launch;
- skip dependents whose prerequisites fail to start, surfacing a clear dependency error instead of allowing a partial boot;
- stop running dependents automatically when an upstream service crashes, preventing workloads from running against unhealthy backends.
For example:
```yaml
services:
database:
command: "postgres -D /var/lib/postgres"
web:
command: "python app.py"
depends_on:
- database
```
If `database` fails to come up, `web` will remain stopped and log the dependency failure until the database is healthy again.
## Testing
To run the test suite:
```sh
# Run all tests
cargo test
# Run specific test
cargo test test_service_lifecycle
```
## Build from Source
To build systemg from source:
```sh
# Clone the repository
git clone https://github.com/ra0x3/systemg.git
cd systemg
# Build the project
cargo build --release
# The binary will be available at target/release/sysg
```
## Contributing
Contributions to systemg are welcome! Please see the [CONTRIBUTING.md](CONTRIBUTING.md) file for guidelines.