FlashCron

Why FlashCron?

Traditional cron daemons get the job done, but they weren't built for speed. FlashCron is engineered from the ground up for blazing-fast performance:

The Flash Philosophy

• Priority Queue Scheduling: O(log n) operations, no polling loops
• Zero-Copy Parsing: Minimal allocations in hot paths
• Precise Sleep: CPU stays idle until the exact moment needed
• Concurrent Execution: Configurable parallelism with async I/O
• Optimized Binaries: LTO, stripped symbols, maximum optimization

Features

Core Functionality

• Standard Cron Expressions: Full 5-field cron syntax support
• TOML Configuration: Human-readable, version-control friendly
• Hot Reload: Automatic config reload on file changes
• Graceful Shutdown: Waits for running jobs to complete

Job Management

• Timeout Handling: Kill runaway jobs automatically
• Retry Support: Configurable retry count and delay
• Environment Variables: Per-job environment injection
• Working Directory: Per-job working directory
• Concurrent Limits: Prevent resource exhaustion

Observability

• Structured Logging: Human-readable or JSON format
• Execution History: Track job success/failure rates
• Prometheus Metrics: Optional metrics endpoint (feature flag)

Cross-Platform

• Linux: Native support, systemd integration
• macOS: Full support including Apple Silicon
• Windows: Native Windows support

Installation

From Releases (Recommended)

Linux (x86_64)

curl -LO https://github.com/alfredo-baratta/flashcron/releases/latest/download/flashcron-linux-x86_64.tar.gz
tar xzf flashcron-linux-x86_64.tar.gz
sudo mv flashcron /usr/local/bin/

Linux (ARM64)

curl -LO https://github.com/alfredo-baratta/flashcron/releases/latest/download/flashcron-linux-aarch64.tar.gz
tar xzf flashcron-linux-aarch64.tar.gz
sudo mv flashcron /usr/local/bin/

macOS (Intel)

curl -LO https://github.com/alfredo-baratta/flashcron/releases/latest/download/flashcron-macos-x86_64.tar.gz
tar xzf flashcron-macos-x86_64.tar.gz
sudo mv flashcron /usr/local/bin/

macOS (Apple Silicon)

curl -LO https://github.com/alfredo-baratta/flashcron/releases/latest/download/flashcron-macos-aarch64.tar.gz
tar xzf flashcron-macos-aarch64.tar.gz
sudo mv flashcron /usr/local/bin/

Windows Download flashcron-windows-x86_64.zip from releases and extract to a directory in your PATH.

From Cargo

cargo install flashcron

From Source

git clone https://github.com/alfredo-baratta/flashcron
cd flashcron
cargo build --release

Docker

docker pull ghcr.io/alfredo-baratta/flashcron:latest

Quick Start

1. Generate Configuration

flashcron init -o flashcron.toml

2. Edit Configuration

[settings]
log_level = "info"
max_concurrent_jobs = 10

[jobs.backup]
schedule = "0 2 * * *"  # Daily at 2 AM
command = "/usr/local/bin/backup.sh"
description = "Daily backup"
timeout = 3600
retry_count = 3

[jobs.cleanup]
schedule = "0 */6 * * *"  # Every 6 hours
command = "find /tmp -mtime +7 -delete"
description = "Clean old temp files"
enabled = true

3. Validate Configuration

flashcron validate -c flashcron.toml

4. Start the Daemon

flashcron run -c flashcron.toml

CLI Reference

Options

Configuration Reference

Global Settings

[settings]
log_level = "info"           # trace, debug, info, warn, error
json_logs = false            # JSON format for log aggregators
max_concurrent_jobs = 10     # 0 = unlimited
shell = "/bin/sh"            # Default shell
watch_config = true          # Hot reload on config changes
history_size = 1000          # Job execution history size
shutdown_grace_period = 30   # Seconds to wait on shutdown

Job Configuration

[jobs.example]
schedule = "*/5 * * * *"     # Cron expression (required)
command = "echo 'Hello'"     # Command to execute (required)
description = "Example job"  # Optional description
enabled = true               # Enable/disable job
working_dir = "/app"         # Working directory
environment = { KEY = "value" }  # Environment variables
timeout = 300                # Timeout in seconds (0 = none)
shell = "/bin/bash"          # Override default shell
retry_count = 3              # Retry on failure
retry_delay = 60             # Seconds between retries
max_output_size = 1048576    # Max stdout/stderr capture (bytes)
run_on_startup = false       # Run immediately on daemon start

Cron Expression Format

┌───────────── minute (0-59)
│ ┌───────────── hour (0-23)
│ │ ┌───────────── day of month (1-31)
│ │ │ ┌───────────── month (1-12)
│ │ │ │ ┌───────────── day of week (1-7, Sunday = 7)
│ │ │ │ │
* * * * *

Examples:

Performance Benchmarks

Measured on AMD Ryzen 5 / Intel i7 equivalent:

Memory Profile

Deployment

systemd Service

# /etc/systemd/system/flashcron.service
[Unit]
Description=FlashCron - Lightning-fast Cron Daemon
After=network.target

[Service]
Type=simple
User=flashcron
ExecStart=/usr/local/bin/flashcron run -c /etc/flashcron/config.toml
Restart=on-failure
RestartSec=5
Environment=RUST_LOG=info

[Install]
WantedBy=multi-user.target

sudo systemctl enable flashcron
sudo systemctl start flashcron

Docker Compose

version: '3.8'
services:
  flashcron:
    image: ghcr.io/alfredo-baratta/flashcron:latest
    volumes:
      - ./flashcron.toml:/app/config/flashcron.toml:ro
      - ./scripts:/scripts:ro
    restart: unless-stopped
    logging:
      driver: json-file
      options:
        max-size: "10m"
        max-file: "3"

Kubernetes

apiVersion: apps/v1
kind: Deployment
metadata:
  name: flashcron
spec:
  replicas: 1
  selector:
    matchLabels:
      app: flashcron
  template:
    metadata:
      labels:
        app: flashcron
    spec:
      containers:
      - name: flashcron
        image: ghcr.io/alfredo-baratta/flashcron:latest
        resources:
          requests:
            memory: "8Mi"
            cpu: "10m"
          limits:
            memory: "32Mi"
            cpu: "100m"
        volumeMounts:
        - name: config
          mountPath: /app/config
      volumes:
      - name: config
        configMap:
          name: flashcron-config

Comparison with Alternatives

Contributing

Contributions are welcome! See CONTRIBUTING.md for guidelines.

# Clone the repository
git clone https://github.com/alfredo-baratta/flashcron
cd flashcron

# Run tests
cargo test

# Run benchmarks
cargo bench

# Build release
cargo build --release

License

MIT License - see LICENSE for details.

Author

Alfredo Baratta - alfredobaratta@outlook.com

Acknowledgments

• cron - Cron expression parsing
• tokio - Async runtime
• clap - CLI framework
• tracing - Structured logging