cronmaster

Modern UI: Beautiful, responsive interface with dark/light mode.
System Information: Display hostname, IP address, uptime, memory, network and CPU info.
Cron Job Management: View, create, and delete cron jobs with comments.
Script management: View, create, and delete bash scripts on the go to use within your cron jobs.
Job Execution Logging: Optional logging for cronjobs with automatic cleanup, capturing stdout, stderr, exit codes, and timestamps.
Docker Support: Runs entirely from a Docker container.
Easy Setup: Quick presets for common cron schedules.

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Before we start

Hey there! 👋 Just a friendly heads-up: I'm a big believer in open source and love sharing my work with the community. Everything you find in my GitHub repos is and always will be 100% free. If someone tries to sell you a "premium" version of any of my projects while claiming to be me, please know that this is not legitimate. 🚫

If you find my projects helpful and want to fuel my late-night coding sessions with caffeine, I'd be super grateful for any support! ☕

Quick Start

Using Docker (Recommended)

Create a docker-compose.yml file with this content:

services:
  cronmaster:
    image: ghcr.io/fccview/cronmaster:latest
    container_name: cronmaster
    user: "root"
    ports:
      # Feel free to change port, 3000 is very common so I like to map it to something else
      - "40123:3000"
    environment:
      - NODE_ENV=production
      - DOCKER=true
      - NEXT_PUBLIC_CLOCK_UPDATE_INTERVAL=30000

      # --- SET LOCALE TO ONE OF OUR SUPPORTED LOCALES - see the /app/_translations/ folder for supported locales
      # - LOCALE=en

      # --- UNCOMMENT TO SET DIFFERENT LOGGING VALUES
      # - MAX_LOG_AGE_DAYS=30
      # - MAX_LOGS_PER_JOB=50

      # --- PASSWORD PROTECTION
      # Uncomment to enable password protection (replace "password" with your own)
      - AUTH_PASSWORD=very_strong_password

      # --- CRONTAB USERS
      # This is used to read the crontabs for the specific user.
      # replace root with your user - find it with: ls -asl /var/spool/cron/crontabs/
      # For multiple users, use comma-separated values: HOST_CRONTAB_USER=root,user1,user2
      - HOST_CRONTAB_USER=root
    volumes:
      # --- MOUNT DOCKER SOCKET
      # Mount Docker socket to execute commands on host
      - /var/run/docker.sock:/var/run/docker.sock

      # --- MOUNT DATA
      # These are needed if you want to keep your data on the host machine and not wihin the docker volume.
      # DO NOT change the location of ./scripts once you create crons as all cronjobs that use custom
      # scripts created via the app will target this folder
      - ./scripts:/app/scripts
      - ./data:/app/data
      - ./snippets:/app/snippets

    # --- USE HOST PID NAMESPACE FOR HOST COMMAND EXECUTION
    # --- RUN IN PRIVILEGED MODE FOR NSENTER ACCESS
    pid: "host"
    privileged: true
    restart: always
    init: true

    # --- DEFAULT PLATFORM IS SET TO AMD64, UNCOMMENT TO USE ARM64.
    #platform: linux/arm64

ARM64 Support

The application supports both AMD64 and ARM64 architectures:

For AMD64 users: No changes needed - the default configuration works out of the box.

For ARM64 users: Uncomment the platform line in your docker-compose.yml:

platform: linux/arm64

Note: Multi-platform Docker images are automatically built for both architectures. The image will automatically use the correct architecture for your platform.

Build and run with Docker Compose:

docker compose up --build

Open your browser and navigate to http://localhost:40123

Note: The Docker implementation uses direct file access to read and write crontab files, ensuring real-time synchronization with the host system's cron jobs. This approach bypasses the traditional crontab command limitations in containerized environments

Local Development

Install dependencies:

yarn install

Run the development server:

yarn dev

Open your browser and navigate to http://localhost:3000

Environment Variables

The following environment variables can be configured:

Variable	Default	Description
`NEXT_PUBLIC_CLOCK_UPDATE_INTERVAL`	`30000`	Clock update interval in milliseconds (30 seconds)
`HOST_PROJECT_DIR`	`N/A`	Mandatory variable to make sure cron runs on the right path.
`DOCKER`	`false`	ONLY set this to true if you are runnign the app via docker, in the docker-compose.yml file
`HOST_CRONTAB_USER`	`root`	Comma separated list of users that run cronjobs on your host machine
`AUTH_PASSWORD`	`N/A`	If you set a password the application will be password protected with basic next-auth

Important Notes for Docker

Root user is required for cron operations and direct file access. There is no way around this, if you don't feel comfortable in running it as root feel free to run the app locally with yarn install, yarn build and yarn start
HOST_PROJECT_DIR is required in order for the scripts created within the app to run properly
The DOCKER=true environment variable enables direct file access mode for crontab operations. This is REQUIRED when running the application in docker mode.

Important Note on Root Commands: When running commands as root within Cronmaster, ensure that these commands also function correctly as root on your host machine. If a command works as root on your host but fails within Cronmaster, please open an issue with detailed information.

Usage

Viewing System Information

The application automatically detects your operating system and displays:

System Uptime
Memory Usage
CPU Information
GPU Information (if supported)

Managing Cron Jobs

View Existing Jobs: All current cron jobs are displayed with their schedules and commands
Create New Jobs: Use the form on the right side to create new cron jobs
Quick Presets: Click on preset buttons for common schedules
Add Comments: Include descriptions for your cron jobs
Delete Jobs: Remove unwanted cron jobs with the delete button
Clone Jobs: Clone jobs to quickly edit the command in case it's similar
Enable Logging: Optionally enable execution logging for any cronjob to capture detailed execution information

Job Execution Logging

CronMaster includes an optional logging feature that captures detailed execution information for your cronjobs:

How It Works

When you enable logging for a cronjob, CronMaster automatically wraps your command with a log wrapper script. This wrapper:

Captures stdout and stderr output
Records the exit code of your command
Timestamps the start and end of execution
Calculates execution duration
Stores all this information in organized log files

Enabling Logs

When creating or editing a cronjob, check the "Enable Logging" checkbox
The wrapper is automatically added to your crontab entry
Jobs run independently - they continue to work even if CronMaster is offline

Log Storage

Logs are stored in the ./data/logs/ directory with descriptive folder names:

If a job has a description/comment: {sanitized-description}_{jobId}/
If a job has no description: {jobId}/

Example structure:

./data/logs/
├── backup-database_root-0/
│   ├── 2025-11-10_14-30-00.log
│   ├── 2025-11-10_15-30-00.log
│   └── 2025-11-10_16-30-00.log
├── daily-cleanup_root-1/
│   └── 2025-11-10_14-35-00.log
├── root-2/  (no description provided)
│   └── 2025-11-10_14-40-00.log

Note: Folder names are sanitized to be filesystem-safe (lowercase, alphanumeric with hyphens, max 50 chars for the description part).

Log Format

Each log file includes:

==========================================
=== CronMaster Job Execution Log ===
==========================================
Log Folder: backup-database_root-0
Command: bash /app/scripts/backup.sh
Started: 2025-11-10 14:30:00
==========================================

[command output here]

==========================================
=== Execution Summary ===
==========================================
Completed: 2025-11-10 14:30:45
Duration: 45 seconds
Exit code: 0
==========================================

Automatic Cleanup

Logs are automatically cleaned up to prevent disk space issues:

Maximum logs per job: 50 log files
Maximum age: 30 days
Cleanup trigger: When viewing logs or after manual execution
Method: Oldest logs are deleted first when limits are exceeded

Custom Wrapper Script

You can override the default log wrapper by creating your own at ./data/wrapper-override.sh. This allows you to:

Customize log format
Add additional metadata
Integrate with external logging services
Implement custom retention policies

Example custom wrapper:

#!/bin/bash
JOB_ID="$1"
shift

# Your custom logic here
LOG_FILE="/custom/path/${JOB_ID}_$(date '+%Y%m%d').log"

{
  echo "=== Custom Log Format ==="
  echo "Job: $JOB_ID"
  "$@"
  echo "Exit: $?"
} >> "$LOG_FILE" 2>&1

Docker Considerations

Mount the ./data directory to persist logs on the host
The wrapper script location: ./data/cron-log-wrapper.sh. This will be generated automatically the first time you enable logging.

Non-Docker Considerations

Logs are stored at ./data/logs/ relative to the project directory
The codebase wrapper script location: ./app/_scripts/cron-log-wrapper.sh
The running wrapper script location: ./data/cron-log-wrapper.sh

Important Notes

Logging is optional and disabled by default
Jobs with logging enabled are marked with a blue "Logged" badge in the UI
Logs are captured for both scheduled runs and manual executions
Commands with file redirections (>, >>) may conflict with logging
The crontab stores the wrapped command, so jobs run independently of CronMaster

Cron Schedule Format

The application uses standard cron format: * * * * *

First field: Minute (0-59)
Second field: Hour (0-23)
Third field: Day of month (1-31)
Fourth field: Month (1-12)
Fifth field: Day of week (0-7, where 0 and 7 are Sunday)

Managing Scripts

View Existing Scripts: All current user created scripts are displayed with their name and descriptions
Create New Script: Use the editor and snippets to quickly create scripts for your cron jobs.
Quick Snippets: Pre-set of snippets, with ability to add new ones. Check README.md in Snippets
Delete Scripts: Remove unwanted scripts (this won't delete the cronjob, you will need to manually remove these yourself)
Clone Scripts: Clone scripts to quickly edit them in case they are similar to one another.