Monitor: Functional Go Job Scheduler with Bash, JSON Logic, and Prometheus

This project is a functional Go application for running scheduled jobs defined in a YAML config. Each job can execute a bash script, evaluate the result with JSON logic, and publish metrics to Prometheus. It is designed for extensibility and ease of use in monitoring and automation scenarios.

Features

• YAML-based job configuration
• Frequency and strict (time-based) scheduling
• Runs bash scripts with full output capture
• Evaluates job results using JSON logic
• Publishes job status metrics to Prometheus
• Runs easily in Docker with all common Unix tools (curl, jq, sed, etc.)

Getting Started

1. Clone the repository

git clone <your-repo-url>
cd <repo-directory>

2. Configure jobs

Edit config.yaml to define your jobs, schedules, scripts, and decision logic. Example:

jobs:
  - name: "Test HTTP Check"
    description: "Check if a website is accessible"
    schedule:
        type: "frequency"
        data:
            daysOfWeek: [1, 1, 1, 1, 1, 1, 1]
            intervalInSeconds: 30
    action:
        plugin: "bash_check"
        script: |
          echo "testing job"
          if curl -s -o /dev/null -w "%{http_code}" https://httpbin.org/status/200 | grep -q "200"; then
            exit 0
          else
            exit 1
          fi
    decision_logic: >
      {
          "if": [
              {  
                  "==": [{"var": "bash_check_result.exit_code"}, 0]
              },
              "GOOD",
              "BAD"
          ]
      }

3. Build and Run Locally

Prerequisites

• Go 1.21+
• Docker (for containerized runs)

Run with Go

go run main.go

Build and Run with Docker

docker build -t monitor .
docker run -p 2112:2112 monitor

4. Prometheus Metrics

• Metrics are exposed at http://localhost:2112/metrics
• You can scrape this endpoint with Prometheus or view it in your browser.

5. Customizing Scripts

• Scripts are run in a real bash shell with all common Unix tools (curl, jq, sed, grep, etc.) available.
• Use YAML | for multiline scripts to preserve line breaks.

6. Adding Jobs

• Add more jobs to config.yaml with different schedules, scripts, and logic.
• Both frequency and strict (specific time) schedules are supported.

Development

• All code is in main.go for simplicity.
• Uses only functional programming (no OOP/struct methods for core logic).
• Dependencies are managed with Go modules.

License

MIT