How to install Eye on Ubuntu or Debian?

Install Ruby first (version >= 1.9.3), then use 'gem install eye' via RubyGems. For production, ensure Celluloid dependencies are met, and test with 'eye check config.eye' to validate configurations.

Eye vs Bluepill: which is better for Ruby apps?

Eye is designed as a more stable alternative to Bluepill, with fewer crashes and added features like dynamic config updates. However, Bluepill might be simpler for basic use, while Eye excels in complex, production-grade scenarios with its health checks and chaining.

How to monitor a Sidekiq process with Eye?

Define a process in the Eye config with 'start_command' for Sidekiq, set 'pid_file', and add health checks for memory or CPU. Use 'working_dir' for the app path and 'stdall' for logs, similar to the Thin example in the README.

Can Eye handle process flapping and automatic restarts?

Yes, configure flapping detection with 'trigger :flapping' in the application block, specifying times and windows. Eye will delay restarts after excessive failures, as shown in the config with 'retry_in' options to prevent resource exhaustion.

How to update Eye configs without stopping processes?

Use 'eye load config.eye' to reload configurations dynamically; new processes are added, removed ones stopped if configured, and existing ones updated. This allows live changes, but test carefully to avoid unintended stops.

What health checks does Eye support for web services?

Eye includes HTTP checks with URL patterns and socket checks for TCP connections. For example, the Thin process uses an HTTP check to verify response content, while EventMachine uses a socket check with send/expect data.

Is Eye suitable for non-Ruby applications?

Yes, Eye can supervise any process via start/stop commands, but configuration requires Ruby knowledge. Health checks work universally, but integration might need custom scripts for non-Ruby apps, adding complexity.

Open-Awesome

Eye

MITRubyv0.9.1

A Ruby process monitoring tool inspired by Bluepill and God, built for production stability with advanced features like chained restarts and health checks.

GitHub

1.2k stars87 forks0 contributors

What is Eye?

Eye is a Ruby-based process monitoring tool designed to supervise and manage long-running applications and daemons. It automatically restarts failed processes, performs health checks on CPU, memory, sockets, and HTTP endpoints, and provides a flexible configuration system. It solves the problem of unreliable process supervision in production environments, offering stability and advanced features over predecessors.

Target Audience

System administrators, DevOps engineers, and Ruby developers who need to monitor and manage production services, especially those running daemonized processes or background jobs.

Value Proposition

Developers choose Eye for its production stability, rich feature set (like chained restarts and dynamic config updates), and reliability compared to alternatives like God and Bluepill, which often had bugs and crashes in production.

Overview

Process monitoring tool. Inspired from Bluepill and God.

Use Cases

Best For

Monitoring Ruby web servers like Thin or EventMachine in production
Supervising daemonized background job processors (e.g., Sidekiq, Resque)
Managing forking applications with multiple child processes
Implementing health checks for TCP sockets or HTTP services
Automatically restarting failed processes with configurable triggers
Updating monitoring configurations live without downtime

Not Ideal For

Environments not running Ruby, as Eye requires Ruby MRI >= 1.9.3 and specific gems like Celluloid.
Containerized or orchestrated deployments (e.g., Docker, Kubernetes) where built-in process management makes external supervisors redundant.
Teams preferring graphical interfaces or web dashboards for monitoring, as Eye is CLI-focused with limited GUI options.
Lightweight scripting or short-lived tasks where full process supervision with health checks is overkill.

Pros & Cons

Pros

Production Stability Focus

Built to address bugs in God and Bluepill, Eye emphasizes reliability with features like flapping detection to prevent restart loops, as noted in its README philosophy.

Dynamic Configuration Updates

Allows live reloading of monitoring configurations via 'eye load' without restarting the daemon, enabling zero-downtime changes in production environments.

Comprehensive Health Checks

Supports configurable checks for CPU, memory, sockets, and HTTP endpoints with customizable intervals and thresholds, as shown in the example config with checks for Thin and EventMachine.

Chained Process Management

Enables graceful start and restart chains with intervals, useful for managing dependencies between processes, demonstrated in the group 'samples' with 'chain grace: 5.seconds'.

Child Process Supervision

Can monitor forking applications and their children individually, with configurable restart commands and checks, as illustrated in the 'forking' process example.

Cons

Ruby-Only Dependency

Requires Ruby MRI >= 1.9.3 and gems like Celluloid, limiting adoption in polyglot stacks or environments where Ruby isn't installed or maintained.

Complex Configuration DSL

The Ruby-based DSL, while flexible, has a steep learning curve and can be error-prone for non-Ruby developers or those unfamiliar with its syntax, as seen in the detailed config examples.

Limited Plugin Ecosystem

Compared to tools like systemd or supervisord, Eye has fewer third-party plugins and integrations, requiring custom development for specific monitoring needs beyond the built-in features.

No Built-in Web Interface

Lacks a graphical dashboard for real-time monitoring; status checks and logs are CLI-only, which can hinder usability for teams accustomed to web-based management tools.

Open Source Alternative To

Eye is an open-source alternative to the following products:

Bluepill

Bluepill is a testing framework for iOS that runs tests in parallel using multiple simulators, developed by LinkedIn to speed up iOS UI testing.

God

God is a process monitoring framework written in Go, designed to keep applications running and restart them if they fail.

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