Troubleshooting Ruby Processes: Leveraging System Tools when the Usual Ruby Tricks Stop Working (Digital Short Cut)

by Philippe Hanrigou

Overview

This is the eBook version of the printed book.

This short cut introduces key system diagnostic tools to Ruby developers creating and deploying web applications. When programmers develop a Ruby application they commonly experience complex problems which require some understanding of the underlying operating system to be solved. Difficult to diagnose, these problems can make the difference between a project's failure or success. This short cut demonstrates how to leverage system tools available on Mac OS X, Linux, Solaris, BSD or any other Unix flavor. You will learn how to leverage the raw power of tools such as lsof, strace or gdb to resolve problems that are difficult to diagnose with the standard Ruby development tools. You will also find concrete examples that illustrate how these tools solve real-life problems in Ruby development. This expertise will prove especially relevant during the deployment phase of your application. In this way, should your production Mongrel cluster freeze and stop serving HTTP requests, it will not take you 2 days to figure out why!

Product Details

ISBN-13:	9780132701891
Publisher:	Pearson Education
Publication date:	10/29/2007
Series:	Addison-Wesley Professional Ruby Series
Sold by:	Barnes & Noble
Format:	eBook
Pages:	58
File size:	900 KB

About the Author

Philippe Hanrigou is a software engineer, architect, and consultant. He is interested in lots of topics around software development but primarily focuses on designing enterprise software—understanding what makes a good design and implementing practices that encourage it. He has over ten years of experience developing enterprise software and web applications, mostly in Java.

 

For the last year he has enthusiastically embraced Ruby and used it to deliver large enterprise systems as a ThoughtWorks consultant. Philippe continually seeks ways to improve the state of the software craft and found agile methodologies to be especially efficient and rewarding for developing enterprise software. He spent a great deal of the last four years sharpening his expertise in and advocating agile methodologies.

Table of Contents

What This Shortcut Covers

Ruby Troubleshooting: The Usual Suspects

    raise, puts and debug()

    irb or script/console

    Writing a Test

    Log Files

    Sending Signals

    Debugger and Breakpointer

Lsof

    What is It?

    Usage

        Typical Usage Scenarios

        Combining Multiple Selections

    Concrete Examples Using lsof to Troubleshoot a Problem with a Ruby Process

        Checking that a Mongrel Cluster is Up and Listening on the Right Ports

        Checking that You Are Using a Native Database Driver

        Detecting Connection Leaks

    Exploring Other Tricks

    Exploring Other lsof Options

        Repeat Mode

        Field Output

        Terse Output

    What is lsof Good For?

strace

    What is It?

    Interpreting strace Output

    How Do I Find Out About a Specific System Call?

    What is strace Good For?

    Some Concrete Examples

        Hanging Mongrel

        Where Did That Library Come From? Peeking at the Load Path

        Permission Denied

    Other Interesting strace Options

        Filtering Options

        Tracing Child Processes

        Basic System Level Profiling

    strace Siblings

        Mac OS X

        Solaris and OpenSolaris

        BSD

        Windows

        Linux

gdb

    The Basics: Attaching to a Running Process and Getting the C-Level Backtrace

    Raising a Ruby Exception from gdb to Get the Ruby Stack Trace

    Easy Access to your gdb Tricks: Define Macros in .gdbinit

    Pushing the Envelope: Evaluate Arbitrary Ruby Code from gdb

        A Ruby Interpreter Within gdb

        Using gdb Inline Documentation

    Learning about Ruby Interpreter Internals

    What is gdb Good For?

    A Classic Gotcha: Unattachable Processes

Conclusion

Acknowledgments

About the Author