Ruby

Making the Operation of Code More Transparent and Obvious with SystemTap

Making the Operation of Code More Transparent and Obvious with SystemTap

You can study source code and manually instrument functions as described in the “Use the dynamic tracing tools, Luke” blog article, but why not make it easier to find key points in the software by adding user-space markers to the application code? User-space markers have been available in Linux for quite some time (since 2009). The inactive user-space markers do not significantly slow down the code. Having them available allows you to get a more accurate picture of what the software is doing internally when unexpected issues occur. The diagnostic instrumentation can be more portable with the user-space markers, because the instrumentation does not need to rely on instrumenting particular function names or lines numbers in source code. The naming of the instrumentation points can also make clearer what event is associated with a particular instrumentation point.

For example, Ruby MRI on Red Hat Enterprise Linux 7 has a number of different instrumentation points made available as a SystemTap tapset. If SystemTap is installed on the system, as described by What is SystemTap and how to use it?, the installed Ruby MRI instrumentation points can be listed with the stap -L” command shown below. These events show the start and end of various operations in the Ruby runtime, such as the start and end of garbage collection (GC) marking and sweeping.

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“Use the dynamic tracing tools, Luke”

“Use the dynamic tracing tools, Luke”

A common refrain for tracking down issues on computer systems running open source software is “Use the source, Luke.” Reviewing the source code can be helpful in understanding how the code works, but the static view may not give you a complete picture of how things work (or are broken) in the code. The paths taken through code are heavily data dependent. Without knowledge about specific values at key locations in code, you can easily miss what is happening. Dynamic instrumentation tools, such as SystemTap, that trace and instrument the software can help provide a more complete understanding of what the code is actually doing

I have wanted to better understand how the Ruby interpreter works. This is an opportunity to use SystemTap to investigate Ruby MRI internals on Red Hat Enterprise Linux 7. The article What is SystemTap and how to use it? has more information about installing SystemTap. The x86_64 RHEL 7 machine has ruby-2.0.0648-33.el7_4.x86_64.rpm installed, so the matching debuginfo RPM is installed to provide SystemTap with information about function parameters and to provide me with human-readable source code. The debuginfo RPM is installed by running the following command as root:

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Towards The Ruby 3×3 Performance Goal

Towards The Ruby 3×3 Performance Goal

This blog post is about my work to improve CRuby performance by introducing new virtual machine instructions and a JIT. It is loosely based on my presentation at RubyKaigi 2017 in Hiroshima, Japan.

As many Ruby people know, the author of Ruby, Yukihiro Matsumoto (Matz), set up a very ambitious goal for performance of CRuby version 3. Version 3 should be 3 times faster than version 2.

Koichi Sasada did a great job improving the performance of CRuby version 2 by about 3 times over version 1, by introducing a byte code virtual machine (VM). So I guess it is symbolic to set up the same goal for CRuby version 3.

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Now available – Red Hat Software Collections 2.4 and Red Hat Developer Toolset 6.1

Now available – Red Hat Software Collections 2.4 and Red Hat Developer Toolset 6.1

Today, we are announcing the general availability of Red Hat Software Collections 2.4, Red Hat’s latest set of open source web development tools, dynamic languages, and databases. We are also announcing Red Hat Developer Toolset 6.1, which helps to streamline application development on Red Hat Enterprise Linux by giving developers access to some of the latest, stable open source C and C++ compilers and complementary development tools.

New language additions to Red Hat Software Collections 2.4 include:

  • Nginx 1.10
  • Node.js v6
  • Ruby 2.4
  • Ruby on Rails 5.0
  • Scala 2.10

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Towards Faster Ruby Hash Tables

Towards Faster Ruby Hash Tables

Hash tables are an important part of dynamic programming languages. They are widely used because of their flexibility, and their performance is important for the overall performance of numerous programs. Ruby is not an exception. In brief, Ruby hash tables provide the following API:

  • insert an element with given key if it is not yet on the table or update the element value if it is on the table
  • delete an element with given key from the table
  • get the value of an element with given key if it is in the table
  • the shift operation (remove the earliest element inserted into the table)
  • traverse elements in their inclusion order, call a given function and depending on its return value, stop traversing or delete the current element and continue traversing
  • get the first N or all keys or values of elements in the table as an array
  • copy the table
  • clear the table

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Eclipse Vert.x Core Cheat Sheet

Eclipse Vert.x Core Cheat Sheet

Eclipse Vert.x is a toolkit used to build reactive and distributed systems on the Java Virtual Machine. Vert.x supports a variety of languages letting you choose which one you’d prefer. The Vert.x Core cheat sheet covers the creation of a project using Apache Maven, Gradle or the Vert.x CLI, and references most common Vert.x Core APIs, in 3 different languages (Java, JavaScript, and Groovy). Forgot how to create an HTTP server, use the HTTP client, implement a request-response on the event bus?  Just check the cheat sheet. Together with the Red Hat Developer Team, I’ve put together this handy cheat sheet – hopefully, you’ll find it useful too!

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Red Hat Software Collections 2.3 now beta

Red Hat Software Collections 2.3 now beta

Today, Red Hat announced the beta availability of Red Hat Software Collections 2.3, Red Hat’s newest installment of open source web development tools, dynamic languages, and databases. Delivered on a separate lifecycle from Red Hat Enterprise Linux with a more frequent release cadence, Red Hat Software Collections bridges developer agility and production stability by helping to accelerate the creation of modern applications that can then be more confidently deployed into production.

New additions to Red Hat Software Collections 2.3 Beta include:

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Using API keys securely in your OpenShift microservices and applications

Using API keys securely in your OpenShift microservices and applications

In the microservices landscape, the API provides an essential form of communication between components. To allow secure communication between microservices components, as well as third-party applications, it’s important to be able to consume API keys and other sensitive data in a manner that doesn’t place the data at risk. Secret objects are specifically designed to hold sensitive information, and OpenShift makes exposing this information to the applications that need it easy.

In this post, I’ll demonstrate securely consuming API keys in OpenShift Enterprise 3. We’ll deploy a Sinatra application that uses environment variables to interact with the Twitter API; create a Kubernetes Secret object to store the API keys; expose the secret to the application via environment variables; and then perform a rolling update of the environment variables across our pods.

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