I previously designed a robust distributed locking algorithm based on Google Cloud. Now I'm releasing a Ruby implementation of this algorithm: distributed-lock-google-cloud-storage-ruby.
To use this, add to your Gemfile:
gem 'distributed-lock-google-cloud-storage'
Many workloads nowadays involve many systems that operate concurrently. This ranges from microservice fleets to workflow orchestration to CI/CD pipelines. Sometimes it's important to coordinate these systems so that concurrent operations don't step on each other. One way to do that is by using distributed locks that work across multiple systems.
Distributed locks used to require complex algorithms or complex-to-operate infrastructure, making them expensive both in terms of costs as well as in upkeep. With the emergence of fully managed and serverless cloud systems, this reality has changed.
In this post I'll look into a distributed locking algorithm based on Google Cloud. I'll discuss several existing implementations and suggest algorithmic improvements in terms of performance and robustness.
When needing to perform HTTP calls in shell scripts, Curl is the go-to tool: it's flexible and installed almost everywhere. But Curl is not primarily designed for use in shell scripts. This article explores common caveats when using Curl in shell scripts, and showcases best practices to adhere to.
When you run a command or a script that runs for a long time, it may be helpful to have all its output prefixed with a timestamp. For example we want to change this:
foo
bar
baz
to this:
[2020-12-13 12:20:38] foo
[2020-12-13 12:21:32] bar
[2020-12-13 12:22:20] baz
Here's how you can do it.
I was recently in a discussion between developers about improving the test coverage of a major software project. They needed guidance about what kind of tests to write, and how to write them.
The discussion quickly became confusing: the topic was too large, too general, and it turns out that there wasn't even a well-defined shared vocabulary for testing concepts! The latter turns out to be a wider problem in the software development community: it simply doesn't have well-defined testing terms!
In this post, I'd like to provide some guidance w.r.t. this matter. I'll discuss:
When developing a Rails app, have there been times when you’re wondering “what properties/columns does this model have”? The easiest way to find out is by inspecting db/schema.rb, but that gets annoying quickly. If only there’s a way to keep your schema closer to you. Enter the annotate gem.
At Phusion, we recently unveiled an important feature in Passenger 6: generic language support. We also held a coding livestream and Q&A session on November 1st. Here’s wa recording of the livestream, as well as a overview and table of contents.
Selenium + Chrome Headless fail with mysterious errors when run in GitLab CI and Docker. Here’s why, and also how we fixed it.
Passenger is not an easy project to debug. Being written in C++, it occasionally runs into failures caused by low-level issues. Such is the case with a strange bug report that we received last week. Users reported that Passenger crashes during startup on FreeBSD 11.2, but not on earlier FreeBSD versions. This blog post describes my debugging journey.