Full Width [alt+shift+f] Shortcuts [alt+shift+k]
Sign Up [alt+shift+s] Log In [alt+shift+l]
40

My adventures hunting down a Ruby memory leak 🎢

from 37signals Dev [alt+shift+b] in programming

In this article, I tell the story of a memory leak we had in our HEY app, the cool tools I could use to investigate and how I finally figured out the root cause. Memory leaks can be tricky to diagnose and having the right set of tools makes a huge difference. I hope my adventures help you the next time you’re in a similar situation. The beginning Everything started with a report from our Operations team mentioning that HEY memory usage was often getting close to boiling over. We rarely deploy HEY during the weekends, and that’s when the issue manifested itself the most: The leak After a few days without deploying the app, the memory usage almost reached 100%, and then a deployment would reset it back to normal. This signals a slow and steady memory leak. Checking Ruby heap allocations The first approach I tried was logging and analyzing the Ruby Heap allocation stats. In particular, I looked for endpoints where: A minor (or major) GC run happened. heap_available_slots increased greatly. The theory is that when GC runs, it should clear most of the newly allocated objects, hence an increase of heap_available_slots paired with a GC run shouldn’t happen unless there is a leak. The analysis exposed 2 endpoints: MessagesController#update TopicsController#show These are the most heavily used endpoints of the app, so the result wasn’t conclusive at all. Heap dump I decided to proceed by extracting a Ruby heap dump. Luckily this can be done by running rbtrace in the app servers: bundle exec rbtrace -p $worker_pid -e 'Thread.new{GC.start; require "objspace"; File.open("/tmp/0.json","w"){|f| ObjectSpace.dump_all(output: f) }}' This command writes the $worker_pid heap dump to /tmp/0.json. Unfortunately, a heap dump extracted without enabling object trace allocation doesn’t contain key information such as: The GC generation it was allocated in The filename and line number it was allocated in A truncated value Object bytesize So even the basic heap dump...
7th Mar 2024

Stay updated

Get a weekly newsletter with the top 5 articles worth reading every week.

More from 37signals Dev

Lexxy: A new rich text editor for Rails

Today, we are introducing Lexxy, a new rich text editor for Action Text. It’s based on Lexical — Meta’s text editing framework — and it brings a much better text editing experience to Rails: Good HTML semantics. Paragraphs are real <p> tags, as they should be. Markdown support: shortcuts, auto-formatting on paste. Real-time code syntax highlighting. Create links by pasting URLs on selected text. Configurable prompts. Support for mentions and other interactive prompts with multiple loading and filtering strategies. Preview attachments like PDFs and Videos in the editor. Works seamlessly with Action Text and Active Storage. We created Lexxy because Trix was falling short of expectations in certain areas, and we encountered technical barriers when attempting to offer the experience we wanted. Lexxy comes with a bunch of juicy improvements, but more than that, we now have a fantastic foundation to build on top of. Lexxy will also bring a great improvement to Action Text: we will let you configure the editor in Action Text just like you configure the database in Active Record. This will open the door to integrating other editors in Rails. Text editing is central to our products. We believe Lexxy will let us deliver the editing experience we want. We are launching an early beta today, give it a try!

4th Sep 2025 • 1 votes
Introducing Action Push Native

Note: Shortly after releasing this gem, we renamed it from Action Native Push to Action Push Native, in case you arrived here looking for the gem of the former name. More details here. We’ve open-sourced Action Push Native, a Rails gem for sending push notifications to mobile platforms. It supports both Apple and Google push notification services. Why did we build it? We created it to migrate off Amazon SNS and Pinpoint, as part of our broader cloud exit. We’re using it in Basecamp and HEY to send more than 10 million push notifications per day without a hitch. Action Push Native relies on HTTP/2 persistent connections to the Apple Push Notification service, which significantly reduced job duration compared to our previous HTTP/1 setup with AWS Pinpoint: AWS Pinpoint jobs duration Action Push Native jobs duration How does it work? The gem connects directly to the Apple (APNs) and Google (FCM) push notification services. It handles retries, rate-limiting, and deleting dead devices automatically. Configure each platform with your credentials, and you can start sending notifications like this: device = ApplicationPushDevice.create! \ name: "iPhone 16", token: "6c267f26b173cd9595ae2f6702b1ab560371a60e7c8a9e27419bd0fa4a42e58f", platform: "apple" notification = ApplicationPushNotification.new \ title: "Hello world!", body: "Welcome to Action Push Native" notification.deliver_later_to(device) Version 0.1.0 is available now. You can read more on GitHub. We hope you find it useful!

18th Aug 2025 • 1 votes
Announcing Hotwire Native 1.2

We’ve just launched Hotwire Native v1.2 and it’s the biggest update since the initial launch last year. The update has several key improvements, bug fixes, and more API consistency between platforms. And we’ve created all new iOS and Android demo apps to show it off! A web-first framework for building native mobile apps Improvements There are a few significant changes in v1.2 that are worth specifically highlighting. Route decision handlers Hotwire Native apps route internal urls to screens in your app, and route external urls to the device’s browser. Historically, though, it wasn’t straightforward to customize the default behavior for unique app needs. In v1.2, we’ve introduced the RouteDecisionHandler concept to iOS (formerly only on Android). Route decisions handlers offer a flexible way to decide how to route urls in your app. Out-of-the-box, Hotwire Native registers these route decision handlers to control how urls are routed: AppNavigationRouteDecisionHandler: Routes all internal urls on your app’s domain through your app. SafariViewControllerRouteDecisionHandler: (iOS Only) Routes all external http/https urls to a SFSafariViewController in your app. BrowserTabRouteDecisionHandler: (Android Only) Routes all external http/https urls to a Custom Tab in your app. SystemNavigationRouteDecisionHandler: Routes all remaining external urls (such as sms: or mailto:) through device’s system navigation. If you’d like to customize this behavior you can register your own RouteDecisionHandler implementations in your app. See the documentation for details. Server-driven historical location urls If you’re using Ruby on Rails, the turbo-rails gem provides the following historical location routes. You can use these to manipulate the navigation stack in Hotwire Native apps. recede_or_redirect_to(url, **options) — Pops the visible screen off of the navigation stack. refresh_or_redirect_to(url, **options) — Refreshes the visible screen on the navigation stack. resume_or_redirect_to(url, **options) — Resumes the visible screen on the navigation stack with no further action. In v1.2 there is now built-in support to handle these “command” urls with no additional path configuration setup necessary. We’ve also made improvements so they handle dismissing modal screens automatically. See the documentation for details. Bottom tabs When starting with Hotwire Native, one of the most common questions developers ask is how to support native bottom tab navigation in their apps. We finally have an official answer! We’ve introduced a HotwireTabBarController for iOS and a HotwireBottomNavigationController for Android. And we’ve updated the demo apps for both platforms to show you exactly how to set them up. New demo apps To better show off all the features in Hotwire Native, we’ve created new demo apps for iOS and Android. And there’s a brand new Rails web app for the native apps to leverage. Hotwire Native demo app Clone the GitHub repos to build and run the demo apps to try them out: iOS repo Android repo Rails app Huge thanks to Joe Masilotti for all the demo app improvements. If you’re looking for more resources, Joe even wrote a Hotwire Native for Rails Developers book! Release notes v1.2 contains dozens of other improvements and bug fixes across both platforms. See the full release notes to learn about all the additional changes: iOS release notes Android release notes Take a look If you’ve been curious about using Hotwire Native for your mobile apps, now is a great time to take a look. We have documentation and guides available on native.hotwired.dev and we’ve created really great demo apps for iOS and Android to help you get started.

23rd Apr 2025 • 71 votes
Monitoring 10 Petabytes of data in Pure Storage

As the final part of our move out of the cloud, we are working on moving 10 petabytes of data out of AWS Simple Storage Service (S3). After exploring different alternatives, we decided to go with Pure Storage FlashBlade solution. We store different kinds of information on S3, from the attachments customers upload to Basecamp to the Prometheus long-term metrics. On top of that, Pure’s system also provides filesystem-based capabilities, enabling other relevant usages, such as database backup storage. This makes the system a top priority for observability. Although the system has great reliability, out-of-the-box internal alerting, and autonomous ticket creation, it would also be good to have our metrics and alerts to facilitate problem-solving and ensure any disruptions are prioritized and handled. For more context on our current Prometheus setup, see how we use Prometheus at 37signals. Pure OpenMetrics exporter Pure maintains two OpenMetrics exporters, pure-fb-openmetrics-exporter and pure-fa-openmetrics-exporter. Since we use Pure Flashblade (fb), this post covers pure-fb-openmetrics-exporter, although overall usage should be similar. The setup is straightforward and requires only binary and basic authentication installation. Here is a snippet of our Chef recipe that installs it: pure_api_token = "token" # If you use Chef, your token should come from an ecrypted databag. Changed to hardcoded here to simplify PURE_EXPORTER_VERSION = "1.0.13".freeze # Generally, we use Chef node metadata for version management. Changed to hardcoded to simplify directory "/opt/pure_exporter/#{PURE_EXPORTER_VERSION}" do recursive true owner 'pure_exporter' group 'pure_exporter' end # Avoid recreating under /tmp after reboot if target_binary is already there target_binary = "/opt/pure_exporter/#{PURE_EXPORTER_VERSION}/pure-fb-openmetrics-exporter" remote_file "/tmp/pure-fb-openmetrics-exporter-v#{PURE_EXPORTER_VERSION}-linux-amd64.tar.gz" do source "https://github.com/PureStorage-OpenConnect/pure-fb-openmetrics-exporter/releases/download/v#{PURE_EXPORTER_VERSION}/pure-fb-openmetrics-exporter-v#{PURE_EXPORTER_VERSION}-linux-amd64.tar.gz" not_if { ::File.exist?(target_binary) } end archive_file "/tmp/pure-fb-openmetrics-exporter-v#{PURE_EXPORTER_VERSION}-linux-amd64.tar.gz" do destination "/tmp/pure-fb-openmetrics-exporter-v#{PURE_EXPORTER_VERSION}" action :extract not_if { ::File.exist?(target_binary) } end execute "copy binary" do command "sudo cp /tmp/pure-fb-openmetrics-exporter-v#{PURE_EXPORTER_VERSION}/pure-fb-openmetrics-exporter /opt/pure_exporter/#{PURE_EXPORTER_VERSION}/pure-exporter" creates "/opt/pure_exporter/#{PURE_EXPORTER_VERSION}/pure-exporter" not_if { ::File.exist?(target_binary) } end tokens = <<EOF main: address: purestorage-mgmt.mydomain.com api_token: #{pure_api_token['token']} EOF file "/opt/pure_exporter/tokens.yml" do content tokens owner 'pure_exporter' group 'pure_exporter' sensitive true end systemd_unit 'pure-exporter.service' do content <<-EOU # Caution: Chef managed content. This is a file resource from #{cookbook_name}::#{recipe_name} # [Unit] Description=Pure Exporter After=network.target [Service] Restart=on-failure PIDFile=/var/run/pure-exporter.pid User=pure_exporter Group=pure_exporter ExecStart=/opt/pure_exporter/#{PURE_EXPORTER_VERSION}/pure-exporter \ --tokens=/opt/pure_exporter/tokens.yml ExecReload=/bin/kill -HUP $MAINPID SyslogIdentifier=pure-exporter [Install] WantedBy=multi-user.target EOU action [ :create, :enable, :start ] notifies :reload, "service[pure-exporter]" end service 'pure-exporter' Prometheus Job Configuration The simplest way of ingesting the metrics is to configure a basic Job without any customization: - job_name: pure_exporter metrics_path: /metrics static_configs: - targets: ['<%= @hostname %>:9491'] labels: environment: 'production' job: pure_exporter params: endpoint: [main] # From the tokens configuration above For a production-ready setup, we are using a slightly different approach. The exporter supports the usage of specific metric paths to allow for split Prometheus jobs configuration that reduces the overhead of pulling the metrics all at once: - job_name: pure_exporter_array metrics_path: /metrics/array static_configs: - targets: ['<%= @hostname %>:9491'] labels: environment: 'production' job: pure_exporter metric_relabel_configs: - source_labels: [name] target_label: ch regex: "([^.]+).*" replacement: "$1" action: replace - source_labels: [name] target_label: fb regex: "[^.]+\\.([^.]+).*" replacement: "$1" action: replace - source_labels: [name] target_label: bay regex: "[^.]+\\.[^.]+\\.([^.]+)" replacement: "$1" action: replace params: endpoint: [main] # From the tokens configuration above - job_name: pure_exporter_clients metrics_path: /metrics/clients static_configs: - targets: ['<%= @hostname %>:9491'] labels: environment: 'production' job: pure_exporter params: endpoint: [main] # From the tokens configuration above - job_name: pure_exporter_usage metrics_path: /metrics/usage static_configs: - targets: ['<%= @hostname %>:9491'] labels: environment: 'production' job: pure_exporter params: endpoint: [main] - job_name: pure_exporter_policies metrics_path: /metrics/policies static_configs: - targets: ['<%= @hostname %>:9491'] labels: environment: 'production' job: pure_exporter params: endpoint: [main] # From the tokens configuration above We also configure some metric_relabel_configs to extract labels from name using regex. Those labels help reduce the complexity of queries that aggregate metrics by different components. Detailed documentation on the available metrics can be found here. Alerts Auto Generated Alerts As I shared earlier, the system has an internal Alerting module that automatically triggers alerts for critical situations and creates tickets. To cover those alerts on the Prometheus side, we added an alerting configuration of our own that relies on the incoming severities: - alert: PureAlert annotations: summary: '{{ $labels.summary }}' description: '{{ $labels.component_type }} - {{ $labels.component_name }} - {{ $labels.action }} - {{ $labels.kburl }}' dashboard: 'https://grafana/your-dashboard' expr: purefb_alerts_open{environment="production"} == 1 for: 1m We still need to evaluate how the pure-generated alerts will interact with the custom alerts I will cover below, and we might decide to stick to one or the other depending on what we find out. Hardware Before I continue, the image below helps visualize how some of the Pure FlashBlade components are physically organized: Because of Pure’s reliability, most isolated hardware failures do not require the immediate attention of an Ops team member. To cover the most basic hardware failures, we configure an alert that sends a message to the Ops Basecamp 4 project chat: - alert: PureHardwareFailed annotations: summary: Hardware {{ $labels.name }} in chassis {{ $labels.ch }} is failed description: 'The Pure Storage hardware {{ $labels.name }} in chassis {{ $labels.ch }} is failed' dashboard: 'https://grafana/your-dashboard' expr: purefb_hardware_health == 0 for: 1m labels: severity: chat-notification We also configure alerts that check for multiple hardware failures of the same type. This doesn’t mean two simultaneous failures will result in a critical state, but it is a fair guardrail for unexpected scenarios. We also expect those situations to be rare, keeping the risk of causing unnecessary noise low. - alert: PureMultipleHardwareFailed annotations: summary: Pure chassis {{ $labels.ch }} has {{ $value }} failed {{ $labels.type }} description: 'The Pure Storage chassis {{ $labels.ch }} has {{ $value }} failed {{ $labels.type }}, close to the healthy limit of two simultaneous failures. Ensure that the hardware failures are being worked on' dashboard: 'https://grafana/your-dashboard' expr: count(purefb_hardware_health{type!~"eth|mgmt_port|bay"} == 0) by (ch,type,environment) > 1 for: 1m labels: severity: page # We are looking for multiple failed bays in the same blade - alert: PureMultipleBaysFailed annotations: summary: Pure chassis {{ $labels.ch }} has fb {{ $labels.fb }} with {{ $value }} failed bays description: 'The Pure Storage chassis {{ $labels.ch }} has fb {{ $labels.fb }} with {{ $value }} failed bays, close to the healthy limit of two simultaneous failures. Ensure that the hardware failures are being worked on' dashboard: 'https://grafana/your-dashboard' expr: count(purefb_hardware_health{type="bay"} == 0) by (ch,type,fb,environment) > 1 for: 1m labels: severity: page Finally, we configure high-level alerts for chassis and XFM failures: - alert: PureChassisFailed annotations: summary: Chassis {{ $labels.name }} is failed description: 'The Pure Storage hardware chassis {{ $labels.name }} is failed' dashboard: 'https://grafana/your-dashboard' expr: purefb_hardware_health{type="ch"} == 0 for: 1m labels: severity: page - alert: PureXFMFailed annotations: summary: Xternal Fabric Module {{ $labels.name }} is failed description: 'The Pure Storage hardware Xternal fabric module {{ $labels.name }} is failed' dashboard: 'https://grafana/your-dashboard' expr: purefb_hardware_health{type="xfm"} == 0 for: 1m labels: severity: page Latency Using the metric purefb_array_performance_latency_usec we can set a threshold for all the different protocols and dimensions (read, write, etc), so we are alerted if any problem causes the latency to go above an expected level. - alert: PureLatencyHigh annotations: summary: Pure {{ $labels.dimension }} - {{ $labels.protocol }} latency high description: 'Pure {{ $labels.protocol }} latency for dimension {{ $labels.dimension }} is above 100ms' dashboard: 'https://grafana/your-dashboard' expr: (avg_over_time(purefb_array_performance_latency_usec{protocol="all"}[30m]) * 0.001) for: 1m labels: severity: chat-notification Saturation For saturation, we are primarily worried about something unexpected causing excessive use of array space, increasing the risk of hitting the cluster capacity. With that in mind, it’s good to have a simple alert in place, even if we don’t expect it to fire anytime soon: - alert: PureArraySpace annotations: summary: Pure Cluster {{ $labels.instance }} available space is expected to be below 10% description: 'The array space for pure cluster {{ $labels.instance }} is expected to be below 10% in a month, please investigate and ensure there is no risk of running out of capacity' dashboard: 'https://grafana/your-dashboard' expr: (predict_linear(purefb_array_space_bytes{space="empty",type="array"}[30d], 730 * 3600)) < (purefb_array_space_bytes{space="capacity",type="array"} * 0.10) for: 1m labels: severity: chat-notification HTTP We use BigIp load balancers to front-end the cluster, which means that all the alerts we already had in place for the BigIp HTTP profiles, virtual servers, and pools also cover access to Pure. The solution for each organization on this topic will be different, but it is a good practice to keep an eye on HTTP status codes and throughput. Grafana Dashboards The project’s GitHub repository includes JSON files for Grafana dashboards that are based on the metrics generated by the exporter. With simple adjustments to fit each setup, it’s possible to import them quickly. Wrapping up On top of the system’s built-in capabilities, Pure also provides options to integrate their system into well-known tools like Prometheus and Grafana, facilitating the process of managing the cluster the same way we manage everything else. I hope this post helps any other team interested in working with them better understand the effort involved. Thanks for reading!

2nd Jan 2025 • 92 votes
Mission Control — Jobs 1.0 released

We’ve just released Mission Control — Jobs v1.0.0, the dashboard and set of extensions to operate background jobs that we introduced earlier this year. This new version is the result of 92 pull requests, 67 issues and the help of 35 different contributors. It includes many bugfixes and improvements, such as: Support for Solid Queue’s recurring tasks, including running them on-demand. Support for API-only apps. Allowing immediate dispatching of scheduled and blocked jobs. Backtrace cleaning for failed jobs’ backtraces. A safer default for authentication, with Basic HTTP authentication enabled and initially closed unless configured or explicitly disabled. Recurring tasks in Mission Control — Jobs, with a subset of the tasks we run in production We use Mission Control — Jobs daily to manage jobs HEY and Basecamp 4, with both Solid Queue and Resque, and it’s the dashboard we recommend if you’re using Solid Queue for your jobs. Our plan is to upstream some of the extensions we’ve made to Active Job and continue improving it until it’s ready to be included by default in Rails together with Solid Queue. If you want to help us with that, are interested in learning more or have any issues or questions, head over to the repo in GitHub. We hope you like it!

4th Dec 2024 • 65 votes

More in programming

If we do not stop to help each other, what do we become?

Yesterday, I received this email as a response to You Can't Vibe Code Love. It's such a remarkable and powerful statement that I asked permission to share it here, in its entirety, with personal information redacted: Hey Jeff, Hope you and your family are doing well.

2 days ago • 1 votes
You are still valuable

A frustrated Reddit post about being a condom between an AI and production made the rounds in our team. Here is why I think the opposite is true and what it means for how we review code, plan work and think.

3 days ago • 2 votes
A Short Update on Designing for Foldable Devices

And here we are three years after I wrote about the Google Pixel Fold being announced, followed now with the announcement of the iPhone Duo...(I have questions about the naming by the way). Four years ago I was talking about web primitives in the platform for the Surface Duo. My how time flies. There are CSS media features, a Viewport Segments API, a Device Posture API but Chromium based browsers are the only ones currently supporting these things. I haven't been able to find any signal yet on whether Safari will support these things in the web platform as the developer docs focus on application development. If you're interested in trying out the platform features, you can emulate the Surface Duo and Galaxy Z Fold in the developer tools. And if you're thinking, do I really have to have my website adapt to two screens? The answer is no. Adding a design to an application or dual screen makes sense if you have an experience that has two simulataneous contexts that are useful e.g. a list of email messages/inbox on one screen, an open message, email thread or email composer on the other. Here's one of my talks from 2022 if you're interested in learning more about what's available in the browser for dual screen/foldable devices. Happy building :)

3 days ago • 1 votes
Mommy bloggers react

After a write-up in the New York Times, Mommy Bloggers had two options. Either lean in, or step back. Given how popular it became after that, it's not hard to guess which option they chose. The post Mommy bloggers react appeared first on The History of the Web.

5 days ago • 2 votes
Haunt 0.4.0 released

I'm quite a bit late on this one, but Haunt version 0.4.0 was released released back in July. I haven't had much time for blogging, but I'm catching up now! This release contains a small set of improvements and bug fixes since the 0.3.0 release in 2024. About Haunt Haunt is a static site generator that uses the Guile Scheme as its configuration language. It aims to be simple, functional, and extensible. Features include: Easy blog and Atom/RSS feed generation Markdown post support Simple development server for viewing edits before publishing Purely functional build process User extensibility Notable changes Added support for HTML in Markdown documents. This was a long time coming because guile-markdown did not support it and the library was abandoned by the original maintainer. As part of my work at Spritely, we forked it, implemented the relevant portions of the CommonMark specification, and released it. Spritely's guile-commonmark fork is now considered to be the official upstream by Guix and others. A further consequence of this is that guile-lib is now a required dependency for building Haunt as we need the (htmlprag) module to parse Markdown documents with embedded HTML. html->shtml from guile-lib's (htmlprag) module is now used instead of xml->sxml in the HTML reader. It was silly of me to use xml->sxml for this purpose years ago, but at the time I wanted guile-lib to be an optional dependency. Added haunt new subcommand for creating a new site. Added default directory, template, and prefix arguments to flat-pages procedure. Added support for index metadata flag to flat pages for pretty URLs. Flat pages now receive all page metadata, not just the page title. This is a breaking change from 0.3.0. Added .scm as an additional extension for sxml-reader. make-file-extension-matcher now supports multiple extensions. Fixed emission of <script> and <style> elements. Fixed handling of no available reader in flat pages builder. Fixed unreachable error handling clause when a reader is not found for a post. Fixed default blog theme template missing an <html> tag. Fixed overloaded -h option in haunt serve. Deprecated post in Skribe reader in favor of document. Download Haunt 0.4.0 is already available in Guix: guix pull guix install haunt See the Haunt project page for information on how to build from source. Thank you to Camilo Rodrigues, Noé Lopez, jgart, Jakob L. Kreuze, and Daniel Meißner for their contributions to this release! Happy haunting!

5 days ago • 1 votes
📚 BoredReading

You seem to be enjoying this.

Join free to unlock everything.

Create free account

Already have an account? Sign in