Sometimes I cache: implementing lock-free probabilistic caching

HTTP caching is conceptually simple: if the response to a request is in the cache, serve it, and if not, pull it from your origin, put it in the cache, and return it. When the response is old, you repeat the process. If you are worried about too many requests going to your origin at once, you protect it with a cache lock: a small program, possibly distinct from your cache, that indicates if a request is already going to your origin. This is called cache revalidation.

In this blog post, we dive into how cache revalidation works, and present a new approach based on probability. For every request going to the origin, we simulate a die roll. If it’s 6, the request can go to the origin. Otherwise, it stays stale to protect our origin from being overloaded. To see how this is built and optimised, read on.

Background

Let's take the example of an online image library. When a client requests an image, the service first checks its cache to see if the resource is present. If it is, it returns it. If it is not, the image server processes the request, places the response into the Continue reading

Un experimento rápido: translating Cloudflare Stream captions with Workers AI

Cloudflare Stream launched AI-powered automated captions to transcribe English in on-demand videos in March 2024. Customers' immediate next questions were about other languages — both transcribing audio from other languages, and translating captions to make subtitles for other languages. As the Stream Product Manager, I've thought a lot about how we might tackle these, but I wondered…

What if I just translated a generated VTT (caption file)? Can we do that? I hoped to use Workers AI to conduct a quick experiment to learn more about the problem space, challenges we may find, and what platform capabilities we can leverage.

There is a sample translator demo in Workers documentation that uses the “m2m100-1.2b” Many-to-Many multilingual translation model to translate short input strings. I decided to start there and try using it to translate some of the English captions in my Stream library into Spanish.

Selecting test content

I started with my short demo video announcing the transcription feature. I wanted a Worker that could read the VTT captions file from Stream, isolate the text content, and run it through the model as-is.

The first step was parsing the input. A VTT file is a text file that Continue reading

When the world logs off: Christmas, New Year’s, and the Internet’s holiday rhythm

As January approaches and the year comes to a close, distinct changes in global Internet usage emerge. Year-end traditions — ranging from Christmas feasts to New Year’s Eve (NYE) countdowns — shape online behavior across continents and cultures. Looking back at Christmas and NYE 2023 offers insights into how these trends may repeat this year, and by January 2025, we’ll be able to directly compare patterns. Examining data from 50 countries and regions reveals how people celebrated in 2023-2024, providing a timely reminder of typical holiday trends.

With Cloudflare’s global reach, we observe planet-wide and local Internet habits during the holiday season. In the past, unintended trends during Christmas and New Year’s Eve have surfaced through our Outage Center, which uses automatic traffic anomaly alerts to detect Internet outages or unusual patterns. In the 2023 overview below, traffic dropped enough on those days to trigger dozens of anomaly alerts (orange and pink bubbles):

While Christmas dominates in many regions, other cultural and religious holidays — like Hanukkah or regional festivities — shape online rhythms in places where Western traditions are less central.

In countries and regions where Christmas is deeply rooted, Internet traffic slows during Christmas Eve dinners, Continue reading

Grinch Bots strike again: defending your holidays from cyber threats

Grinch Bots are still stealing Christmas

Back in 2021, we covered the antics of Grinch Bots and how the combination of proposed regulation and technology could prevent these malicious programs from stealing holiday cheer.

Fast-forward to 2024 — the Stop Grinch Bots Act of 2021 has not passed, and bots are more active and powerful than ever, leaving businesses to fend off increasingly sophisticated attacks on their own. During Black Friday 2024, Cloudflare observed:

  • 29% of all traffic on Black Friday was Grinch Bots. Humans still accounted for the majority of all traffic, but bot traffic was up 4x from three years ago in absolute terms. 

  • 1% of traffic on Black Friday came from AI bots. The majority of it came from Claude, Meta, and Amazon. 71% of this traffic was given the green light to access the content requested. 

  • 63% of login attempts across our network on Black Friday were from bots. While this number is high, it was down a few percentage points compared to a month prior, indicating that more humans accessed their accounts and holiday deals. 

  • Human logins on e-commerce sites increased 7-8% compared to the previous month. 

These days, holiday shopping Continue reading

Global elections in 2024: Internet traffic and cyber threat trends

Elections define the course of democracies (even as there are several types of democracies), and 2024 was a landmark year, with over 60 countries — plus the European Union — holding national elections, impacting half the world’s population. As highlighted in Pew Research’s global elections report, this was a year of “political disruption,” where the Internet was a relevant stage for both democratic engagement and cyber threats.

At Cloudflare, with our presence in over 330 cities and 120 countries and interconnection with 12,500 networks, we’ve witnessed firsthand the digital impact of these elections. From monitoring Internet traffic patterns to mitigating cyberattacks, we’ve observed trends that reveal how elections increasingly play out online. As detailed in our just-published Cloudflare Impact report, we’ve also worked to protect media outlets, political campaigns, and help elections worldwide.

Here’s the map of countries with national elections that took place in 2024, from our elections report.

We’ve been monitoring 2024 elections worldwide on our blog and in the 2024 Election Insights report available on Cloudflare Radar.

In terms of Internet patterns, we’ve observed how cyber activity in 2024 continues to intersect with real-world events. Online attacks are clearly a significant part of elections, Continue reading

Running Cisco CML in Proxmox

Running Cisco CML in Proxmox

For the past few years, I’ve been running all my virtual machines on VMware Workstation Pro, installed on Windows 11. While it worked well for the most part, there were a few recurring issues. Windows would occasionally reboot to install updates, and when it did, my VMs would go down with it. This dependency on Windows to keep my VMs running became frustrating. Recently, I switched to Proxmox, a type-1 hypervisor, and the difference has been night and day.

In this blog post, we'll go through how to install Cisco CML (specifically CML 2.8 Free Tier) on Proxmox. If you're looking to install Cisco CML on VMware Workstation, check out my other blog post linked below.

Cisco CML Free Tier (No Kidding)
My initial reaction was, ‘Cisco giving something away for free? That can’t be true!’ But it turns out, it is. I couldn’t wait to try it. I believe it’s limited to five nodes, but I’ll take it.
Running Cisco CML in ProxmoxPacketswitchSuresh Vina
Running Cisco CML in Proxmox

Download the Cisco CML Image

Head over to the Cisco download page and select CML (2.8 Free Tier). You need a Cisco account, which is easy to create. Once you create the account and log Continue reading

HN762: A Network Automation Roadmap

Once you get past a handful of Python scripts, network automation can be…daunting. If you want to make network automation process-driven, repeatable, reliable, and something that doesn’t just rely on your scripts and the knowledge inside your head, there’s an entire landscape that opens up before you. Have you thought about network discovery? How about... Read more »

Hi Claude, build an MCP server on Cloudflare Workers

In late November 2024, Anthropic announced a new way to interact with AI, called Model Context Protocol (MCP). Today, we’re excited to show you how to use MCP in combination with Cloudflare to extend the capabilities of Claude to build applications, generate images and more. You’ll learn how to build an MCP server on Cloudflare to make any service accessible through an AI assistant like Claude with just a few lines of code using Cloudflare Workers. 

A quick primer on the Model Context Protocol (MCP)

MCP is an open standard that provides a universal way for LLMs to interact with services and applications. As the introduction on the MCP website puts it,

“Think of MCP like a USB-C port for AI applications. Just as USB-C provides a standardized way to connect your devices to various peripherals and accessories, MCP provides a standardized way to connect AI models to different data sources and tools.” 

From an architectural perspective, MCP is comprised of several components:

  • MCP hosts: Programs or tools (like Claude) where AI models operate and interact with different services

  • MCP clients: Client within an AI assistant that initiates requests and communicates with MCP servers to Continue reading

Bring multimodal real-time interaction to your AI applications with Cloudflare Calls

OpenAI announced support for WebRTC in their Realtime API on December 17, 2024. Combining their Realtime API with Cloudflare Calls allows you to build experiences that weren’t possible just a few days earlier.

Previously, interactions with audio and video AIs were largely single-player: only one person could be interacting with the AI unless you were in the same physical room. Now, applications built using Cloudflare Calls and OpenAI’s Realtime API can now support multiple users across the globe simultaneously seeing and interacting with a voice or video AI.

Have your AI join your video calls 

Here’s what this means in practice: you can now invite ChatGPT to your next video meeting:

We built this into our Orange Meets demo app to serve as an inspiration for what is possible, but the opportunities are much broader.

In the not-too-distant future, every company could have a  'corporate AI' they invite to their internal meetings that is secure, private and has access to their company data. Imagine this sort of real-time audio and video interactions with your company’s AI:

"Hey ChatGPT, do we have any open Jira tickets about this?"

"Hey Company AI, who are the competitors in the space doing Continue reading

Using Multiple AWS Regions with Pulumi and S3 Backend

For a while now, I’ve been using Direnv to manage environment variables when I enter or leave certain directories. Since I have to work with more than one AWS account, one of the use cases for me has been populating AWS-specific environment variables, like AWS_REGION or AWS_PROFILE. This generally works really well for me, but recently I ran into a bit of a corner case involving multiple AWS regions, Pulumi, and using S3 as the Pulumi backend. In this post, I’ll share the workaround that allows this configuration to work as expected.

I describe this as a “bit of a corner case” because it only affects specific configurations (which included my configuration):

  • You must be setting the AWS_REGION environment variable and not setting the aws:region configuration value used by the Pulumi AWS provider.
  • You must be using S3 as the backend for Pulumi, and using an S3 URL of s3://bucket-name.
  • You want to deploy resources into an AWS region that is different than the AWS region where the backend state bucket resides.

In my specific situation, my backend state bucket resides in the AWS us-west-2 (Oregon) region, as this offers the lowest latencies from my home office in Colorado. Continue reading

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