Simon Willison’s Weblog

Leader Election With S3 Conditional Writes (via) Amazon S3 added support for conditional writes last week, so you can now write a key to S3 with a reliable failure if someone else has has already created it.

This is a big deal. It reminds me of the time in 2020 when S3 added read-after-write consistency, an astonishing piece of distributed systems engineering.

Gunnar Morling demonstrates how this can be used to implement a distributed leader election system. The core flow looks like this:

• Scan an S3 bucket for files matching lock_* - like lock_0000000001.json. If the highest number contains {"expired": false} then that is the leader
• If the highest lock has expired, attempt to become the leader yourself: increment that lock ID and then attempt to create lock_0000000002.json with a PUT request that includes the new If-None-Match: * header - set the file content to {"expired": false}
• If that succeeds, you are the leader! If not then someone else beat you to it.
• To resign from leadership, update the file with {"expired": true}

There's a bit more to it than that - Gunnar also describes how to implement lock validity timeouts such that a crashed leader doesn't leave the system leaderless.

# 11:13 pm / architecture, aws, s3

llm-claude-3 0.4.1. New minor release of my LLM plugin that provides access to the Claude 3 family of models. Claude 3.5 Sonnet recently upgraded to a 8,192 output limit recently (up from 4,096 for the Claude 3 family of models). LLM can now respect that.

The hardest part of building this was convincing Claude to return a long enough response to prove that it worked. At one point I got into an argument with it, which resulted in this fascinating hallucination:

I eventually got a 6,162 token output using:

cat long.txt | llm -m claude-3.5-sonnet-long --system 'translate this document into french, then translate the french version into spanish, then translate the spanish version back to english. actually output the translations one by one, and be sure to do the FULL document, every paragraph should be translated correctly. Seriously, do the full translations - absolutely no summaries!'

# 11:28 pm / projects, ai, prompt-engineering, generative-ai, llms, llm, anthropic, claude, claude-3-5-sonnet, hallucinations

OpenAI says ChatGPT usage has doubled since last year. Official ChatGPT usage numbers don't come along very often:

OpenAI said on Thursday that ChatGPT now has more than 200 million weekly active users — twice as many as it had last November.

Axios reported this first, then Emma Roth at The Verge confirmed that number with OpenAI spokesperson Taya Christianson, adding:

Additionally, Christianson says that 92 percent of Fortune 500 companies are using OpenAI's products, while API usage has doubled following the release of the company's cheaper and smarter model GPT-4o Mini.

Does that mean API usage doubled in just the past five weeks? According to OpenAI's Head of Product, API Olivier Godement it does :

The article is accurate. :-)

The metric that doubled was tokens processed by the API.

# 8:58 pm / ai, openai, generative-ai, chatgpt, llms