Vector Embedding Server

Server to generate vector embeddings for arbitrary-length documents using E5 model, in under 100 lines of code.

Contains a Dockerfile which downloads e5-small-v2 during build time (hence avoiding any runtime surprises), and runs app.py.

app.py uses this model to generate embeddings, even for longer documents, by chunking them up at sentence level, and taking a mean at the end. The sentences are chunked at 500 tokens each, to avoid crossing the 512 token limit enforced by E5 models.

Why build this?

I was looking for a Docker-based server, which can expose a simple endpoint to generate vector embeddings for documents. The solution needs to deal with lengthy documents that exceed the 512-token limit enforced by E5 models. Such documents require intelligent chunking, ideally at sentence boundaries, followed by taking a mean of the vectors, to work effectively. Since I couldn't find a solution that met these criteria, I decided to create this setup myself.

This setup doesn't deal with storing and searching over the vectors. It only deals with generation of the vectors. To search over the vectors, you'd need another system.

Build

$ docker build -t <tag> .
$ docker run -p 10002:10002 <tag>

By default, this is using e5-small-v2 model. If you wish to change the model, you'd have to update the name in both Dockerfile and app.py.

Usage

When passing a document, use the prefix: passage: . When querying for similar documents, use the prefix query: . e5-small-v2 has a question about these prefixes in the FAQ.

If a single sentence exceeds the 512 tokens limit, then we ignore that sentence, considering it invalid, and adding its tokens to the invalid_tokens count.

num_tokens is the total number of tokens the document has, including the invalid_tokens.

$ curl http://localhost:10002/embed -XPOST -H "content-type: application/json" -d '{"prefix": "passage: ", "text": "This is a sentence."}' | jq

{
  "embedding": [
    -0.07240722328424454,
    0.03763573244214058,
    0.02595547027885914,
    -0.017270879819989204,
    -0.023462336510419846,
    0.05062587931752205,
    0.07775235176086426,
    -0.06687597930431366,
    ...
        -0.06454016268253326,
    0.006377237383276224,
    -0.0546715222299099,
    -0.002629948779940605,
    -0.0011916998773813248,
    0.026298822835087776
  ],
  "invalid_tokens": 0,
  "num_tokens": 5
}