Initial Python implementation with ONNX Runtime

- Multi-stage Docker build (simplified to single-stage with pre-converted ONNX)
- HTTP server with ONNX inference
- API secret authentication
- Uses pre-converted all-MiniLM-L6-v2 ONNX model from onnx-community
- Image size: ~373 MB

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>
This commit is contained in:
Christoph Haas 2026-06-28 12:04:00 +02:00
commit 6101df3bfe
3 changed files with 227 additions and 0 deletions

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# Minimal image: ~200-250MB
# Uses pre-converted ONNX model from onnx-community
FROM python:3.11-slim
WORKDIR /app
# Install runtime dependencies and download model
RUN apt-get update && \
apt-get install -y --no-install-recommends wget && \
pip install --no-cache-dir onnxruntime numpy && \
# Download pre-converted ONNX model and tokenizer files
wget -q https://huggingface.co/onnx-community/all-MiniLM-L6-v2-ONNX/resolve/main/onnx/model.onnx -O /app/model.onnx && \
wget -q https://huggingface.co/onnx-community/all-MiniLM-L6-v2-ONNX/resolve/main/onnx/model.onnx_data -O /app/model.onnx_data && \
wget -q https://huggingface.co/onnx-community/all-MiniLM-L6-v2-ONNX/resolve/main/tokenizer.json -O /app/tokenizer.json && \
wget -q https://huggingface.co/onnx-community/all-MiniLM-L6-v2-ONNX/resolve/main/tokenizer_config.json -O /app/tokenizer_config.json && \
wget -q https://huggingface.co/onnx-community/all-MiniLM-L6-v2-ONNX/resolve/main/vocab.txt -O /app/vocab.txt && \
wget -q https://huggingface.co/onnx-community/all-MiniLM-L6-v2-ONNX/resolve/main/config.json -O /app/config.json && \
# Clean up
apt-get remove -y wget 2>/dev/null || true && \
apt-get clean && \
rm -rf /var/lib/apt/lists/* /tmp/* /root/.cache /var/cache/apt/*
COPY server.py .
EXPOSE 8080
ENV PORT=8080
CMD ["python", "server.py"]

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# Vector Service
A minimal Docker container that provides text embedding vectors using the all-MiniLM-L6-v2 model. The service accepts POST requests with text and returns a 384-dimensional embedding vector.
## Features
- **Small image size**: ~373 MB (much smaller than typical Python-based solutions)
- **Fast inference**: Uses ONNX Runtime for efficient model execution
- **API authentication**: Optional API secret protection
- **Pre-converted ONNX**: Uses ready-to-use ONNX model from HuggingFace
## Usage
### Build the container
```bash
podman build -t vector-service .
```
Or with Docker:
```bash
docker build -t vector-service .
```
The build process will:
1. Download the pre-converted ONNX model from `onnx-community/all-MiniLM-L6-v2-ONNX` on HuggingFace
2. Install only the runtime dependencies (ONNX Runtime + NumPy)
3. Create a minimal image (~373 MB)
### Run the service
Without authentication:
```bash
podman run --rm -p 8080:8080 -d vector-service
```
With API secret authentication:
```bash
podman run --rm -p 8080:8080 -e API_SECRET=your-secret-key -d vector-service
```
### Query the service
Send a POST request with JSON body:
```bash
curl -X POST http://localhost:8080/vector \
-H "Content-Type: application/json" \
-H "Authorization: Bearer your-secret-key" \
-d '{"text": "Hello World"}'
```
Response:
```json
{
"vector": [0.1868536774709355, 0.8120285351760685, ...]
}
```
The vector has 384 dimensions.
### Without authentication
If you didn't set `API_SECRET`, you can query without the Authorization header:
```bash
curl -X POST http://localhost:8080/vector \
-H "Content-Type: application/json" \
-d '{"text": "Hello World"}'
```
## Files
- `Dockerfile`: Single-stage build with pre-downloaded ONNX model
- `server.py`: HTTP server with ONNX inference
## Technical Details
### Model
- **Model**: all-MiniLM-L6-v2 (80 MB on disk)
- **Source**: Pre-converted ONNX from [onnx-community/all-MiniLM-L6-v2-ONNX](https://huggingface.co/onnx-community/all-MiniLM-L6-v2-ONNX)
- **Dimensions**: 384
- **Format**: ONNX (pre-converted)
### Dependencies
- Runtime: Python 3.11, ONNX Runtime, NumPy
- No build-time dependencies needed (uses pre-converted model)
### Image Size Breakdown
- Model files (ONNX + ONNX data + tokenizer + vocab): ~95 MB
- Python runtime and dependencies: ~278 MB
- Total: ~373 MB
## Notes
- The build will download the pre-converted ONNX model from HuggingFace (~95 MB total)
- Much faster builds since no PyTorch or model conversion is needed
- The ONNX model includes an external data file (`model.onnx_data`) which is normal for larger models
- For production use, consider adding rate limiting and HTTPS

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#!/usr/bin/env python3
import json, os, sys, numpy as np
import onnxruntime as ort
from http.server import BaseHTTPRequestHandler, HTTPServer
# Load model at startup
session = ort.InferenceSession("/app/model.onnx")
# Load vocab from vocab.txt
vocab = {}
with open("/app/vocab.txt", "r", encoding="utf-8") as f:
for idx, token in enumerate(f):
token = token.strip()
vocab[token] = idx
# Token IDs from tokenizer_config.json
with open("/app/tokenizer_config.json", "r") as f:
tokenizer_config = json.load(f)
# Map token strings to IDs using vocab
cls_token_id = vocab.get(tokenizer_config["cls_token"], 0)
sep_token_id = vocab.get(tokenizer_config["sep_token"], 0)
pad_token_id = vocab.get(tokenizer_config["pad_token"], 0)
unk_token_id = vocab.get(tokenizer_config["unk_token"], 0)
def wordpiece_tokenize(text):
text = text.lower()
tokens = []
buffer = ""
for char in text:
if char.isspace():
if buffer:
tokens.append(buffer if buffer in vocab else "[UNK]")
buffer = ""
else:
buffer += char
if buffer:
tokens.append(buffer if buffer in vocab else "[UNK]")
return tokens
def encode(text, max_len=128):
token_ids = [vocab.get(t, unk_token_id) for t in wordpiece_tokenize(text)]
input_ids = [cls_token_id] + token_ids + [sep_token_id]
if len(input_ids) > max_len:
input_ids = input_ids[:max_len]
else:
input_ids = input_ids + [pad_token_id] * (max_len - len(input_ids))
attention_mask = [1] * len(input_ids)
token_type_ids = [0] * len(input_ids)
return input_ids, attention_mask, token_type_ids
print("Model loaded. Starting server on port 8080...")
API_SECRET = os.getenv("API_SECRET")
class VectorHandler(BaseHTTPRequestHandler):
def do_POST(self):
if self.path != "/vector":
self.send_error(404)
return
# Check API secret
if API_SECRET:
auth_header = self.headers.get("Authorization", "")
if auth_header != f"Bearer {API_SECRET}":
self.send_error(401, "Unauthorized - Invalid or missing API key")
return
content_length = int(self.headers.get("Content-Length", 0))
body = self.rfile.read(content_length)
try:
req = json.loads(body)
text = req.get("text", "")
if not text:
self.send_error(400, "Text is required")
return
input_ids, attention_mask, token_type_ids = encode(text)
input_ids_np = np.array([input_ids], dtype=np.int64)
attention_mask_np = np.array([attention_mask], dtype=np.int64)
token_type_ids_np = np.array([token_type_ids], dtype=np.int64)
outputs = session.run(
["last_hidden_state"],
{"input_ids": input_ids_np, "attention_mask": attention_mask_np, "token_type_ids": token_type_ids_np}
)
token_embeddings = outputs[0][0]
input_mask_expanded = np.expand_dims(attention_mask_np[0], axis=-1)
sum_embeddings = np.sum(token_embeddings * input_mask_expanded, axis=0)
sum_mask = np.maximum(np.sum(input_mask_expanded, axis=0), 1e-9)
sentence_embedding = (sum_embeddings / sum_mask).tolist()
resp = json.dumps({"vector": sentence_embedding})
self.send_response(200)
self.send_header("Content-Type", "application/json")
self.end_headers()
self.wfile.write(resp.encode())
except Exception as e:
self.send_error(500, str(e))
def log_message(self, format, *args):
pass # Suppress logs
HTTPServer(("0.0.0.0", int(os.getenv("PORT", 8080))), VectorHandler).serve_forever()