This guide will walk you through the process of connecting to a Milvus database using Node.js within your Sealos DevBox project.

Prerequisites

A Sealos DevBox project with Node.js environment
A Milvus database created using the Database app in Sealos

Install Required Packages

In your Cursor terminal, install the necessary packages:

npm install @zilliz/milvus2-sdk-node dotenv

This command installs:

@zilliz/milvus2-sdk-node: The official Milvus Node.js SDK
dotenv: A zero-dependency module that loads environment variables from a .env file

Connection Setup

Set up the environment variables

First, let's set up the environment variables for our Milvus connection. Create a .env file in your project root with the following content:

.env

MILVUS_HOST=your_milvus_host
MILVUS_PORT=19530
COLLECTION_NAME=test_collection
DIMENSION=128

Replace the placeholders with your actual Milvus credentials from the Database app in Sealos.

Create a connection file

Create a new file named milvusClient.js with the following content:

milvusClient.js

const { MilvusClient } = require('@zilliz/milvus2-sdk-node');
require('dotenv').config();
 
const client = new MilvusClient({
  address: `${process.env.MILVUS_HOST}:${process.env.MILVUS_PORT}`,
});
 
module.exports = client;

Create database operations

Now, let's create a file named milvusOperations.js to handle our database operations:

milvusOperations.js

const client = require('./milvusClient');
require('dotenv').config();
 
async function createCollection() {
  try {
    const collectionName = process.env.COLLECTION_NAME;
    const dimension = parseInt(process.env.DIMENSION);
 
    // Define collection schema
    const collectionSchema = {
      collection_name: collectionName,
      fields: [
        {
          name: 'id',
          data_type: 'Int64',
          is_primary_key: true,
          auto_id: true
        },
        {
          name: 'vector',
          data_type: 'FloatVector',
          dim: dimension
        },
        {
          name: 'metadata',
          data_type: 'VarChar',
          max_length: 255
        }
      ]
    };
 
    // Create collection
    await client.createCollection(collectionSchema);
    console.log(`Collection ${collectionName} created successfully`);
 
    // Create index
    const indexParams = {
      collection_name: collectionName,
      field_name: 'vector',
      extra_params: {
        index_type: 'IVF_FLAT',
        metric_type: 'L2',
        params: JSON.stringify({ nlist: 1024 })
      }
    };
    await client.createIndex(indexParams);
    console.log('Index created successfully');
  } catch (error) {
    console.error('Error creating collection:', error);
    throw error;
  }
}
 
async function insertData(vectors, metadata) {
  try {
    const collectionName = process.env.COLLECTION_NAME;
    
    const data = {
      collection_name: collectionName,
      fields_data: vectors.map((vector, index) => ({
        id: [],
        vector,
        metadata: metadata[index]
      }))
    };
 
    const result = await client.insert(data);
    console.log('Data inserted successfully:', result);
    return result;
  } catch (error) {
    console.error('Error inserting data:', error);
    throw error;
  }
}
 
async function search(queryVector, topK = 5) {
  try {
    const collectionName = process.env.COLLECTION_NAME;
 
    // Load collection
    await client.loadCollection({
      collection_name: collectionName
    });
 
    const searchParams = {
      collection_name: collectionName,
      vector: queryVector,
      output_fields: ['metadata'],
      limit: topK,
      params: { nprobe: 10 }
    };
 
    const result = await client.search(searchParams);
    console.log('Search results:', result);
    return result;
  } catch (error) {
    console.error('Error searching:', error);
    throw error;
  }
}
 
module.exports = {
  createCollection,
  insertData,
  search
};

Create a main script

Finally, let's create a main.js file to demonstrate all the operations:

main.js

const { createCollection, insertData, search } = require('./milvusOperations');
 
async function main() {
  try {
    // Create collection
    await createCollection();
 
    // Generate sample vectors and metadata
    const sampleVectors = [
      new Array(128).fill(0).map(() => Math.random()),
      new Array(128).fill(0).map(() => Math.random())
    ];
    const sampleMetadata = ['Sample 1', 'Sample 2'];
 
    // Insert data
    await insertData(sampleVectors, sampleMetadata);
 
    // Perform search
    const queryVector = new Array(128).fill(0).map(() => Math.random());
    await search(queryVector, 2);
 
  } catch (error) {
    console.error('An error occurred:', error);
  }
}
 
main();

Usage

To run the script, use the following command in your Cursor terminal:

node main.js

This will execute all the operations defined in the main function, demonstrating the connection to Milvus, collection creation, data insertion, and vector search.

Best Practices

Use environment variables for Milvus connection details.
Create indexes for better search performance.
Load collections before performing search operations.
Implement proper error handling.
Use batch operations for inserting multiple vectors.
Release resources by releasing collections when they're no longer needed.

Troubleshooting

If you encounter connection issues:

Verify your Milvus credentials in the .env file.
Ensure your Milvus database is running and accessible.
Check for any network restrictions in your DevBox environment.
Confirm that the required packages are correctly installed.
Verify that the vector dimensions match your collection schema.

For more detailed information on using Milvus with Node.js, refer to the Milvus Node.js SDK documentation.

Node.js