Flowise/packages/components/nodes/vectorstores/Milvus/Milvus_Existing.ts

import { DataType, ErrorCode } from '@zilliz/milvus2-sdk-node'
import { MilvusLibArgs, Milvus } from '@langchain/community/vectorstores/milvus'
import { Embeddings } from '@langchain/core/embeddings'
import { Document } from '@langchain/core/documents'
import { getBaseClasses, getCredentialData, getCredentialParam } from '../../../src/utils'
import { ICommonObject, INode, INodeData, INodeOutputsValue, INodeParams } from '../../../src/Interface'

class Milvus_Existing_VectorStores implements INode {
    label: string
    name: string
    version: number
    description: string
    type: string
    icon: string
    category: string
    badge: string
    baseClasses: string[]
    inputs: INodeParams[]
    credential: INodeParams
    outputs: INodeOutputsValue[]

    constructor() {
        this.label = 'Milvus Load Existing collection'
        this.name = 'milvusExistingCollection'
        this.version = 2.0
        this.type = 'Milvus'
        this.icon = 'milvus.svg'
        this.category = 'Vector Stores'
        this.description = 'Load existing collection from Milvus (i.e: Document has been upserted)'
        this.baseClasses = [this.type, 'VectorStoreRetriever', 'BaseRetriever']
        this.badge = 'DEPRECATING'
        this.credential = {
            label: 'Connect Credential',
            name: 'credential',
            type: 'credential',
            optional: true,
            credentialNames: ['milvusAuth']
        }
        this.inputs = [
            {
                label: 'Embeddings',
                name: 'embeddings',
                type: 'Embeddings'
            },
            {
                label: 'Milvus Server URL',
                name: 'milvusServerUrl',
                type: 'string',
                placeholder: 'http://localhost:19530'
            },
            {
                label: 'Milvus Collection Name',
                name: 'milvusCollection',
                type: 'string'
            },
            {
                label: 'Milvus Filter',
                name: 'milvusFilter',
                type: 'string',
                optional: true,
                description:
                    'Filter data with a simple string query. Refer Milvus <a target="_blank" href="https://milvus.io/blog/2022-08-08-How-to-use-string-data-to-empower-your-similarity-search-applications.md#Hybrid-search">docs</a> for more details.',
                placeholder: 'doc=="a"',
                additionalParams: true
            },
            {
                label: 'Top K',
                name: 'topK',
                description: 'Number of top results to fetch. Default to 4',
                placeholder: '4',
                type: 'number',
                additionalParams: true,
                optional: true
            }
        ]
        this.outputs = [
            {
                label: 'Milvus Retriever',
                name: 'retriever',
                baseClasses: this.baseClasses
            },
            {
                label: 'Milvus Vector Store',
                name: 'vectorStore',
                baseClasses: [this.type, ...getBaseClasses(Milvus)]
            }
        ]
    }

    async init(nodeData: INodeData, _: string, options: ICommonObject): Promise<any> {
        // server setup
        const address = nodeData.inputs?.milvusServerUrl as string
        const collectionName = nodeData.inputs?.milvusCollection as string
        const milvusFilter = nodeData.inputs?.milvusFilter as string

        // embeddings
        const embeddings = nodeData.inputs?.embeddings as Embeddings
        const topK = nodeData.inputs?.topK as string

        // output
        const output = nodeData.outputs?.output as string

        // format data
        const k = topK ? parseInt(topK, 10) : 4

        // credential
        const credentialData = await getCredentialData(nodeData.credential ?? '', options)
        const milvusUser = getCredentialParam('milvusUser', credentialData, nodeData)
        const milvusPassword = getCredentialParam('milvusPassword', credentialData, nodeData)

        // init MilvusLibArgs
        const milVusArgs: MilvusLibArgs = {
            url: address,
            collectionName: collectionName
        }

        if (milvusUser) milVusArgs.username = milvusUser
        if (milvusPassword) milVusArgs.password = milvusPassword

        const vectorStore = await Milvus.fromExistingCollection(embeddings, milVusArgs)

        // Avoid Illegal Invocation
        vectorStore.similaritySearchVectorWithScore = async (query: number[], k: number, filter?: string) => {
            const hasColResp = await vectorStore.client.hasCollection({
                collection_name: vectorStore.collectionName
            })
            if (hasColResp.status.error_code !== ErrorCode.SUCCESS) {
                throw new Error(`Error checking collection: ${hasColResp}`)
            }
            if (hasColResp.value === false) {
                throw new Error(`Collection not found: ${vectorStore.collectionName}, please create collection before search.`)
            }

            const filterStr = milvusFilter ?? filter ?? ''

            await vectorStore.grabCollectionFields()

            const loadResp = await vectorStore.client.loadCollectionSync({
                collection_name: vectorStore.collectionName
            })

            if (loadResp.error_code !== ErrorCode.SUCCESS) {
                throw new Error(`Error loading collection: ${loadResp}`)
            }

            const outputFields = vectorStore.fields.filter((field) => field !== vectorStore.vectorField)

            const searchResp = await vectorStore.client.search({
                collection_name: vectorStore.collectionName,
                search_params: {
                    anns_field: vectorStore.vectorField,
                    topk: k.toString(),
                    metric_type: vectorStore.indexCreateParams.metric_type,
                    params: vectorStore.indexSearchParams
                },
                output_fields: outputFields,
                vector_type: DataType.FloatVector,
                vectors: [query],
                filter: filterStr
            })
            if (searchResp.status.error_code !== ErrorCode.SUCCESS) {
                throw new Error(`Error searching data: ${JSON.stringify(searchResp)}`)
            }
            const results: [Document, number][] = []
            searchResp.results.forEach((result) => {
                const fields = {
                    pageContent: '',
                    metadata: {} as Record<string, any>
                }
                Object.keys(result).forEach((key) => {
                    if (key === vectorStore.textField) {
                        fields.pageContent = result[key]
                    } else if (vectorStore.fields.includes(key) || key === vectorStore.primaryField) {
                        if (typeof result[key] === 'string') {
                            const { isJson, obj } = checkJsonString(result[key])
                            fields.metadata[key] = isJson ? obj : result[key]
                        } else {
                            fields.metadata[key] = result[key]
                        }
                    }
                })
                results.push([new Document(fields), result.score])
            })
            return results
        }

        if (output === 'retriever') {
            const retriever = vectorStore.asRetriever(k)
            return retriever
        } else if (output === 'vectorStore') {
            ;(vectorStore as any).k = k
            if (milvusFilter) {
                ;(vectorStore as any).filter = milvusFilter
            }
            return vectorStore
        }
        return vectorStore
    }
}

function checkJsonString(value: string): { isJson: boolean; obj: any } {
    try {
        const result = JSON.parse(value)
        return { isJson: true, obj: result }
    } catch (e) {
        return { isJson: false, obj: null }
    }
}

module.exports = { nodeClass: Milvus_Existing_VectorStores }