101 lines
3.7 KiB
JavaScript
101 lines
3.7 KiB
JavaScript
'use strict';
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const crypto = require('crypto');
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const { createEmbeddingClient } = require('./embedding');
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const SIM_THRESHOLD = 0.85;
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// 语义缓存：只缓存确定性政策问答，避免订单/库存等实时数据被缓存。
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function createLlmCache(cfg, deps = {}) {
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if (!cfg.pgUrl || !cfg.embApiKey || !cfg.embBaseUrl) {
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return { enabled: false, get: async () => null, store: async () => false };
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}
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const emb = deps.embedding || createEmbeddingClient(cfg, { pgUrl: cfg.pgUrl });
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const pool = deps.pool || emb.pool;
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let ready = null;
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let failed = false;
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function ensureTable() {
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if (failed) return Promise.reject(new Error('cache unavailable'));
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if (!ready) {
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ready = (async () => {
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await pool.query('CREATE EXTENSION IF NOT EXISTS vector');
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await pool.query(`
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CREATE TABLE IF NOT EXISTS bridge_llm_cache (
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id SERIAL PRIMARY KEY,
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query_vec vector(${Number(cfg.embDim) || 1024}),
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query_text TEXT NOT NULL,
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intent TEXT NOT NULL,
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verified_scope TEXT NOT NULL,
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lang TEXT NOT NULL,
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kb_fingerprint TEXT,
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system_hash TEXT,
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reply TEXT NOT NULL,
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hit_count INTEGER NOT NULL DEFAULT 0,
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created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
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UNIQUE (query_text, intent, verified_scope, lang)
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)
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`);
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await pool.query('CREATE INDEX IF NOT EXISTS bridge_llm_cache_vec_idx ON bridge_llm_cache USING hnsw (query_vec vector_cosine_ops)');
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})().catch((err) => {
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failed = true;
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console.error(JSON.stringify({ ts: new Date().toISOString(), warn: `llm cache init failed: ${err.message}` }));
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throw err;
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});
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}
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return ready;
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}
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async function get({ query, intent, verifiedScope, lang, kbFingerprint, systemHash }) {
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try {
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await ensureTable();
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const vec = await emb.embedQuery(query);
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const r = await pool.query(
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`SELECT id, reply, kb_fingerprint, system_hash,
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1 - (query_vec <=> $1::vector) AS sim
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FROM bridge_llm_cache
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WHERE intent = $2 AND verified_scope = $3
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AND 1 - (query_vec <=> $1::vector) > ${SIM_THRESHOLD}
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ORDER BY query_vec <=> $1::vector
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LIMIT 1`,
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[emb.vecStr(vec), intent, verifiedScope || 'anonymous']
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);
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const hit = r.rows && r.rows[0];
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if (!hit) return null;
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if (hit.kb_fingerprint && hit.kb_fingerprint !== (kbFingerprint || '')) return null;
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if (hit.system_hash && hit.system_hash !== (systemHash || '')) return null;
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pool.query('UPDATE bridge_llm_cache SET hit_count = hit_count + 1 WHERE id = $1', [hit.id]).catch(() => {});
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return hit.reply;
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} catch {
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return null;
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}
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}
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async function store({ query, intent, verifiedScope, lang, kbFingerprint, systemHash, reply }) {
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try {
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if (!reply) return false;
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await ensureTable();
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const vec = await emb.embedQuery(query);
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await pool.query(
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`INSERT INTO bridge_llm_cache
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(query_vec, query_text, intent, verified_scope, lang, kb_fingerprint, system_hash, reply)
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VALUES ($1,$2,$3,$4,$5,$6,$7,$8)
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ON CONFLICT (query_text, intent, verified_scope, lang) DO UPDATE SET
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query_vec = EXCLUDED.query_vec,
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kb_fingerprint = EXCLUDED.kb_fingerprint,
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system_hash = EXCLUDED.system_hash,
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reply = EXCLUDED.reply,
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created_at = NOW()`,
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[emb.vecStr(vec), String(query).slice(0, 500), intent, verifiedScope || 'anonymous', lang || 'en', kbFingerprint || '', systemHash || '', reply]
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);
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return true;
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} catch {
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return false;
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}
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}
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return { enabled: true, get, store };
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}
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module.exports = { createLlmCache, SIM_THRESHOLD };
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