/**
* Embedding Provider Factory
*
* Creates embedding providers based on configuration and availability.
* Supports OpenAI (when API key available) and Transformers.js (local fallback).
*/
import type { EmbeddingProvider, EmbeddingConfig } from "./types.js";
import { createLogger } from "../shared/logger.js";
import { withSpan, SpanAttributes, SpanOperations } from "../shared/index.js";
import { getConfig } from "../config/index.js";
import { OpenAIEmbeddingProvider } from "./openai.js";
import { TransformersEmbeddingProvider } from "./transformers.js";
const logger = createLogger("Embeddings");
let cachedProvider: EmbeddingProvider | null = null;
/**
* Get the configured embedding provider.
* Uses factory pattern with automatic fallback.
*/
export async function getEmbeddingProvider(
config?: Partial<EmbeddingConfig>
): Promise<EmbeddingProvider> {
return withSpan(`embedding.get-provider`, SpanOperations.EMBEDDING_GENERATE, async (span) => {
if (cachedProvider) {
span?.setAttribute("provider.cached", true);
span?.setAttribute(SpanAttributes.EMBEDDING_PROVIDER, cachedProvider.providerId);
span?.setAttribute(SpanAttributes.EMBEDDING_MODEL, cachedProvider.modelId);
return cachedProvider;
}
span?.setAttribute("provider.cached", false);
const appConfig = getConfig();
const provider = config?.provider ?? appConfig.embeddingProvider ?? "auto";
const openaiKey = config?.openaiApiKey ?? appConfig.openaiApiKey;
span?.setAttribute("provider.requested", provider);
// Explicit provider selection
if (provider === "openai") {
if (!openaiKey) {
throw new Error("OpenAI provider requested but OPENAI_API_KEY not set");
}
cachedProvider = new OpenAIEmbeddingProvider(openaiKey, config?.openaiModel);
span?.setAttribute(SpanAttributes.EMBEDDING_PROVIDER, cachedProvider.providerId);
span?.setAttribute(SpanAttributes.EMBEDDING_MODEL, cachedProvider.modelId);
logger.info("Using OpenAI embedding provider", {
model: cachedProvider.modelId,
});
return cachedProvider;
}
if (provider === "transformers") {
cachedProvider = await TransformersEmbeddingProvider.create();
span?.setAttribute(SpanAttributes.EMBEDDING_PROVIDER, cachedProvider.providerId);
span?.setAttribute(SpanAttributes.EMBEDDING_MODEL, cachedProvider.modelId);
logger.info("Using Transformers.js embedding provider", {
model: cachedProvider.modelId,
});
return cachedProvider;
}
// Auto mode: prefer OpenAI if available, fallback to Transformers.js
if (openaiKey) {
const openaiProvider = new OpenAIEmbeddingProvider(openaiKey, config?.openaiModel);
if (await openaiProvider.isAvailable()) {
cachedProvider = openaiProvider;
span?.setAttribute(SpanAttributes.EMBEDDING_PROVIDER, cachedProvider.providerId);
span?.setAttribute(SpanAttributes.EMBEDDING_MODEL, cachedProvider.modelId);
logger.info("Auto-selected OpenAI embedding provider", {
model: cachedProvider.modelId,
});
return cachedProvider;
}
logger.warn("OpenAI API key provided but API unavailable, falling back to Transformers.js");
}
// Fallback to Transformers.js
cachedProvider = await TransformersEmbeddingProvider.create();
span?.setAttribute(SpanAttributes.EMBEDDING_PROVIDER, cachedProvider.providerId);
span?.setAttribute(SpanAttributes.EMBEDDING_MODEL, cachedProvider.modelId);
logger.info("Auto-selected Transformers.js embedding provider (local)", {
model: cachedProvider.modelId,
});
return cachedProvider;
});
}
/**
* Reset the cached provider (useful for testing).
*/
export function resetEmbeddingProvider(): void {
cachedProvider = null;
}
export type {
EmbeddingProvider,
EmbeddingConfig,
EmbeddingResult,
BatchEmbeddingResult,
} from "./types.js";
