@middy/service-discovery/index.js

import { canPrefetch, createPrefetchClient, createClient, getCache, getInternal, processCache, modifyCache } from '@middy/util';
import { ServiceDiscoveryClient, DiscoverInstancesCommand } from '@aws-sdk/client-servicediscovery';
const defaults = {
    AwsClient: ServiceDiscoveryClient,
    awsClientOptions: {},
    awsClientAssumeRole: undefined,
    awsClientCapture: undefined,
    fetchData: {},
    disablePrefetch: false,
    cacheKey: 'cloud-map',
    cacheKeyExpiry: {},
    cacheExpiry: -1,
    setToContext: false
};
const serviceDiscoveryMiddleware = (opts = {})=>{
    const options = {
        ...defaults,
        ...opts
    };
    const fetch = (request, cachedValues = {})=>{
        const values = {};
        for (const internalKey of Object.keys(options.fetchData)){
            if (cachedValues[internalKey]) continue;
            values[internalKey] = client.send(new DiscoverInstancesCommand(options.fetchData[internalKey])).then((resp)=>resp.Instances).catch((e)=>{
                const value = getCache(options.cacheKey).value ?? {};
                value[internalKey] = undefined;
                modifyCache(options.cacheKey, value);
                throw e;
            });
        }
        return values;
    };
    let client;
    if (canPrefetch(options)) {
        client = createPrefetchClient(options);
        processCache(options, fetch);
    }
    const serviceDiscoveryMiddlewareBefore = async (request)=>{
        if (!client) {
            client = await createClient(options, request);
        }
        const { value } = processCache(options, fetch, request);
        Object.assign(request.internal, value);
        if (options.setToContext) {
            const data = await getInternal(Object.keys(options.fetchData), request);
            if (options.setToContext) Object.assign(request.context, data);
        }
    };
    return {
        before: serviceDiscoveryMiddlewareBefore
    };
};
export default serviceDiscoveryMiddleware;