Serverless MCP

import { Logger } from '@aws-lambda-powertools/logger'; import { DynamoDBClient } from '@aws-sdk/client-dynamodb'; import middy from '@middy/core'; import { getInternal } from '@middy/util'; import { AwsCredentialIdentity } from '@smithy/types'; import { OneSchema, Table } from 'dynamodb-onetable'; import Dynamo from 'dynamodb-onetable/Dynamo'; import { logger } from '#powertools'; import { getProcessEnv } from './util.js'; /** * Get the table name from the environment variable * @throws {Error} Throws an error if the table name is not set in the environment variables. */ export const getTableName = () => getProcessEnv('TABLE', 'no table name given'); export const getTable = (client: Dynamo, logger: Logger, name: string, tenantId?: string) => (schema: OneSchema) => new Table({ client: new Dynamo({ client }), logger: (level, message, context) => { switch (level) { case 'data': case 'trace': logger.debug(message, context); break; case 'error': case 'exception': logger.error(message, context); break; case 'warn': logger.warn(message, context); break; default: logger.info(message, context); } }, name, partial: false, schema, }).setContext(tenantId ? { tenantId } : {}); /** * Middleware for DynamoDB * This middleware retrieves the table name from the environment variables and creates a DynamoDB client. * It also adds the table name and a function to get the table to the internal state of the request. * @returns {middy.MiddlewareObj} A Middy middleware object with a 'before' hook */ export const dynamoDB = (): middy.MiddlewareObj => ({ before: async (request) => { const tableName = getTableName(); const { credentials, tenantId } = (await getInternal( ['credentials', 'tenantId'], request )) as unknown as { credentials: AwsCredentialIdentity; tenantId: string; }; const client = new DynamoDBClient({ credentials }); Object.assign(request.internal, { getTable: getTable(new Dynamo({ client }), logger, tableName, tenantId), tableName, }); Object.assign(request.context, { dynamoDB: { ...(await getInternal(['getTable'], request)), ...(await getInternal(['tableName'], request)), }, }); }, });