aws-lambda-graphql
Version:
Apollo server for AWS Lambda with WebSocket subscriptions support over API Gateway v1 + v2
119 lines • 6.58 kB
JavaScript
;
var __asyncValues = (this && this.__asyncValues) || function (o) {
if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
var m = o[Symbol.asyncIterator], i;
return m ? m.call(o) : (o = typeof __values === "function" ? __values(o) : o[Symbol.iterator](), i = {}, verb("next"), verb("throw"), verb("return"), i[Symbol.asyncIterator] = function () { return this; }, i);
function verb(n) { i[n] = o[n] && function (v) { return new Promise(function (resolve, reject) { v = o[n](v), settle(resolve, reject, v.done, v.value); }); }; }
function settle(resolve, reject, d, v) { Promise.resolve(v).then(function(v) { resolve({ value: v, done: d }); }, reject); }
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.DynamoDBEventProcessor = void 0;
const aws_sdk_1 = require("aws-sdk");
const iterall_1 = require("iterall");
const ArrayPubSub_1 = require("./ArrayPubSub");
const formatMessage_1 = require("./formatMessage");
const execute_1 = require("./execute");
const protocol_1 = require("./protocol");
const isTTLExpired_1 = require("./helpers/isTTLExpired");
/**
* DynamoDBEventProcessor
*
* Processes DynamoDB stream event in order to send events to subscribed clients
*/
class DynamoDBEventProcessor {
constructor(options = {}) {
this.log = options.log || console.log;
this.onError = options.onError || ((err) => this.log(err));
this.debug = options.debug || false;
}
createHandler(server) {
return async (lambdaEvent, lambdaContext) => {
var e_1, _a;
const connectionManager = server.getConnectionManager();
const subscriptionManager = server.getSubscriptionManager();
const { Records } = lambdaEvent;
for (const record of Records) {
// process only INSERT events
if (record.eventName !== 'INSERT') {
continue;
}
// now construct event from dynamodb image
const event = aws_sdk_1.DynamoDB.Converter.unmarshall(record.dynamodb.NewImage);
// skip if event is expired
if (isTTLExpired_1.isTTLExpired(event.ttl)) {
if (this.debug)
this.log('Discarded event : TTL expired', event);
continue;
}
this.log('Processing event', event);
try {
// iterate over subscribers that listen to this event
// and for each connection:
// - create a schema (so we have subscribers registered in PubSub)
// - execute operation from event againt schema
// - if iterator returns a result, send it to client
// - clean up subscriptions and follow with next page of subscriptions
// - if they are no more subscriptions, process next event
// make sure that you won't throw any errors otherwise dynamo will call
// handler with same events again
for (var _b = (e_1 = void 0, __asyncValues(subscriptionManager.subscribersByEvent(event))), _c; _c = await _b.next(), !_c.done;) {
const subscribers = _c.value;
const promises = subscribers
.map(async (subscriber) => {
// create PubSub for this subscriber
const pubSub = new ArrayPubSub_1.ArrayPubSub([event]);
const options = await server.createGraphQLServerOptions(lambdaEvent, lambdaContext, {
// this allows createGraphQLServerOptions() to append more extra data
// to context from connection.data.context
connection: subscriber.connection,
operation: subscriber.operation,
pubSub,
});
// execute operation by executing it and then publishing the event
const iterable = await execute_1.execute({
connectionManager,
subscriptionManager,
schema: options.schema,
event: lambdaEvent,
lambdaContext,
context: options.context,
connection: subscriber.connection,
operation: subscriber.operation,
pubSub,
registerSubscriptions: false,
});
if (!iterall_1.isAsyncIterable(iterable)) {
// something went wrong, probably there is an error
this.log('Execution result: non iterable', event);
return Promise.resolve();
}
const iterator = iterall_1.getAsyncIterator(iterable);
const result = await iterator.next();
if (result.value != null) {
if (this.debug)
this.log('Send event ', result);
return connectionManager.sendToConnection(subscriber.connection, formatMessage_1.formatMessage({
id: subscriber.operationId,
payload: result.value,
type: protocol_1.SERVER_EVENT_TYPES.GQL_DATA,
}));
}
return Promise.resolve();
})
.map((promise) => promise.catch(this.onError));
await Promise.all(promises);
}
}
catch (e_1_1) { e_1 = { error: e_1_1 }; }
finally {
try {
if (_c && !_c.done && (_a = _b.return)) await _a.call(_b);
}
finally { if (e_1) throw e_1.error; }
}
}
};
}
}
exports.DynamoDBEventProcessor = DynamoDBEventProcessor;
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