I'm getting started with AWS Lambda and I'm trying to request an external service from my handler function. According to this answer, HTTP requests should work just fine, and I haven't found any documentation that says otherwise. (In fact, people have posted code that use the Twilio API to send SMS.)
My handler code is:
var http = require('http');
exports.handler = function(event, context) {
console.log('start request to ' + event.url)
http.get(event.url, function(res) {
console.log("Got response: " + res.statusCode);
}).on('error', function(e) {
console.log("Got error: " + e.message);
});
console.log('end request to ' + event.url)
context.done(null);
}
and I see the following 4 lines in my CloudWatch logs:
2015-02-11 07:38:06 UTC START RequestId: eb19c89d-b1c0-11e4-bceb-d310b88d37e2
2015-02-11 07:38:06 UTC eb19c89d-b1c0-11e4-bceb-d310b88d37e2 start request to http://www.google.com
2015-02-11 07:38:06 UTC eb19c89d-b1c0-11e4-bceb-d310b88d37e2 end request to http://www.google.com
2015-02-11 07:38:06 UTC END RequestId: eb19c89d-b1c0-11e4-bceb-d310b88d37e2
I'd expect another line in there:
2015-02-11 07:38:06 UTC eb19c89d-b1c0-11e4-bceb-d310b88d37e2 Got response: 302
but that's missing. If I'm using the essential part without the handler wrapper in node on my local machine, the code works as expected.
The inputfile.txt I'm using is for the invoke-async call is this:
{
"url":"http://www.google.com"
}
It seems like the part of the handler code that does the request is skipped entirely. I started out with the request lib and fell back to using plain http to create a minimal example. I've also tried to request a URL of a service I control to check the logs and there's no requests coming in.
I'm totally stumped. Is there any reason Node and/or AWS Lambda would not execute the HTTP request?
Of course, I was misunderstanding the problem. As AWS themselves put it:
For those encountering nodejs for the first time in Lambda, a common
error is forgetting that callbacks execute asynchronously and calling
context.done() in the original handler when you really meant to wait
for another callback (such as an S3.PUT operation) to complete, forcing
the function to terminate with its work incomplete.
I was calling context.done way before any callbacks for the request fired, causing the termination of my function ahead of time.
The working code is this:
var http = require('http');
exports.handler = function(event, context) {
console.log('start request to ' + event.url)
http.get(event.url, function(res) {
console.log("Got response: " + res.statusCode);
context.succeed();
}).on('error', function(e) {
console.log("Got error: " + e.message);
context.done(null, 'FAILURE');
});
console.log('end request to ' + event.url);
}
Update: starting 2017 AWS has deprecated the old Nodejs 0.10 and only the newer 4.3 run-time is now available (old functions should be updated). This runtime introduced some changes to the handler function. The new handler has now 3 parameters.
function(event, context, callback)
Although you will still find the succeed, done and fail on the context parameter, AWS suggest to use the callback function instead or null is returned by default.
callback(new Error('failure')) // to return error
callback(null, 'success msg') // to return ok
Complete documentation can be found at http://docs.aws.amazon.com/lambda/latest/dg/nodejs-prog-model-handler.html
Simple Working Example of Http request using node.
const http = require('https')
exports.handler = async (event) => {
return httprequest().then((data) => {
const response = {
statusCode: 200,
body: JSON.stringify(data),
};
return response;
});
};
function httprequest() {
return new Promise((resolve, reject) => {
const options = {
host: 'jsonplaceholder.typicode.com',
path: '/todos',
port: 443,
method: 'GET'
};
const req = http.request(options, (res) => {
if (res.statusCode < 200 || res.statusCode >= 300) {
return reject(new Error('statusCode=' + res.statusCode));
}
var body = [];
res.on('data', function(chunk) {
body.push(chunk);
});
res.on('end', function() {
try {
body = JSON.parse(Buffer.concat(body).toString());
} catch(e) {
reject(e);
}
resolve(body);
});
});
req.on('error', (e) => {
reject(e.message);
});
// send the request
req.end();
});
}
Yeah, awendt answer is perfect. I'll just show my working code... I had the context.succeed('Blah'); line right after the reqPost.end(); line. Moving it to where I show below solved everything.
console.log('GW1');
var https = require('https');
exports.handler = function(event, context) {
var body='';
var jsonObject = JSON.stringify(event);
// the post options
var optionspost = {
host: 'the_host',
path: '/the_path',
method: 'POST',
headers: {
'Content-Type': 'application/json',
}
};
var reqPost = https.request(optionspost, function(res) {
console.log("statusCode: ", res.statusCode);
res.on('data', function (chunk) {
body += chunk;
});
context.succeed('Blah');
});
reqPost.write(jsonObject);
reqPost.end();
};
I faced this issue on Node 10.X version.
below is my working code.
const https = require('https');
exports.handler = (event,context,callback) => {
let body='';
let jsonObject = JSON.stringify(event);
// the post options
var optionspost = {
host: 'example.com',
path: '/api/mypath',
method: 'POST',
headers: {
'Content-Type': 'application/json',
'Authorization': 'blah blah',
}
};
let reqPost = https.request(optionspost, function(res) {
console.log("statusCode: ", res.statusCode);
res.on('data', function (chunk) {
body += chunk;
});
res.on('end', function () {
console.log("Result", body.toString());
context.succeed("Sucess")
});
res.on('error', function () {
console.log("Result Error", body.toString());
context.done(null, 'FAILURE');
});
});
reqPost.write(jsonObject);
reqPost.end();
};
Modern Async/Await Example
You need to prevent the lambda from finishing before the https request has completed. It makes code with multiple requests easier to read as well.
const https = require('https');
// Helper that turns https.request into a promise
function httpsRequest(options) {
return new Promise((resolve, reject) => {
const req = https.request(options, (res) => {
if (res.statusCode < 200 || res.statusCode >= 300) {
return reject(new Error('statusCode=' + res.statusCode));
}
var body = [];
res.on('data', function(chunk) {
body.push(chunk);
});
res.on('end', function() {
try {
body = JSON.parse(Buffer.concat(body).toString());
} catch(e) {
reject(e);
}
resolve(body);
});
});
req.on('error', (e) => {
reject(e.message);
});
req.end();
});
}
// Lambda starts executing here
exports.handler = async event => {
// --- GET example request
var options = {
method: 'GET',
hostname: 'postman-echo.com',
path: encodeURI('/get?foo1=bar1'),
headers: {
},
};
try {
const getBody = await httpsRequest(options);
// The console.log below will not run until the GET request above finishes
console.log('GET completed successfully! Response body:', getBody);
} catch (err) {
console.error('GET request failed, error:', err);
}
// --- POST example request
var options = {
method: 'POST',
hostname: 'postman-echo.com',
path: encodeURI('/hi/there?hand=wave'),
headers: {
},
};
try {
const postBody = await httpsRequest(options);
// The console.log below will not run until the POST request above finishes
console.log('POST response body:', postBody);
} catch (err) {
console.error('POST request failed, error:', err);
}
};
I had the very same problem and then I realized that programming in NodeJS is actually different than Python or Java as its based on JavaScript. I'll try to use simple concepts as there may be a few new folks that would be interested or may come to this question.
Let's look at the following code :
var http = require('http'); // (1)
exports.handler = function(event, context) {
console.log('start request to ' + event.url)
http.get(event.url, // (2)
function(res) { //(3)
console.log("Got response: " + res.statusCode);
context.succeed();
}).on('error', function(e) {
console.log("Got error: " + e.message);
context.done(null, 'FAILURE');
});
console.log('end request to ' + event.url); //(4)
}
Whenever you make a call to a method in http package (1) , it is created as event and this event gets it separate event. The 'get' function (2) is actually the starting point of this separate event.
Now, the function at (3) will be executing in a separate event, and your code will continue it executing path and will straight jump to (4) and finish it off, because there is nothing more to do.
But the event fired at (2) is still executing somewhere and it will take its own sweet time to finish. Pretty bizarre, right ?. Well, No it is not. This is how NodeJS works and its pretty important you wrap your head around this concept. This is the place where JavaScript Promises come to help.
You can read more about JavaScript Promises here. In a nutshell, you would need a JavaScript Promise to keep the execution of code inline and will not spawn new / extra threads.
Most of the common NodeJS packages have a Promised version of their API available, but there are other approaches like BlueBirdJS that address the similar problem.
The code that you had written above can be loosely re-written as follows.
'use strict';
console.log('Loading function');
var rp = require('request-promise');
exports.handler = (event, context, callback) => {
var options = {
uri: 'https://httpbin.org/ip',
method: 'POST',
body: {
},
json: true
};
rp(options).then(function (parsedBody) {
console.log(parsedBody);
})
.catch(function (err) {
// POST failed...
console.log(err);
});
context.done(null);
};
Please note that the above code will not work directly if you will import it in AWS Lambda. For Lambda, you will need to package the modules with the code base too.
I've found lots of posts across the web on the various ways to do the request, but none that actually show how to process the response synchronously on AWS Lambda.
Here's a Node 6.10.3 lambda function that uses an https request, collects and returns the full body of the response, and passes control to an unlisted function processBody with the results. I believe http and https are interchangable in this code.
I'm using the async utility module, which is easier to understand for newbies. You'll need to push that to your AWS Stack to use it (I recommend the serverless framework).
Note that the data comes back in chunks, which are gathered in a global variable, and finally the callback is called when the data has ended.
'use strict';
const async = require('async');
const https = require('https');
module.exports.handler = function (event, context, callback) {
let body = "";
let countChunks = 0;
async.waterfall([
requestDataFromFeed,
// processBody,
], (err, result) => {
if (err) {
console.log(err);
callback(err);
}
else {
const message = "Success";
console.log(result.body);
callback(null, message);
}
});
function requestDataFromFeed(callback) {
const url = 'https://put-your-feed-here.com';
console.log(`Sending GET request to ${url}`);
https.get(url, (response) => {
console.log('statusCode:', response.statusCode);
response.on('data', (chunk) => {
countChunks++;
body += chunk;
});
response.on('end', () => {
const result = {
countChunks: countChunks,
body: body
};
callback(null, result);
});
}).on('error', (err) => {
console.log(err);
callback(err);
});
}
};
Use promises with resolve reject. It worked for me!
Add above code in API gateway under GET-Integration Request> mapping section.
Yes, there's in fact many reasons why you can access AWS Lambda like and HTTP Endpoint.
The architecture of AWS Lambda
It's a microservice. Running inside EC2 with Amazon Linux AMI (Version 3.14.26–24.46.amzn1.x86_64) and runs with Node.js. The memory can be beetwen 128mb and 1gb. When the data source triggers the event, the details are passed to a Lambda function as parameter's.
What happen?
AWS Lambda run's inside a container, and the code is directly uploaded to this container with packages or modules. For example, we NEVER can do SSH for the linux machine running your lambda function. The only things that we can monitor are the logs, with CloudWatchLogs and the exception that came from the runtime.
AWS take care of launch and terminate the containers for us, and just run the code. So, even that you use require('http'), it's not going to work, because the place where this code runs, wasn't made for this.
Related
I am trying to write a function that creates an HTTPS request.
This is all part of an expressjs project with Typescript.
I can get the HTTPS request working and getting a response - but the response is encoded with GZIP. I am trying my best to follow the documentation. But no luck, the response stays zipped.
This is my code
private getData = (host, pathname): Promise<string> => {
return new Promise((resolve, reject) => {
const options = {
hostname: host,
path: pathname,
gzip: true,
method: 'GET',
headers: {'x-apikey': 'XXXX'}
}
const req = https.request(options, (res) => {
if (res.statusCode < 200 || res.statusCode >= 300) {
console.log('error!')
return reject(new Error('statusCode=' + res.statusCode));
}
let body = '';
res.on('data', function (chunk) {
body += chunk;
});
res.on('end', function () {
try {
console.log('res.headers', res.headers)
console.log('res.headers', body)
body = JSON.parse.toString();
resolve(body);
} catch (e) {
reject(e);
}
resolve(body);
});
req.on('error', (e) => {
reject(e.message);
});
// send the request
});
req.end();
});
}
The console log statement shows this
So obviously the JSONparsing is failing. What am I missing?
Thanks heaps for the help
https.request() does not natively support gzip compression. So, you will have to either add support for it yourself as shown here or use an https request library such as got() that already supports gzip (and also already supports promises too).
import got from 'got';
private getData = (host, pathname): Promise<string> => {
const options = {
method: 'GET',
headers: {'x-apikey': 'XXXX'}
}
return got(`https://${host}${pathname}`, options).json();
}
FYI, it's not clear in your question what type of response you are expecting. You attempt to use:
body = JSON.parse.toString();
which doesn't make any sense because JSON.parse.toString() is trying to get string version of the JSON.parse function without actually even calling that function - very odd. Perhaps you meant JSON.parse(body)? But, your typescript makes it look like you're expecting a promise that resolves to a string so that wouldn't usually be the result of JSON parsing.
If you are expecting a gzipped JSON response, then you would use the:
return got(`https://${host}${pathname}`, options).json();
I show above. If you are expecting just a string, not JSON, then you would change that line to:
return got(`https://${host}${pathname}`, options).text();
I have code like this:
const https = require('https');
const request = async (data, options) => {
return new Promise((resolve, reject) => {
const req = https.request(options, function(res) {
const chunks = [];
res.on('data', function(chunk) {
chunks.push(Buffer.from(chunk));
});
res.on('end', function() {
let body = Buffer.concat(chunks);
body = body.toString();
resolve(body);
});
});
if (data) {
req.write(JSON.stringify(data));
}
// this never fires, tried after comment below
req.on('timeout', () => {
console.log("This timed out")
})
// handle connection errors
req.on('error', reject);
req.end();
});
};
async function run() {
try {
const response = await request(null, {
method: 'GET',
hostname: 'example.com',
timeout: 1,
path: '/',
headers: {
'Content-Type': 'application/json'
}
});
console.log(response);
} catch (e) {
console.log(e);
}
}
run();
The docs at https://nodejs.org/api/http.html#http_http_request_options_callback say this about timeout:
A number specifying the socket timeout in milliseconds. This will set the timeout before the socket is connected.
My call is obviously going to take more than 1MS, yet I am not getting any errors thrown. What am I missing here?
Update
I am able to get req.on('timeout' to work when I am using http module rather than https. Not sure why that would be different? I literally can change require('https') to require('http') and see everything work as expected. The docs say options should be identical, but with different defaults.
Your exact code with require('https') runs properly on Node.js 10, 12 and 13 on macOS Catalina with nvm. I get the following console log:
This timed out
{"error_code":"401013","message":"Oauth token is not valid"}
This means that whatever issue you are facing, it is related to your environment or to a bug in a specific (old) Node.js version.
Try reinstalling Node.js after clearing all your system cache, temporary files and Node.js-related configuration files.
Essentially the issue is that I have multiple chained promised in an async function. So obviously the code should be waiting for the response before proceeding onto the next part. However with my test case it only works properly after multiple runs. Otherwise it shows the console.log statements sequentially after each run until around 5 runs or so when the final data appears. Sorry if this is an obvious answer or my code is atrocious. I'm rather new to both NodeJS and Async functions. It should also be noted I'm using NodeJS v8.10.
The order is essentially: Call to s3 to get ID in text file -> async function to call api to verify group details -> async function to call api to get other information based on the last function etc.
I've tried messing with the order of the async functions, and searching online for anything like this phenomenon but I was unable to find any examples.
const https = require('https');
var AWS = require('aws-sdk');
var s3 = new AWS.S3();
exports.handler = async (event, context) => {
var groupData;
var groupID;
await fetchGroupID().then(function(fetchedGroupID){
groupID = fetchedGroupID;
return fetchedGroupID;
}).then(function(data){
fetchGroupInfo().then(function(groupInfo){
groupData = groupInfo;
var fetchedGroupID = groupInfo.id;
fetchGroupEvents(fetchedGroupID).then(function(data){
console.log("Group Events: ", data);
});
});
});
console.log(groupData);
};
// Example of one of the async functions
async function fetchGroupEvents(fetchedGroupID)
{
console.log("Fetched GI: ", fetchedGroupID);
console.log("GI: ", groupID);
return new Promise((resolve, reject) => {
const options = {
protocol: 'https:',
hostname: 'api.boomset.com',
port: 443,
path: '/events?group_id=' + groupID,
method: 'GET',
headers: {
'Content-Type' : 'application/json',
'Authorization' : 'Token ****',
'Accept-Encoding': 'gzip, deflate'
}
};
const req = https.request(options, (res) => {
//console.log(`statusCode: ${res.statusCode}`);
res.setEncoding('utf8');
res.on('data', function(data) {
console.log(data);
//var jsonData = JSON.parse(data);
//console.log(jsonData);
resolve(data);
});
});
req.on('error', (error) => {
//console.error(error);
reject(error.message);
});
req.end();
});
};
Ideally this would all be completed in one run.
I have an AWS Lambda function which triggers https request to Google API. I want the function to be awaitable, so that it does not end immediately, but only after getting response from Google API.
Yes, I know I pay for the execution, but this will not be called often, so it is fine.
The problem is that the http request does not seem to fire correctly. The callback is never executed.
I have made sure that the async/await works as expected by using setTimeout in a Promise. So the issue is somewhere in the https.request.
Also note that I am using Pulumi to deploy to AWS, so there might be some hidden problem in there. I just can't figure out where.
The relevant code:
AWS Lambda which calls the Google API
import config from '../../config';
import { IUserInfo } from '../../interfaces';
const https = require('https');
function sendHttpsRequest(options: any): Promise<any> {
console.log(`sending request to ${options.host}`);
console.log(`Options are ${JSON.stringify(options)}`);
return new Promise(function (resolve, reject) {
console.log(` request to ${options.host} has been sent A`);
let body = new Array<Buffer>();
const request = https.request(options, function (res: any) {
console.log('statusCode:', res.statusCode);
console.log('headers:', res.headers);
if (res.statusCode != 200) {
reject(res.statusCode);
}
res.on('data', (data: any) => {
console.log(`body length is ${body.length}`);
console.log('data arrived', data);
body.push(data);
console.log('pushed to array');
console.log(data.toString());
});
});
request.on('end', () => {
console.error('Request ended');
// at this point, `body` has the entire request body stored in it as a string
let result = Buffer.concat(body).toString();
resolve(result);
});
request.on('error', async (err: Error) => {
console.error('Errooooorrrr', err.stack);
console.error('Errooooorrrr request failed');
reject(err);
});
request.end();
console.log(` request to ${options.host} has been sent B`);
});
}
/**
* AWS Lambda to create new Google account in TopMonks domain
*/
export default async function googleLambdaImplementation(userInfo: IUserInfo) {
const payload = JSON.stringify({
"primaryEmail": userInfo.topmonksEmail,
"name": {
"givenName": userInfo.firstName,
"familyName": userInfo.lastName
},
"password": config.defaultPassword,
"changePasswordAtNextLogin": true
});
const resultResponse: Response = {
statusCode: 200,
body: 'Default response. This should not come back to users'
}
console.log('Calling google api via post request');
try {
const options = {
host: 'www.googleapis.com',
path: '/admin/directory/v1/users',
method: 'POST',
headers: {
'Content-Type': 'application/json',
'Content-Length': payload.length.toString()
},
form: payload
}
const responseFromGoogle = await sendHttpsRequest(options);
console.log('responseFromGoogle', JSON.stringify(responseFromGoogle));
}
catch (err) {
console.log('Calling google api failed with error', err);
resultResponse.statusCode = 503;
resultResponse.body = `Error creating new Google Account for ${userInfo.topmonksEmail}.`;
return resultResponse;
}
console.log('request to google sent');
return resultResponse;
}
The problem is that the http request does not seem to fire correctly. The callback is never executed.
I believe this part of the issue is related to some combination of (a) potentially not actually sending the https request and (b) not using the correct callback signature for https.request. See the documentation at https://nodejs.org/api/https.html#https_https_request_options_callback for details on both of these.
Use node-fetch package
The following example works for me using node-fetch:
import * as aws from "#pulumi/aws";
import fetch from "node-fetch";
const api = new aws.apigateway.x.API("api", {
routes: [{
method: "GET", path: "/", eventHandler: async (ev) => {
const resp = await fetch("https://www.google.com");
const body = await resp.text();
return {
statusCode: resp.status,
body: body,
}
},
}],
})
export const url = api.url;
Pulumi complains, it something like "Can not serialize native function" or something like that. The problematic part is that node-fetch relies on Symbol.iterator
As noted in the comments, some of the conditions that can lead to this are documented at https://pulumi.io/reference/serializing-functions.html. However, I don't see any clear reason why this code would hit any of those limitations. There may be details of how this is used outside the context of the snippet shared above which lead to this.
TLDR: How do I log http 500 errors in Lambda?
I'm trying to log errors from my internal API method (not accessible to SNS subscription directly), invoked in Lambda, in CloudWatch. Here is my Lambda method in nodejs 6.10:
var http = require('http');
exports.handler = function(event, context, callback) {
var post_data = event.Records[0].Sns.Message;
var post_options = {
host: 'myhost.com',
port: 80,
path: '/path/to/api/',
method: 'POST',
headers: {
'Content-Type': 'application/json',
'Content-Length': post_data.length
}
};
var post_request = http.request(post_options, function(res) {
var body = '';
res.on('data', function(chunk) {
body += chunk;
});
res.on('end', function() {
callback(null, body);//This event happens, even when server returns 500
});
res.on('error', function(e) {
callback(e);//This event never gets called
});
});
post_request.on('error', function(e) {
callback(e);//This event never gets called either
});
post_request.end(post_data);
};
My API method is returning a 500. However, my post_request.on('error') or res.on('error') event is never executing. It always runs the res.on('end') instead.
I'd like to report the full error in cloudwatch, but instead it just gives me a generic error message, while saying the lambda method was successful.
It's a quirk with the what node considers an 'error'. As far as the http library is concerned, there was no error. It connected successfully to your api and successfully returned the result the server gave. The error handler will only fire with things like TCP errors or a mangled repsponse. If you want sensible behavior then you'll need to check the status code on the response.
var post_request = http.request(post_options, function(res) {
if (res.statusCode < 200 || res.statusCode > 299)
// handle non-200 https errors;
}
// more code
})