Process exited before completing request (Lambda + DynamoDB) - json

Question

For some reason I am getting the Process exited before completing request error.
Here is my code:
var http = require('http');
var aws = require('aws-sdk');
var ddb = new aws.DynamoDB();
function getUser(userid) {
var q = ddb.getItem({
TableName: "clients",
Key: {
ClientID: { S: userid } }
}, function(err, data) {
if (err) {
console.log(err);
return err;
}
else {
console.log(data);
}
});
//console.log(q);
}
exports.handler = function(event, context) {
getUser('user23');
console.log("called DynamoDB");
};
After googling a few people suggested changing the time out to a higher amount. Which I did to one minute.
However the function only took:
Duration : 2542.23 ms
I have also checked and double checked the table name and the key name etc...
The console log has this :
2016-03-21T04:09:46.390Z - Received event
2016-03-21T04:09:46.751Z - called DynamoDB
2016-03-21T04:09:47.012Z - {}
END RequestId: id123
Can anyone see why this is not working?
Edit
As per the answer below I tried:
console.log('Loading event');
var AWS = require('aws-sdk');
var dynamodb = new AWS.DynamoDB({apiVersion: '2012-08-10'});
exports.handler = function(event, context) {
console.log(JSON.stringify(event, null, ' '));
dynamodb.listTables(function(err, data) {
console.log(JSON.stringify(data, null, ' '));
});
var tableName = "clients";
var datetime = new Date().getTime().toString();
dynamodb.getItem({
TableName: tableName,
Key: {
ClientID: { S: "gr5f4sgnca25hki" } }
}, function(err, data) {
if (err) {
context.done('error','putting item into dynamodb failed: '+err);
}
else {
context.done(data);
}
});
};
but now my response is:
"errorMessage": "[object Object]"
What I am trying to do is this: Check if Item exists in database. Get the parameters from the entry if exists, then do something with the parameters
Can anyone help me?

Answer 1

First of all, context.done expects an Error object as the first argument, not a string containing the word "error".
Second, if the Error object is null or undefined, then the termination will be taken as a succeed.
Now, consider your callback function:
function (err, data)
{
if (err) {
context.done('error', 'putting item into dynamodb failed: ' + err);
}
else {
context.done(data);
}
}
If you have an error, then your lambda will terminate in a failure, which is expected, but the errorMessage you'll get would simply be "error", which isn't much informative.
If you don't have an error, then your lambda will also terminate in a failure, because you are passing in data as the first argument to context.done, and remember that the first argument is always the Error object.
To fix this, you can simply do:
function (err, data)
{
if (err) {
context.done(err);
} else {
context.done(null, data);
}
}
Or even better:
function (err, data)
{
context.done(err, data);
}
If you don't want to handle the item and just return it immediately, you can use context.done as your callback function to the DynamoDB operation:
dynamodb.getItem({
TableName: tableName,
Key: {
ClientID: { S: "gr5f4sgnca25hki" }
}
}, context.done);

Answer 2

You need to signal Lambda end of function.
Important
To properly terminate your Lambda function execution, you must call context.succeed(), context.fail(), or context.done() method. If you don't, either your Lambda function will continue to run until the Node.js event queue is empty, or your Lambda function times out.
Here is an example:
https://gist.github.com/markusklems/1e7218d76d7583f1f7b3

Answer 3

"errorMessage": "[object Object]"
can be solved by a small change as follows
function(err, data) {
if (err) {
context.done(err);
}
else {
context.succeed(data);
}
});
Note where context.succeed differs() from context.done()