DynamoDB ignored in AWS Lambda Local - node.js

Question

I have DynamoDB running locally:
java -Djava.library.path=./DynamoDBLocal_lib -jar DynamoDBLocal.jar -sharedDb
and I'm trying to run lambda-local example:
lambda-local -f aws -e event.json
However, I don't get any output from dynamodb at all. There is no error and it looks like the call to dynamodb.listTables() is skipped/ignored. What's wrong?
My aws.js is as follows:
var AWS = require("aws-sdk");
AWS.config.update({
region: "us-west-2",
endpoint: "http://localhost:8000",
accessKeyId: "BLAH",
secretAccessKey: "BLAH"
});
var dynamodb = new AWS.DynamoDB();
exports.handler = function(event, context) {
console.log("EVENT: ", event);
event.int++;
console.log("LIST TABLES:");
dynamodb.listTables(function(err, data) {
if (err) {
console.log("Error: ", err.code);
} else {
console.log("Table names are: ", data.TableNames);
}
});
console.log("---SUCCEED:---");
context.succeed(event);
};
and event.json:
{
"obj" : { "a" : "b" },
"int" : 1,
"str" : "qwerty",
"arr" : [ 1, 2, 3, 4 ]
}
Output is:
EVENT: { obj: { a: 'b' }, int: 1, str: 'qwerty', arr: [ 1, 2, 3, 4 ] }
LIST TABLES:
---SUCCEED:---
OUTPUT
--------------------------------
{
"obj": {
"a": "b"
},
"int": 2,
"str": "qwerty",
"arr": [
1,
2,
3,
4
]
}
I'm expecting to see at least something between LIST TABLES and --SUCCEED:---
Yet there is no output and no error. I also checked DynamoDB log and there is nothing there. The line event.int++ worked fine and I see all other console.log() calls.
Additionally, I run this code from node just to prove that the DynamoDB is working and it does list tables fine:
node ListTables.js
Content of ListTables.js (which is basically same code as above):
var AWS = require("aws-sdk");
AWS.config.update({
region: "us-west-2",
endpoint: "http://localhost:8000",
accessKeyId: "BLAH",
secretAccessKey: "BLAH"
});
var dynamodb = new AWS.DynamoDB();
dynamodb.listTables(function(err, data) {
if (err) {
console.log("Error: ", err.code);
} else {
console.log("Table names are: ", data.TableNames);
}
});
Outputs as expected:
Table names are: [ 'Movies' ]
I created that table earlier just to prove that DynamoDB is actually running and accepting connections from node.

Answer 1

The problem and solution is that the DynamoDB function is called asynchronous and therefore, the script finished earlier.
Once I moved context.succeed(event); line from the end to inside of dynamodb.listTables(function(err, data) { then I've got the output fine:
dynamodb.listTables(function(err, data) {
console.log("INSIDE");
if (err) {
console.log("Error: ", err.code);
} else {
console.log("Table names are: ", data.TableNames);
}
context.succeed(event);
});
lambda-local -f aws -e event.json
OUTPUTS:
EVENT: { obj: { a: 'b' }, int: 1, str: 'qwerty', arr: [ 1, 2, 3, 4 ] }
LIST TABLES:
---SUCCEED:---
INSIDE
Table names are: [ 'Image', 'Movies' ]
OUTPUT
--------------------------------
...