pmosconi/aws-lambda-local

Run AWS Lambda functions locally

aws-lambda-local

Run AWS Lambda function locally! The most lightweight library - no external dependencies. Less than 200 lines of code.

Windows, Mac and Linux tested!

Installation

npm install -g aws-lambda-local

Inputs

-f functionName     | --function=functionName       required       Path to Lambda function main file
-e eventPath        | --event=eventPath             optional       Path to .json file contains event object
-l event            | --linevent=jsonEvent          optional       Event object (takes precedence over -e/--event)
-c contextPath      | --context=contextPath         optional       Path to .json file contains context object
-t seconds          | --timeout=seconds             optional       Force quit Lambda function after XX seconds
-h handler          | --handler=exports.handler     optional       Module.exports.handler name. Default is first function from the module 

Usage

Just specify function name (can be in nested directory), event object file. Optionally you also may replace default context object and timeout (30 seconds by default).

$ cat function.js

exports.handler = function(event, context)
{
    context.done(event, context);
    // or
    return new Promise((resolve, reject) => {})
};

Or

exports.handler = function(event, context, callback)
{
    callback(null, dataToRetun);
};

Or

exports.handler = function(event)
{
    return new Promise((resolve, reject) => {})
};

Or even

exports.handler = async (event) =>
{
    return 'ret';
}

Check the event object. You can create any set of input data (and use them for functional testing or something else)

$ cat event.json
{
    "obj"   : { "a" : "b" },
    "int"   : 1,
    "str"   : "qwerty",
    "arr"   : [ 1, 2, 3, 4 ]
}

$ lambda-local -f function -e event.json -t 20
ERROR
--------------------------------
{
    "obj": {
        "a": "b"
    },
    "int": 1,
    "str": "qwerty",
    "arr": [
        1,
        2,
        3,
        4
    ]
}
OUTPUT
--------------------------------
{
    "awsRequestId": "wn26j4dm-m8zd-d7vi-j94j-50t4zsjlwhfr",
    "logGroupName": "/aws/lambda/function",
    "logStreamName": "2015/11/12/[$LATEST]wn26j4dmtm8zd7vij94j50t4zsjlwhfr",
    "functionName": "function",
    "memoryLimitInMB": "128",
    "functionVersion": "$LATEST",
    "invokedFunctionArn": "arn:aws:lambda:aws-region:1234567890123:function:function",
    "invokeId": "wn26j4dm-m8zd-d7vi-j94j-50t4zsjlwhfr"
}

Example passing event directly in command line. Make sure quotes are properly escaped

$ lambda-local -f function -l "{\"obj\": {\"a\": \"b\"}, \"int\": 1, \"str\": \"qwerty\", \"arr\": [1, 2, 3, 4]}"

CLI script will return non-zero exit code (1) in case of any failure.

If you missed to call context.succeed()|fail()|done() function and your Lambda function runs forever - just use timeout option!

Check out my aws-lambda-build package!