Commandline tool to run Lambda functions on your local machine.
npm install @skn0tt/lambda-local
Lambda-local lets you test NodeJS Amazon Lambda functions on your local machine, by providing a simplistic API and command-line tool.
It does not aim to be perfectly feature proof as projects like serverless-offline or docker-lambda, but rather to remain very light (it still provides a fully built Context, handles all of its parameters and functions, and everything is customizable easily).
The main target are unit tests and running lambda functions locally.
``bash`
npm install -g lambda-local
`bash`
make build
Orbash`
npm install
npm install --only=dev
npm run build
- As an API: You can also use Lambda local directly in a script. For instance, it is interesting in a [MochaJS][1] test suite in order to get test coverage.
- As a command line tool: You can use Lambda-local as a command line tool.
If you're unsure about some definitions, see Definitions for terminology.
API accessible with:
`js`
const lambdaLocal = require("lambda-local");
Or on TypeScript (supported on 1.7.0+):
`js`
import lambdaLocal = require("lambda-local");
#### lambdaLocal.execute(options)
Executes a lambda given the options object, which is a dictionary where the keys may be:
| Key name | Description |
| --- | --- |
| event|requested event as a json object|lambdaPath
| |requested path to the lambda function|lambdaFunc
| |pass the lambda function. You cannot use it at the same time as lambdaPath|profilePath
| |optional, path to your AWS credentials file|profileName
| |optional, aws profile name. Must be used with |lambdaHandler
| |optional handler name, default to handler|region
| |optional, AWS region, default to us-east-1|| callbackWaitsForEmptyEventLoop|optional, default to false. Setting it to True will wait for an empty loop before returning.|timeoutMs
| |optional, timeout, default to 3000 ms|esm
| |boolean, marks that the script is an ECMAScript module (use import), default false|environment
| |optional, extra environment variables for the lambda|envfile
| |optional, load an environment file before booting|envdestroy
| |optional, destroy added environment on closing, default to false|verboseLevel
| |optional, default 3. Level 2 dismiss handler() text, level 1 dismiss lambda-local text and level 0 dismiss also the result.|callback
| |optional, lambda third parameter [callback][1]. When left out a Promise is returned|onInvocationEnd
| |optional. called once the invocation ended. useful when awslambda.streamifyResponse is used to distinguish between end of response stream and end of invocation. |clientContext
| |optional, used to populated clientContext property of lambda second parameter (context)
#### lambdaLocal.setLogger(logger)
####
Those functions allow to access the winston logger used by lambda-local.
A lot of examples, especially used among Mocha, may be found in the test files over: here
##### Basic usage: Using Promises
`js
const lambdaLocal = require('lambda-local');
var jsonPayload = {
'key': 1,
'another_key': "Some text"
}
lambdaLocal.execute({
event: jsonPayload,
lambdaPath: path.join(__dirname, 'path_to_index.js'),
profilePath: '~/.aws/credentials',
profileName: 'default',
timeoutMs: 3000
}).then(function(done) {
console.log(done);
}).catch(function(err) {
console.log(err);
});
`
#### Basic usage: using callbacks
`js
const lambdaLocal = require('lambda-local');
var jsonPayload = {
'key': 1,
'another_key': "Some text"
}
lambdaLocal.execute({
event: jsonPayload,
lambdaPath: path.join(__dirname, 'path_to_index.js'),
profilePath: '~/.aws/credentials',
profileName: 'default',
timeoutMs: 3000,
callback: function(err, data) {
if (err) {
console.log(err);
} else {
console.log(data);
}
},
clientContext: JSON.stringify({clientId: 'xxxx'})
});
`
(required) Specify Lambda function file name.
* -e, --event-path (required --watch is not in use) Specify event data file name.
* -h, --handler (optional) Lambda function handler name. Default is "handler".
* -t, --timeout (optional) Seconds until lambda function timeout. Default is 3 seconds.
* --esm (optional) Load lambda function as ECMAScript module.
* -r, --region (optional) Sets the AWS region, defaults to us-east-1.
* -P, --profile-path (optional) Read the specified AWS credentials file.
* -p, --profile (optional) Use with -P: Read the AWS profile of the file.
* -E, --environment (optional) Set extra environment variables for the lambda
* --wait-empty-event-loop (optional) Sets callbackWaitsForEmptyEventLoop=True => will wait for an empty loop before returning. This is false by default because our implementation isn\'t perfect and only "emulates" it.
* --envdestroy (optional) Destroy added environment on closing. Defaults to false
* -v, --verboselevel <3/2/1/0> (optional) Default 3. Level 2 dismiss handler() text, level 1 dismiss lambda-local text and level 0 dismiss also the result.
* --envfile (optional) Set extra environment variables from an env file
* --inspect [[host:]port] (optional) Starts lambda-local using the NodeJS inspector (available in nodejs > 8.0.0)
* -W, --watch [port] (optional) Starts lambda-local in watch mode listening to the specified port [1-65535].$3
`bash
Simple usage
lambda-local -l index.js -h handler -e examples/s3-put.jsInput environment variables
lambda-local -l index.js -h handler -e examples/s3-put.js -E '{"key":"value","key2":"value2"}'
`#### Running lambda functions as a HTTP Server (Amazon API Gateway payload format version 2.0.)
A simple way you can run lambda functions locally, without the need to create any special template files (like Serverless plugin and SAM requires), just adding the parameter
. It will raise a http server listening to the specified port (default is 8008). You can then call the lambda as mentionned here:
https://docs.aws.amazon.com/lambda/latest/dg/urls-invocation.html`bash
lambda-local -l examples/handler_gateway2.js -h handler --watch 8008curl --request POST \
--url http://localhost:8008/ \
--header 'content-type: application/json' \
--data '{
"key1": "value1",
"key2": "value2",
"key3": "value3"
}'
{"message":"This is a response"}
`You can also use the following format for your event, in order to avoid using the Amazon API Gateway format:
{
"event": {
"key1": "value1",
"key2": "value2",
"key3": "value3"
}
}
In this case, the event will be passed directly to the handler.
About: Definitions
$3
Event sample data are placed in folder - feel free to use the files in here, or create your own event data.
Event data are just JSON objects exported:`js
// Sample event data
module.exports = {
foo: "bar"
};
`$3
The object has been sampled from what's visible when running an actual Lambda function on AWS, and the available documentation
They may change the internals of this object, and Lambda-local does not guarantee that this will always be up-to-date with the actual context object.$3
As of version 2.0.0, lambda-local no longer packages AWS-SDK in its dependencies. To run a function that makes use of this module, make sure to install it as a dependency in your project.Other links
- If you are willing to test an app based on the ASK-SDK, have a look at https://github.com/taimos/ask-sdk-test
Development
* Run
make to install npm modules. (Required to develop & test lambda-local)
* Run make test to execute the mocha test.
* Run make clean` to reset the repository.This library is released under the MIT license.
[1]: http://docs.aws.amazon.com/lambda/latest/dg/nodejs-prog-model-handler.html