marchio-lambda-post

REST POST to DynamoDB via Lambda

Installation

$ npm init
$ npm install marchio-lambda-post --save

Lambda Setup

References

• Create an API with Lambda Proxy Integration through a Proxy Resource
• A Lambda Function in Node.js for Proxy Integration
• Build an API Gateway API Using Proxy Integration and a Proxy Resource
• Create and Test an API with HTTP Proxy Integration through a Proxy Resource

Steps

Create Test Role

• Browse to: https://console.aws.amazon.com/iam/
• Click: Roles (from the left column)
• Click: Create new role
• Step 1: Select role type
• For AWS Lambda, click: Select
• Step 2 is automatically skipped
• Step 3: Attach policy
• Select both AmazonDynamoDB* policies
• Click: Next Step
• Create a name for the role (like lambda-db-test)
• Click: Create role

Create Lambda Function

• Browse to: https://console.aws.amazon.com/lambda
• Click: Create a Lambda Function
• Select: Blank Function
• Click: Next
• Name: marchio
• Description: Marchio service
• Runtime: Node.js 4.3
• Set the Role values
• Click: Next
• Click: Create Function

Setup API Gateway

• Browse to: https://console.aws.amazon.com/apigateway
• Click: Create API
• Select: New API
• API name: marchio
• Description: Marchio service
• Click: Create API
• Click on the slash (/)
• Drop down: Actions
• Select: Create Resource
• Check: Configure as proxy resource
• (Optionally enabled CORS)
• Click: Create Resource
• For Integration type select: Lambda Function Proxy
• Lambda Region: For example: us-east-1
• Lambda Function: marchio
• Click: Save
• Add Permission to Lambda Function: OK
• Drop down: Actions
• Select: Deploy API
• Define a new stage (call it "test")
• Click: Deploy
• Save the Invoke URL

Create DynamoDB Table

• Browse to: https://console.aws.amazon.com/dynamodb/
• Click: Create Table
• Table name: mldb
• Primary key: eid
• The type should be the default (string)
• Click: Create
• After some churning, click the Capacity tab
• Set the Read / Write capacity units to 1 to save money while testing
• Click: Save

Example and Deploy

See the deployment example located in the repo under:

• examples/deploy

It contains a deployment script and an example lambda source file.

• Install the dependencies by running:

$ npm install

To run the script you must first make it runnable:

$ chmod +x deploy-lambda.sh

To test:

• Deploy the API via API Gateway
• Create an environment variable called AWS_HOST_MARCHIO which is set to the invocation url
• Test the deployment using curl:

$ curl -i -X POST -H "Content-Type: application/json" -d '{"email":"[email protected]"}' $AWS_HOST_MARCHIO/test/marchio

• The response should contain a 201 status code and a copy of the created record, along with its id (eid)
• Browse the DynamoDB table to see the new record.

Modules

marchio-lambda-post

Module

marchio-lambda-post-factory

Factory module

marchio-lambda-post-factory.create(spec) ⇒ Promise

Factory method It takes one spec parameter that must be an object with named parameters

Kind: static method of marchio-lambda-post-factory
Returns: Promise - that resolves to {module:marchio-lambda-post}

| Param | Type | Description | | --- | --- | --- | | spec | Object | Named parameters object | | spec.event | Object | Lambda event | | spec.context | Object | Lambda context | | spec.callback | function | Lambda callback | | spec.model | Object | Table model | | [spec.filter] | function | A function that takes the original record and returns a {Promise} that resolves to a filtered record |

Example (Usage example)

// Lambda root file
"use strict";

var mlFactory = require('marcio-lambda-post'); 

var getRandomInt = function (min, max) {
    return Math.floor(Math.random() * (max - min + 1) + min);
};

// Why not just demo hashing with bcrypt?
// Because bcrypt requires installing on AWS Linux before packaging
// That's beyond the scope of this example, so we fake it.
 
function fakeHash( record ) {
   // Not a real hash function - do not use in production
   return new Promise( (resolve, reject) => {
        if(!record) {
            return reject('record not defined');
        }
        if(!record.password) {
            return reject('record.password not defined');
        }
        // fake hashing - do not use in production
        record.password = '$' + getRandomInt(10000, 10000000);
        resolve(record);
   });
}

exports.handler = function(event, context, callback) {

    var model = {
        name: 'mldb',   // must match DynamoDB table name
        partition: 'eid', // primary partition key - cannot be reserved word (like uuid)
        // sort: 'gid', // primary sort key
        fields: {
            email:    { type: String, required: true },
            status:   { type: String, required: true, default: "NEW" },
            // Password will be (fake) hashed by filter before being saved
            password: { type: String, select: false },  // select: false, exclude from query results
        }
    };

    mlFactory.create({ 
        event: event, 
        context: context,
        callback: callback,
        model: model,
        filter: fakeHash
    })
    .catch(function(err) {
        callback(err);
    });
 };

Testing

To test:

• Deploy the example (examples/deploy)

• Go to the root folder and type (sans $):

  $ npm test

Repo(s)

• bitbucket.org/mitchallen/marchio-lambda-post.git
• github.com/mitchallen/marchio-lambda-post.git

Contributing

In lieu of a formal style guide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint and test your code.

Version History

Version 0.3.1

• updated deploy example with latest build
• removed model name from test case url

Version 0.3.0

• removed model/table name from url
• updated example url's

Version 0.2.2

• added support for sort key (model.sort) - see examples

Version 0.2.1

• updated example project

Version 0.2.0

• changed model.primary to model.partition

Version 0.1.6

• Updated documentation with filtered example

Version 0.1.5

• Added filter support

Version 0.1.4

• Fixed dependency issue

Version 0.1.3

• Refactored db-post module

Version 0.1.2

• Refactored db-post module

Version 0.1.1

• Fixed some doc issues

Version 0.1.0

• initial release