marchio-lambda-get

REST GET from DynamoDB via Lambda

Installation

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

Lambda Setup

References

• marchio-lambda-post

• 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
• Expand Section: AWS Service Role
• For AWS Lambda, click: Select
• Step 2 is automatically skipped
• Step 3: Attach policy
• Select AmazonDynamoDBReadOnlyAccess policiy
• Click: Next Step
• Create a name for the role (like lambda-db-get-only)
• 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-get
• Description: Marchio service
• Runtime: Node.js 4.3
• Set the Role
• Role: Choose and existing role
• Existing role: service-role/(name of role you created earlier)
• 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-get
• 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-get
• 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

If you've already setup a demo for marchio-lambda-post then you may have this table already. If not, create it and load it with a few test records.

• 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_GET which is set to the invocation url
• Test the deployment using curl (substitute a valid eid value):

$ curl -i -X GET -H "Accept: applications/json" \
  $AWS_HOST_MARCHIO_GET/test/marchio-get/110ec58a-a0f2-4ac4-8393-c866d813b8d1

• The response should contain a 200 status code and a copy of the record.

Modules

marchio-lambda-get

Module

marchio-lambda-get-factory

Factory module

marchio-lambda-get-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-get-factory
Returns: Promise - that resolves to {module:marchio-lambda-get}

| 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 |

Example (Usage example)

// Lambda root file
"use strict";

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

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',
        fields: {
            eid:      { type: String },  // return eid / primary partition in GET results
            // gid:      { type: String },  // return gid / primary sort in GET results
            email:    { type: String, required: true },
            status:   { type: String, required: true, default: "NEW" },
            password: { type: String, select: false },  // select: false, exclude from query results
        }
    };

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

Testing

To test, go to the root folder and type (sans $):

$ npm test

Repo(s)

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

Version 0.3.0

• removed model/table name from url
• updated deploy-build examples

Version 0.2.2

• removed comment from demo

Version 0.2.1

• Added support for primary sort key

Version 0.2.0

• Change model.primary to model.partition

Version 0.1.5

• Updated doc and demo deploy to show how to return primary key if required

Version 0.1.4

• Integrated module documentation into readme

Version 0.1.3

• Updated role documentation

Version 0.1.2

• Updated service to only return record and not Item wrapper.

Version 0.1.1

• Fixed issue with object passed to DynamoDB.getItem

Version 0.1.0

• initial release