Moesif AWS Lambda Middleware for Node.js

Node.js Middleware for AWS Lambda that automatically logs API calls and sends to Moesif for API analytics and monitoring.

Designed for APIs that are hosted on AWS Lambda using Amazon API Gateway or Application Load Balancer as a trigger. Works with REST APIs, GraphQL APIs (such as with apollo-server-lambda) and more.

Source Code on GitHub

Express apps

Alternatively, if you're running the Node.js Express Framework on AWS Lambda and prefer to not have any AWS specific dependencies, Moesif has Express Middleware also available. However, moesif-nodejs won't capture lambda specific context like Trace Id.

How to install

npm install --save moesif-aws-lambda

How to use

The following shows how import the controllers and use:

1. Import the module:

// Import Modules
'use strict'
const moesif = require('moesif-aws-lambda');
 
const moesifOptions = {
    applicationId: 'Your Moesif Application Id',
 
    identifyUser: function (event, context) {
        return event.requestContext.identity.cognitoIdentityId
    },
    identifyCompany: function (event, context) {
        return '5678'
    }
};
 
exports.handler = function (event, context, callback) {
    callback(null, {
        statusCode: '200',
        body: JSON.stringify({key: 'hello world'}),
        headers: {
            'Content-Type': 'application/json',
        },
    });
};
 
exports.handler = moesif(moesifOptions, exports.handler);

2. Enter Moesif Application Id

Your Moesif Application Id can be found in the Moesif Portal. After signing up for a Moesif account, your Moesif Application Id will be displayed during the onboarding steps.

You can always find your Moesif Application Id at any time by logging into the Moesif Portal, click on the top right menu, and then clicking Installation.

Repo file structure

lib/index.js the middleware lib
app.js sample AWS Lambda function using the middleware

Configuration options

`logBody`

Type: Boolean logBody is default to true, set to false to remove logging request and response body to Moesif.

`identifyUser`

Type: (event, context) => String identifyUser is a function that takes AWS lambda event and context objects as arguments and returns a userId. This enables Moesif to attribute API requests to individual unique users so you can understand who calling your API. This can be used simultaneously with identifyCompany to track both individual customers and the companies their a part of.

options.identifyUser = function (event, context) {
  // your code here, must return a string
  return event.requestContext.identity.cognitoIdentityId
}

`identifyCompany`

Type: (event, context) => String identifyCompany is a function that takes AWS lambda event and context objects as arguments and returns a companyId. If your business is B2B, this enables Moesif to attribute API requests to specific companies or organizations so you can understand which accounts are calling your API. This can be used simultaneously with identifyUser to track both individual customers and the companies their a part of.

options.identifyCompany = function (event, context) {
  // your code here, must return a string
  return '5678'
}

`getSessionToken`

Type: (event, context) => String getSessionToken a function that takes AWS lambda event and context objects as arguments and returns a session token (i.e. such as an API key).

options.getSessionToken = function (event, context) {
  // your code here, must return a string.
  return event.headers['Authorization'];
}

`getApiVersion`

Type: (event, context) => String getApiVersion is a function that takes AWS lambda event and context objects as arguments and returns a string to tag requests with a specific version of your API.

options.getApiVersion = function (event, context) {
  // your code here. must return a string.
  return '1.0.5'
}

`getMetadata`

Type: (event, context) => String getMetadata is a function that AWS lambda event and context objects as arguments and returns an object that allows you to add custom metadata that will be associated with the req. The metadata must be a simple javascript object that can be converted to JSON. For example, you may want to save a VM instance_id, a trace_id, or a tenant_id with the request.

options.getMetadata = function (event, context)  {
  // your code here:
  return {
    foo: 'custom data',
    bar: 'another custom data'
  };
}

`skip`

Type: (event, context) => Boolean skip is a function that takes AWS lambda event and context objects as arguments and returns true if the event should be skipped (i.e. not logged)
The default is shown below and skips requests to the root path "/".

options.skip = function (event, context) {
  // your code here. must return a boolean.
  if (event.path === '/') {
    // Skip probes to home page.
    return true;
  }
  return false
}

`maskContent`

Type: MoesifEventModel => MoesifEventModel maskContent is a function that takes the final Moesif event model (rather than the AWS lambda event/context objects) as an argument before being sent to Moesif. With maskContent, you can make modifications to headers or body such as removing certain header or body fields.

options.maskContent = function(moesifEvent) {
  // remove any field that you don't want to be sent to Moesif.
  return moesifEvent;
}

EventModel format:

{
  "request": {
    "time": "2019-08-08T04:45:42.914",
    "uri": "https://api.acmeinc.com/items/83738/reviews/",
    "verb": "POST",
    "api_version": "1.1.0",
    "ip_address": "61.48.220.123",
    "headers": {
      "Host": "api.acmeinc.com",
      "Accept": "*/*",
      "Connection": "Keep-Alive",
      "Content-Type": "application/json",
      "Content-Length": "126",
      "Accept-Encoding": "gzip"
    },
    "body": {
      "items": [
        {
          "direction_type": 1,
          "item_id": "fwdsfrf",
          "liked": false
        },
        {
          "direction_type": 2,
          "item_id": "d43d3f",
          "liked": true
        }
      ]
    }
  },
  "response": {
    "time": "2019-08-08T04:45:42.924",
    "status": 500,
    "headers": {
      "Vary": "Accept-Encoding",
      "Pragma": "no-cache",
      "Expires": "-1",
      "Content-Type": "application/json; charset=utf-8",
      "Cache-Control": "no-cache"
    },
    "body": {
      "Error": "InvalidArgumentException",
      "Message": "Missing field location"
    }
  },
  "user_id": "my_user_id",
  "company_id": "my_company_id",
  "session_token":"end_user_session_token",
  "tags": "tag1, tag2"
}

`debug`

Type: Boolean Set to true to print debug logs if you're having integration issues.

For more documentation regarding what fields and meaning, see below or the Moesif Node API Documentation.

Name	Required	Description
request	true	The object that specifies the request message
request.time	true	Timestamp for the request in ISO 8601 format
request.uri	true	Full uri such as https://api.com/?query=string including host, query string, etc
request.verb	true	HTTP method used, i.e. `GET`, `POST`
request.api_version	false	API Version you want to tag this request with such as 1.0.0
request.ip_address	false	IP address of the requester, If not set, we use the IP address of your logging API calls.
request.headers	true	Headers of the request as a `Map<string, string>`. Multiple headers with the same key name should be combined together such that the values are joined by a comma. HTTP Header Protocol on w3.org
request.body	false	Body of the request in JSON format or Base64 encoded binary data (see transfer_encoding)
request.transfer_encoding	false	A string that specifies the transfer encoding of Body being sent to Moesif. If field nonexistent, body assumed to be JSON or text. Only possible value is base64 for sending binary data like protobuf

response	false	The object that specifies the response message, not set implies no response received such as a timeout.
response.time	true	Timestamp for the response in ISO 8601 format
response.status	true	HTTP status code as number such as 200 or 500
response.ip_address	false	IP address of the responding server
response.headers	true	Headers of the response as a `Map<string, string>`. Multiple headers with the same key name should be combined together such that the values are joined by a comma. HTTP Header Protocol on w3.org
response.body	false	Body of the response in JSON format or Base64 encoded binary data (see transfer_encoding)
response.transfer_encoding	false	A string that specifies the transfer encoding of Body being sent to Moesif. If field nonexistent, body assumed to be JSON or text. Only possible value is base64 for sending binary data like protobuf

session_token	Recommend	The end user session token such as a JWT or API key, which may or may not be temporary. Moesif will auto-detect the session token automatically if not set.
user_id	Recommend	Identifies this API call to a permanent user_id
metadata	false	A JSON Object consisting of any custom metadata to be stored with this event.

Capture Outgoing

If you want to capture all outgoing API calls from your Node.js app to third parties like Stripe or to your own dependencies, call startCaptureOutgoing() to start capturing.

const moesif = require('moesif-aws-lambda');
var moesifMiddleware = moesif(options);
moesifMiddleware.startCaptureOutgoing();

The same set of above options is also applied to outgoing API calls, with a few key differences:

For options functions that take req and res as input arguments, the request and response objects passed in are not Express or Node.js req or res objects when the request is outgoing, but Moesif does mock some of the fields for convenience. Only a subset of the Node.js req/res fields are available. Specifically:

_mo_mocked: Set to true if it is a mocked request or response object (i.e. outgoing API Call)
headers: object, a mapping of header names to header values. Case sensitive
url: string. Full request URL.
method: string. Method/verb such as GET or POST.
statusCode: number. Response HTTP status code
getHeader: function. (string) => string. Reads out a header on the request. Name is case insensitive
get: function. (string) => string. Reads out a header on the request. Name is case insensitive
body: JSON object. The request body as sent to Moesif

Update a Single User

Create or update a user profile in Moesif. The metadata field can be any customer demographic or other info you want to store. Only the userId field is required. This method is a convenient helper that calls the Moesif API lib. For details, visit the Node.js API Reference.

var moesifMiddleware = moesif(options);
 
// Only userId is required.
// Campaign object is optional, but useful if you want to track ROI of acquisition channels
// See https://www.moesif.com/docs/api#users for campaign schema
// metadata can be any custom object
var user = {
  userId: '12345',
  companyId: '67890', // If set, associate user with a company object
  campaign: {
    utmSource: 'google',
    utmMedium: 'cpc', 
    utmCampaign: 'adwords',
    utmTerm: 'api+tooling',
    utmContent: 'landing'
  },
  metadata: {
    email: 'john@acmeinc.com',
    firstName: 'John',
    lastName: 'Doe',
    title: 'Software Engineer',
    salesInfo: {
        stage: 'Customer',
        lifetimeValue: 24000,
        accountOwner: 'mary@contoso.com'
    }
  }
};
 
moesifMiddleware.updateUser(user, callback);

Update Users in Batch

Similar to updateUser, but used to update a list of users in one batch. Only the userId field is required. This method is a convenient helper that calls the Moesif API lib. For details, visit the Node.js API Reference.

var moesifMiddleware = moesif(options);
 
// Only userId is required.
// Campaign object is optional, but useful if you want to track ROI of acquisition channels
// See https://www.moesif.com/docs/api#users for campaign schema
// metadata can be any custom object
var user = {
  userId: '12345',
  companyId: '67890', // If set, associate user with a company object
  campaign: {
    utmSource: 'google',
    utmMedium: 'cpc', 
    utmCampaign: 'adwords',
    utmTerm: 'api+tooling',
    utmContent: 'landing'
  },
  metadata: {
    email: 'john@acmeinc.com',
    firstName: 'John',
    lastName: 'Doe',
    title: 'Software Engineer',
    salesInfo: {
        stage: 'Customer',
        lifetimeValue: 24000,
        accountOwner: 'mary@contoso.com'
    }
  }
};
 
var users = [user]
 
moesifMiddleware.updateUsersBatch(users, callback);

Update a Single Company

Create or update a company profile in Moesif. The metadata field can be any company demographic or other info you want to store. Only the companyId field is required. This method is a convenient helper that calls the Moesif API lib. For details, visit the Node.js API Reference.

var moesifMiddleware = moesif(options);
 
// Only companyId is required.
// Campaign object is optional, but useful if you want to track ROI of acquisition channels
// See https://www.moesif.com/docs/api#update-a-company for campaign schema
// metadata can be any custom object
var company = {
  companyId: '67890',
  companyDomain: 'acmeinc.com', // If domain is set, Moesif will enrich your profiles with publicly available info 
  campaign: { 
    utmSource: 'google',
    utmMedium: 'cpc', 
    utmCampaign: 'adwords',
    utmTerm: 'api+tooling',
    utmContent: 'landing'
  },
  metadata: {
    orgName: 'Acme, Inc',
    planName: 'Free Plan',
    dealStage: 'Lead',
    mrr: 24000,
    demographics: {
      alexaRanking: 500000,
      employeeCount: 47
    }
  }
};
 
moesifMiddleware.updateCompany(company, callback);

Update Companies in Batch

Similar to updateCompany, but used to update a list of companies in one batch. Only the companyId field is required. This method is a convenient helper that calls the Moesif API lib. For details, visit the Node.js API Reference.

var moesifMiddleware = moesif(options);
 
// Only companyId is required.
// Campaign object is optional, but useful if you want to track ROI of acquisition channels
// See https://www.moesif.com/docs/api#update-a-company for campaign schema
// metadata can be any custom object
var company = {
  companyId: '67890',
  companyDomain: 'acmeinc.com', // If domain is set, Moesif will enrich your profiles with publicly available info 
  campaign: { 
    utmSource: 'google',
    utmMedium: 'cpc', 
    utmCampaign: 'adwords',
    utmTerm: 'api+tooling',
    utmContent: 'landing'
  },
  metadata: {
    orgName: 'Acme, Inc',
    planName: 'Free Plan',
    dealStage: 'Lead',
    mrr: 24000,
    demographics: {
      alexaRanking: 500000,
      employeeCount: 47
    }
  }
};
 
var companies = [company]
 
moesifMiddleware.updateCompaniesBatch(companies, callback);

Examples

Other integrations

To view more documentation on integration options, please visit the Integration Options Documentation.

npm