Moesif AWS Lambda Middleware for Python documentation

by Moesif, the API analytics and API monetization platform.

With Moesif Python middleware for AWS Lambda, you can automatically log API calls and send them to Moesif for API analytics and monitoring. This middleware allows you to integrate Moesif’s API analytics and API monetization features into your Python applications with minimal configuration.

If you’re new to Moesif, see our Getting Started resources to quickly get up and running.

Who This Middleware is For

We’ve designed Moesif Python middleware for AWS Lambda for APIs that you host on AWS Lambda using Amazon API Gateway or Application Load Balancer as a trigger. This middleware expects the Lambda proxy integration type. If you’re using AWS Lambda with API Gateway, you are most likely using the proxy integration type.

Prerequisites

Before using this middleware, make sure you have the following:

Get Your Moesif Application ID

After you log into Moesif Portal, you can get your Moesif Application ID during the onboarding steps. You can always access the Application ID any time by following these steps from Moesif Portal after logging in:

Select the account icon to bring up the settings menu.
Select Installation or API Keys.
Copy your Moesif Application ID from the Collector Application ID field.

Install the Middleware

Install with pip using the following command:

pip install moesif_aws_lambda

Configure the Middleware

See the available configuration options to learn how to configure the middleware for your use case.

How to Use

1. Add the Middleware to your Lambda Application

from moesif_aws_lambda.middleware import MoesifLogger
import json

moesif_options = {
    'LOG_BODY': True
}

@MoesifLogger(moesif_options)
def lambda_handler(event, context):
    return {
        'statusCode': 200,
        'isBase64Encoded': False,
        'body': json.dumps({
            'msg': 'Hello from Lambda!'
        }),
        'headers': {
            'Content-Type': 'application/json'
        }
    }

Important: Make sure you set the body field to a JSON-formatted string using json.dumps(). Otherwise, API Gateway returns a 502 Bad Gateway error response.

2. Set the MOESIF_APPLICATION_ID Environment Variable

The middleware expects the MOESIF_APPLICATION_ID environment variable to be able to connect with your Moesif account and send analytics. This variable holds the value of your Moesif Application ID. For instructions on how to set environment variables in Lambda, see Use Lambda environment variables to configure values in code.

3. Deploy your Lambda Function

To deploy your Lambda function code with Moesif AWS Lambda middleware, you must archive them in a zip file. For archiving instructions, see our example Lambda function repository. Then follow the instructions in AWS Lambda docs to upload and deploy your Lambda function code as a zip file archive.

4. Call your API

Finally, grab the URL to your API Gateway or Application Load Balancer and make some HTTP requests using a tool like Postman or cURL.

In order for your events to log to Moesif, you must test using the Amazon API Gateway trigger. Do not invoke your Lambda directly using AWS Console as the payload won’t contain a valid HTTP payload.

Troubleshoot

For a general troubleshooting guide that can help you solve common problems, see Server Troubleshooting Guide.

Other troubleshooting supports:

Repository Structure

.
├── eventV1.json
├── eventV2.json
├── images/
├── lambda_function.py
├── LICENSE
├── moesif_aws_lambda/
├── package.sh
├── README.md
├── requirements.txt
├── setup.cfg
└── setup.py

These are the most important files:

moesif_aws_lambda/middleware.py: the middleware library
lambda_function.py: sample AWS Lambda function using the middleware

Configuration Options

The following sections describe the available configuration options for this middleware. You can set these options in a Python object and then pass that object as argument to the MoesifLogger decorator. See the sample AWS Lambda middleware function code for an example.

`IDENTIFY_USER`

Data type	Parameters	Return type
Function	`(event, context)`	`String`

A function that takes AWS Lambda event and context objects as arguments and returns a user ID. This allows Moesif to attribute API requests to individual unique users so you can understand who is calling your API. You can use this simultaneously with identify_company to track both individual customers and the companies they are a part of.

def identify_user(event, context):
  # your code here, must return a string
  return event["requestContext"]["identity"]["cognitoIdentityId"]

`IDENTIFY_COMPANY`

Data type	Parameters	Return type
Function	`(event, context)`	`String`

A function that takes AWS Lambda event and context objects as arguments and returns a company ID. If you have a B2B business, this allows Moesif to attribute API requests to specific companies or organizations so you can understand which accounts are calling your API. You can use this simultaneously with identify_user to track both individual customers and the companies they are a part of.

def identify_company(event, context):
  # your code here, must return a string
  return '7890'
}

`GET_SESSION_TOKEN`

Data type	Parameters	Return type
Function	`(event, context)`	`String`

A function that takes AWS lambda event and context objects as arguments and returns a session token such as an API key.

def get_session_token(event, context):
    # your code here, must return a string.
    return 'XXXXXXXXX'

`GET_API_VERSION`

Data type	Parameters	Return type
Function	`(event, context)`	`String`

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.

def get_api_version(event, context):
  # your code here. must return a string.
  return '1.0.0'

`GET_METADATA`

Data type	Parameters	Return type
Function	`(event, context)`	`Object`

A function that takes AWS lambda event and context objects as arguments and returns an object.

This function allows you to add custom metadata that Moesif can associate with the request. The metadata must be a simple Python object that can be converted to JSON.

For example, you may want to save a virtual machine instance ID, a trace ID, or a tenant ID with the request.

def get_metadata(event, context):
  # your code here:
  return {
        'trace_id': context.aws_request_id,
        'function_name': context.function_name,
        'request_context': event['requestContext']
    }

`SKIP`

Data type	Parameters	Return type
Function	`(event, context)`	`Boolean`

A function that takes AWS lambda event and context objects as arguments and returns True if you want to skip the event. Skipping an event means Moesif doesn’t log the event.

The following example skips requests to the root path /:

def should_skip(event, context):
    # your code here. must return a boolean.
    return "/" in event['path']

`MASK_EVENT_MODEL`

Data type	Parameters	Return type
Function	`(MASK_EVENT_MODEL)`	`MASK_EVENT_MODEL`

A function that takes the final Moesif event model, rather than the AWS lambda event or context objects, as an argument before the middleware sends the event model object to Moesif.

With MASK_EVENT_MODEL, you can make modifications to headers or body such as removing certain header or body fields.

def mask_event(eventmodel):
  # remove any field that you don't want to be sent to Moesif.
  return eventmodel

For an example of how Moesif event model looks like, see the eventV1.json and eventV2.json files.

For more information about the different fields of Moesif’s event model, see Moesif Python API documentation.

`DEBUG`

Data type	Default
`Boolean`	`undefined`

Set to True to print debug logs if you’re having integration issues.

`LOG_BODY`

Data type	Default
`Boolean`	`True`

Whether to log request and response body to Moesif.

Optional: Capturing Outgoing API Calls

If you want to capture all outgoing API calls from your Python app to third parties like Stripe or to your own dependencies, call start_capture_outgoing() to start capturing. This mechanism works by patching Requests.

from moesif_aws_lambda.middleware import *
start_capture_outgoing(moesif_options) # moesif_options are the configuration options.

Options for Logging Outgoing Calls

The following options are available for capturing and logging outgoing calls. The request and response objects passed in correspond to the Request and Response objects respectively of the Python Requests library.

`SKIP_OUTGOING`

Data type	Parameters	Return type
Function	`(request, response)`	`Boolean`

Optional.

This function takes Requests Request and Response objects and returns True if you want to skip this particular event.

`IDENTIFY_USER_OUTGOING`

Data type	Parameters	Return type
Function	`(request, response)`	`String`

Optional, but highly recommended.

This function takes Requests Request and Response objects and returns a string that represents the user ID used by your system. While Moesif tries to identify users automatically, different frameworks and your implementation might be very different. So we highly recommend that you accurately provide a user ID using this function.

`IDENTIFY_COMPANY_OUTGOING`

Data type	Parameters	Return type
Function	`(request, response)`	`String`

Optional.

This function takes Requests Request and Response objects and returns a string that represents the company ID for this event.

`GET_METADATA_OUTGOING`

Data type	Parameters	Return type
Function	`(request, response)`	`Dictionary`

Optional.

This function takes Requests Request and Response objects and returns a Python dictionary. The dictionary must be such that it can be converted into valid JSON. This allows you to associate this event with custom metadata.

For example, you may want to save a virtual machine instance ID, a trace ID, or a tenant ID with the request.

`GET_SESSION_TOKEN_OUTGOING`

Data type	Parameters	Return type
Function	`(request, response)`	`String`

Optional.

This function takes Requests Request and Response objects and returns a string that represents the session token for this event. Similar to user IDs, Moesif tries to get the session token automatically. However, if you setup differs from the standard, this function can help tying up events together and help you replay the events.

`LOG_BODY_OUTGOING`

Data type	Default
`Boolean`	`True`

Optional.

Whether to log request and response body to Moesif.

Examples

See the example AWS Lambda function that uses this middleware.

The following examples demonstrate how to add and update customer information.

Update A Single User

To create or update a user profile in Moesif, use the update_user() function.

from moesif_aws_lambda.middleware import *

moesif_options = {
    'LOG_BODY': True,
    'DEBUG': True,
}

# Only user_id 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
user = {
  'user_id': '12345',
  'company_id': '67890', # If set, associate user with a company object
  'campaign': {
    'utm_source': 'google',
    'utm_medium': 'cpc',
    'utm_campaign': 'adwords',
    'utm_term': 'api+tooling',
    'utm_content': 'landing'
  },
  'metadata': {
    'email': 'john@acmeinc.com',
    'first_name': 'John',
    'last_name': 'Doe',
    'title': 'Software Engineer',
    'sales_info': {
        'stage': 'Customer',
        'lifetime_value': 24000,
        'account_owner': 'mary@contoso.com'
    },
  }
}

update_user(user, moesif_options)

The metadata field can contain any customer demographic or other info you want to store. Moesif only requires the user_id field.

For more information, see the function documentation in Moesif Python API Reference.

Update Users in Batch

To update a list of users in one batch, use the update_users_batch() function.

from moesif_aws_lambda.middleware import *

moesif_options = {
    'LOG_BODY': True,
    'DEBUG': True,
}

userA = {
  'user_id': '12345',
  'company_id': '67890', # If set, associate user with a company object
  'metadata': {
    'email': 'john@acmeinc.com',
    'first_name': 'John',
    'last_name': 'Doe',
    'title': 'Software Engineer',
    'sales_info': {
        'stage': 'Customer',
        'lifetime_value': 24000,
        'account_owner': 'mary@contoso.com'
    },
  }
}

userB = {
  'user_id': '54321',
  'company_id': '67890', # If set, associate user with a company object
  'metadata': {
    'email': 'mary@acmeinc.com',
    'first_name': 'Mary',
    'last_name': 'Jane',
    'title': 'Software Engineer',
    'sales_info': {
        'stage': 'Customer',
        'lifetime_value': 48000,
        'account_owner': 'mary@contoso.com'
    },
  }
}
update_users_batch([userA, userB], moesif_options)

The metadata field can contain any customer demographic or other info you want to store. Moesif only requires the user_id field.

For more information, see the function documentation in Moesif Python API Reference.

Update A Single Company

To update a single company, use the update_company() function.

from moesif_aws_lambda.middleware import *

moesif_options = {
    'LOG_BODY': True,
    'DEBUG': True,
}

# Only company_id 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
company = {
  'company_id': '67890',
  'company_domain': 'acmeinc.com', # If domain is set, Moesif will enrich your profiles with publicly available info
  'campaign': {
    'utm_source': 'google',
    'utm_medium': 'cpc',
    'utm_campaign': 'adwords',
    'utm_term': 'api+tooling',
    'utm_content': 'landing'
  },
  'metadata': {
    'org_name': 'Acme, Inc',
    'plan_name': 'Free',
    'deal_stage': 'Lead',
    'mrr': 24000,
    'demographics': {
        'alexa_ranking': 500000,
        'employee_count': 47
    },
  }
}

update_company(company, moesif_options)

The metadata field can contain any company demographic or other information you want to store. Moesif only requires the company_id field. For more information, see the function documentation in Moesif Python API Reference.

Update Companies in Batch

To update a list of companies in one batch, use the update_companies_batch() function.

from moesif_aws_lambda.middleware import *

moesif_options = {
    'LOG_BODY': True,
    'DEBUG': True,
}

companyA = {
  'company_id': '67890',
  'company_domain': 'acmeinc.com', # If domain is set, Moesif will enrich your profiles with publicly available info
  'metadata': {
    'org_name': 'Acme, Inc',
    'plan_name': 'Free',
    'deal_stage': 'Lead',
    'mrr': 24000,
    'demographics': {
        'alexa_ranking': 500000,
        'employee_count': 47
    },
  }
}

companyB = {
  'company_id': '09876',
  'company_domain': 'contoso.com', # If domain is set, Moesif will enrich your profiles with publicly available info
  'metadata': {
    'org_name': 'Contoso, Inc',
    'plan_name': 'Free',
    'deal_stage': 'Lead',
    'mrr': 48000,
    'demographics': {
        'alexa_ranking': 500000,
        'employee_count': 53
    },
  }
}

update_companies_batch([companyA, companyB], moesif_options)

Additional Documentation

See Moesif AWS Lambda Example for Python for an example Lambda function using this middleware.

How to Get Help

If you face any issues using this middleware, try the troubheshooting guidelines. For further assistance, reach out to our support team.

Explore Other integrations

Explore other integration options from Moesif in the Server Integration Options documentation.