Whatsup -- A frugal serverless up/down monitor

Purpose

This is a simple serverless up/down monitor that runs every 5 minutes and sends you an alert in Slack if your website is down (or goes from down->up).

I wanted to see if I could use AWS SSM Parameter Store as a free key-value DB. Nothing as brazen as @QuinnyPig's route53 database, but still interesting:

• Use AWS Chalice to define a scheduled AWS Lambda job that runs every 5 minutes.
• Uses SSM Parameter Store as a database to store the last known status of each endpoint.

That's it!

Prerequisites

• You must have an AWS account, and have your default credentials and AWS Region configured as described in the AWS Tools and SDKs Shared Configuration and Credentials Reference Guide.
• Python 3.7 or later
• Boto3 1.14.20 or later
• AWS Chalice 1.15.1 or later
• Requests 2.23.0 or later
• PyTest 5.3.5 or later (to run unit tests)
• Access to AWS SSM Parameter Store.

Cautions

• As an AWS best practice, grant this code least privilege, or only the permissions required to perform a task. For more information, see Grant Least Privilege in the AWS Identity and Access Management User Guide.
• This is an early version and has not been tested very thoroughly.
• Running this code might result in charges to your AWS account.

Running the code

1. Clone the whatsup repository, initialize a virtual env, and install prerequisite packages.

   git clone https://github.com/foretheta/whatsup.git
   cd whatsup
   python3 -m venv
   source venv/bin/activate
   pip install -r requirements
   

2. Make a copy of the sample_confg.yaml file and edit to add the endpoints you want to monitor. Add your Slack webhook for notifications.

   cp sample_config.yaml config.yaml && vim config.yaml
   

3. Deploy the app to your AWS account.

   whatsup deploy
   

Example structure

The example is divided into the following files:

app.py

Defines the scheduled function to monitor your endpoints.. Uses Chalice to decorate scheduled functions and handle associated actions. Stores data in AWS SSM Parameter Store.

requirements.txt

Defines the minimum package versions to deploy to AWS Lambda.

config.json

Configuration for the application. It has a list of endpoints you want to monitor and provide the Slack webhook that will send a simple up/down notication to the channel associated with the webhook.

Running the tests (coming soon)

The unit tests in this module use the moto AWS Services mocker. This captures requests before they are sent to AWS, and returns a mocked response.

python -m pytest

Additional information

• AWS Chalice Quickstart
• Boto3 AWS Lambda service reference
• AWS Systems Manager Parameter Store

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Copyright Foretheta, Inc. All Rights Reserved.

SPDX-License-Identifier: Apache-2.0