cdk-library-certbot

A CDK Construct Library to automate the creation and renewal of Let's Encrypt certificates.

Features

• Creates a lambda function that utilizes Certbot to request a certificate from Let's Encrypt
• Uploads the resulting certificate data to S3 for later retrieval
• Imports the certificate to AWS Certificate Manager for tracking expiration
• Creates a trigger to re-run and re-new if the cert will expire in the next 30 days (customizable)

API Doc

See API

References

Original [gist](# Modified from original gist https://gist.github.com/arkadiyt/5d764c32baa43fc486ca16cb8488169a) that was modified for the Lambda code

Examples

This construct utilizes a Route 53 hosted zone lookup so it will require that your stack has [environment variables set for account and region](See https://docs.aws.amazon.com/cdk/latest/guide/environments.html for more details.).

Typescript

Typescript with Default Setup

import * as cdk from '@aws-cdk/core';
import { Certbot } from '@renovosolutions/cdk-library-certbot';
import { Architecture } from '@aws-cdk/aws-lambda';

export class CdkExampleCertsStack extends cdk.Stack {
  constructor(scope: cdk.Construct, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    let domains = [
      'example.com',
      'www.example.com'
    ]

    new Certbot(this, 'cert', {
      letsencryptDomains: domains.join(','),
      letsencryptEmail: 'webmaster+letsencrypt@example.com',
      hostedZoneNames: [
        'example.com'
      ]
    })
  }
}

Typescript with alternate storage location (Secrets Manager)

import * as cdk from '@aws-cdk/core';
import { Certbot, CertificateStorageType } from '@renovosolutions/cdk-library-certbot';
import { Architecture } from '@aws-cdk/aws-lambda';

export class CdkExampleCertsStack extends cdk.Stack {
  constructor(scope: cdk.Construct, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    let domains = [
      'example.com',
      'www.example.com'
    ]

    new Certbot(this, 'cert', {
      letsencryptDomains: domains.join(','),
      letsencryptEmail: 'webmaster+letsencrypt@example.com',
      hostedZoneNames: [
        'example.com'
      ]
      certificateStorage: CertificateStorageType.SECRETS_MANAGER
      // Optional path
      secretsManagerPath: '/path/to/secret/'
    })
  }
}

Typescript with alternate storage location (Parameter Store)

import * as cdk from '@aws-cdk/core';
import { Certbot, CertificateStorageType } from '@renovosolutions/cdk-library-certbot';
import { Architecture } from '@aws-cdk/aws-lambda';

export class CdkExampleCertsStack extends cdk.Stack {
  constructor(scope: cdk.Construct, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    let domains = [
      'example.com',
      'www.example.com'
    ]

    new Certbot(this, 'cert', {
      letsencryptDomains: domains.join(','),
      letsencryptEmail: 'webmaster+letsencrypt@example.com',
      hostedZoneNames: [
        'example.com'
      ]
      certificateStorage: CertificateStorageType.SSM_SECURE
      // Optional path
      ssmSecurePath: '/path/to/secret/'
    })
  }
}

Typescript with zone creation in the same stack

import * as cdk from '@aws-cdk/core';
import * as route53 from '@aws-cdk/aws_route53';
import { Certbot } from '@renovosolutions/cdk-library-certbot';
import { Architecture } from '@aws-cdk/aws-lambda';

export class CdkExampleCertsStack extends cdk.Stack {
  constructor(scope: cdk.Construct, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    const hostedZone = new r53.HostedZone(this, 'authZone', {
      zoneName: 'auth.example.com',
    });

    let domains = [
      'example.com',
      'www.example.com',
      'auth.example.com'
    ]

    new Certbot(this, 'cert', {
      letsencryptDomains: domains.join(','),
      letsencryptEmail: 'webmaster+letsencrypt@example.com',
      hostedZoneNames: [
        'example.com'
      ],
      hostedZones: [
        hostedZone,
      ]
    })
  }
}

Python

from aws_cdk import (
    core as cdk
)
from certbot import Certbot

class CdkExampleCertsStack(cdk.Stack):

    def __init__(self, scope: cdk.Construct, construct_id: str, **kwargs) -> None:
        super().__init__(scope, construct_id, **kwargs)

        Certbot(self, "certbot",
            letsencrypt_email="webmaster+letsencrypt@example.com",
            letsencrypt_domains="example.com",
            hosted_zone_names=["example.com"]
        )

Testing the handler in this project

• Set up a python virtual env with python3.10 -m venv .venv
• Use the virtual env with source .venv/bin/activate
• Install dependencies with pip install -r function/tests/requirements.txt
• Run pytest -v

The testing using moto to mock AWS services and verify the function does what is expected for each given storage type.