1. Getting Started
2. What you will need
3. Amazon Web Services (AWS)
- 3.1. AWS CLI
- 3.2. Administrator IAM user
4. Solution
5. Writing the Application
6. Running the Application
- 6.1. Local tests
7. Testing the Application
- 7.1. Cleanup
8. Next Steps
9. License

Secure a Pyronaut application with Cognito

Learn how to create a Pyronaut application and secure it with an Authorization Server provided by Cognito.

1. Getting Started

In this guide, we will create a Python application built with Pyronaut.

2. What you will need

To complete this guide, you will need the following:

Some time on your hands
GraalPy installed and the Pyronaut CLI available locally

3. Amazon Web Services (AWS)

If you don’t have one already, create an AWS Account.

3.1. AWS CLI

Follow the AWS documentation for installing or updating the latest version of the AWS CLI.

3.2. Administrator IAM user

Instead of using your AWS root account, it is recommended that you use an IAM administrative user. If you don’t have one already, follow the steps below to create one:

aws iam create-group --group-name Administrators
aws iam create-user --user-name Administrator
aws iam add-user-to-group --user-name Administrator --group-name Administrators
aws iam attach-group-policy --group-name Administrators --policy-arn $(aws iam list-policies --query 'Policies[?PolicyName==`AdministratorAccess`].{ARN:Arn}' --output text)
aws iam create-access-key --user-name Administrator

Then, run aws configure to configure your AWS CLI to use the Administrator IAM user just created.

4. Solution

We recommend that you follow the instructions in the next sections and create the application step by step. However, you can go right to the completed example.

Download and unzip the source

5. Writing the Application

Create an application using the Pyronaut CLI (Command Line Interface) or Pyronaut Launch

pyronaut create example.micronaut.micronautguide

The views-jinjava feature uses Micronaut Views' Jinjava integration to render Jinja templates from Python dictionaries.

Add the Jinjava dependency:

pyproject.toml

[tool.pyronaut.dependencies]
runtime = [
    "io.micronaut.views:micronaut-views-jinjava",
]

Configure HTML as the default template extension:

config/application.toml

[micronaut.views.jinja]
default-extension = "html"

5.1. OAuth 2.0

To provide authentication, sign in to your AWS account and go to AWS Cognito.

With the Amazon Cognito SDK, you just write a few lines of code to enable your users to sign-up and sign-in to your mobile and web apps.

Standards-based authentication

Amazon Cognito uses common identity management standards including OpenID Connect, OAuth 2.0, and SAML 2.0.

First, create an Amazon Cognito User Pool:

Amazon Cognito User Pools - A directory for all your users

You can quickly create your own directory to sign up and sign in users, and to store user profiles using Amazon Cognito User Pools. User Pools provide a user interface you can customize to match your application. User Pools also enable easy integration with social identity providers such as Facebook, Google, and Amazon, and enterprise identity providers such as Microsoft Active Directory through SAML.

Amazon Cognito Pools are regional. Thus, annotate the region you are using.

While you setup the Amazon Cognito User Pool, you will need to save the pool id:

Save the client id and client secret:

5.2. Add a domain

5.3. Using the AWS CLI

Some of the following commands use jq

jq is a lightweight and flexible command-line JSON processor

Alternatively, you can use the AWS CLI to create the user pool and client (change the region to your desired value):

export COGNITO_REGION=eu-west-1
export COGNITO_POOL_ID=$(aws cognito-idp create-user-pool --pool-name "Micronaut Guides" --username-attributes "email" --auto-verified-attributes "email" | jq -r '.UserPool.Id')
export OAUTH_CLIENT_ID=$(aws cognito-idp create-user-pool-client --generate-secret --user-pool-id $COGNITO_POOL_ID --client-name "AWS Cognito Micronaut Tutorial" --callback-urls "http://localhost:8080/oauth/callback/cognito" --logout-urls "http://localhost:8080/logout" --supported-identity-providers COGNITO --allowed-o-auth-flows "code" --allowed-o-auth-scopes "phone" "email" "openid" "profile" "aws.cognito.signin.user.admin" --allowed-o-auth-flows-user-pool-client | jq -r '.UserPoolClient.ClientId')
export OAUTH_CLIENT_SECRET=$(aws cognito-idp describe-user-pool-client --user-pool-id $COGNITO_POOL_ID --client-id $OAUTH_CLIENT_ID | jq -r '.UserPoolClient.ClientSecret')
export COGNITO_DOMAIN="micronaut-guides-$RANDOM"
aws cognito-idp create-user-pool-domain --domain $COGNITO_DOMAIN --user-pool-id $COGNITO_POOL_ID

Configure the appropriate callback, make sure you allow the Authorization code grant OAuth flow, and select the openid and email scopes.

To use OAuth 2.0 integration, add the following dependency:

pyproject.toml

[tool.pyronaut.dependencies]
runtime = [
    "io.micronaut.security:micronaut-security-oauth2",
]

Also add Micronaut JWT support dependencies:

pyproject.toml

[tool.pyronaut.dependencies]
runtime = [
    "io.micronaut.security:micronaut-security-jwt",
]

Add the following OAuth 2.0 configuration:

config/application.toml

(1)
[micronaut.security]
authentication = "idtoken"

(2)
(3)
[micronaut.security.oauth2.clients.cognito]
client-id = "${OAUTH_CLIENT_ID:xxx}"
(4)
client-secret = "${OAUTH_CLIENT_SECRET:yyy}"

(5)
[micronaut.security.oauth2.clients.cognito.openid]
issuer = "https://cognito-idp.${COGNITO_REGION:us-east-1}.amazonaws.com/${COGNITO_POOL_ID:12345}/"

[micronaut.security.endpoints.logout]
(6)
get-allowed = true

1	Set `micronaut.security.authentication` as `idtoken`. The `idtoken` provided by Cognito when the OAuth 2.0 Authorization code flow ends will be saved in a cookie. The id token is a signed JWT. For every request, the Micronaut framework extracts the JWT from the Cookie and validates the JWT signature with the remote Json Web Key Set exposed by Cognito. JWKS is exposed by the `jws-uri` entry of Cognito `.well-known/openid-configuration`.
2	The provider identifier must match the last part of the URL you entered as a redirect URL: `/oauth/callback/cognito`.
3	Client ID. See previous screenshot.
4	Client Secret. See previous screenshot.
5	`issuer` URL. It allows the Micronaut framework to discover the configuration of the OpenID Connect server. Note: we will use the pool id and region mentioned previously.
6	Accept GET request to the `/logout` endpoint.

The previous configuration uses several placeholders. If you used the AWS CLI, then you are all set.

Otherwise, you will need to set up OAUTH_CLIENT_ID, OAUTH_CLIENT_SECRET, COGNITO_REGION, and COGNITO_POOL_ID environment variables.

export OAUTH_CLIENT_ID=XXXXXXXXXX
export OAUTH_CLIENT_SECRET=YYYYYYYYYY
export COGNITO_REGION=eu-west-1
export COGNITO_POOL_ID=eu-west-XXCCCAZZZ

Although undocumented in the Amazon Cognito User Pools Auth API Reference, Cognito provides an openid-configuration endpoint which the Micronaut framework uses to configure your application.

curl https://cognito-idp.${COGNITO_REGION}.amazonaws.com/${COGNITO_POOL_ID}/.well-known/openid-configuration

We want to use an Authorization Code grant type flow, which is described in the following diagram:

5.4. Home

Create a route function for / that returns an empty Python dictionary. @View renders the home.html Jinja template. Micronaut’s security model processor supplies the authenticated user’s details without injecting a principal into the route.

src/example/micronaut/home_controller.py

from micronaut.http.annotation import Get
from micronaut.security.annotation import Secured
from micronaut.security.rules import SecurityRule
from micronaut.views import View


@Secured(SecurityRule.IS_ANONYMOUS)  (1)
@View("home")  (2)
@Get("/")  (3)
def index() -> dict:
    return {}

1	Annotate with `io.micronaut.security.Secured` to configure secured access. The `SecurityRule.IS_ANONYMOUS` expression will allow access without authentication.
2	Use View annotation to specify which template to use to render the response.
3	The @Get annotation maps the `index` method to an HTTP GET request on `/`.

Create a Jinja template. The e filter escapes the authenticated user’s email for HTML:

config/views/home.html

<!DOCTYPE html>
<html>
<head>
    <title>Home</title>
</head>
<body>
<h1>Micronaut - Cognito example</h1>
<h2>username: {% if security %}{{ security.attributes.email | e }}{% else %}Anonymous{% endif %}</h2>
<nav>
    <ul>
        {% if security %}
        <li><a href="/oauth/logout">Logout</a></li>
        {% else %}
        <li><a href="/oauth/login/cognito">Enter</a></li>
        {% endif %}
    </ul>
</nav>
</body>
</html>

Also, note that we return an empty model, but access security in the template.

The SecurityViewModelProcessor injects into the model a security map with the authenticated user. See User in a view documentation.

6. Running the Application

To run the application, use the pyronaut dev command, which starts the application on port 8080.

6.1. Local tests

The tests verify anonymous HTML rendering and the provider’s login link. Application startup may attempt OpenID discovery at the configured issuer. The tests do not verify a live provider login.

tests/example/micronaut/test_home_controller.py

import pytest
import requests

from pyronaut.test import MicronautTest, micronaut_test_fixture


@pytest.fixture(scope="module")
def my_context(request):
    fixture = micronaut_test_fixture(
        request,
        MicronautTest(environments=["test"], transactional=False),
    )
    try:
        yield fixture
    finally:
        fixture.stop()


@pytest.fixture
def client(my_context):
    with requests.with_context(my_context) as session:
        yield session


def test_home_page_renders_anonymous_user(client):
    response = client.get("/", timeout=90)

    assert response.status_code == 200, response.text
    assert "username: Anonymous" in response.text


def test_anonymous_user_sees_provider_login(client):
    response = client.get("/", timeout=90)

    assert response.status_code == 200, response.text
    assert 'href="/oauth/login/cognito"' in response.text
    assert 'href="/oauth/logout"' not in response.text


def test_home_page_is_rendered_html(client):
    response = client.get("/", timeout=90)

    assert response.status_code == 200, response.text
    assert response.headers["Content-Type"].startswith("text/html")
    assert "{{" not in response.text
    assert "{%" not in response.text

Run the tests:

7. Testing the Application

To run the tests:

pyronaut install
pyronaut validate-config
pyronaut test

Complete the provider configuration above and verify the authorization-code login and logout flow manually with your own account. The local tests do not verify a live provider login, so the authenticated branch of the template (the escaped email and the logout link) is only covered by this manual check.

7.1. Cleanup

Once you are done with this guide, you can stop/delete the AWS resources created to avoid incurring unnecessary charges.

aws cognito-idp delete-user-pool-domain --domain $COGNITO_DOMAIN --user-pool-id $COGNITO_POOL_ID
aws cognito-idp delete-user-pool-client --client-id $OAUTH_CLIENT_ID --user-pool-id $COGNITO_POOL_ID
aws cognito-idp delete-user-pool --user-pool-id $COGNITO_POOL_ID

8. Next Steps

Read Micronaut OAuth 2.0 documentation to learn more.

9. License

All guides are released with an Apache License 2.0 for the code and a Creative Commons Attribution 4.0 license for the writing and media (images).

Table of Contents

Secure a Pyronaut application with Cognito

1. Getting Started

2. What you will need

3. Amazon Web Services (AWS)

3.1. AWS CLI

3.2. Administrator IAM user

4. Solution

5. Writing the Application

5.1. OAuth 2.0

5.2. Add a domain

5.3. Using the AWS CLI

5.4. Home

6. Running the Application

6.1. Local tests

7. Testing the Application

7.1. Cleanup

8. Next Steps

9. License