DA AYR Beta WebApp

This is a repo created and maintained by The National Archives for the Access Your Records (AYR) project. It holds a Flask application based from the Land Registry GOV.UK Frontend Flask template repo. Currently the intention is to deploy this via AWS Lambda and API Gateway but you can run it however you would like.

Getting started

Setup Poetry environment

Install poetry Check poetry has been installed using:

poetry --version

Then install the required dependencies using:

poetry install

You can now access the virtual environment created by poetry with:

poetry shell

in which you can run all of the following commands. Alternatively you can prefix all of the following commands with poetry run.

Install PostgreSQL

PostgrSQL is a dependency required for running unit tests, which are reliant on testing.postgresql. Download & Install PostgreSQL

To verify that PostgreSQL is installed on your machine you can use:

psql --version

and

initdb --version

Optionally, you can also install pgAdmin for easier administration and monitoring of the PostgreSQL database. PgAdmin is a tool that provides a modern GUI and tools that make it easier to perform actions.

(Optional) Download & Install pgAdmin

Set up commit signing

GitHub rulesets for the AYR repo prevent pull requests that contain unsigned commits from being merged with the main branch. To avoid having to modify PRs that contain unsigned commits, you should configure signed commits before making a first PR using the guide below.

Configure signed commits using the TDR dev documentation

Get GOV.UK Frontend assets

For convenience a shell script has been provided to download and extract the GOV.UK Frontend distribution assets

./build.sh

CSS / SCSS

We have the app/static/src/scss/main.scss file in the repo which we include all scss via partial scss files.

This needs to be converted using sass to a app/static/src/css/main.css file which we include in the app/templates/base.html template which we use as a base for all of our html files.

To build main.css file you can run the npm build script which runs sass by first installing the npm packages and then using:

npm run build

or if you'd like to watch for changes use:

npm run dev

To lint all CSS use:

npm run lint

SCSS files

If you need to add any new style files, then you can create a partial scss file, with filename prefixed by an underscore to mark it as such and then include it in the main.scss file using @import.

e.g. for _foo.scss, add @import "includes/foo";.

Set up SSL Certificate

For local development we have decided to require an SSL certificate so that we run our development server with SSL so we are closer to a production system where we intend to use SSL also. We specify the flask cli flags FLASK_RUN_CERT=cert.pem and FLASK_RUN_KEY=key.pem in the .flaskenv, which expect a cert.pem and corresponding key.pem file in the root of the repo.

You will need to create the cert-key pair with:

poetry run openssl req -x509 -newkey rsa:4096 -nodes -out cert.pem -keyout key.pem -days 365

and fill out the its prompts with information that you want (it does not matter as it is only being used for a development server).

Note: this command creates a cert-key pair valid for 365 days, but you can amend this as you wish.

When you access the application in a new browser for the first time with one of these keys you will have to tell it you trust the certificate, but then you should not be asked again.

Note: flask-talisman should redirect http requests to https but whenever running the flask development server with a certificate, this doesn't seem to do the redirection. We plan to investigate but for now we will have to deal without this redirection in local dev.

Set Flask Configuration Variables

Set the Flask Configuration Variables either with either:

• Environment Variables:

  1. Set all desired environment variables for all of the variables specified in .env.env_var.template. For convenience you can do this by running the following in the root of the repo:

  cp .env.env_var.template .env

  and filling out the .env file as desired.

• AWS Secrets Manager values:

  1. Set up your AWS credentials or log into an AWS account with the AWS CLI environment so that the desired AWS IAM user or role is set up.
  2. Make sure all of the properties (not the hardcoded values) in the BaseConfig class are set in the AWS Secrets Manager for this account.
  3. Set all desired environment variables for all of the variables specified in env.aws_secrets_manager.template. For convenience you can do this by running the following in the root of the repo:

  cp .env.aws_secrets_manager.template .env

  and filling out the .env file as desired.

Note: AWSSecretsManagerConfig depends on a boto3 session which, when developing locally, can be set to use a specific AWS Profile by setting the environment variable DEFAULT_AWS_PROFILE.

Run app

Ensure you set the above environment variables in the .env file as appropriate before running the Flask application with:

flask run

You should now have the app running on https://localhost:5000/

Note: Unless you have changed the FLASK_APP value in the .flaskenv file to point to another application entrypoint other than main_app, you must specify the CONFIG_SOURCE environment variable (as populated by the env file templates), to be either AWS_SECRETS_MANAGER or ENVIRONMENT_VARIABLES otherwise flask run will raise an error.

Local development with docker

The webapp depends on keycloak, a postgres instance holding metadata, an s3 bucket storing associated records and then an opensearch instance that is populated from those 2 via data_management/opensearch_indexer. For ease of use, we provide a docker-compose.yml file inside the local_services which spins up all these dependencies, using minio as a local replacement for an actual AWS s3, and populates them with consistent test data. Feel free to expand this data but data consistency is left up to you.

There are some dependencies for running this docker compose stack.

1. Have docker installed
2. Create certs for the webapp postgres instance in local_services/webapp_postgres_certs by running generate_webapp_postgres_certs.sh inside it
3. Create certs for the opensearch nodes in local_services/opensearch_certs by running generate_opensearch_certs.sh inside it
4. Create a .env file inside of local_services using local_services/.env.template

Then you can run: docker compose up -d

It will take a minute or two to spin up the stack, in particular opensearch and keycloak take a little while. You can check their progress in each container's logs.

Once the stack is running:

1. Create your users in the keycloak admin console at http://localhost:8080/admin/master/console/#/tdr/users using the keycloak admin credentials specified in the .env file, assigning appropriate groups to each. For local dev it's simple enough to set the passwords in the credentials tab.
2. Regenerate the keycloak client's client secret at http://localhost:8080/admin/master/console/#/tdr/clients/<UUID-OF-CLIENT>/settings.
3. Update the .env of the webapp in the root directory of the repo, making sure the following env vars are set according to the values set for the associated service in the docker compose stack.

export KEYCLOAK_BASE_URI=http://localhost:8080
export KEYCLOAK_REALM_NAME=tdr
export KEYCLOAK_CLIENT_ID=ayr-beta
export KEYCLOAK_CLIENT_SECRET=<secret regenerated above>


export DB_PORT=5433
export DB_HOST=localhost
export DB_NAME=local_db
export DB_USER=local_db_user
export DB_PASSWORD=local_db_user_password


export AWS_ENDPOINT_URL=http://localhost:9000
export AWS_ACCESS_KEY_ID=ROOTNAME
export AWS_SECRET_ACCESS_KEY=CHANGEME123

export OPEN_SEARCH_HOST=https://localhost:9200
export OPEN_SEARCH_USERNAME=admin
export OPEN_SEARCH_PASSWORD=FOOBARCARabc123!
export OPEN_SEARCH_CA_CERTS=local_services/opensearch_certs/root-ca.pem
export OPEN_SEARCH_TIMEOUT=10

export DB_SSL_ROOT_CERTIFICATE=local_services/webapp_postgres_certs/root-ca.pem

Finally you can populate the opensearch cluster with the corresponding data stored in snapshot 1 in local_services/snapshots/ by running source .env && local_services/opensearch-entrypoint.sh.

Then you can run the flask server with flask run

Local dev without docker

Running webapp postgres db without docker

Provided is the file dev-data.sql which can be used to restore a database on a postgres instance. This is the database that is assumed to be used for our end to end tests which depend on data. To use this database, you will need to:

1. connect to a database on a postgres instance with the user you want to own the new database: psql -U username
2. create a new database, e.g. CREATE DATABASE ayr;
3. exit from the psql connection
4. restore the data dump dev-data.sql with psql -U username -d ayr -f dev-data.sql

NOTE: The db info used here will need to be used in the config as detailed in the config section.

Connecting your own opensearch cluster

You will need to specify:

• OPEN_SEARCH_HOST
• OPEN_SEARCH_USERNAME (can be left empty if running with the AWS config as that would use AWS4Auth signing)
• OPEN_SEARCH_PASSWORD (can be left empty if running with the AWS config as that would use AWS4Auth signing)
• OPEN_SEARCH_CA_CERTS can be left empty if running on a system where the certificate for the opensearch cluster is already trusted by the system.
• OPEN_SEARCH_TIMEOUT

If creating your own cluster, you can create the keys as detailed in the docker section.

Running Keycloak without docker

It is possible to set up a local Keylcoak instance for development of Keycloak authentication pages. This repository: https://github.com/nationalarchives/tdr-auth-server/blob/master/README.md contains a readme which can be used to setup Keycloak or follow the steps below.

1. Clone the TDR Auth Server repository
2. Sign in to Keycloak
3. Select realm settings
4. [Top right] Select Action dropdown
5. Select Partial Export
6. Save the file as tdr-realm-export.json in the root directory
7. Build the keycloak docker image using the following command

docker build -t tdr-auth-server .

8. Run the docker image with the following command:

docker run -it --rm --name tdr-auth-server -p 8081:8080 \
-e KEYCLOAK_ADMIN=admin \
-e KEYCLOAK_ADMIN_PASSWORD=admin \
-e KEYCLOAK_IMPORT=/keycloak-configuration/tdr-realm.json \
-e REALM_ADMIN_CLIENT_SECRET=someValue \
-e CLIENT_SECRET=someValue \
-e BACKEND_CHECKS_CLIENT_SECRET=someValue \
-e REPORTING_CLIENT_SECRET=someValue \
-e USER_ADMIN_CLIENT_SECRET=someValue \
-e ROTATE_CLIENT_SECRETS_CLIENT_SECRET=someValue \
-e KEYCLOAK_CONFIGURATION_PROPERTIES=intg_properties.json \
-e FRONTEND_URL=someValue \
-e GOVUK_NOTIFY_API_KEY_PATH=someValue \
-e GOVUK_NOTIFY_TEMPLATE_ID_PATH=someTemplateId \
-e DB_VENDOR=h2 \
-e SNS_TOPIC_ARN=someTopicArn \
-e TDR_ENV=intg \
-e KEYCLOAK_HOST=localhost:8081 \
-e KC_DB_PASSWORD=password \
-e BLOCK_SHARED_PAGES=false tdr-auth-server

9. Set the TDR Keycloak theme via the admin panel

Tip: the quickest way to view the TDR login theme (that is displayed to TDR users) is to (while logged into the console):

10. Select the "Master" Realm (top left, below the keycloak logo) if it's not already selected
11. Select "Realm roles" in the sidebar
12. Select "default-roles-master"
13. Select the "Themes" tab
14. Under "login theme", select "tdr" from the dropdown menu
15. Sign out (click "Admin" on the top right and select "Sign out")

Please see: https://github.com/nationalarchives/tdr-auth-server/blob/master/README.md#running-locally

Update TDR Theme Locally

1. Rebuild the image locally and run. docker build -t tdr-auth-server .
2. Make necessary changes to the TDR theme (freemarker templates/sass/static resources)
3. Run following command from the root directory: [root directory] $ npm run build-local --container_name=tdr-auth-server
4. Refresh the locally running Keycloak pages to see the changes.
5. Repeat steps 3 to 5 as necessary.

Flask App Configuration Details

Our application uses configuration values defined using Flask Config classes to set up the application's settings and connect it to various services. The pattern we are using consists of a base config class, BaseConfig, which is where we specify any hardcoded values, and all other configurable values are defined as a property, for example:

    @property
    def EXAMPLE_VARIABLE(self):
        return self._get_config_value("EXAMPLE_VARIABLE")

where _get_config_value is treated as an abstract method which is implemented in the child config classes that extend BaseConfig.

Hardcoded values:

• SESSION_COOKIE_HTTPONLY: Configure session cookies to be HTTP-only. Is True.
• SESSION_COOKIE_SECURE: Configure session cookies to be secure. Is True.
• CONTACT_EMAIL: Email address for contact information.
• CONTACT_PHONE: Phone number for contact information.
• DEPARTMENT_NAME: The name of the department.
• DEPARTMENT_URL: The URL of the department's website.
• SERVICE_NAME: The name of the service.
• SERVICE_PHASE: The phase of the service.
• SERVICE_URL: The URL of the service.

Properties configurable at runtime:

• AWS_REGION: The AWS region used for AWS services.
• DB_PORT: The port of the database to connect to.
• DB_HOST: The host of the database to connect to.
• DB_USER: The username of the database to connect to.
• DB_PASSWORD: The password of the database to connect to.
• DB_NAME: The name of the database to connect to.
• DB_SSL_ROOT_CERTIFICATE: The path of the database certificate to connect with.
• KEYCLOAK_BASE_URI: The base URI of the Keycloak authentication service.
• KEYCLOAK_CLIENT_ID: The client ID used for Keycloak authentication.
• KEYCLOAK_REALM_NAME: The name of the Keycloak realm.
• KEYCLOAK_CLIENT_SECRET: The client secret used for Keycloak authentication.
• SECRET_KEY: Secret key used for Flask session and security.
• DEFAULT_PAGE_SIZE: set value for no. of records to show on browse/search view.
• DEFAULT_DATE_FORMAT: set value to show date in specific format cross the application. i.e. "DD/MM/YYYY"
• RECORD_BUCKET_NAME: name of s3 bucket that holds all of the record objects themselves
• FLASKS3_ACTIVE: whether to fetch static assets from s3/Cloudfront rather than the usual url_for.
• FLASKS3_CDN_DOMAIN: CDN domain to fetch assets from if FLASKS3_ACTIVE is set to True
• FLASKS3_BUCKET_NAME: S3 bucket assets are uploaded to and served to Cloudfront from.
• PERF_TEST: Enable to allow access tokens generated via API to be accepted for performance testing.
• OPEN_SEARCH_HOST: The host of the opensearch cluster to connect to.
• OPEN_SEARCH_USERNAME: The username of the opensearch cluster to connect to.
• OPEN_SEARCH_PASSWORD: The password of the opensearch cluster to connect to.
• OPEN_SEARCH_CA_CERTS: The path of the opensearch cluster certificate to connect with.
• OPEN_SEARCH_TIMEOUT: The timeout for api calls to the opensearch cluster.

Calculated values:

• SQLALCHEMY_DATABASE_URI: The PostgreSQL database URI with format postgresql+psycopg2://<DB_USER>:<DB_PASSWORD>@<DB_HOST>:<DB_PORT>/<DB_NAME>.

We have two usable configs which extend BaseConfig for running the application:

• EnvConfig which implements _get_config_value so it reads from environment variables.
• AWSSecretsManagerConfig which implements _get_config_value so it reads from AWS Secrets Manager values.

When configuring flask run run the app created by main_app.py, as we do with the line export FLASK_APP=main_app in the .flaskenv, we can either use EnvConfig or AWSSecretsManagerConfig by setting CONFIG_SOURCE as either ENVIRONMENT_VARIABLES or AWS_SECRETS_MANAGER respectively. If using AWSSecretsManagerConfig, then you must also set AWS_SM_CONFIG_SECRET_ID which is the secret id of the Secrets Manager secret used to read in all the config values.

We also have a TestingConfig that extends BaseConfig which is only used for Flask tests as detailed below. Its implementation of _get_config_value returns an empty string for all the configurable properties just so we don't need to worry about setting values in tests we don't care about them in. We may revisit this, as the fact that config vars are unnecessary in some tests that access them seems like a code smell that could be worth addressing; specifying them in any test that needs them and refactoring the code if we still find asserting anything about them unnecessary could be a better approach long term. As well as the confgiurable values discussed above, we also hardcode the following on the TestingConfig:

• TESTING to True to disable error catching (further info here), and changes certain extension's logic as well as own on (e.g. disables forcing of https) to facilitate easier testing.
• SECRET_KEY to "TEST_SECRET_KEY" so that Flask sessions work in the tests.

The .flaskenv file

In addition to the .env file discussed above, which can be created from template files, we have a .flaskenv file with Flask specific configuration values which is committed to the repo and we don't expect to change these.

Environment loading

Both the .env and .flask_env are loaded automatically when we run the flask application as outlined in the following section, thanks to the use of python-dotenv. More information on Flask environment variable hierarchies can be found here.

Metadata Store Postgres Database

The webapp is set up to read data from an externally defined postgres database referred to as the Metadata Store.

We currently use the python package, Flask-SQLAlchemy to leverage some benefits of the ORM (Object Relationship Mapping) it provides, making our queries using the python classes we create as opposed to explicit SQL queries.

The database connection is configured with the SQLALCHEMY_DATABASE_URI variable built up in the Flask Config.

Database Infrastructure and Connection

The database is assumed to be a PostgreSQL database.

This could be spun up by PostgreSQL or from Amazon RDS, for example.

One thing to note is that our database connection's ssl mode is verify-full therefore your db instance must have a root certificate on its server, and you must have a copy of a leaf certificate signed by the root certificate in a location accessible by this flask webapp, specified by DB_SSL_ROOT_CERTIFICATE.

When choosing the configuration choice AWS_SECRETS_MANAGER, we assume the database is an RDS database with an RDS proxy sitting in front, in the same AWS account as the Secrets Manager and lambda and resides in a VPC which the lambda is in so that the webapp hosted in the lambda can communicate with it securely.

Database Tables, Schema and Data

We do not define the database tables ourselves, nor write any information to the database, both of which are assumed to be handled externally. To leverage the use of the ORM we reflect the tables from the existing database with the following line in our Flask app setup.

db.Model.metadata.reflect(bind=db.engine, schema="public")

More info on relecting database tables can be found here.

Further, to this, we do define models and columns from the corresponding tables we do use in our queries we use so that when developing we will know what attributes are available but this has to be manually kept in sync with the externally determined schema through discussion with the maintainers of the Metadata Store database.

Data management

We have a few functions in data_management/opensearch_indexer to index an opensearch cluster with data from a postgres database with the schema detailed above holding metadata and byte stream of the corresponding file content. Depending on environment we have different levels of function to do this:

• independently with data_management/opensearch_indexer/opensearch_indexer/index_file_content_and_metadata_in_opensearch.py
• at AWS level where config options come from an AWS secretsmanager secret and the file stream is built from an s3 object with data_management/opensearch_indexer/opensearch_indexer/index_file_content_and_metadata_in_opensearch_from_aws.py
• at AWS lambda level with s3 bucket and secret id determined on each run with data_management/opensearch_indexer/opensearch_indexer/lambda_function.py.

We also have a way to do this for all files in a postgres database with data_management/opensearch_indexer/opensearch_indexer/index_all_in_db.py.

Testing

Unit and Integration tests

For running flask app tests, we have the client fixture which uses the app fixture which utilises TestingConfig as discussed above.

To run the unit and integration tests you can run:

python -m pytest --cov=app --cov-report=term-missing --cov-branch -vvv

This also will generate a test coverage report.

Mocking user permissions in tests

We have 2 fixtures used for mocking a user and their permissions in our non end to end, flask tests:

• mock_standard_user
• mock_all_access_user

which can be called like

mock_standard_user(client, "foo")

mock_all_access_user(client)

respectively.

These mock the get_user_groups permissions helper which abstracts away the external api call to keycloak, which we do not want to call in our non end to end tests.

• mock_standard_user gives the user and results in an AYRUser where:

  • can_access_ayr: True
  • is_standard_user: True
  • is_all_access_user: False
  • transferring_bodies: same list as pass in as second arg to mock_standard_user

• mock_standard_user gives the user and results in an AYRUser where:

  • can_access_ayr: True
  • is_standard_user: False
  • is_all_access_user: True
  • transferring_bodies: None

End-To-End Tests

We have a separate End To End suite of Playwright tests in the e2e_tests/ directory. These are also written in python and use the pytest-playwright PyPi package to run the tests as specified in the poetry dependencies.

In addition to installing the package, before you run the tests for the first time on your machine, you will need to run playwright install to install the required browsers for the end-to-end tests.

Before running our Playwright tests,

• AYR_AAU_USER_USERNAME
• AYR_AAU_USER_PASSWORD
• AYR_STANDARD_USER_USERNAME
• AYR_STANDARD_USER_PASSWORD

set environment variables with appropriate test user credentials for the instance you want to test. When encountering any issues around getting the environment variables to be picked up by the e2e tests, exporting them manually should remediate it.

Note: a .env.e2e_tests.template file has been provided, which you can then cp .env.e2e_tests.template .env.e2e_tests, then fill, and then source source .env.e2e_tests

You can then run all of our Playwright tests against an instance, localhost for example, by running:

pytest e2e_tests/ --base-url=https://localhost:5000

You can swap out the base-url for another if you want to run the tests against another instance of the application.

To enable this flexibility we suggest any Playwright tests added to the repo use relative paths when referring to urls of the application itself.

In addition, we recommend that any tests that have dependencies on data, do not make assumptions about any particular database or instance involved, and instead do the test data set up and teardown as part of the test suite.

Visual regression E2E tests

In order to ensure a consistent and stable testing environment, we make use of a Docker image (and subsequently container) that is defined in structure inside of e2e_tests/dockerfile. If an example of this image is stored inside of AWS ERC (or any other Docker container registry), it can be run from the root directory using:

docker run --platform linux/arm64/v8 --rm --env-file .env.e2e_tests --network=host -v $PWD/e2e_tests:/e2e_tests <URL-TO-IMAGE>

Otherwise, to build the image locally you should:

First, switch current working directory to e2e_tests

cd e2e_tests/

Then, to build and run the E2E visual regression suite

bash e2e_tests.reg_build_and_run.sh

To just run the E2E tests once the container has already been built

bash e2e_tests.reg_run.sh

Whilst the Docker container is running, snapshots of visual regression for pages that have been modified will be automatically saved inside of e2e_tests/snapshots/test_css_no_visual_regression and e2e_tests/snapshots/test_css_no_visual_regression_mobile.

Useful playwright pytest run modes

browser

• To run the tests on specific browsers, as long as they have been installed already with playwright install you can add as many --browser flags as you want, e.g.

pytest e2e_tests/ --base-url=https://localhost:5000 --browser chromium --browser firefox --browser webkit

will run all the tests against chromium, firefox and webkit

headed

• To view the browser when the tests are running, you can add the --headed flag, e.g.

pytest e2e_tests/ --base-url=https://localhost:5000 --headed

PWDEBUG

• To utilise the playwright debugger, you can set the PWDEBUG=1 environment variable, e.g.

PWDEBUG=1 poetry run pytest e2e_tests/test_search.py --base-url=https://localhost:5000 --headed

1. individual tests in file with multiple tests (use -k): poetry run pytest e2e_tests/test_record_metadata.py -k test_page_title_and_header --base-url=https://localhost:5000 --headed

Generate playwright tests using GUI

Run poetry run playwright codegen https://localhost:5000 --ignore-https-errors to spin up a browser instance which you can interact with, where each interaction will be captured as a pytest playwright line, which builds out a test skeleton file for you to add assertions to.

When to add an E2E Tests?

End to end tests have prod and cons, such as the following:

Pros:

• Testing Real User Flows
• Complex User Scenarios (such as sign in flows)

Cons:

• Execution Time
• Harder to debug errors

Therefore we should try to add them sparingly on critical workflows.

E2E Tests (Progressive Enhancement Support)

E2E Tests by default run without JavaScript & CSS.

To enable JavaScript to run during E2E Tests the flag java_script_enabled should be set to True within conftest.py.

To enable a test to run with CSS ensure each test is prefixed with with the term test_css_test_name.

e.g.:

def test_css_has_title(page: Page):

Performance Tests

Performance tests have been set up with Locust: https://github.com/locustio/locust

The following ENV Vars are required:

• CERT_PATH=False
• AYR_AAU_USER_USERNAME=""
• AYR_AAU_USER_PASSWORD=""
• KEYCLOAK_AUTH_URL="https://example.co.uk/realms/realm-name/protocol/openid-connect/token"
• KEYCLOAK_CLIENT_ID=""
• KEYCLOAK_CLIENT_SECRET=""

1. Run the flask app on a specific environment LOCAL / INT / TEST
2. Ensure Locust is installed with pip install locust
3. Run locust with the following command: locust --host=https://127.0.0.1:5000
4. Ensure the ENV variable PERF_TEST = True
5. Access locust via the provided URL and start a new test with the required amount of users

Logging

Configuration

The application logger configuration is detailed in setup_logging in app/logger_config.py.

This config includes:

• a formatter specifying request-specific information such as the remote address and URL when a request context is available
• setting the logging level to INFO.

setup_logging is called during the initialization of the Flask app.

Usage

We use two loggers in this application:

• app_logger for application-related logs
• audit_logger for audit-specific logs

Both are attached to the Flask app instance for easy access across the app. Since we define routes using blueprints instead of directly on the app, we access these loggers through Flask’s current_app.

To use these loggers in your code, import current_app from Flask:

from flask import current_app

Then, call the appropriate logger as follows:

current_app.app_logger.info('Some info message')
current_app.app_logger.debug('Some debug message')
current_app.app_logger.warning('Some warning message')
current_app.app_logger.error('Some error message')

current_app.audit_logger.info('Some info message')
current_app.audit_logger.debug('Some debug message')
current_app.audit_logger.warning('Some warning message')
current_app.audit_logger.error('Some error message')

Output

The logs from the webapp, when used as above are output as a stream to stdout in the following format:

[2023-12-15 15:40:14,119] 127.0.0.1 requested https://localhost:5000/logger_test?log_level=error
ERROR in routes: Some error

Extensions and package logs

Some of the Flask extensions used,as detailed in the Features section below, may produce their own logs and may have their own configuration and format different to the above.

Testing logs

With pytest we can assert the logs we expect to be written by utilising pytest's inbuilt caplog fixture.

Features

Please refer to the specific packages documentation for more details. Details can be found in the pytest logging documentation.

Forms generation and validation

Uses Flask WTF and WTForms to define and validate forms. Forms are rendered in your template using regular Jinja syntax.

Form error handling

If a submitted form has any validation errors, an error summary component is shown at the top of the page, along with individual field error messages. This follows the GOV.UK Design System validation pattern and is built into the base page template.

Flash messages

Messages created with Flask's flash function will be rendered using the GOV.UK Design System notification banner component. By default the blue "important" banner style will be used, unless a category of "success" is passed to use the green version.

HTTP security headers

Uses Flask Talisman to set HTTP headers that can help protect against a few common web application security issues.

• Forces all connections to https, unless running with debug enabled or in testing. Note: This seems to not be working when running the local development with a SSL certificate as discussed above
• Enables HTTP Strict Transport Security.
• Sets Flask's session cookie to secure, so it will never be set if your application is somehow accessed via a non-secure connection.
• Sets Flask's session cookie to httponly, preventing JavaScript from being able to access its content.
• Sets X-Frame-Options to SAMEORIGIN to avoid clickjacking.
• Sets X-XSS-Protection to enable a cross site scripting filter for IE and Safari (note Chrome has removed this and Firefox never supported it).
• Sets X-Content-Type-Options to prevent content type sniffing.
• Sets a strict Referrer-Policy of strict-origin-when-cross-origin that governs which referrer information should be included with requests made.

Content Security Policy

A strict default Content Security Policy (CSP) is set using Flask Talisman to mitigate Cross Site Scripting (XSS) and packet sniffing attacks. This prevents loading any resources that are not in the same domain as the application.

Response compression

Uses Flask Compress to compress response data. This inspects the Accept-Encoding request header, compresses using either gzip, deflate or brotli algorithms and sets the Content-Encoding response header. HTML, CSS, XML, JSON and JavaScript MIME types will all be compressed.

Support

This software is provided "as-is" without warranty. Support is provided on a "best endeavours" basis by the maintainers and open source community.

Please see the contribution guidelines for how to raise a bug report or feature request.