Modularise folders (#31)

* refactor to modularise layout
* update readme
* add section on updating deps

README.md

@@ -8,6 +8,8 @@ This repository contains an example application demonstrating Operations Enginee
 
 1. [Prerequisites](#prerequisites)
 1. [How to use](#how-to-use)
+1. [Updating dependencies](#updating-dependencies)
+1. [Generic settings](#generic-settings)
 1. [Deployment](#deployment)
 1. [Contributing](#contributing)
 1. [Contact](#contact)
@@ -48,6 +50,10 @@ We rely on naming conventions to facilitate use of this template. All Operations
 - Create Cloud Platform namespaces called  `<TEAM_NAME>-<NAME>-<ENV>` for example, `operations-engineering-example-dev` and `operations-engineering-example-prod` and link to the repo. Follow instructions here: [Creating a Cloud Platform environment](https://user-guide.cloud-platform.service.justice.gov.uk/documentation/getting-started/env-create.html#creating-a-cloud-platform-environment).
 - The app is available at `<TEAM_NAME>-<NAME>-<ENV>.cloud-platform.service.justice.gov.uk`
 
+### Updating dependencies
+
+This app is set up with dependabot to automatically raise PRs to update dependencies. Note that the `govuk-frontend` package version is hardcoded in `build.py` and `application/templates/components/base.html`, which must be updated manually if another version is required. The version of `govuk-frontend` is determined by the version of `govuk-frontend-jijna` set in the `requirements.txt` file. The current verison of `govuk-frontend` is recorded in `application/static/VERSION.txt`. For example, `govuk-frontend-jinja` 2.7.0 requires `govuk-frontend` 4.7.0.
+
 ### Generic settings
 
 The flask app itself is deliberately generically named `application` and does not need to be changed. If you choose to change it then corresponding changes are required in `build.py`, `Dockerfile`, `makefile` and possibly elsewhere. The app is hardcoded to run and listen on port `1551` as appuser `1051` (see `Dockerfile` and `compose.yaml`).
@@ -81,9 +87,9 @@ The production namespace on [Cloud Platform](https://user-guide.cloud-platform.s
 
 To deploy the app to the production namespace do the following:
 
-- on the `main` branch.
-- create a new tag using `git tag vx.y.z` where `x.y.z` is the version number. Please follow [semantic versioning](https://semver.org/).
-- push the tag to the remote repository using `git push origin --tags`
+- Switch to the `main` branch and ensure it is up to date.
+- Create a new tag using `git tag vx.y.z` where `x.y.z` is the new version number, and the `v` prefix provides the match criterion to trigger deployment. Please follow [semantic versioning](https://semver.org/).
+- Push the tag to the remote repository using `git push origin --tags`
 
 This triggers the `deploy-to-prod` GitHub workflow to create a release and deploy the app to the production namespace.
 

application/__init__.py

@@ -8,10 +8,22 @@
 
 from config import Config
 
+# from application.main.views import (main)
+
+from application.main.middleware.error_handler import (
+    server_forbidden,
+    page_not_found,
+    too_many_requests,
+    unknown_server_error,
+    gateway_timeout,
+)
+
 
 app = Flask(__name__)
 app.config.from_object(Config)
 
+# app.register_blueprint(main)
+
 app.jinja_loader = ChoiceLoader(
     [
         PackageLoader("application"),
@@ -22,7 +34,11 @@
 app.jinja_env.trim_blocks = True
 app.jinja_env.lstrip_blocks = True
 
+app.register_error_handler(403, server_forbidden)
+app.register_error_handler(404, page_not_found)
+app.register_error_handler(500, unknown_server_error)
+app.register_error_handler(504, gateway_timeout)
 
 @app.route("/", methods=["GET", "POST"])
 def index(): 
-    return render_template("index.html")
+    return render_template("pages/index.html")

application/main/middleware/error_handler.py

@@ -0,0 +1,27 @@
+import logging
+
+from flask import (
+    render_template,
+)
+
+logger = logging.getLogger(__name__)
+
+def server_forbidden(err):
+    logger.error("server_forbidden(): %s", err)
+    return render_template("pages/errors/403.html"), 403
+
+def page_not_found(err):
+    logger.error("A request was made to a page that doesn't exist %s", err)
+    return render_template("pages/errors/404.html"), 404
+
+def too_many_requests(err):
+    logger.error("Too many attempts to access this page %s", err)
+    return render_template("pages/errors/429.html"), 429
+
+def unknown_server_error(err):
+    logger.error("An unknown server error occurred: %s", err)
+    return render_template("pages/errors/500.html"), 500
+
+def gateway_timeout(err):
+    logger.error("A gateway timeout error occurred: %s", err)
+    return render_template("pages/errors/504.html"), 504

application/main/views.py

@@ -0,0 +1,12 @@
+import datetime
+import logging
+import os
+from collections import Counter
+from functools import wraps
+from urllib.parse import quote_plus, urlencode
+
+from flask import (Blueprint, abort, current_app, jsonify, redirect,
+                   render_template, render_template_string, request, session,
+                   url_for)
+
+# Empty as yet

application/templates/accessibility.html → application/templates/pages/accessibility.html

@@ -1,4 +1,4 @@
-{% extends "base.html" %}
+{% extends "components/base.html" %}
 
 {%- from 'govuk_frontend_jinja/components/back-link/macro.html' import govukBackLink -%}
 {%- from 'govuk_frontend_jinja/components/inset-text/macro.html' import govukInsetText -%}

application/templates/cookies.html → application/templates/pages/cookies.html

@@ -1,4 +1,4 @@
-{% extends "base.html" %}
+{% extends "components/base.html" %}
 
 {%- from 'govuk_frontend_jinja/components/back-link/macro.html' import govukBackLink -%}
 {%- from 'govuk_frontend_jinja/components/table/macro.html' import govukTable -%}

application/templates/pages/errors/403.html

@@ -0,0 +1,17 @@
+{% extends "components/base.html" %}
+
+{% block pageTitle %}
+    Web server forbids you from accessing the page you’re trying to open (403 error)
+{% endblock %}
+
+{% set mainClasses = "govuk-main-wrapper--l" %}
+
+{% block content %}
+    <div class="govuk-grid-row">
+        <div class="govuk-grid-column-two-thirds">
+            <h1 class="govuk-heading-xl">Web server forbids you from accessing the page you’re trying to open (403
+                error)</h1>
+            <p class="govuk-body">If you entered a web address, please check it was correct.</p>
+        </div>
+    </div>
+{% endblock %}

application/templates/404.html → application/templates/pages/errors/404.html

@@ -1,6 +1,8 @@
-{% extends "base.html" %}
+{% extends "components/base.html" %}
 
-{% block pageTitle %}Page not found – {{config['SERVICE_NAME']}} – GOV.UK{% endblock %}
+{% block pageTitle %}
+    Page not found – {{config['SERVICE_NAME']}} – GOV.UK (404 error)
+{% endblock %}
 
 {% set mainClasses = "govuk-main-wrapper--l" %}
 

application/templates/429.html → application/templates/pages/errors/429.html

@@ -1,6 +1,8 @@
-{% extends "base.html" %}
+{% extends "components/base.html" %}
 
-{% block pageTitle %}Too many requests – {{config['SERVICE_NAME']}} – GOV.UK{% endblock %}
+{% block pageTitle %}
+    Too many requests – {{config['SERVICE_NAME']}} – GOV.UK (429 error)
+{% endblock %}
 
 {% set mainClasses = "govuk-main-wrapper--l" %}
 

application/templates/500.html → application/templates/pages/errors/500.html

@@ -1,6 +1,8 @@
-{% extends "base.html" %}
+{% extends "components/base.html" %}
 
-{% block pageTitle %}Sorry, there is a problem with the service – {{config['SERVICE_NAME']}} – GOV.UK{% endblock %}
+{% block pageTitle %}
+    Sorry, there is a problem with the service – {{config['SERVICE_NAME']}} – GOV.UK (500 error)
+{% endblock %}
 
 {% set mainClasses = "govuk-main-wrapper--l" %}
 

application/templates/503.html → application/templates/pages/errors/503.html

@@ -1,6 +1,8 @@
-{% extends "base.html" %}
+{% extends "components/base.html" %}
 
-{% block pageTitle %}Sorry, the service is unavailable – {{config['SERVICE_NAME']}} – GOV.UK{% endblock %}
+{% block pageTitle %}
+    Sorry, the service is unavailable – {{config['SERVICE_NAME']}} – GOV.UK (503 error)
+{% endblock %}
 
 {% set mainClasses = "govuk-main-wrapper--l" %}
 

application/templates/index.html → application/templates/pages/index.html

@@ -1,4 +1,4 @@
-{% extends "base.html" %}
+{% extends "components/base.html" %}
 
 {% block beforeContent %}
 {{ super() }}
@@ -9,7 +9,7 @@
   <html>
   <body>
 
-  <h1>Good afternoon!</h1>
+  <h1>Good morning!</h1>
 
   <p>I hope you're having a lovely day.</p>
 

application/templates/privacy.html → application/templates/pages/privacy.html

@@ -1,4 +1,4 @@
-{% extends "base.html" %}
+{% extends "components/base.html" %}
 
 {%- from 'govuk_frontend_jinja/components/back-link/macro.html' import govukBackLink -%}