Generate PDF reports from HTML using grover gem

Before, the [`wicked_pdf` gem][wicked] was used to generate PDF files for the
means and merits reports from HTML templates. This gem relies on
[`wkhtmltopdf`][wk] to generate PDFs from HTML.

As part of the [work to upgrade to Ruby version to 3.1.3][ruby], we discovered that
`wkhtmltopdf` was no longer available as part the Alpine image.

As outlined in the repo, the project is no longer actively maintained —so we
took a decision to migrate away from that tool and consider alternatives.

The [`grover` gem][grover] makes use of [`puppeteer`][puppeteer] to render HTML
in a headless browser and save a PDF file. Other approaches were identified (e.g
writing PDFs [using `prawn`][prawn]), but ultimately `grover` was chosen as a
drop-in replacement.

This replaces `wicked_pdf` with `grover` for means and merits report creation
(which are subsequently sent to CCMS), and updates the respective controllers so
that PDF files can be rendered in the browser for testing purposes.

Ensuring Puppeteer and Chromium are available in each scenario (locally, unit
tests in CI, and in alpine environments) requires a slightly different
approach in each instance. This is not ideal, but it is necessary.

Puppeteer is not run in a sandbox environment (running as a non-root user in
Alpine is convoluted), but since the only PDFs we generate are from HTML we
write and control, this should not pose a security risk.

[wicked]: https://github.com/mileszs/wicked_pdf
[wk]: https://github.com/wkhtmltopdf/wkhtmltopdf
[ruby]: #4663 (comment)
[grover]: https://github.com/Studiosity/grover
[puppeteer]: https://github.com/puppeteer/puppeteer
[prawn]: https://github.com/prawnpdf/prawn

.circleci/config.yml

@@ -14,9 +14,9 @@ executors:
     docker:
       - image: cimg/ruby:3.1.2-browsers
         environment:
-          - RAILS_ENV=test
-          - TZ: "Europe/London"
-          - CI: true
+          RAILS_ENV: test
+          TZ: "Europe/London"
+          CACHE_VERSION: v1
   cloud-platform-executor:
     docker:
       - image: ministryofjustice/cloud-platform-tools:2.1
@@ -33,7 +33,7 @@ executors:
       - image: ministryofjustice/apply-ci:latest-3.1.2
         environment:
           GITHUB_TEAM_NAME_SLUG: laa-apply-for-legal-aid
-          CI: true
+          CACHE_VERSION: v1
       - image: cimg/postgres:10.18
       - image: cimg/redis:5.0
       - image: ghcr.io/ministryofjustice/hmpps-clamav:latest
@@ -99,24 +99,22 @@ references:
   restore_gems_cache: &restore_gems_cache
     restore_cache:
       keys:
-        - v2.7-gems-cache-{{ checksum "Gemfile.lock" }}
-        - v2.7-gems-cache-
+        - v2.7-gems-cache-{{ .Environment.CACHE_VERSION }}-{{ checksum "Gemfile.lock" }}
 
   restore_js_packages_cache: &restore_js_packages_cache
     restore_cache:
       keys:
-        - v2.7-yarn-packages-cache-{{ checksum "yarn.lock" }}
-        - v2.7-yarn-packages-cache-
+        - v2.7-yarn-packages-cache-{{ .Environment.CACHE_VERSION }}-{{ checksum "yarn.lock" }}
 
   save_gems_cache: &save_gems_cache
     save_cache:
-        key: v2.7-gems-cache-{{ checksum "Gemfile.lock" }}
+        key: v2.7-gems-cache-{{ .Environment.CACHE_VERSION }}-{{ checksum "Gemfile.lock" }}
         paths:
           - vendor/bundle
 
   save_js_packages_cache: &save_js_packages_cache
     save_cache:
-      key: v2.7-yarn-packages-cache-{{ checksum "yarn.lock" }}
+      key: v2.7-yarn-packages-cache-{{ .Environment.CACHE_VERSION }}-{{ checksum "yarn.lock" }}
       paths:
         - node_modules
 
@@ -190,6 +188,19 @@ jobs:
     - *restore_js_packages_cache
     - *install_js_packages
     - *save_js_packages_cache
+    - run:
+        name: Install Headless Chrome dependencies
+        command: |
+          sudo apt-get install -yq \
+          gconf-service libasound2 libatk1.0-0 libatk-bridge2.0-0 libc6 libcairo2 libcups2 libdbus-1-3 \
+          libexpat1 libfontconfig1 libgcc1 libgconf-2-4 libgdk-pixbuf2.0-0 libglib2.0-0 libgtk-3-0 libnspr4 \
+          libpango-1.0-0 libpangocairo-1.0-0 libstdc++6 libx11-6 libx11-xcb1 libxcb1 libxcomposite1 libxcursor1 \
+          libxdamage1 libxext6 libxfixes3 libxi6 libxrandr2 libxrender1 libxss1 libxtst6 ca-certificates \
+          fonts-liberation libappindicator1 libnss3 lsb-release xdg-utils wget
+    - run:
+        name: Install Puppeteer with Chromium
+        command: |
+          yarn add [email protected]
     - run:
         name: Setup Code Climate test-reporter
         command: |

.gitignore

@@ -62,3 +62,6 @@ Brewfile.lock.json
 # Ignore payload files generated by CCMS integration specs
 /ccms_integration/generated/*
 !/ccms_integration/generated/.keep
+
+# Ignore Puppeteer cache
+.cache

.rubocop_todo.yml

@@ -149,11 +149,6 @@ RSpec/AnyInstance:
     - 'spec/services/reports/merits_report_creator_spec.rb'
     - 'spec/services/reports/mis/application_details_report_spec.rb'
 
-# Offense count: 1
-RSpec/BeforeAfterAll:
-  Exclude:
-    - 'spec/requests/providers/means_reports_spec.rb'
-
 # Offense count: 1939
 # Configuration parameters: Prefixes.
 # Prefixes: when, with, without
@@ -426,9 +421,7 @@ RSpec/FilePath:
     - 'spec/requests/providers/identify_types_of_outgoings_spec.rb'
     - 'spec/requests/providers/income_summary_spec.rb'
     - 'spec/requests/providers/limitations_spec.rb'
-    - 'spec/requests/providers/means_reports_spec.rb'
     - 'spec/requests/providers/means_summaries_spec.rb'
-    - 'spec/requests/providers/merits_reports_spec.rb'
     - 'spec/requests/providers/no_employment_incomes_spec.rb'
     - 'spec/requests/providers/no_income_summaries_spec.rb'
     - 'spec/requests/providers/no_outgoings_summaries_spec.rb'
@@ -543,7 +536,6 @@ RSpec/LetSetup:
     - 'spec/requests/providers/confirm_offices_spec.rb'
     - 'spec/requests/providers/income_summary_spec.rb'
     - 'spec/requests/providers/legal_aid_applications_spec.rb'
-    - 'spec/requests/providers/merits_reports_spec.rb'
     - 'spec/requests/providers/outgoings_summary_spec.rb'
     - 'spec/requests/providers/proceeding_merits_task/chances_of_success_spec.rb'
     - 'spec/requests/providers/submitted_applications_spec.rb'
@@ -707,9 +699,7 @@ RSpec/NamedSubject:
     - 'spec/requests/providers/income_summary_spec.rb'
     - 'spec/requests/providers/legal_aid_applications_spec.rb'
     - 'spec/requests/providers/limitations_spec.rb'
-    - 'spec/requests/providers/means_reports_spec.rb'
     - 'spec/requests/providers/means_summaries_spec.rb'
-    - 'spec/requests/providers/merits_reports_spec.rb'
     - 'spec/requests/providers/merits_task_lists_controller_spec.rb'
     - 'spec/requests/providers/no_employment_incomes_spec.rb'
     - 'spec/requests/providers/no_income_summaries_spec.rb'
@@ -851,7 +841,6 @@ RSpec/NotToNot:
     - 'spec/requests/providers/confirm_dwp_non_passported_applications_spec.rb'
     - 'spec/requests/providers/employed_incomes_spec.rb'
     - 'spec/requests/providers/limitations_spec.rb'
-    - 'spec/requests/providers/means_reports_spec.rb'
     - 'spec/requests/providers/proceeding_merits_task/attempts_to_settle_controller_spec.rb'
     - 'spec/requests/providers/proceeding_merits_task/chances_of_success_spec.rb'
     - 'spec/requests/providers/proceeding_merits_task/linked_children_spec.rb'

Gemfile

@@ -89,7 +89,7 @@ gem "webpacker", "~> 5", ">= 5.4.3"
 gem "wdm", ">= 0.1.0" if Gem.win_platform?
 
 # generating PDFs
-gem "wicked_pdf"
+gem "grover"
 
 # DFE formbuilder
 gem "govuk_design_system_formbuilder"

Gemfile.lock

@@ -158,6 +158,9 @@ GEM
     coderay (1.1.3)
     coercible (1.0.0)
       descendants_tracker (~> 0.0.1)
+    combine_pdf (1.0.22)
+      matrix
+      ruby-rc4 (>= 0.1.5)
     concurrent-ruby (1.1.10)
     connection_pool (2.3.0)
     crack (0.4.5)
@@ -312,6 +315,9 @@ GEM
     govuk_notify_rails (2.2.0)
       notifications-ruby-client (~> 5.1)
       rails (>= 4.1.0)
+    grover (1.1.2)
+      combine_pdf (~> 1.0)
+      nokogiri (~> 1.0)
     guard (2.18.0)
       formatador (>= 0.2.4)
       listen (>= 2.7, < 4.0)
@@ -603,6 +609,7 @@ GEM
     rubocop-rspec (2.15.0)
       rubocop (~> 1.33)
     ruby-progressbar (1.11.0)
+    ruby-rc4 (0.1.5)
     ruby-saml (1.15.0)
       nokogiri (>= 1.13.10)
       rexml
@@ -715,8 +722,6 @@ GEM
     websocket-driver (0.7.5)
       websocket-extensions (>= 0.1.0)
     websocket-extensions (0.1.5)
-    wicked_pdf (2.6.3)
-      activesupport
     xpath (3.2.0)
       nokogiri (~> 1.8)
     zeitwerk (2.6.6)
@@ -754,6 +759,7 @@ DEPENDENCIES
   govuk-components
   govuk_design_system_formbuilder
   govuk_notify_rails (~> 2.2.0)
+  grover
   guard-cucumber
   guard-livereload
   guard-rspec
@@ -819,7 +825,6 @@ DEPENDENCIES
   webmock
   webpacker (~> 5, >= 5.4.3)
   webrick
-  wicked_pdf
 
 RUBY VERSION
    ruby 3.1.2p20

app/controllers/providers/means_reports_controller.rb

@@ -5,9 +5,14 @@ class MeansReportsController < ProviderBaseController
     def show
       @cfe_result = @legal_aid_application.cfe_result
       @manual_review_determiner = CCMS::ManualReviewDeterminer.new(@legal_aid_application)
-      render pdf: "Means report",
-             layout: "pdf",
-             show_as_html: params.key?(:debug)
+
+      if params.key?(:debug)
+        render "show", layout: "pdf"
+      else
+        html = render_to_string "show", layout: "pdf"
+        pdf = Grover.new(html).to_pdf
+        send_data pdf, filename: "means_report.pdf", type: "application/pdf", disposition: "inline"
+      end
     end
   end
 end

app/controllers/providers/merits_reports_controller.rb

@@ -1,10 +1,12 @@
 module Providers
   class MeritsReportsController < ProviderBaseController
     authorize_with_policy_method :show_submitted_application?
+
     def show
-      render pdf: "Merit report",
-             layout: "pdf",
-             show_as_html: params.key?(:debug)
+      html = render_to_string "show", layout: "pdf"
+      pdf = Grover.new(html).to_pdf
+
+      send_data pdf, filename: "merits_report.pdf", type: "application/pdf", disposition: "inline"
     end
   end
 end

app/services/reports/base_report_creator.rb

@@ -13,7 +13,7 @@ def initialize(legal_aid_application)
   private
 
     def pdf_report
-      WickedPdf.new.pdf_from_string(html_report)
+      Grover.new(html_report).to_pdf
     end
 
     def ensure_case_ccms_reference_exists

app/views/layouts/pdf.html.erb

@@ -3,8 +3,7 @@
   <head>
     <meta charset="utf-8">
     <title><%= t("layouts.application.header.title") %></title>
-    <%= apply_webpacker_stylesheet_pack_tag("styles") %>
-    <%= render "layouts/govuk_base64_fonts" %>
+    <%= stylesheet_pack_tag "styles", media: "all" %>
   </head>
 
   <body class="govuk-template__body" style="padding-left: 3em; padding-top: 3em;">

config/initializers/grover.rb

@@ -0,0 +1,24 @@
+Grover.configure do |config|
+  protocol = if Rails.env.development?
+               "http://"
+             else
+               "https://"
+             end
+
+  config.options = {
+    format: "A4",
+    emulate_media: "print",
+    prefer_css_page_size: true,
+    bypass_csp: true,
+    cache: false,
+    wait_until: "networkidle2",
+    display_url: protocol + ENV.fetch("HOST", "localhost:3002"),
+    margin: {
+      top: "10mm",
+      bottom: "10mm",
+      left: "10mm",
+      right: "20mm",
+    },
+    launch_args: ["--no-sandbox"],
+  }
+end

docker/apply_base.dockerfile

@@ -37,6 +37,25 @@ RUN apk --no-cache add --virtual build-dependencies \
                   py3-pip
 RUN pip3 install awscli
 
+# Install Chromium and Puppeteer for PDF generation
+# Installs latest Chromium package available on Alpine (Chromium 108)
+RUN apk add --no-cache \
+        chromium \
+        nss \
+        freetype \
+        harfbuzz \
+        ca-certificates \
+        ttf-freefont \
+        nodejs \
+        yarn
+
+# Tell Puppeteer to skip installing Chrome. We'll be using the installed package.
+ENV PUPPETEER_SKIP_CHROMIUM_DOWNLOAD=true
+ENV PUPPETEER_EXECUTABLE_PATH=/usr/bin/chromium-browser
+
+# Install latest version of Puppeteer that works with Chromium 108
+RUN yarn add [email protected]
+
 # Install kubectl
 RUN curl -Lo /usr/local/bin/kubectl \
         --retry 3 \

package.json

@@ -26,7 +26,8 @@
     "stylelint": "^14.16.1",
     "stylelint-config-gds": "^0.2.0",
     "stylelint-order": "^5.0.0",
-    "webpack-dev-server": "^4.11.1"
+    "webpack-dev-server": "^4.11.1",
+    "puppeteer": "^19.2.0"
   },
   "resolutions": {
     "acorn": "^7.1.1",

puppeteer.config.cjs

@@ -0,0 +1,8 @@
+const { join } = require('path')
+
+/**
+ * @type {import("puppeteer").Configuration}
+ */
+module.exports = {
+  cacheDirectory: join(__dirname, '.cache', 'puppeteer')
+}