Merge pull request #22 from alphagov/emergency-banner

Add Emergency Banner handling

Gemfile.lock

@@ -2,8 +2,10 @@ PATH
   remote: .
   specs:
     govuk_web_banners (0.2.0)
+      govuk_app_config
       govuk_publishing_components
       rails (>= 7)
+      redis
 
 GEM
   remote: https://rubygems.org/
@@ -465,6 +467,10 @@ GEM
     rake (13.2.1)
     rdoc (6.8.1)
       psych (>= 4.0.0)
+    redis (5.3.0)
+      redis-client (>= 0.22.0)
+    redis-client (0.22.2)
+      connection_pool
     regexp_parser (2.9.3)
     reline (0.5.12)
       io-console (~> 0.5)

README.md

@@ -3,7 +3,7 @@ Proof of Concept for centralising handling of Recruitment, Global, and Emergency
 banners (currently spread across apps)
 
 ## Usage
-Currently supports recruitment banners
+Currently supports the emergency banner and recruitment banners.
 
 ## Adding the gem to your application
 Add this line to your application's Gemfile:
@@ -28,6 +28,39 @@ Add the JS dependencies to your existing asset dependencies file:
 //= require govuk_web_banners/dependencies
 ```
 
+## Adding emergency banners
+
+Emergency banners are passed to the [Layout for Public](https://components.publishing.service.gov.uk/component-guide/layout_for_public) component, which is currently applied to each frontend app by the slimmer/static wrapping code - so you will only need to handle emergency banners in your app when Slimmer is removed from it. Once Slimmer is removed and you are calling the layout_for_public component directly in your app, add the emergency banner partial to the component's `emergency_banner:` key:
+
+```
+<%= render "govuk_publishing_components/components/layout_for_public", {
+  draft_watermark: draft_environment,
+  emergency_banner: render("govuk_web_banners/emergency_banner"), # <-- Add this line
+  full_width: false,
+  ...etc
+```
+
+if you want the homepage variant of the banner, you can add `homepage: true` to the render call:
+
+```
+<%= render "govuk_publishing_components/components/layout_for_public", {
+  draft_watermark: draft_environment,
+  emergency_banner: render("govuk_web_banners/emergency_banner", homepage: true), # <-- Add this line
+  full_width: full_width,
+  ...etc
+```
+
+Your app will also need access to the whitehall shared redis cluster (which is used to signal the emergency banner is up), via the `EMERGENCY_BANNER_REDIS_URL` environment variable (here is an example of [setting this in govuk-helm-charts](https://github.com/alphagov/govuk-helm-charts/blob/7818eaa22fc194d21548f316bcc5a46c2023dcb6/charts/app-config/values-staging.yaml#L3337-L3338)). You'll need to allow this in all three environments.
+
+Finally, you'll need to configure a connection to the redis cluster, available at `Rails.application.config.emergency_banner_redis_client`. The suggested way of doing this is creating an initializer at `/config/initializers/govuk_web_banners.rb` with the content:
+
+```
+Rails.application.config.emergency_banner_redis_client = Redis.new(
+  url: ENV["EMERGENCY_BANNER_REDIS_URL"],
+  reconnect_attempts: [15, 30, 45, 60],
+)
+```
+
 ## Adding recruitment banners
 
 Add a call to the partial in the layout or view that you want banners to appear

app/views/govuk_web_banners/_emergency_banner.html.erb

@@ -0,0 +1,11 @@
+<% emergency_banner = GovukWebBanners::EmergencyBanner.new %>
+<% if emergency_banner.active? %>
+  <%= render "govuk_publishing_components/components/emergency_banner", {
+      campaign_class: emergency_banner.campaign_class,
+      heading: emergency_banner.heading,
+      link: emergency_banner.link,
+      link_text: emergency_banner.link_text,
+      short_description: emergency_banner.short_description,
+      homepage: local_assigns[:homepage] || false,
+  } %>
+<% end %>

govuk_web_banners.gemspec

@@ -19,8 +19,10 @@ Gem::Specification.new do |spec|
 
   spec.files = Dir["{app,config,db,lib}/**/*", "MIT-LICENSE", "Rakefile", "README.md"].reject { |f| f.match(/validators/) }
 
+  spec.add_dependency "govuk_app_config"
   spec.add_dependency "govuk_publishing_components"
   spec.add_dependency "rails", ">= 7"
+  spec.add_dependency "redis"
 
   spec.add_development_dependency "byebug"
   spec.add_development_dependency "govuk_test"

lib/govuk_web_banners.rb

@@ -1,5 +1,6 @@
 require "govuk_publishing_components"
 
+require "govuk_web_banners/emergency_banner"
 require "govuk_web_banners/engine"
 require "govuk_web_banners/recruitment_banner"
 require "govuk_web_banners/version"

lib/govuk_web_banners/emergency_banner.rb

@@ -0,0 +1,37 @@
+require "govuk_app_config/govuk_error"
+require "redis"
+
+module GovukWebBanners
+  class EmergencyBanner
+    attr_reader :campaign_class, :heading, :short_description, :link, :link_text
+
+    def initialize
+      content = content_from_redis
+
+      @campaign_class = content[:campaign_class].presence
+      @heading = content[:heading].presence
+      @short_description = content[:short_description].presence
+      @link = content[:link].presence
+      @link_text = content[:link_text].presence
+    end
+
+    def active?
+      [campaign_class, heading].all?
+    end
+
+  private
+
+    def redis_client
+      Rails.application.config.emergency_banner_redis_client
+    end
+
+    def content_from_redis
+      Rails.cache.fetch("#emergency_banner/config", expires_in: 1.minute) do
+        redis_client.hgetall("emergency_banner").try(:symbolize_keys)
+      end
+    rescue StandardError => e
+      GovukError.notify(e, extra: { context: "Emergency Banner Redis" })
+      {}
+    end
+  end
+end

spec/dummy/app/assets/config/manifest.js

@@ -1 +1,18 @@
 //= link govuk_web_banners_manifest.js
+
+// Everything below here is needed for the layout_for_public component in the system tests
+
+//= link govuk_publishing_components/vendor/lux/lux-measurer.js
+//= link govuk_publishing_components/vendor/lux/lux-reporter.js
+//= link govuk_publishing_components/rum-loader.js
+//= link govuk_publishing_components/load-analytics.js
+//= link govuk_publishing_components/ie.js
+
+//= link application.css
+//= link application.js
+//= link favicon.ico
+//= link favicon.svg
+//= link govuk-icon-mask.svg
+
+//= link govuk-icon-180.png
+//= link govuk-opengraph-image.png

spec/dummy/app/assets/javascripts/application.js

@@ -0,0 +1 @@
+// Empty - needed for the layout_for_public component in the system tests

spec/dummy/app/assets/stylesheets/application.css

@@ -0,0 +1 @@
+/* Empty - needed for the layout_for_public component in the system tests */

spec/dummy/app/views/banner_pages/emergency.html.erb

@@ -0,0 +1,4 @@
+<%= render "govuk_publishing_components/components/layout_for_public", {
+    emergency_banner: render("govuk_web_banners/emergency_banner")
+  }
+%>

spec/dummy/app/views/banner_pages/emergency_on_homepage.html.erb

@@ -0,0 +1,4 @@
+<%= render "govuk_publishing_components/components/layout_for_public", {
+    emergency_banner: render("govuk_web_banners/emergency_banner", homepage: true)
+  }
+%>

spec/dummy/config/initializers/govuk_web_banners.rb

@@ -0,0 +1 @@
+Rails.application.config.emergency_banner_redis_client = Redis.new

spec/dummy/config/routes.rb

@@ -2,6 +2,9 @@
   mount GovukPublishingComponents::Engine, at: "/component-guide"
   mount GovukWebBanners::Engine => "/govuk_web_banners"
 
-  get "/page-with-banners", to: "banner_pages#show"
-  get "/page-with-no-banners", to: "banner_pages#show"
+  get "/recruitment-with-banners", to: "banner_pages#recruitment"
+  get "/recruitment-with-no-banners", to: "banner_pages#recruitment"
+
+  get "/emergency", to: "banner_pages#emergency"
+  get "/", to: "banner_pages#emergency_on_homepage"
 end

spec/fixtures/requests_banners.yml

@@ -1,8 +1,8 @@
 # Fixture - elements for request tests with dummy app
 banners:
 - name: Banner 1
-  suggestion_text: "This banner appears at /pages-with-banners!"
+  suggestion_text: "This banner appears at /recruitment-with-banners!"
   suggestion_link_text: "Sign up to take part in user research (opens in a new tab)"
   survey_url: https://google.com
   page_paths:
-  - /page-with-banners
+  - /recruitment-with-banners

spec/requests/emergency_banner_spec.rb

@@ -0,0 +1,38 @@
+RSpec.describe "Emergency Banners" do
+  context "getting a path with the banner partial" do
+    context "with the emergency banner active" do
+      before do
+        allow_any_instance_of(Redis).to receive(:hgetall).with("emergency_banner").and_return(
+          heading: "Emergency!",
+          campaign_class: "notable-death",
+        )
+      end
+
+      it "shows a banner in the page" do
+        get "/emergency"
+
+        expect(response.body).to include("Emergency!")
+        expect(response.body).not_to include("gem-c-emergency-banner__heading--homepage")
+      end
+
+      it "shows the homepage varient banner in the homepage" do
+        get "/"
+
+        expect(response.body).to include("Emergency!")
+        expect(response.body).to include("gem-c-emergency-banner__heading--homepage")
+      end
+    end
+
+    context "with the emergency banner inactive" do
+      before do
+        allow_any_instance_of(Redis).to receive(:hgetall).with("emergency_banner").and_return({})
+      end
+
+      it "does not show a banner in the page" do
+        get "/emergency"
+
+        expect(response.body).not_to include("Emergency!")
+      end
+    end
+  end
+end

spec/requests/recruitment_banner_spec.rb

@@ -11,17 +11,17 @@
 
     context "with an active banner" do
       it "shows a banner in the page" do
-        get "/page-with-banners"
+        get "/recruitment-with-banners"
 
-        expect(response.body).to include("This banner appears at /pages-with-banners!")
+        expect(response.body).to include("This banner appears at /recruitment-with-banners!")
       end
     end
 
     context "with no active banner" do
       it "does not show a banner in the page" do
-        get "/page-with-no-banners"
+        get "/recruitment-with-no-banners"
 
-        expect(response.body).not_to include("This banner appears at /pages-with-banners!")
+        expect(response.body).not_to include("This banner appears at /recruitment-with-banners!")
       end
     end
   end

spec/units/govuk_web_banners/emergency_banner_spec.rb

@@ -0,0 +1,56 @@
+RSpec.describe GovukWebBanners::EmergencyBanner do
+  let(:redis_client) { instance_double(Redis, hgetall: {}) }
+
+  before do
+    Rails.application.config.emergency_banner_redis_client = redis_client
+  end
+
+  describe "caching" do
+    context "with a Rails cache" do
+      it "caches calls to the redis client for one minute" do
+        allow(Rails).to receive(:cache).and_return(ActiveSupport::Cache.lookup_store(:memory_store))
+        Rails.cache.clear
+
+        described_class.new
+        described_class.new
+
+        expect(redis_client).to have_received(:hgetall).once
+
+        travel_to(Time.now + 61.seconds)
+
+        described_class.new
+        expect(redis_client).to have_received(:hgetall).twice
+
+        travel_back
+      end
+    end
+  end
+
+  describe "#active?" do
+    subject(:emergency_banner) { described_class.new }
+
+    context "with the emergency banner inactive" do
+      it "returns false" do
+        expect(emergency_banner.active?).to be false
+      end
+    end
+
+    context "with the emergency banner active" do
+      let(:redis_client) { instance_double(Redis, hgetall: { heading: "Emergency!", campaign_class: "notable-death" }) }
+
+      it "returns true" do
+        expect(emergency_banner.active?).to be true
+      end
+    end
+
+    context "with a failing call to Redis fails" do
+      before do
+        allow(redis_client).to receive(:hgetall).with("emergency_banner").and_raise(StandardError)
+      end
+
+      it "returns false" do
+        expect(emergency_banner.active?).to be false
+      end
+    end
+  end
+end