[deploy] Add App, Database, and Search Health Check Endpoints (#8071)

app/controllers/api/v0/health_checks_controller.rb

@@ -0,0 +1,37 @@
+module Api
+  module V0
+    class HealthChecksController < ApiController
+      before_action :authenticate_with_token
+
+      def app
+        render json: { message: "App is up!" }, status: :ok
+      end
+
+      def search
+        if Search::Client.ping
+          render json: { message: "Search ping succeeded!" }, status: :ok
+        else
+          render json: { message: "Search ping failed!" }, status: :internal_server_error
+        end
+      end
+
+      def database
+        if ActiveRecord::Base.connected?
+          render json: { message: "Database connected" }, status: :ok
+        else
+          render json: { message: "Database NOT connected!" }, status: :internal_server_error
+        end
+      end
+
+      private
+
+      def authenticate_with_token
+        key = request.headers["health-check-token"]
+
+        return if key == SiteConfig.health_check_token
+
+        error_unauthorized
+      end
+    end
+  end
+end

app/models/site_config.rb

@@ -116,4 +116,7 @@ class SiteConfig < RailsSettings::Base
 
   # Shop
   field :shop_url, type: :string, default: "https://shop.dev.to"
+
+  # Special API tokens
+  field :health_check_token, type: :string, default: "secret"
 end

app/views/internal/configs/show.html.erb

@@ -293,7 +293,6 @@
               <div class="alert alert-info">URL campaign sidebar image will link to</div>
             </div>
 
-
             <div class="form-group">
               <%= f.label :campaign_featured_tags %>
               <%= f.text_field :campaign_featured_tags,
@@ -596,6 +595,27 @@
              </div>
           </div>
         </div>
+
+        <div class="card mt-3">
+          <%= render partial: "card_header",
+                     locals: {
+                       header: "API",
+                       state: "collapse",
+                       target: "apiBodyContainer",
+                       expanded: "false"
+                     } %>
+          <div id="apiBodyContainer" class="card-body collapse hide" aria-labelledby="apiBodyContainer">
+            <div class="form-group">
+              <%= f.label :health_check_token, "Health Check Token" %>
+              <%= f.text_field :health_check_token,
+                               class: "form-control",
+                               value: SiteConfig.health_check_token,
+                               placeholder: "a secure token" %>
+              <div class="alert alert-info">Used to authenticate with your health check endpoints.</div>
+            </div>
+          </div>
+        </div>
+
         <% if current_user.has_role?(:single_resource_admin, Config) %>
           <div class="card mt-3">
             <div class="card-header">Confirm and Submit</div>

config/routes.rb

@@ -143,6 +143,14 @@ Rails.application.routes.draw do
       get "/analytics/historical", to: "analytics#historical"
       get "/analytics/past_day", to: "analytics#past_day"
       get "/analytics/referrers", to: "analytics#referrers"
+
+      resources :health_checks, only: [] do
+        collection do
+          get :app
+          get :search
+          get :database
+        end
+      end
     end
   end
 

spec/requests/api/v0/health_checks_spec.rb

@@ -0,0 +1,53 @@
+require "rails_helper"
+
+RSpec.describe "HealthCheck", type: :request do
+  let(:token) { "secret" }
+  let(:headers) { { "health-check-token" => token } }
+
+  before { SiteConfig.health_check_token = token }
+
+  context "without a token" do
+    it "returns an unauthorized request" do
+      get app_api_health_checks_path
+      expect(response.status).to eq(401)
+    end
+  end
+
+  describe "GET /api/health_checks/app" do
+    it "returns json success" do
+      get app_api_health_checks_path, headers: headers
+      expect(response.status).to eq(200)
+      expect(response.parsed_body["message"]).to eq("App is up!")
+    end
+  end
+
+  describe "GET /api/health_checks/search" do
+    it "returns json success if ping succeeds" do
+      get search_api_health_checks_path, headers: headers
+      expect(response.status).to eq(200)
+      expect(response.parsed_body["message"]).to eq("Search ping succeeded!")
+    end
+
+    it "returns json failure if ping fails" do
+      allow(Search::Client).to receive(:ping).and_return(false)
+      get search_api_health_checks_path, headers: headers
+      expect(response.status).to eq(500)
+      expect(response.parsed_body["message"]).to eq("Search ping failed!")
+    end
+  end
+
+  describe "GET /api/health_checks/database" do
+    it "returns json success if connection check succeeds" do
+      get database_api_health_checks_path, headers: headers
+      expect(response.status).to eq(200)
+      expect(response.parsed_body["message"]).to eq("Database connected")
+    end
+
+    it "returns json failure if connection check fails" do
+      allow(ActiveRecord::Base).to receive(:connected?).and_return(false)
+      get database_api_health_checks_path, headers: headers
+      expect(response.status).to eq(500)
+      expect(response.parsed_body["message"]).to eq("Database NOT connected!")
+    end
+  end
+end