Adds /health endpoint using the OKComputer gem

- Adds the OKComputer gem as a framework for health checking.
- Configures checks for AR/migrations and Solr.
- Checks are served as JSON on /health.

Author: danschmidt5189

Gemfile

@@ -13,6 +13,7 @@ gem 'geoblacklight', '~> 4.4.2'
 gem 'importmap-rails'
 gem 'jbuilder'
 gem 'jquery-rails'
+gem 'okcomputer', '~> 1.19'
 gem 'omniauth'
 gem 'omniauth-cas', '3.0.0'
 gem 'omniauth-rails_csrf_protection', '~> 1.0'

Gemfile.lock

@@ -166,6 +166,7 @@ GEM
     faraday-retry (2.2.1)
       faraday (~> 2.0)
     ffi (1.17.0-aarch64-linux-gnu)
+    ffi (1.17.0-arm64-darwin)
     ffi (1.17.0-x86_64-darwin)
     ffi (1.17.0-x86_64-linux-gnu)
     ffi (1.17.0-x86_64-linux-musl)
@@ -281,13 +282,16 @@ GEM
     nio4r (2.7.4)
     nokogiri (1.16.7-aarch64-linux)
       racc (~> 1.4)
+    nokogiri (1.16.7-arm64-darwin)
+      racc (~> 1.4)
     nokogiri (1.16.7-x86_64-darwin)
       racc (~> 1.4)
     nokogiri (1.16.7-x86_64-linux)
       racc (~> 1.4)
     oj (3.16.7)
       bigdecimal (>= 3.0)
       ostruct (>= 0.2)
+    okcomputer (1.19.0)
     omniauth (2.1.2)
       hashie (>= 3.4.6)
       rack (>= 2.2.3)
@@ -542,6 +546,7 @@ DEPENDENCIES
   importmap-rails
   jbuilder
   jquery-rails
+  okcomputer (~> 1.19)
   omniauth
   omniauth-cas (= 3.0.0)
   omniauth-rails_csrf_protection (~> 1.0)

config/initializers/okcomputer.rb

@@ -0,0 +1,14 @@
+# initializers/okcomputer.rb
+# Health checks configuration
+
+OkComputer.mount_at = false
+OkComputer.logger = Rails.logger
+OkComputer.check_in_parallel = true
+
+# Check the Solr connection
+# Requires the ping handler on the solr core (<core>/admin/ping).
+core_baseurl = Blacklight.default_index.connection.uri.to_s.chomp('/')
+OkComputer::Registry.register 'solr', OkComputer::SolrCheck.new(core_baseurl)
+
+# Check that DB migrations have run
+OkComputer::Registry.register 'database-migrations', OkComputer::ActiveRecordMigrationsCheck.new

config/routes.rb

@@ -1,3 +1,5 @@
+require 'okcomputer'
+
 Rails.application.routes.draw do
   mount Blacklight::Engine => '/'
   root to: 'catalog#index'
@@ -40,4 +42,8 @@
     concerns :gbl_downloadable
   end
   resources :download, only: [:show]
+
+  # Map OkComputer's /health/all.json to /health
+  # Don't mount any other routes
+  get "/health", to: "ok_computer/ok_computer#index", defaults: { format: :json }
 end

solr/geodata-test/solrconfig.xml

@@ -182,7 +182,7 @@
          the PingRequestHandler.
          relative paths are resolved against the data dir
       -->
-    <str name="healthcheckFile">server-enabled.txt</str>
+    <!-- <str name="healthcheckFile">server-enabled.txt</str> -->
   </requestHandler>
 
   <requestHandler name="/analysis/field"

solr/geodata/solrconfig.xml

@@ -182,7 +182,7 @@
          the PingRequestHandler.
          relative paths are resolved against the data dir
       -->
-    <str name="healthcheckFile">server-enabled.txt</str>
+    <!-- <str name="healthcheckFile">server-enabled.txt</str> -->
   </requestHandler>
 
   <requestHandler name="/analysis/field"

spec/requests/health_spec.rb

@@ -0,0 +1,14 @@
+require 'rails_helper'
+
+RSpec.describe '/health', type: :request do
+  it 'renders health checks' do
+    get '/health'
+    expect(response).to have_http_status :ok
+    expect(response.parsed_body.keys).to match_array %w(
+      default
+      database
+      database-migrations
+      solr
+    )
+  end
+end