Refactor the usage of `HealthChecks`

Move the `CHECKS` into its own file.

To `Result` add `name` to fix `gitaly_checks`.

app/controllers/health_controller.rb

@@ -4,19 +4,15 @@ class HealthController < ActionController::Base
   protect_from_forgery with: :exception, prepend: true
   include RequiresWhitelistedMonitoringClient
 
-  CHECKS = [
-    Gitlab::HealthChecks::DbCheck,
-    Gitlab::HealthChecks::Redis::RedisCheck,
-    Gitlab::HealthChecks::Redis::CacheCheck,
-    Gitlab::HealthChecks::Redis::QueuesCheck,
-    Gitlab::HealthChecks::Redis::SharedStateCheck,
-    Gitlab::HealthChecks::GitalyCheck
-  ].freeze
-
   def readiness
-    results = CHECKS.map { |check| [check.name, check.readiness] }
+    results = checks.flat_map(&:readiness)
+    success = results.all?(&:success)
 
-    render_check_results(results)
+    # disable static error pages at the gitlab-workhorse level, we want to see this error response even in production
+    headers["X-GitLab-Custom-Error"] = 1 unless success
+
+    response = results.map { |result| [result.name, result.payload] }.to_h
+    render json: response, status: success ? :ok : :service_unavailable
   end
 
   def liveness
@@ -25,26 +21,7 @@ class HealthController < ActionController::Base
 
   private
 
-  def render_check_results(results)
-    flattened = results.flat_map do |name, result|
-      if result.is_a?(Gitlab::HealthChecks::Result)
-        [[name, result]]
-      else
-        result.map { |r| [name, r] }
-      end
-    end
-    success = flattened.all? { |name, r| r.success }
-
-    response = flattened.map do |name, r|
-      info = { status: r.success ? 'ok' : 'failed' }
-      info['message'] = r.message if r.message
-      info[:labels] = r.labels if r.labels
-      [name, info]
-    end
-
-    # disable static error pages at the gitlab-workhorse level, we want to see this error response even in production
-    headers["X-GitLab-Custom-Error"] = 1 unless success
-
-    render json: response.to_h, status: success ? :ok : :service_unavailable
+  def checks
+    ::Gitlab::HealthChecks::CHECKS
   end
 end

ee/spec/workers/geo/repository_sync_worker_spec.rb

@@ -101,6 +101,6 @@ describe Geo::RepositorySyncWorker, :geo, :clean_gitlab_redis_cache do
   end
 
   def result(success, shard)
-    Gitlab::HealthChecks::Result.new(success, nil, { shard: shard })
+    Gitlab::HealthChecks::Result.new('gitaly_check', success, nil, { shard: shard })
   end
 end

ee/spec/workers/geo/repository_verification/primary/batch_worker_spec.rb

@@ -80,6 +80,6 @@ describe Geo::RepositoryVerification::Primary::BatchWorker, :clean_gitlab_redis_
   end
 
   def result(success, shard)
-    Gitlab::HealthChecks::Result.new(success, nil, { shard: shard })
+    Gitlab::HealthChecks::Result.new('gitaly_check', success, nil, { shard: shard })
   end
 end

ee/spec/workers/geo/repository_verification/secondary/scheduler_worker_spec.rb

@@ -82,6 +82,6 @@ describe Geo::RepositoryVerification::Secondary::SchedulerWorker, :clean_gitlab_
   end
 
   def result(success, shard)
-    Gitlab::HealthChecks::Result.new(success, nil, { shard: shard })
+    Gitlab::HealthChecks::Result.new('gitaly_check', success, nil, { shard: shard })
   end
 end

ee/spec/workers/geo/scheduler/per_shard_scheduler_worker_spec.rb

@@ -26,9 +26,9 @@ describe Geo::Scheduler::PerShardSchedulerWorker do
     let(:other_shard_name) { 'other' }
     let(:unhealthy_shard_name) { 'unhealthy' }
 
-    let(:default_shard) { Gitlab::HealthChecks::Result.new(true, nil, shard: default_shard_name) }
-    let(:other_shard) { Gitlab::HealthChecks::Result.new(true, nil, shard: other_shard_name) }
-    let(:unhealthy_shard) { Gitlab::HealthChecks::Result.new(false, '14:Connect Failed', shard: unhealthy_shard_name) }
+    let(:default_shard) { Gitlab::HealthChecks::Result.new('gitaly_check', true, nil, shard: default_shard_name) }
+    let(:other_shard) { Gitlab::HealthChecks::Result.new('gitaly_check', true, nil, shard: other_shard_name) }
+    let(:unhealthy_shard) { Gitlab::HealthChecks::Result.new('gitaly_check', false, '14:Connect Failed', shard: unhealthy_shard_name) }
 
     before do
       allow(Gitlab::HealthChecks::GitalyCheck).to receive(:readiness).and_return([default_shard, other_shard, unhealthy_shard])

lib/gitlab/health_checks/checks.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module HealthChecks
+    CHECKS = [
+      Gitlab::HealthChecks::DbCheck,
+      Gitlab::HealthChecks::Redis::RedisCheck,
+      Gitlab::HealthChecks::Redis::CacheCheck,
+      Gitlab::HealthChecks::Redis::QueuesCheck,
+      Gitlab::HealthChecks::Redis::SharedStateCheck,
+      Gitlab::HealthChecks::GitalyCheck
+    ].freeze
+  end
+end

lib/gitlab/health_checks/gitaly_check.rb

@@ -29,7 +29,13 @@ module Gitlab
         def check(storage_name)
           serv = Gitlab::GitalyClient::HealthCheckService.new(storage_name)
           result = serv.check
-          HealthChecks::Result.new(result[:success], result[:message], shard: storage_name)
+
+          HealthChecks::Result.new(
+            name,
+            result[:success],
+            result[:message],
+            shard: storage_name
+          )
         end
 
         private

lib/gitlab/health_checks/metric.rb

 # frozen_string_literal: true
 
-module Gitlab::HealthChecks
-  Metric = Struct.new(:name, :value, :labels)
+module Gitlab
+  module HealthChecks
+    Metric = Struct.new(:name, :value, :labels)
+  end
 end

lib/gitlab/health_checks/prometheus_text_format.rb

-# frozen_string_literal: true
-
-module Gitlab
-  module HealthChecks
-    class PrometheusTextFormat
-      def marshal(metrics)
-        "#{metrics_with_type_declarations(metrics).join("\n")}\n"
-      end
-
-      private
-
-      def metrics_with_type_declarations(metrics)
-        type_declaration_added = {}
-
-        metrics.flat_map do |metric|
-          metric_lines = []
-
-          unless type_declaration_added.key?(metric.name)
-            type_declaration_added[metric.name] = true
-            metric_lines << metric_type_declaration(metric)
-          end
-
-          metric_lines << metric_text(metric)
-        end
-      end
-
-      def metric_type_declaration(metric)
-        "# TYPE #{metric.name} gauge"
-      end
-
-      def metric_text(metric)
-        labels = metric.labels&.map { |key, value| "#{key}=\"#{value}\"" }&.join(',') || ''
-
-        if labels.empty?
-          "#{metric.name} #{metric.value}"
-        else
-          "#{metric.name}{#{labels}} #{metric.value}"
-        end
-      end
-    end
-  end
-end

lib/gitlab/health_checks/result.rb

 # frozen_string_literal: true
 
-module Gitlab::HealthChecks
-  Result = Struct.new(:success, :message, :labels)
+module Gitlab
+  module HealthChecks
+    Result = Struct.new(:name, :success, :message, :labels) do
+      def payload
+        {
+          status: success ? 'ok' : 'failed',
+          message: message,
+          labels: labels
+        }.compact
+      end
+    end
+  end
 end

lib/gitlab/health_checks/simple_abstract_check.rb

@@ -8,14 +8,14 @@ module Gitlab
       def readiness
         check_result = check
         if successful?(check_result)
-          HealthChecks::Result.new(true)
+          HealthChecks::Result.new(name, true)
         elsif check_result.is_a?(Timeout::Error)
-          HealthChecks::Result.new(false, "#{human_name} check timed out")
+          HealthChecks::Result.new(name, false, "#{human_name} check timed out")
         else
-          HealthChecks::Result.new(false, "unexpected #{human_name} check result: #{check_result}")
+          HealthChecks::Result.new(name, false, "unexpected #{human_name} check result: #{check_result}")
         end
       rescue => e
-        HealthChecks::Result.new(false, "unexpected #{human_name} check result: #{e}")
+        HealthChecks::Result.new(name, false, "unexpected #{human_name} check result: #{e}")
       end
 
       def metrics

spec/controllers/health_controller_spec.rb

@@ -32,7 +32,8 @@ describe HealthController do
       end
 
       it 'responds with readiness checks data when a failure happens' do
-        allow(Gitlab::HealthChecks::Redis::RedisCheck).to receive(:readiness).and_return(Gitlab::HealthChecks::Result.new(false, "check error"))
+        allow(Gitlab::HealthChecks::Redis::RedisCheck).to receive(:readiness).and_return(
+          Gitlab::HealthChecks::Result.new('redis_check', false, "check error"))
 
         subject
 

spec/lib/gitlab/health_checks/gitaly_check_spec.rb

@@ -18,13 +18,13 @@ describe Gitlab::HealthChecks::GitalyCheck do
     context 'Gitaly server is up' do
       let(:gitaly_check) { double(check: { success: true }) }
 
-      it { is_expected.to eq([result_class.new(true, nil, shard: 'default')]) }
+      it { is_expected.to eq([result_class.new('gitaly_check', true, nil, shard: 'default')]) }
     end
 
     context 'Gitaly server is down' do
       let(:gitaly_check) { double(check: { success: false, message: 'Connection refused' }) }
 
-      it { is_expected.to eq([result_class.new(false, 'Connection refused', shard: 'default')]) }
+      it { is_expected.to eq([result_class.new('gitaly_check', false, 'Connection refused', shard: 'default')]) }
     end
   end
 

spec/lib/gitlab/health_checks/prometheus_text_format_spec.rb

-describe Gitlab::HealthChecks::PrometheusTextFormat do
-  let(:metric_class) { Gitlab::HealthChecks::Metric }
-  subject { described_class.new }
-
-  describe '#marshal' do
-    let(:sample_metrics) do
-      [metric_class.new('metric1', 1),
-       metric_class.new('metric2', 2)]
-    end
-
-    it 'marshal to text with non repeating type definition' do
-      expected = <<-EXPECTED.strip_heredoc
-        # TYPE metric1 gauge
-        metric1 1
-        # TYPE metric2 gauge
-        metric2 2
-      EXPECTED
-
-      expect(subject.marshal(sample_metrics)).to eq(expected)
-    end
-
-    context 'metrics where name repeats' do
-      let(:sample_metrics) do
-        [metric_class.new('metric1', 1),
-         metric_class.new('metric1', 2),
-         metric_class.new('metric2', 3)]
-      end
-
-      it 'marshal to text with non repeating type definition' do
-        expected = <<-EXPECTED.strip_heredoc
-          # TYPE metric1 gauge
-          metric1 1
-          metric1 2
-          # TYPE metric2 gauge
-          metric2 3
-        EXPECTED
-        expect(subject.marshal(sample_metrics)).to eq(expected)
-      end
-    end
-  end
-end

spec/workers/repository_check/dispatch_worker_spec.rb

@@ -30,8 +30,8 @@ describe RepositoryCheck::DispatchWorker do
   context 'with unhealthy shard' do
     let(:default_shard_name) { 'default' }
     let(:unhealthy_shard_name) { 'unhealthy' }
-    let(:default_shard) { Gitlab::HealthChecks::Result.new(true, nil, shard: default_shard_name) }
-    let(:unhealthy_shard) { Gitlab::HealthChecks::Result.new(false, '14:Connect Failed', shard: unhealthy_shard_name) }
+    let(:default_shard) { Gitlab::HealthChecks::Result.new('gitaly_check', true, nil, shard: default_shard_name) }
+    let(:unhealthy_shard) { Gitlab::HealthChecks::Result.new('gitaly_check', false, '14:Connect Failed', shard: unhealthy_shard_name) }
 
     before do
       allow(Gitlab::HealthChecks::GitalyCheck).to receive(:readiness).and_return([default_shard, unhealthy_shard])