Add reload stats at the instance level

Reload stats are currently reported at the pipeline level. The instance
level aggregates these stats across the pipelines

Fixes #6350

Fixes #6367

Gemfile

@@ -116,3 +116,24 @@ gem "logstash-output-stdout"
 gem "logstash-output-tcp"
 gem "logstash-output-udp"
 gem "logstash-output-webhdfs"
+gem "logstash-filter-multiline"
+gem "jar-dependencies", ">= 0"
+gem "ruby-maven", "~> 3.3"
+gem "logstash-patterns-core", ">= 0"
+gem "pry", ">= 0"
+gem "rspec-wait", ">= 0"
+gem "childprocess", ">= 0"
+gem "ftw", "~> 0.0.42"
+gem "rspec-sequencing", ">= 0"
+gem "gmetric", ">= 0"
+gem "gelf", "= 1.3.2"
+gem "timecop", ">= 0"
+gem "jdbc-derby", ">= 0"
+gem "coveralls", ">= 0"
+gem "addressable", "~> 2.3.0"
+gem "elasticsearch", ">= 0"
+gem "sinatra", ">= 0"
+gem "webrick", ">= 0"
+gem "poseidon", ">= 0"
+gem "snappy", ">= 0"
+gem "webmock", "~> 1.21.0"

logstash-core/spec/api/lib/api/node_stats_spec.rb

@@ -80,7 +80,11 @@ describe LogStash::Api::Modules::NodeStats do
         "filtered" => Numeric,
         "out" => Numeric
      }
-    }
+   },
+   "reloads" => {
+     "successes" => Numeric,
+     "failures" => Numeric
+   }
   }
 
   test_api_and_resources(root_structure)

logstash-core/spec/logstash/agent_spec.rb

@@ -479,7 +479,9 @@ describe LogStash::Agent do
       it "increases the successful reload count" do
         snapshot = subject.metric.collector.snapshot_metric
         value = snapshot.metric_store.get_with_path("/stats/pipelines")[:stats][:pipelines][:main][:reloads][:successes].value
+        instance_value = snapshot.metric_store.get_with_path("/stats")[:stats][:reloads][:successes].value
         expect(value).to eq(1)
+        expect(instance_value).to eq(1)
       end
 
       it "does not set the failure reload timestamp" do

qa/integration/specs/reload_config_spec.rb

@@ -64,11 +64,14 @@ describe "Test Logstash service when config reload is enabled" do
     
     # check reload stats
     reload_stats = logstash_service.monitoring_api.pipeline_stats["reloads"]
+    instance_reload_stats = logstash_service.monitoring_api.node_stats["reloads"]
     expect(reload_stats["successes"]).to eq(1)
     expect(reload_stats["failures"]).to eq(0)
     expect(reload_stats["last_success_timestamp"].blank?).to be false
     expect(reload_stats["last_error"]).to eq(nil)
     
+    expect(instance_reload_stats["successes"]).to eq(1)
+    expect(instance_reload_stats["failures"]).to eq(0)
     # parse the results and validate
     re = JSON.load(File.new(output_file2))
     expect(re["clientip"]).to eq("74.125.176.147")