Add JVM uptime stats

Fixes #6236

logstash-core/lib/logstash/api/commands/stats.rb

@@ -8,8 +8,6 @@ module LogStash
     module Commands
       class Stats < Commands::Base
         def jvm
-          require "pry"
-          binding.pry
           {
             :threads => extract_metrics(
               [:jvm, :threads],

logstash-core/lib/logstash/instrument/periodic_poller/jvm.rb

@@ -101,7 +101,7 @@ module LogStash module Instrument module PeriodicPoller
     
     def collect_jvm_metrics(data)
       runtime_mx_bean = ManagementFactory.getRuntimeMXBean()
-      metric.gauge(:jvm, :uptime_in_millis, runtime_mx_bean.getUptime())
+      metric.gauge([:jvm], :uptime_in_millis, runtime_mx_bean.getUptime())
       collect_heap_metrics(data)
       collect_non_heap_metrics(data)
     end  

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

@@ -14,6 +14,7 @@ describe LogStash::Api::Modules::NodeStats do
   # DSL describing response structure
   root_structure = {
     "jvm"=>{
+      "uptime_in_millis" => Numeric,
       "threads"=>{
         "count"=>Numeric,
         "peak_count"=>Numeric

qa/integration/services/monitoring_api.rb

@@ -5,9 +5,7 @@ require "json"
 class MonitoringAPI
 
   def pipeline_stats
-    resp = Manticore.get("http://localhost:9600/_node/stats/pipeline").body
-    stats_response = JSON.parse(resp)
-    stats_response["pipeline"]
+    node_stats["pipeline"]
   end
 
   def event_stats
@@ -27,4 +25,9 @@ class MonitoringAPI
     JSON.parse(resp)
   end
 
+  def node_stats
+    resp = Manticore.get("http://localhost:9600/_node/stats").body
+    JSON.parse(resp)
+  end
+
 end

qa/integration/specs/monitoring_api_spec.rb

@@ -32,4 +32,15 @@ describe "Test Monitoring API" do
     end
   end
 
+  it "can retrieve JVM stats" do
+    logstash_service = @fixture.get_service("logstash")
+    logstash_service.start_with_stdin
+    logstash_service.wait_for_logstash
+
+    Stud.try(max_retry.times, RSpec::Expectations::ExpectationNotMetError) do
+       result = logstash_service.monitoring_api.node_stats
+       expect(result["jvm"]["uptime_in_millis"]).to be > 100
+    end
+  end
+
 end