Adapt vitals (mem and cpu) for Puma

Return the summed up memory bytes and cpu for the Puma process and its
worker subprocesses.

lib/vcap/stats.rb

@@ -5,9 +5,14 @@ module VCAP
   class Stats
     class << self
       def process_memory_bytes_and_cpu
-        rss, pcpu = `ps -o rss=,pcpu= -p #{Process.pid}`.split.map(&:to_i)
-        rss_bytes = rss * 1024
-        [rss_bytes, pcpu]
+        rss = []
+        pcpu = []
+
+        ps_out = ps_pid
+        ps_out += ps_ppid if VCAP::CloudController::Config.config.get(:webserver) == 'puma'
+        ps_out.split.each_with_index { |e, i| i.even? ? rss << e : pcpu << e }
+
+        [rss.map(&:to_i).sum * 1024, pcpu.map(&:to_f).sum.round]
       end
 
       def memory_used_bytes
@@ -23,6 +28,16 @@ def memory_free_bytes
       def cpu_load_average
         Vmstat.load_average.one_minute
       end
+
+      private
+
+      def ps_pid
+        `ps -o rss=,pcpu= --pid #{Process.pid}`
+      end
+
+      def ps_ppid
+        `ps -o rss=,pcpu= --ppid #{Process.pid}`
+      end
     end
   end
 end

spec/unit/lib/vcap/stats_spec.rb

@@ -0,0 +1,29 @@
+require 'spec_helper'
+
+RSpec.describe VCAP::Stats do
+  describe '#process_memory_bytes_and_cpu' do
+    before do
+      allow(VCAP::Stats).to receive_messages(ps_pid: "123456 7.8\n", ps_ppid: "121212 3.4\n343434 5.6\n")
+    end
+
+    it 'returns the memory bytes and cpu for the process' do
+      rss_bytes, pcpu = VCAP::Stats.process_memory_bytes_and_cpu
+
+      expect(rss_bytes).to eq(126_418_944)
+      expect(pcpu).to eq(8)
+    end
+
+    context 'when Puma is configured as webserver' do
+      before do
+        TestConfig.override(webserver: 'puma')
+      end
+
+      it 'returns the summed up memory bytes and cpu for the process and its subprocesses' do
+        rss_bytes, pcpu = VCAP::Stats.process_memory_bytes_and_cpu
+
+        expect(rss_bytes).to eq(602_216_448)
+        expect(pcpu).to eq(17)
+      end
+    end
+  end
+end