Add Process memory usage and fix process state update

app/models/good_job/process.rb

@@ -12,6 +12,22 @@ class Process < BaseRecord
     STALE_INTERVAL = 30.seconds
     # Interval until the process record is treated as expired
     EXPIRED_INTERVAL = 5.minutes
+    PROCESS_MEMORY = case RUBY_PLATFORM
+                     when /linux/
+                       ->(pid) {
+                         File.readlines("/proc/#{pid}/status").each do |line|
+                           next unless line.start_with?('VmRSS:')
+
+                           break line.split[1].to_i
+                         end
+                       }
+                     when /darwin|bsd/
+                       ->(pid) {
+                         `ps -o pid,rss -p #{pid}`.lines.last.split.last.to_i
+                       }
+                     else
+                       ->(_pid) { 0 }
+                     end
 
     self.table_name = 'good_job_processes'
     self.implicit_order_column = 'created_at'
@@ -56,6 +72,10 @@ def self.cleanup
       end
     end
 
+    def self.memory_usage(pid)
+      (PROCESS_MEMORY.call(pid) / 1024).to_i
+    end
+
     def self.find_or_create_record(id:, with_advisory_lock: false)
       attributes = {
         id: id,
@@ -83,6 +103,7 @@ def self.process_state
       {
         hostname: Socket.gethostname,
         pid: ::Process.pid,
+        memory: memory_usage(::Process.pid),
         proctitle: $PROGRAM_NAME,
         preserve_job_records: GoodJob.preserve_job_records,
         retry_on_unhandled_error: GoodJob.retry_on_unhandled_error,
@@ -98,8 +119,8 @@ def self.process_state
     end
 
     def refresh
-      self.state = self.class.process_state
       reload # verify the record still exists in the database
+      self.state = self.class.process_state
       update(state: state, updated_at: Time.current)
     rescue ActiveRecord::RecordNotFound
       @new_record = true

app/views/good_job/processes/index.html.erb

@@ -38,6 +38,7 @@
               <span class="badge rounded-pill bg-body-secondary text-secondary"><%= process.state["pid"] %></span>
               <span class="text-muted small">@</span>
               <span class="badge rounded-pill bg-body-secondary text-secondary"><%= process.state["hostname"] %></span>
+              <span class="badge rounded-pill bg-body-secondary text-secondary"><%= process.state["memory"] %>mb</span>
             </div>
           </div>
           <div class="col">

spec/app/models/good_job/process_spec.rb

@@ -77,7 +77,8 @@
       process = described_class.create! state: {}, updated_at: 1.day.ago
       expect do
         expect(process.refresh).to be true
-      end.to change(process, :updated_at).to within(1.second).of(Time.current)
+      end.to change(process, :state)
+         .and change(process, :updated_at).to within(1.second).of(Time.current)
     end
 
     context 'when the record has been deleted elsewhere' do