Change Puma.stats to return a hash instead of a JSON string (#2086)

Having access to the hash allows to produce stats in other ways (such as StatsD) without having to parse JSON of data that is available in memory. An example of this workaround is fa6ba1f507/lib/puma/plugin/statsd.rb (L112-L114)

History.md

@@ -3,6 +3,7 @@
 * Features
   * Add pumactl `thread-backtraces` command to print thread backtraces (#2053)
   * Configuration: `environment` is read from `RAILS_ENV`, if `RACK_ENV` can't be found (#2022)
+  * `Puma.stats` now returns a Hash instead of a JSON string (#2086)
 
 * Bugfixes
   * Your bugfix goes here (#Github Number)

lib/puma/app/status.rb

@@ -54,7 +54,7 @@ module Puma
           rack_response(200, GC.stat.to_json)
 
         when /\/stats$/
-          rack_response(200, @cli.stats)
+          rack_response(200, @cli.stats.to_json)
 
         when /\/thread-backtraces$/
           backtraces = []

lib/puma/cluster.rb

@@ -73,7 +73,7 @@ module Puma
         @first_term_sent = nil
         @started_at = Time.now
         @last_checkin = Time.now
-        @last_status = '{}'
+        @last_status = {}
         @term = false
       end
 
@@ -94,7 +94,11 @@ module Puma
 
       def ping!(status)
         @last_checkin = Time.now
-        @last_status = status
+        captures = status.match(/{ "backlog":(?<backlog>\d*), "running":(?<running>\d*), "pool_capacity":(?<pool_capacity>\d*), "max_threads": (?<max_threads>\d*) }/)
+        @last_status = captures.names.inject({}) do |hash, key|
+          hash[key.to_sym] = captures[key].to_i
+          hash
+        end
       end
 
       def ping_timeout?(which)
@@ -352,9 +356,26 @@ module Puma
     # the master process.
     def stats
       old_worker_count = @workers.count { |w| w.phase != @phase }
-      booted_worker_count = @workers.count { |w| w.booted? }
+      worker_status = @workers.map do |w|
-      worker_status = '[' + @workers.map { |w| %Q!{ "started_at": "#{w.started_at.utc.iso8601}", "pid": #{w.pid}, "index": #{w.index}, "phase": #{w.phase}, "booted": #{w.booted?}, "last_checkin": "#{w.last_checkin.utc.iso8601}", "last_status": #{w.last_status} }!}.join(",") + ']'
+        {
-      %Q!{ "started_at": "#{@started_at.utc.iso8601}", "workers": #{@workers.size}, "phase": #{@phase}, "booted_workers": #{booted_worker_count}, "old_workers": #{old_worker_count}, "worker_status": #{worker_status} }!
+          started_at: w.started_at.utc.iso8601,
+          pid: w.pid,
+          index: w.index,
+          phase: w.phase,
+          booted: w.booted?,
+          last_checkin: w.last_checkin.utc.iso8601,
+          last_status: w.last_status,
+        }
+      end
+
+      {
+        started_at: @started_at.utc.iso8601,
+        workers: @workers.size,
+        phase: @phase,
+        booted_workers: worker_status.count { |w| w[:booted] },
+        old_workers: old_worker_count,
+        worker_status: worker_status,
+      }
     end
 
     def preload?

lib/puma/single.rb

@@ -14,11 +14,13 @@ module Puma
   # that this inherits from.
   class Single < Runner
     def stats
-      b = @server.backlog || 0
+      {
-      r = @server.running || 0
+        started_at: @started_at.utc.iso8601,
-      t = @server.pool_capacity || 0
+        backlog: @server.backlog || 0,
-      m = @server.max_threads || 0
+        running: @server.running || 0,
-      %Q!{ "started_at": "#{@started_at.utc.iso8601}", "backlog": #{b}, "running": #{r}, "pool_capacity": #{t}, "max_threads": #{m} }!
+        pool_capacity: @server.pool_capacity || 0,
+        max_threads: @server.max_threads || 0,
+      }
     end
 
     def restart

test/test_app_status.rb

@@ -24,7 +24,7 @@ class TestAppStatus < Minitest::Test
     end
 
     def stats
-      "{}"
+      {}
     end
   end
 

test/test_cli.rb

@@ -57,8 +57,7 @@ class TestCLI < Minitest::Test
     body = s.read
     s.close
 
-    assert_match(/{ "started_at": "\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z", "backlog": 0, "running": 0, "pool_capacity": 16, "max_threads": 16 }/, body.split(/\r?\n/).last)
+    assert_match(/{"started_at":"\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z","backlog":0,"running":0,"pool_capacity":16,"max_threads":16}/, body.split(/\r?\n/).last)
-    assert_match(/{ "started_at": "\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z", "backlog": 0, "running": 0, "pool_capacity": 16, "max_threads": 16 }/, Puma.stats)
 
   ensure
     cli.launcher.stop
@@ -92,9 +91,9 @@ class TestCLI < Minitest::Test
       body = http.request(req).body
     end
 
-    expected_stats = /{ "started_at": "\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z", "backlog": 0, "running": 0, "pool_capacity": 16, "max_threads": 16 }/
+    expected_stats = /{"started_at":"\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z","backlog":0,"running":0,"pool_capacity":16,"max_threads":16}/
     assert_match(expected_stats, body.split(/\r?\n/).last)
-    assert_match(expected_stats, Puma.stats)
+    assert_equal([:started_at, :backlog, :running, :pool_capacity, :max_threads], Puma.stats.keys)
 
   ensure
     cli.launcher.stop
@@ -137,7 +136,7 @@ class TestCLI < Minitest::Test
     body = s.read
     s.close
 
-    assert_match(/\{ "started_at": "\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z", "workers": 2, "phase": 0, "booted_workers": 2, "old_workers": 0, "worker_status": \[\{ "started_at": "\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z", "pid": \d+, "index": 0, "phase": 0, "booted": true, "last_checkin": "[^"]+", "last_status": \{ "backlog":0, "running":2, "pool_capacity":2, "max_threads": 2 \} \},\{ "started_at": "\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z", "pid": \d+, "index": 1, "phase": 0, "booted": true, "last_checkin": "[^"]+", "last_status": \{ "backlog":0, "running":2, "pool_capacity":2, "max_threads": 2 \} \}\] \}/, body.split("\r\n").last)
+    assert_match(/\{"started_at":"\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z","workers":2,"phase":0,"booted_workers":2,"old_workers":0,"worker_status":\[\{"started_at":"\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z","pid":\d+,"index":0,"phase":0,"booted":true,"last_checkin":"[^"]+","last_status":\{"backlog":0,"running":2,"pool_capacity":2,"max_threads":2\}\},\{"started_at":"\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z","pid":\d+,"index":1,"phase":0,"booted":true,"last_checkin":"[^"]+","last_status":\{"backlog":0,"running":2,"pool_capacity":2,"max_threads":2\}\}\]\}/, body.split("\r\n").last)
   ensure
     if UNIX_SKT_EXIST && HAS_FORK
       cli.launcher.stop
@@ -172,7 +171,7 @@ class TestCLI < Minitest::Test
     body = s.read
     s.close
 
-    assert_match(/{ "started_at": "\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z", "backlog": 0, "running": 0, "pool_capacity": 16, "max_threads": 16 }/, body.split("\r\n").last)
+    assert_match(/{"started_at":"\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z","backlog":0,"running":0,"pool_capacity":16,"max_threads":16}/, body.split("\r\n").last)
   ensure
     if UNIX_SKT_EXIST
       cli.launcher.stop