Introducing extended app process management.

- Pre-fork 'processes.spare' application processes;
- fork more processes to keep 'processes.spare' idle processes;
- fork on-demand up to 'processes.max' count;
- scale down idle application processes above 'processes.spare' after
  'processes.idle_timeout';
- number of concurrently started application processes also limited by
  'processes.spare' (or 1, if spare is 0).

test/test_python_procman.py

@@ -0,0 +1,237 @@
+import os
+import time
+import unittest
+import unit
+
+class TestUnitApplication(unit.TestUnitControl):
+
+    def setUpClass():
+        u = unit.TestUnit()
+
+        u.check_modules('python')
+        u.check_version('0.3')
+
+    def getWorkerCount(self):
+        n = 0
+        for f in os.listdir(self.testdir):
+            if f.startswith('proctest.'):
+                n += 1
+
+        return n
+
+    def getTestCode(self):
+        return """
+import atexit
+import os
+
+fname = "%s.%%d" %% os.getpid()
+
+def remove_file():
+    os.remove(fname)
+
+atexit.register(remove_file)
+
+open(fname, 'w')
+
+def application(env, start_response):
+    start_response('200 OK', [('Content-Type','text/html')])
+    return [b'body']
+
+""" % (self.testdir + '/proctest')
+
+
+    def test_python_prefork(self):
+        code, name = self.getTestCode(), 'py_app'
+
+        self.python_application(name, code)
+
+        self.conf({
+            "listeners": {
+                "*:7080": {
+                    "application": "app"
+                }
+            },
+            "applications": {
+                "app": {
+                    "type": "python",
+                    "processes": 2,
+                    "path": self.testdir + '/' + name,
+                    "module": "wsgi"
+                }
+            }
+        })
+
+        self.assertEqual(self.getWorkerCount(), 2, 'python prefork 2 processes')
+
+        self.get()
+        self.assertEqual(self.getWorkerCount(), 2, 'python prefork, still 2')
+
+        self.conf('4', '/applications/app/processes')
+
+        time.sleep(0.2)
+
+        self.assertEqual(self.getWorkerCount(), 4, 'python prefork 4 processes')
+
+        self.get()
+        self.assertEqual(self.getWorkerCount(), 4, 'python prefork, still 4')
+
+        self.conf({
+            "listeners": {},
+            "applications": {}
+        })
+
+        time.sleep(0.2)
+        self.assertEqual(self.getWorkerCount(), 0, 'python stop all processes')
+
+        time.sleep(2.2)
+
+
+    def test_python_ondemand(self):
+        code, name = self.getTestCode(), 'py_app'
+
+        self.python_application(name, code)
+
+        self.conf({
+            "listeners": {
+                "*:7080": {
+                    "application": "app"
+                }
+            },
+            "applications": {
+                "app": {
+                    "type": "python",
+                    "processes": {
+                        "spare": 0,
+                        "max": 8,
+                        "idle_timeout": 2
+                    },
+                    "path": self.testdir + '/' + name,
+                    "module": "wsgi"
+                }
+            }
+        })
+
+        self.assertEqual(self.getWorkerCount(), 0, 'python on-demand')
+
+        self.get()
+        self.assertEqual(self.getWorkerCount(), 1, 'python start on-demand')
+
+        self.get()
+        self.assertEqual(self.getWorkerCount(), 1, 'python still 1')
+
+        time.sleep(2.2)
+        self.assertEqual(self.getWorkerCount(), 0, 'python stop idle')
+
+        self.conf({
+            "listeners": {},
+            "applications": {}
+        })
+
+        time.sleep(0.2)
+        self.assertEqual(self.getWorkerCount(), 0, 'python stop all processes')
+
+        time.sleep(2.2)
+
+    def test_python_scale_updown(self):
+        code, name = self.getTestCode(), 'py_app'
+
+        self.python_application(name, code)
+
+        self.conf({
+            "listeners": {
+                "*:7080": {
+                    "application": "app"
+                }
+            },
+            "applications": {
+                "app": {
+                    "type": "python",
+                    "processes": {
+                        "spare": 2,
+                        "max": 8,
+                        "idle_timeout": 2
+                    },
+                    "path": self.testdir + '/' + name,
+                    "module": "wsgi"
+                }
+            }
+        })
+
+        self.assertEqual(self.getWorkerCount(), 2, 'python prefork 2')
+
+        self.get()
+        time.sleep(0.2)
+        self.assertEqual(self.getWorkerCount(), 3, 'python keep 2 idle, 1 busy')
+
+        self.get()
+        time.sleep(0.2)
+        self.assertEqual(self.getWorkerCount(), 3, 'python still 3')
+
+        time.sleep(2.2)
+        self.assertEqual(self.getWorkerCount(), 2, 'python stop idle')
+
+        self.get()
+
+        time.sleep(0.5)
+        self.assertEqual(self.getWorkerCount(), 3, 'python keep 2 idle, 1 busy')
+
+        self.conf({
+            "listeners": {},
+            "applications": {}
+        })
+
+        time.sleep(0.2)
+        self.assertEqual(self.getWorkerCount(), 0, 'python stop all processes')
+
+        time.sleep(2.2)
+
+    def test_python_reconfigure(self):
+        code, name = self.getTestCode(), 'py_app'
+
+        self.python_application(name, code)
+
+        self.conf({
+            "listeners": {
+                "*:7080": {
+                    "application": "app"
+                }
+            },
+            "applications": {
+                "app": {
+                    "type": "python",
+                    "processes": {
+                        "spare": 2,
+                        "max": 6,
+                        "idle_timeout": 2
+                    },
+                    "path": self.testdir + '/' + name,
+                    "module": "wsgi"
+                }
+            }
+        })
+
+        self.assertEqual(self.getWorkerCount(), 2, 'python prefork 2')
+
+        self.get()
+        time.sleep(0.2)
+        self.assertEqual(self.getWorkerCount(), 3, 'python keep 2 idle, 1 busy')
+
+        self.conf('6', '/applications/app/processes/spare')
+        self.assertEqual(self.getWorkerCount(), 6, 'python prefork 6')
+
+        self.get()
+        time.sleep(0.2)
+        self.assertEqual(self.getWorkerCount(), 6, 'python still 6')
+
+        self.conf({
+            "listeners": {},
+            "applications": {}
+        })
+
+        time.sleep(0.2)
+        self.assertEqual(self.getWorkerCount(), 0, 'python stop all processes')
+
+        time.sleep(2.2)
+
+if __name__ == '__main__':
+    unittest.main()