Merge ~pappacena/launchpad:gunicorn-experiments into launchpad:master

[Thiago F. Pappacena]

[DONT MERGE] Experiments to use gunicorn instead of Zope Server.

This MP should not be merged. Instead, we will pave a way to migrate to gunicorn slowly to avoid big production disruption. But anyway, the changes here work with most (all?) tests running successfully and the dev server running smoothly (including auto-reload on code changes).

5fb6bd9... by Thiago F. Pappacena on 2021-01-14

Fixing port binding for brz acceptance tests

7927365... by Thiago F. Pappacena on 2021-01-14

Merge branch 'master' into gunicorn-experiments

40cd43d... by Thiago F. Pappacena on 2021-01-15

Pipe

b7c3579... by Thiago F. Pappacena on 2021-01-15

Merge branch 'master' into gunicorn-experiments

03d978a... by Thiago F. Pappacena on 2021-01-18

Avoiding block gunicorn subprocess due to output buffer not beign consumed

cca3c62... by Thiago F. Pappacena on 2021-01-19

Moving gunicorn config to its own file

8c5ac5f... by Thiago F. Pappacena on 2021-01-20

Fixing output buffer consumption on app server layer

6aef0db... by Thiago F. Pappacena on 2021-01-20

Merge branch 'master' into gunicorn-experiments

f066609... by Thiago F. Pappacena on 2021-01-20

Autoreload in dev

ce702df... by Thiago F. Pappacena on 2021-01-21

Using original HTTPPublicationRequestFactory on startwsgi

Unmerged commits

ce702df... by Thiago F. Pappacena on 2021-01-21

Using original HTTPPublicationRequestFactory on startwsgi

f066609... by Thiago F. Pappacena on 2021-01-20

Autoreload in dev

6aef0db... by Thiago F. Pappacena on 2021-01-20

Merge branch 'master' into gunicorn-experiments

8c5ac5f... by Thiago F. Pappacena on 2021-01-20

Fixing output buffer consumption on app server layer

cca3c62... by Thiago F. Pappacena on 2021-01-19

Moving gunicorn config to its own file

03d978a... by Thiago F. Pappacena on 2021-01-18

Avoiding block gunicorn subprocess due to output buffer not beign consumed

b7c3579... by Thiago F. Pappacena on 2021-01-15

Merge branch 'master' into gunicorn-experiments

40cd43d... by Thiago F. Pappacena on 2021-01-15

Pipe

7927365... by Thiago F. Pappacena on 2021-01-14

Merge branch 'master' into gunicorn-experiments

5fb6bd9... by Thiago F. Pappacena on 2021-01-14

Fixing port binding for brz acceptance tests

diff --git a/configs/development/gunicorn.conf.py b/configs/development/gunicorn.conf.py
new file mode 100644
index 0000000..b667109
--- /dev/null
+++ b/configs/development/gunicorn.conf.py
@@ -0,0 +1,6 @@
+bind = [":8085", ":8086", ":8087", ":8088", ":8089"]
+workers = 2
+threads = 10
+max_requests = 1000
+log_level = "DEBUG"
+reload = True
diff --git a/configs/development/launchpad-lazr.conf b/configs/development/launchpad-lazr.conf
index a4956f3..e56bdd8 100644
--- a/configs/development/launchpad-lazr.conf
+++ b/configs/development/launchpad-lazr.conf
@@ -223,6 +223,7 @@ hostname: xmlrpc.launchpad.test
 
 [vhost.xmlrpc_private]
 hostname: xmlrpc-private.launchpad.test
+private_port: 8087
 
 [vhost.feeds]
 hostname: feeds.launchpad.test
diff --git a/configs/development/launchpad.conf b/configs/development/launchpad.conf
index fe7e088..8281e09 100644
--- a/configs/development/launchpad.conf
+++ b/configs/development/launchpad.conf
@@ -5,52 +5,11 @@ site-definition zcml/webapp.zcml
 # Turn on Zope3 developer mode.
 devmode on
 
-# number of bytecode instructions to execute between checks for
-# interruptions (SIGINTR, thread switches):
-interrupt-check-interval 200
-
-<server>
-  type HTTP
-  address 8085
-</server>
-
-# For debugging purposes, you can use this publisher instead/as well
-# (obviously if it's as well, use a different port number). If there's
-# an exception, Zope will drop into pdb at the point of the exception.
-<server>
-  type PostmortemDebuggingHTTP
-  address 8088
-</server>
-
-<server>
-  type DebugLayerHTTP
-  address 8086
-</server>
-
-<server>
-  type PrivateXMLRPC
-  address 8087
-</server>
-
 # non-persistent in-memory storage
 <zodb>
   <mappingstorage/>
 </zodb>
 
-<accesslog>
-  # This sets up logging to both a file (access.log) and to standard
-  # output (STDOUT).  The "path" setting can be a relative or absolute
-  # filesystem path or the tokens STDOUT or STDERR.
-
-  <logfile>
-    path logs/launchpad-access.log
-  </logfile>
-
-  <logfile>
-    path STDOUT
-  </logfile>
-</accesslog>
-
 <eventlog>
   # This sets up logging to both a file (z3.log) and to standard
   # output (STDOUT).  The "path" setting can be a relative or absolute
@@ -65,13 +24,3 @@ interrupt-check-interval 200
   </logfile>
 </eventlog>
 
-<logger>
-  name zc.tracelog
-  propagate false
-
-  <logfile>
-    format %(message)s
-    path logs/trace.log
-  </logfile>
-
-</logger>
diff --git a/configs/test-playground/launchpad.conf b/configs/test-playground/launchpad.conf
index ec8095a..0ce913b 100644
--- a/configs/test-playground/launchpad.conf
+++ b/configs/test-playground/launchpad.conf
@@ -5,52 +5,11 @@ site-definition zcml/webapp.zcml
 # Turn on Zope3 developer mode.
 devmode on
 
-# number of bytecode instructions to execute between checks for
-# interruptions (SIGINTR, thread switches):
-interrupt-check-interval 200
-
-<server>
-  type HTTP
-  address 8085
-</server>
-
-# For debugging purposes, you can use this publisher instead/as well
-# (obviously if it's as well, use a different port number). If there's
-# an exception, Zope will drop into pdb at the point of the exception.
-<server>
-  type PostmortemDebuggingHTTP
-  address 8089
-</server>
-
-<server>
-  type DebugLayerHTTP
-  address 8086
-</server>
-
-<server>
-  type PrivateXMLRPC
-  address 8087
-</server>
-
 # non-persistent in-memory storage
 <zodb>
   <mappingstorage/>
 </zodb>
 
-<accesslog>
-  # This sets up logging to both a file (access.log) and to standard
-  # output (STDOUT).  The "path" setting can be a relative or absolute
-  # filesystem path or the tokens STDOUT or STDERR.
-
-  <logfile>
-    path logs/launchpad-access.log
-  </logfile>
-
-  <logfile>
-    path STDOUT
-  </logfile>
-</accesslog>
-
 <eventlog>
   # This sets up logging to both a file (z3.log) and to standard
   # output (STDOUT).  The "path" setting can be a relative or absolute
diff --git a/configs/testrunner-appserver/gunicorn.conf.py b/configs/testrunner-appserver/gunicorn.conf.py
new file mode 100644
index 0000000..ba22ec1
--- /dev/null
+++ b/configs/testrunner-appserver/gunicorn.conf.py
@@ -0,0 +1,12 @@
+import os
+config_dir = os.path.dirname(__file__)
+log_dir = os.path.join(config_dir, '..', '..', 'logs')
+
+bind = [":8085", ":8087"]
+workers = 1
+threads = 10
+log_level = "DEBUG"
+
+log_file = os.path.join(log_dir, 'gunicorn.log')
+error_logfile = os.path.join(log_dir, 'gunicorn-error.log')
+access_logfile = os.path.join(log_dir, 'gunicorn-access.log')
diff --git a/configs/testrunner-appserver/launchpad.conf b/configs/testrunner-appserver/launchpad.conf
index 2f9ce03..dde05d8 100644
--- a/configs/testrunner-appserver/launchpad.conf
+++ b/configs/testrunner-appserver/launchpad.conf
@@ -7,31 +7,11 @@ site-definition zcml/webapp.zcml
 # Make this work a little more like production.
 devmode off
 
-# number of bytecode instructions to execute between checks for
-# interruptions (SIGINTR, thread switches):
-interrupt-check-interval 200
-
-<server>
-  type HTTP
-  address 8085
-</server>
-
-<server>
-  type PrivateXMLRPC
-  address 8087
-</server>
-
 # non-persistent in-memory storage
 <zodb>
   <mappingstorage/>
 </zodb>
 
-<accesslog>
-  <logfile>
-    path logs/test-appserver-layer.log
-  </logfile>
-</accesslog>
-
 <eventlog>
   <logfile>
     path logs/test-appserver-layer.log
diff --git a/configs/testrunner/launchpad.conf b/configs/testrunner/launchpad.conf
index e1aee02..252fd3e 100644
--- a/configs/testrunner/launchpad.conf
+++ b/configs/testrunner/launchpad.conf
@@ -5,52 +5,11 @@ site-definition zcml/webapp.zcml
 # Turn on Zope3 developer mode.
 devmode on
 
-# number of bytecode instructions to execute between checks for
-# interruptions (SIGINTR, thread switches):
-interrupt-check-interval 200
-
-<server>
-  type HTTP
-  address 8085
-</server>
-
-# For debugging purposes, you can use this publisher instead/as well
-# (obviously if it's as well, use a different port number). If there's
-# an exception, Zope will drop into pdb at the point of the exception.
-<server>
-  type PostmortemDebuggingHTTP
-  address 8089
-</server>
-
-<server>
-  type DebugLayerHTTP
-  address 8086
-</server>
-
-<server>
-  type PrivateXMLRPC
-  address 8087
-</server>
-
 # non-persistent in-memory storage
 <zodb>
   <mappingstorage/>
 </zodb>
 
-<accesslog>
-  # This sets up logging to both a file (access.log) and to standard
-  # output (STDOUT).  The "path" setting can be a relative or absolute
-  # filesystem path or the tokens STDOUT or STDERR.
-
-  <logfile>
-    path logs/launchpad-access.log
-  </logfile>
-
-  <logfile>
-    path STDOUT
-  </logfile>
-</accesslog>
-
 <eventlog>
   # This sets up logging to both a file (z3.log) and to standard
   # output (STDOUT).  The "path" setting can be a relative or absolute
diff --git a/lib/lp/scripts/runlaunchpad.py b/lib/lp/scripts/runlaunchpad.py
index 969cfd6..42f2806 100644
--- a/lib/lp/scripts/runlaunchpad.py
+++ b/lib/lp/scripts/runlaunchpad.py
@@ -6,6 +6,9 @@ from __future__ import absolute_import, print_function, unicode_literals
 __metaclass__ = type
 __all__ = ['start_launchpad']
 
+import six
+from talisker import run_gunicorn
+
 try:
     from contextlib import ExitStack
 except ImportError:
@@ -16,10 +19,10 @@ import subprocess
 import sys
 
 import fixtures
+from gunicorn.app.wsgiapp import WSGIApplication
 from lazr.config import as_host_port
 from rabbitfixture.server import RabbitServerResources
 from testtools.testresult.real import _details_to_str
-from zope.app.server.main import main
 
 from lp.services.config import config
 from lp.services.daemons import tachandler
@@ -331,6 +334,23 @@ def start_testapp(argv=list(sys.argv)):
                 pass
 
 
+def main(argv):
+    orig_argv = sys.argv
+    try:
+        # This is a bit hacky, but talisker gets the arguments directly from
+        # sys.argv. There is no way to send it using parameters. We set it
+        # back as soon as run_gunicorn finishes.
+        sys.argv = [
+            os.path.join(config.root, "bin", "talisker.gunicorn"),
+            "lp.startwsgi",
+            "-c", os.path.join(config.config_dir, "gunicorn.conf.py")
+        ]
+        run_gunicorn()
+        return
+    finally:
+        sys.argv = orig_argv
+
+
 def start_launchpad(argv=list(sys.argv), setup=None):
     # We really want to replace this with a generic startup harness.
     # However, this should last us until this is developed
diff --git a/lib/lp/services/config/__init__.py b/lib/lp/services/config/__init__.py
index 9d43346..c7828a8 100644
--- a/lib/lp/services/config/__init__.py
+++ b/lib/lp/services/config/__init__.py
@@ -30,6 +30,7 @@ from six.moves.urllib.parse import (
     urlunparse,
     )
 import ZConfig
+from zope.app.appsetup import appsetup
 
 from lp.services.osutils import open_for_writing
 
@@ -124,6 +125,7 @@ class LaunchpadConfig:
         else:
             self._process_name = process_name
         self._instance_name = instance_name
+        self._devmode = None
         self.root = TREE_ROOT
 
     def _make_process_name(self):
@@ -165,7 +167,6 @@ class LaunchpadConfig:
         """Invalidate the config, causing the config to be regenerated."""
         self._config = None
         self._devmode = None
-        self._servers = None
 
     def reloadConfig(self):
         """Reload the config."""
@@ -246,15 +247,6 @@ class LaunchpadConfig:
         """Return the path to the ZConfig file for this instance."""
         return os.path.join(self.config_dir, 'launchpad.conf')
 
-    def _getZConfig(self):
-        """Modify the config, adding automatically generated settings"""
-        with resources.path('zope.app.server', 'schema.xml') as schemafile:
-            schema = ZConfig.loadSchema(str(schemafile))
-        root_options, handlers = ZConfig.loadConfig(
-            schema, self.zope_config_file)
-        self._devmode = root_options.devmode
-        self._servers = root_options.servers
-
     @property
     def devmode(self):
         """Devmode from the zope.app.server.main config.
@@ -262,20 +254,14 @@ class LaunchpadConfig:
         Copied here for ease of access.
         """
         if self._devmode is None:
-            self._getZConfig()
+            self._getConfig()
+            self._devmode = self._config.launchpad.devmode
         return self._devmode
 
     @devmode.setter
     def devmode(self, value):
         self._devmode = value
 
-    @property
-    def servers(self):
-        """The defined servers."""
-        if self._servers is None:
-            self._getZConfig()
-        return self._servers
-
     def generate_overrides(self):
         """Ensure correct config.zcml overrides will be called.
 
diff --git a/lib/lp/services/config/doc/canonical-config.txt b/lib/lp/services/config/doc/canonical-config.txt
index 91f676b..7b70660 100644
--- a/lib/lp/services/config/doc/canonical-config.txt
+++ b/lib/lp/services/config/doc/canonical-config.txt
@@ -86,9 +86,6 @@ ZConfig.
     >>> config.devmode
     True
 
-    >>> len(config.servers)
-    4
-
 
 Working with test configurations
 --------------------------------
diff --git a/lib/lp/services/config/schema-lazr.conf b/lib/lp/services/config/schema-lazr.conf
index aaa9d30..f4d9193 100644
--- a/lib/lp/services/config/schema-lazr.conf
+++ b/lib/lp/services/config/schema-lazr.conf
@@ -539,7 +539,6 @@ storm_cache_size: 10000
 # datatype: existing_directory
 replication_logdir: database/replication
 
-
 [diff]
 # The maximum size in bytes to read from the librarian to make available in
 # the web UI.  512k == 524288 bytes.
@@ -841,8 +840,9 @@ dbuser: karma
 # datatype: integer
 max_scaling: 500
 
-
 [launchpad]
+devmode: true
+
 # A directory of files from which *-lazr.conf will be loaded and
 # overlaid in order on top of the main config.
 # Note that this is relative to the top-level config file, not
@@ -1640,6 +1640,10 @@ althostnames: none
 # datatype: string
 rooturl: none
 
+# Is this vhost enabled?
+# Used to create the correct publishers
+private_port: None
+
 [vhost.mainsite]
 # Can the profile page act as a OpenID delegated identity?
 # data-type: boolean
diff --git a/lib/lp/services/config/tests/test_config.py b/lib/lp/services/config/tests/test_config.py
index 34921fd..faf37a0 100644
--- a/lib/lp/services/config/tests/test_config.py
+++ b/lib/lp/services/config/tests/test_config.py
@@ -25,6 +25,7 @@ from lazr.config.interfaces import ConfigErrors
 import scandir
 import testtools
 import ZConfig
+from zope.app.appsetup import appsetup
 
 import lp.services.config
 from lp.services.config.fixture import ConfigUseFixture
@@ -33,8 +34,8 @@ from lp.services.config.fixture import ConfigUseFixture
 EXCLUDED_CONFIGS = ['lpnet-template']
 
 # Calculate some landmark paths.
-with resources.path('zope.app.server', 'schema.xml') as schema_file:
-    schema = ZConfig.loadSchema(str(schema_file))
+schema = os.path.join(
+    os.path.dirname(appsetup.__file__), 'schema', 'schema.xml')
 
 here = os.path.dirname(lp.services.config.__file__)
 lazr_schema_file = os.path.join(here, 'schema-lazr.conf')
@@ -42,7 +43,8 @@ lazr_schema_file = os.path.join(here, 'schema-lazr.conf')
 
 def make_test(config_file, description):
     def test_function():
-        root, handlers = ZConfig.loadConfig(schema, config_file)
+        loaded_schema = ZConfig.loadSchema(schema)
+        root, handlers = ZConfig.loadConfig(loaded_schema, config_file)
     # Hack the config file name into test_function's __name__ so that the test
     # -vv output is more informative. Unfortunately, FunctionTestCase's
     # description argument doesn't do what we want.
diff --git a/lib/lp/services/webapp/configure.zcml b/lib/lp/services/webapp/configure.zcml
index 95f495d..6642ec3 100644
--- a/lib/lp/services/webapp/configure.zcml
+++ b/lib/lp/services/webapp/configure.zcml
@@ -8,7 +8,6 @@
     xmlns:xmlrpc="http://namespaces.zope.org/xmlrpc"
     i18n_domain="launchpad">
 
-    <include file="servers.zcml" />
     <include file="errorlog.zcml" />
 
     <browser:defaultView name="index.html" />
@@ -354,12 +353,6 @@
         handler="lp.services.webapp.sigdumpmem.setup_sigdumpmem"
         />
 
-    <!-- Confirm that no main thread event handlers use the connection cache -->
-    <subscriber
-        for="zope.processlifetime.IProcessStarting"
-        handler="lp.services.webapp.adapter.break_main_thread_db_access"
-        />
-
     <!-- Set the default timeout function. -->
     <subscriber
         for="zope.processlifetime.IProcessStarting"
diff --git a/lib/lp/services/webapp/doc/webapp-publication.txt b/lib/lp/services/webapp/doc/webapp-publication.txt
index ffe6a69..9b8b53e 100644
--- a/lib/lp/services/webapp/doc/webapp-publication.txt
+++ b/lib/lp/services/webapp/doc/webapp-publication.txt
@@ -417,9 +417,7 @@ listens on a particular port.
 
 Find the port the Private XMLRPC service is listening on.
 
-    >>> for server in config.servers:
-    ...     if server.type == 'PrivateXMLRPC':
-    ...         private_port = server.address[1]
+    >>> private_port = config.vhost.xmlrpc_private.private_port
 
     >>> print_request_and_publication(
     ...     'xmlrpc-private.launchpad.test', method='POST',
diff --git a/lib/lp/services/webapp/publication.py b/lib/lp/services/webapp/publication.py
index 7325d9f..6b1beea 100644
--- a/lib/lp/services/webapp/publication.py
+++ b/lib/lp/services/webapp/publication.py
@@ -28,7 +28,6 @@ from storm.exceptions import (
     )
 from storm.zope.interfaces import IZStorm
 import transaction
-from zc.zservertracelog.interfaces import ITraceLog
 import zope.app.publication.browser
 from zope.authentication.interfaces import IUnauthenticatedPrincipal
 from zope.component import (
@@ -871,6 +870,7 @@ def tracelog(request, prefix, msg):
     easier. ``prefix`` should be unique and contain no spaces, and
     preferably a single character to save space.
     """
-    tracelog = ITraceLog(request, None)
+    #tracelog = ITraceLog(request, None)
+    tracelog = None
     if tracelog is not None:
         tracelog.log('%s %s' % (prefix, six.ensure_str(msg, 'US-ASCII')))
diff --git a/lib/lp/services/webapp/servers.py b/lib/lp/services/webapp/servers.py
index d7bcad2..d592c96 100644
--- a/lib/lp/services/webapp/servers.py
+++ b/lib/lp/services/webapp/servers.py
@@ -23,13 +23,11 @@ from six.moves import xmlrpc_client
 from six.moves.urllib.parse import parse_qs
 import transaction
 from transaction.interfaces import ISynchronizer
-from zc.zservertracelog.tracelog import Server as ZServerTracelogServer
 from zope.app.publication.httpfactory import HTTPPublicationRequestFactory
 from zope.app.publication.interfaces import IRequestPublicationFactory
 from zope.app.publication.requestpublicationregistry import (
     factoryRegistry as publisher_factory_registry,
     )
-from zope.app.server import wsgi
 from zope.app.wsgi import WSGIPublisherApplication
 from zope.component import getUtility
 from zope.formlib.itemswidgets import MultiDataHelper
@@ -1111,36 +1109,6 @@ class LaunchpadAccessLogger(CommonAccessLogger):
            )
 
 
-http = wsgi.ServerType(
-    ZServerTracelogServer,  # subclass of WSGIHTTPServer
-    WSGIPublisherApplication,
-    LaunchpadAccessLogger,
-    8080,
-    True)
-
-pmhttp = wsgi.ServerType(
-    PMDBWSGIHTTPServer,
-    WSGIPublisherApplication,
-    LaunchpadAccessLogger,
-    8081,
-    True)
-
-debughttp = wsgi.ServerType(
-    ZServerTracelogServer,  # subclass of WSGIHTTPServer
-    WSGIPublisherApplication,
-    LaunchpadAccessLogger,
-    8082,
-    True,
-    requestFactory=DebugLayerRequestFactory)
-
-privatexmlrpc = wsgi.ServerType(
-    ZServerTracelogServer,  # subclass of WSGIHTTPServer
-    WSGIPublisherApplication,
-    LaunchpadAccessLogger,
-    8080,
-    True)
-
-
 # ---- mainsite
 
 class MainLaunchpadPublication(LaunchpadBrowserPublication):
@@ -1576,16 +1544,11 @@ def register_launchpad_request_publication_factories():
                               TestOpenIDBrowserPublication))
 
     # We may also have a private XML-RPC server.
-    private_port = None
-    for server in config.servers:
-        if server.type == 'PrivateXMLRPC':
-            ip, private_port = server.address
-            break
-
-    if private_port is not None:
+    if config.vhost.xmlrpc_private.private_port:
         factories.append(XMLRPCRequestPublicationFactory(
             'xmlrpc_private', PrivateXMLRPCRequest,
-            PrivateXMLRPCPublication, port=private_port))
+            PrivateXMLRPCPublication,
+            port=config.vhost.xmlrpc_private.private_port))
 
     # Register those factories, in priority order corresponding to
     # their order in the list. This means picking a large number for
diff --git a/lib/lp/services/webapp/servers.zcml b/lib/lp/services/webapp/servers.zcml
deleted file mode 100644
index 0235cd2..0000000
--- a/lib/lp/services/webapp/servers.zcml
+++ /dev/null
@@ -1,36 +0,0 @@
-<!-- Copyright 2009 Canonical Ltd.  This software is licensed under the
-     GNU Affero General Public License version 3 (see the file LICENSE).
--->
-
-<configure xmlns="http://namespaces.zope.org/zope">
-    <!-- This is the HTTP server, set up to do ZODB-free publication.  -->
-    <utility
-        name="HTTP"
-        component="lp.services.webapp.servers.http"
-        provides="zope.app.server.servertype.IServerType"
-        />
-
-    <!-- This is the HTTP server, with post-mortem debugging support,
-        set up to do ZODB-free publication.  -->
-    <utility
-        name="PostmortemDebuggingHTTP"
-        component="lp.services.webapp.servers.pmhttp"
-        provides="zope.app.server.servertype.IServerType"
-        />
-
-    <!-- This is the HTTP server, but making each request have the
-        DebugLayer as the first layer searched.  Effectively, this turns
-        on the debug error pages. -->
-    <utility
-        name="DebugLayerHTTP"
-        component="lp.services.webapp.servers.debughttp"
-        provides="zope.app.server.servertype.IServerType"
-        />
-
-    <utility
-        name="PrivateXMLRPC"
-        component="lp.services.webapp.servers.privatexmlrpc"
-        provides="zope.app.server.servertype.IServerType"
-        />
-
-</configure>
diff --git a/lib/lp/startwsgi.py b/lib/lp/startwsgi.py
new file mode 100644
index 0000000..92da007
--- /dev/null
+++ b/lib/lp/startwsgi.py
@@ -0,0 +1,26 @@
+# Copyright 2021 Canonical Ltd.  This software is licensed under the
+# GNU Affero General Public License version 3 (see the file LICENSE).
+
+"""WSGI script to start web server."""
+
+from __future__ import absolute_import, print_function, unicode_literals
+
+__metaclass__ = type
+__all__ = []
+
+from zope.app.publication.httpfactory import HTTPPublicationRequestFactory
+from zope.app.wsgi import (
+    getWSGIApplication,
+    )
+from zope.event import notify
+import zope.processlifetime
+
+from lp.services.config import config
+
+
+application = getWSGIApplication(
+    config.zope_config_file,
+    requestFactory=HTTPPublicationRequestFactory
+)
+
+notify(zope.processlifetime.ProcessStarting())
diff --git a/lib/lp/testing/layers.py b/lib/lp/testing/layers.py
index 9089c60..e0722fd 100644
--- a/lib/lp/testing/layers.py
+++ b/lib/lp/testing/layers.py
@@ -48,6 +48,7 @@ __all__ = [
     'reconnect_stores',
     ]
 
+import select
 from cProfile import Profile
 import datetime
 import errno
@@ -80,6 +81,7 @@ from six.moves.urllib.parse import (
     urlparse,
     )
 from six.moves.urllib.request import urlopen
+from six.moves.urllib.error import HTTPError
 import transaction
 from webob.request import environ_from_url as orig_environ_from_url
 import wsgi_intercept
@@ -1794,6 +1796,14 @@ class LayerProcessController:
             raise LayerIsolationError(
                 "App server died in this test (status=%s):\n%s" % (
                     cls.appserver.returncode, cls.appserver.stdout.read()))
+        # Cleanup the app server's output buffer between tests.
+        while True:
+            # Read while we have something available at the stdout.
+            r, w, e = select.select([cls.appserver.stdout], [], [], 0)
+            if cls.appserver.stdout in r:
+                cls.appserver.stdout.readline()
+            else:
+                break
         DatabaseLayer.force_dirty_database()
 
     @classmethod
@@ -1820,7 +1830,9 @@ class LayerProcessController:
         environ['LPCONFIG'] = _config.instance_name
         cls.appserver = subprocess.Popen(
             cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT,
+            stdin=subprocess.PIPE,
             env=environ, cwd=_config.root)
+        cls.appserver.stdin.close()
 
     @classmethod
     def appserver_root_url(cls):
@@ -1836,6 +1848,12 @@ class LayerProcessController:
             try:
                 connection = urlopen(root_url)
                 connection.read()
+            except HTTPError as error:
+                if error.code == 503:
+                    raise RuntimeError(
+                        "App server is returning unknown error code %s. Is "
+                        "there another instance running in the same port?" %
+                        error.code)
             except URLError as error:
                 # We are interested in a wrapped socket.error.
                 if not isinstance(error.reason, socket.error):
diff --git a/setup.py b/setup.py
index b5696f3..49c56e0 100644
--- a/setup.py
+++ b/setup.py
@@ -233,6 +233,8 @@ setup(
         'Sphinx',
         'statsd',
         'storm',
+        'subvertpy',
+        'talisker[gunicorn]',
         'tenacity',
         'testscenarios',
         'testtools',
@@ -252,7 +254,6 @@ setup(
         'zope.app.http',
         'zope.app.publication',
         'zope.app.publisher',
-        'zope.app.server',
         'zope.app.wsgi[testlayer]',
         'zope.authentication',
         'zope.browser',
@@ -333,6 +334,7 @@ setup(
             'version-info = lp.scripts.utilities.versioninfo:main',
             'watch_jsbuild = lp.scripts.utilities.js.watchjsbuild:main',
             'with-xvfb = lp.scripts.utilities.withxvfb:main',
-        ]
+        ],
+        wsgi=["wsigogogo = lp.startwsgi.gogogo"]
     ),
 )
diff --git a/zcml/webapp.zcml b/zcml/webapp.zcml
index 948c4eb..a574200 100644
--- a/zcml/webapp.zcml
+++ b/zcml/webapp.zcml
@@ -14,6 +14,4 @@
     <includeOverrides file="+config-overrides.zcml" />
 
     <include file="summarizerequests.zcml" />
-    <include package="zc.zservertracelog" />
-
 </configure>