0001-gerrit-add-support-for-report-only-connection.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Tristan Cacqueray <tdecacqu@redhat.com>
Date: Mon, 14 May 2018 07:31:50 +0000
Subject: [PATCH] gerrit: add support for report only connection

A Zuul scheduler used by multiple third party CIs for a single gerrit may
share a single events stream and uses report only connections per account.
This change adds a report_only gerrit connection option to disable the
GerritWatcher thread.

A third party CI reporting using 2 gerrit accounts may reduce the merger
load by 2 when using this option.

Change-Id: I7d9d532f1200c29b30e2f75b4add760dd6d7e8d4
---
 doc/source/admin/drivers/gerrit.rst    |  6 ++++++
 zuul/driver/gerrit/gerritconnection.py | 10 +++++++---
 zuul/driver/gerrit/gerrittrigger.py    |  7 +++++++
 3 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/doc/source/admin/drivers/gerrit.rst b/doc/source/admin/drivers/gerrit.rst
index 5433df3..30571af 100644
--- a/doc/source/admin/drivers/gerrit.rst
+++ b/doc/source/admin/drivers/gerrit.rst
@@ -123,6 +123,12 @@ The supported options in ``zuul.conf`` connections are:
       When using a self-signed certificate, this may be set to
       ``false`` to disable SSL certificate verification.
 
+   .. attr:: report_only
+      :default: False
+
+      Disable the gerrit events stream watcher.
+
+
 Trigger Configuration
 ---------------------
 
diff --git a/zuul/driver/gerrit/gerritconnection.py b/zuul/driver/gerrit/gerritconnection.py
index 1c41730..835844e 100644
--- a/zuul/driver/gerrit/gerritconnection.py
+++ b/zuul/driver/gerrit/gerritconnection.py
@@ -324,6 +324,9 @@ class GerritConnection(BaseConnection):
         self.port = int(self.connection_config.get('port', 29418))
         self.keyfile = self.connection_config.get('sshkey', None)
         self.keepalive = int(self.connection_config.get('keepalive', 60))
+        self.report_only = self.connection_config.get('report_only', False)
+        if self.report_only not in ("True", "true"):
+            self.report_only = False
         self.watcher_thread = None
         self.event_queue = queue.Queue()
         self.client = None
@@ -1076,9 +1079,10 @@ class GerritConnection(BaseConnection):
             sha=sha)
 
     def onLoad(self):
-        self.log.debug("Starting Gerrit Connection/Watchers")
-        self._start_watcher_thread()
-        self._start_event_connector()
+        if not self.report_only:
+            self.log.debug("Starting Gerrit Connection/Watchers")
+            self._start_watcher_thread()
+            self._start_event_connector()
 
     def onStop(self):
         self.log.debug("Stopping Gerrit Connection/Watchers")
diff --git a/zuul/driver/gerrit/gerrittrigger.py b/zuul/driver/gerrit/gerrittrigger.py
index 67608ad..83a2ee8 100644
--- a/zuul/driver/gerrit/gerrittrigger.py
+++ b/zuul/driver/gerrit/gerrittrigger.py
@@ -17,12 +17,19 @@ import voluptuous as v
 from zuul.trigger import BaseTrigger
 from zuul.driver.gerrit.gerritmodel import GerritEventFilter
 from zuul.driver.util import scalar_or_list, to_list
+from zuul.configloader import ConfigurationSyntaxError
 
 
 class GerritTrigger(BaseTrigger):
     name = 'gerrit'
     log = logging.getLogger("zuul.GerritTrigger")
 
+    def __init__(self, driver, connection, config):
+        if connection.report_only:
+            raise ConfigurationSyntaxError(
+                "Connection doesn't support trigger")
+        super().__init__(driver, connection, config)
+
     def getEventFilters(self, trigger_conf):
         efilters = []
         for trigger in to_list(trigger_conf):
-- 
1.8.3.1