Add gitlab disable_connection_pool option

Under adverse network conditions, it may be necessary to disable
connection pooling entirely in order to achive reliable interaction
with the remote server.  Add an option for that.

Change-Id: I336fab1197a8fb6e038db24277b6279013224bb0

1 files changed, 27 insertions, 8 deletions

diff --git a/zuul/driver/gitlab/gitlabconnection.py b/zuul/driver/gitlab/gitlabconnection.py
index 7589474c8..d40981562 100644
--- a/zuul/driver/gitlab/gitlabconnection.py
+++ b/zuul/driver/gitlab/gitlabconnection.py
@@ -32,6 +32,7 @@ from zuul.connection import CachedBranchConnection, ZKChangeCacheMixin
 from zuul.web.handler import BaseWebController
 from zuul.lib.http import ZuulHTTPAdapter
 from zuul.lib.logutil import get_annotated_logger
+from zuul.lib.config import any_to_bool
 from zuul.exceptions import MergeFailure
 from zuul.model import Branch, Project, Ref, Tag
 from zuul.driver.gitlab.gitlabmodel import GitlabTriggerEvent, MergeRequest
@@ -255,18 +256,34 @@ class GitlabAPIClientException(Exception):
 class GitlabAPIClient():
     log = logging.getLogger("zuul.GitlabAPIClient")
 
-    def __init__(self, baseurl, api_token, keepalive):
-        self.session = requests.Session()
-        retry = urllib3.util.Retry(total=8,
-                                   backoff_factor=0.1)
-        adapter = ZuulHTTPAdapter(keepalive=keepalive,
-                                  max_retries=retry)
-        self.session.mount(baseurl, adapter)
+    def __init__(self, baseurl, api_token, keepalive, disable_pool):
+        self._session = None
+        self._orig_baseurl = baseurl
         self.baseurl = '%s/api/v4' % baseurl
         self.api_token = api_token
+        self.keepalive = keepalive
+        self.disable_pool = disable_pool
         self.headers = {'Authorization': 'Bearer %s' % (
             self.api_token)}
 
+        if not self.disable_pool:
+            self._session = self._makeSession()
+
+    def _makeSession(self):
+        session = requests.Session()
+        retry = urllib3.util.Retry(total=8,
+                                   backoff_factor=0.1)
+        adapter = ZuulHTTPAdapter(keepalive=self.keepalive,
+                                  max_retries=retry)
+        session.mount(self._orig_baseurl, adapter)
+        return session
+
+    @property
+    def session(self):
+        if self.disable_pool:
+            return self._makeSession()
+        return self._session
+
     def _manage_error(self, data, code, url, verb, zuul_event_id=None):
         if code < 400:
             return
@@ -442,9 +459,11 @@ class GitlabConnection(ZKChangeCacheMixin, CachedBranchConnection):
         self.api_token = self.connection_config.get(
             'api_token', '')
         self.keepalive = self.connection_config.get('keepalive', 60)
+        self.disable_pool = any_to_bool(self.connection_config.get(
+            'disable_connection_pool', False))
 
         self.gl_client = GitlabAPIClient(self.baseurl, self.api_token,
-                                         self.keepalive)
+                                         self.keepalive, self.disable_pool)
         self.sched = None
         self.source = driver.getSource(self)