Merge ~andreserl/maas:minor_performace_proxy_config into maas:master

[Andres Rodriguez]

Minor performance improvement when accessing proxy settings.

[Newell Jensen (newell-jensen)]

LGTM. No need to update the unit tests I take it?

review: Approve

[MAAS Lander (maas-lander)]

UNIT TESTS
-b minor_performace_proxy_config lp:~andreserl/maas/+git/maas into -b master lp:~maas-committers/maas

STATUS: SUCCESS
COMMIT: 048c74aa43758f64e226615fb48367687d1aff92

review: Approve

[Lee Trager (ltrager)]

LGTM!

Newell, the only test we could do for this is a query count. While I wouldn't be against these functions are simple enough I don't think a query count test should block this from landing.

review: Approve

[Newell Jensen (newell-jensen)]

> LGTM!
>
> Newell, the only test we could do for this is a query count. While I wouldn't
> be against these functions are simple enough I don't think a query count test
> should block this from landing.

Agreed, additionally the reason I approved is because even if there were associated unit tests, the code change itself was to improve the performance while the functionality of the code has stayed the same so I knew it was unlikely that a change to the unit tests would have been needed.

[MAAS Lander (maas-lander)]

LANDING
-b minor_performace_proxy_config lp:~andreserl/maas/+git/maas into -b master lp:~maas-committers/maas

STATUS: FAILED BUILD
LOG: http://maas-ci-jenkins.internal:8080/job/maas/job/branch-tester/3397/consoleText

diff --git a/src/maasserver/compose_preseed.py b/src/maasserver/compose_preseed.py
index ca7f16d..2bfdcf7 100644
--- a/src/maasserver/compose_preseed.py
+++ b/src/maasserver/compose_preseed.py
@@ -36,17 +36,19 @@ RSYSLOG_PORT = 514
 
 def get_apt_proxy(request, rack_controller=None):
     """Return the APT proxy for the `rack_controller`."""
-    if Config.objects.get_config("enable_http_proxy"):
-        http_proxy = Config.objects.get_config("http_proxy")
+    config = Config.objects.get_configs([
+        'enable_http_proxy', 'http_proxy', 'use_peer_proxy',
+        'maas_proxy_port'])
+    if config["enable_http_proxy"]:
+        http_proxy = config["http_proxy"]
         if http_proxy is not None:
             http_proxy = http_proxy.strip()
-        use_peer_proxy = Config.objects.get_config("use_peer_proxy")
+        use_peer_proxy = config["use_peer_proxy"]
         if http_proxy and not use_peer_proxy:
             return http_proxy
         else:
             region_ip = get_default_region_ip(request)
-            maas_proxy_port = Config.objects.get_config("maas_proxy_port")
-            url = "http://:%d/" % maas_proxy_port
+            url = "http://:%d/" % config["maas_proxy_port"]
             return compose_URL(
                 url, get_maas_facing_server_host(
                     rack_controller, default_region_ip=region_ip))
diff --git a/src/maasserver/proxyconfig.py b/src/maasserver/proxyconfig.py
index ae36244..95bc4d0 100644
--- a/src/maasserver/proxyconfig.py
+++ b/src/maasserver/proxyconfig.py
@@ -69,12 +69,12 @@ def proxy_update_config(reload_proxy=True):
     def write_config():
         allowed_subnets = Subnet.objects.filter(allow_proxy=True)
         cidrs = [subnet.cidr for subnet in allowed_subnets]
+        config = Config.objects.get_configs([
+            'http_proxy', 'maas_proxy_port', 'use_peer_proxy',
+            'prefer_v4_proxy', 'enable_http_proxy'])
 
-        http_proxy = Config.objects.get_config("http_proxy")
-        maas_proxy_port = Config.objects.get_config("maas_proxy_port")
-        upstream_proxy_enabled = (
-            Config.objects.get_config("use_peer_proxy") and http_proxy)
-        dns_v4_first = Config.objects.get_config("prefer_v4_proxy")
+        http_proxy = config["http_proxy"]
+        upstream_proxy_enabled = (config["use_peer_proxy"] and http_proxy)
         context = {
             'allowed': allowed_subnets,
             'modified': str(datetime.date.today()),
@@ -85,11 +85,11 @@ def proxy_update_config(reload_proxy=True):
             'snap_data_path': snappy.get_snap_data_path(),
             'snap_common_path': snappy.get_snap_common_path(),
             'upstream_peer_proxy': upstream_proxy_enabled,
-            'dns_v4_first': dns_v4_first,
-            'maas_proxy_port': maas_proxy_port,
+            'dns_v4_first': config['prefer_v4_proxy'],
+            'maas_proxy_port': config['maas_proxy_port'],
         }
 
-        proxy_enabled = Config.objects.get_config("enable_http_proxy")
+        proxy_enabled = config["enable_http_proxy"]
         if proxy_enabled and upstream_proxy_enabled:
             http_proxy_hostname = urlparse(http_proxy).hostname
             http_proxy_port = urlparse(http_proxy).port