From 7f3a55af74de17ab526a0d8baa8fe421c312daeb Mon Sep 17 00:00:00 2001
From: David Ormsbee <dave@edx.org>
Date: Wed, 13 Dec 2017 10:46:35 -0500
Subject: [PATCH] Remove dealer.git (startup optimization).

In the absence of an EDX_PLATFORM_VERSION OS env variable, we used to
calculate the current version by looking at the current git revision of
the edx-platform repo. This was an expensive calculation (~7% of startup
costs). It also turns out that at some point we stopped setting that env
variable anywhere, so it always fell back to recalculating it.

With this commit, we'll start reading the code version from the env JSON
files, and fall back to "unknown" rather than doing the dealer.git call.
---
 cms/envs/aws.py           |  3 +++
 cms/envs/common.py        | 13 ++-----------
 lms/envs/aws.py           |  3 +++
 lms/envs/common.py        | 11 ++---------
 requirements/edx/base.txt |  1 -
 5 files changed, 10 insertions(+), 21 deletions(-)

diff --git a/cms/envs/aws.py b/cms/envs/aws.py
index f7dc2fec54..0aa0e59951 100644
--- a/cms/envs/aws.py
+++ b/cms/envs/aws.py
@@ -95,6 +95,9 @@ CELERY_ROUTES = "{}celery.Router".format(QUEUE_VARIANT)
 with open(CONFIG_ROOT / CONFIG_PREFIX + "env.json") as env_file:
     ENV_TOKENS = json.load(env_file)
 
+# Do NOT calculate this dynamically at startup with git because it's *slow*.
+EDX_PLATFORM_REVISION = ENV_TOKENS.get('EDX_PLATFORM_REVISION', EDX_PLATFORM_REVISION)
+
 # STATIC_URL_BASE specifies the base url to use for static files
 STATIC_URL_BASE = ENV_TOKENS.get('STATIC_URL_BASE', None)
 if STATIC_URL_BASE:
diff --git a/cms/envs/common.py b/cms/envs/common.py
index 0f5160985a..cd035a3104 100644
--- a/cms/envs/common.py
+++ b/cms/envs/common.py
@@ -130,7 +130,6 @@ from warnings import simplefilter
 
 from lms.djangoapps.lms_xblock.mixin import LmsBlockMixin
 from cms.lib.xblock.authoring_mixin import AuthoringMixin
-import dealer.git
 from xmodule.modulestore.edit_info import EditInfoMixin
 from openedx.core.djangoapps.theming.helpers_dirs import (
     get_themes_unchecked,
@@ -333,7 +332,6 @@ CONTEXT_PROCESSORS = (
     'django.template.context_processors.i18n',
     'django.contrib.auth.context_processors.auth',  # this is required for admin
     'django.template.context_processors.csrf',
-    'dealer.contrib.django.staff.context_processor',  # access git revision
     'help_tokens.context_processor',
 )
 
@@ -611,15 +609,8 @@ SERVER_EMAIL = 'devops@example.com'
 ADMINS = []
 MANAGERS = ADMINS
 
-EDX_PLATFORM_REVISION = os.environ.get('EDX_PLATFORM_REVISION')
-
-if not EDX_PLATFORM_REVISION:
-    try:
-        # Get git revision of the current file
-        EDX_PLATFORM_REVISION = dealer.git.Backend(path=REPO_ROOT).revision
-    except TypeError:
-        # Not a git repository
-        EDX_PLATFORM_REVISION = 'unknown'
+# Initialize to 'unknown', but read from JSON in aws.py
+EDX_PLATFORM_REVISION = 'unknown'
 
 # Static content
 STATIC_URL = '/static/studio/'
diff --git a/lms/envs/aws.py b/lms/envs/aws.py
index 94d54fb0df..fb3dbf666d 100644
--- a/lms/envs/aws.py
+++ b/lms/envs/aws.py
@@ -1080,6 +1080,9 @@ ACE_CHANNEL_SAILTHRU_API_KEY = AUTH_TOKENS.get('ACE_CHANNEL_SAILTHRU_API_KEY', A
 ACE_CHANNEL_SAILTHRU_API_SECRET = AUTH_TOKENS.get('ACE_CHANNEL_SAILTHRU_API_SECRET', ACE_CHANNEL_SAILTHRU_API_SECRET)
 ACE_ROUTING_KEY = ENV_TOKENS.get('ACE_ROUTING_KEY', ACE_ROUTING_KEY)
 
+# Do NOT calculate this dynamically at startup with git because it's *slow*.
+EDX_PLATFORM_REVISION = ENV_TOKENS.get('EDX_PLATFORM_REVISION', EDX_PLATFORM_REVISION)
+
 ########################## Extra middleware classes  #######################
 
 # Allow extra middleware classes to be added to the app through configuration.
diff --git a/lms/envs/common.py b/lms/envs/common.py
index 5c5906e238..66e26dcb28 100644
--- a/lms/envs/common.py
+++ b/lms/envs/common.py
@@ -33,7 +33,6 @@ import imp
 import sys
 import os
 
-import dealer.git
 import django
 from path import Path as path
 from warnings import simplefilter
@@ -3452,11 +3451,5 @@ ACE_CHANNEL_SAILTHRU_API_SECRET = None
 
 ACE_ROUTING_KEY = LOW_PRIORITY_QUEUE
 
-EDX_PLATFORM_REVISION = os.environ.get('EDX_PLATFORM_REVISION')
-if not EDX_PLATFORM_REVISION:
-    try:
-        # Get git revision of the current file
-        EDX_PLATFORM_REVISION = dealer.git.Backend(path=REPO_ROOT).revision
-    except TypeError:
-        # Not a git repository
-        EDX_PLATFORM_REVISION = 'unknown'
+# Initialize to 'unknown', but read from JSON in aws.py
+EDX_PLATFORM_REVISION = 'unknown'
diff --git a/requirements/edx/base.txt b/requirements/edx/base.txt
index 2cd5321f57..8295436600 100644
--- a/requirements/edx/base.txt
+++ b/requirements/edx/base.txt
@@ -13,7 +13,6 @@ boto==2.39.0
 celery==3.1.18
 cryptography==1.9
 cssselect==0.9.1
-dealer==2.0.4
 defusedxml==0.4.1
 django-babel-underscore==0.5.2
 markey==0.8  # From django-babel-underscore