Make URL patterns to exclude from tracking configurable

* Add unit test coverage for this "exclusion from tracking" logic
* Exclude based on regex match instead of raw string comparison
* Exclude heartbeat requests from tracking

cms/envs/aws.py

@@ -127,6 +127,10 @@ LOGGING = get_logger_config(LOG_DIR,
 #theming start:
 PLATFORM_NAME = ENV_TOKENS.get('PLATFORM_NAME', 'edX')
 
+# Event Tracking
+if "TRACKING_IGNORE_URL_PATTERNS" in ENV_TOKENS:
+    TRACKING_IGNORE_URL_PATTERNS = ENV_TOKENS.get("TRACKING_IGNORE_URL_PATTERNS")
+
 
 ################ SECURE AUTH ITEMS ###############################
 # Secret things: passwords, access keys, etc.

cms/envs/common.py

@@ -404,3 +404,7 @@ TRACKING_BACKENDS = {
         }
     }
 }
+
+# We're already logging events, and we don't want to capture user
+# names/passwords.  Heartbeat events are likely not interesting.
+TRACKING_IGNORE_URL_PATTERNS = [r'^/event', r'^/login', r'^/heartbeat']