Add config validation for default_data

It is a little difficult to set up default_data.json for users, and
we already have the corresponding schema in the code. JSON-Schema
outputs useful error message when users misconfigures some items.
So this patch makes the schema validation enabled for default_data.

Change-Id: Id0efae913c202a30476d73a3821711c5250fcfee

stackalytics/processor/main.py

@@ -15,6 +15,7 @@
 
 import itertools
 
+import jsonschema
 from oslo_config import cfg
 from oslo_log import log as logging
 import psutil
@@ -32,6 +33,7 @@ from stackalytics.processor import mps
 from stackalytics.processor import rcs
 from stackalytics.processor import record_processor
 from stackalytics.processor import runtime_storage
+from stackalytics.processor import schema
 from stackalytics.processor import utils
 from stackalytics.processor import vcs
 from stackalytics.processor import zanata
@@ -316,6 +318,12 @@ def main():
         LOG.critical('Unable to load default data')
         return not 0
 
+    try:
+        jsonschema.validate(default_data, schema.default_data)
+    except jsonschema.ValidationError as e:
+        LOG.critical('The default data is invalid: %s' % e)
+        return not 0
+
     default_data_processor.process(runtime_storage_inst,
                                    default_data,
                                    CONF.driverlog_data_uri)