Improved exception handling in /swarm/test_db.py (#3738)

* fix asterisk password bug in test_db.py

* raise and handle pymysql error

* clean up exception handling in db test

examples/swarm/test_db.py

@@ -65,10 +65,15 @@ def testDbConnection(host, port, user, passwd):
     cursor.execute("INSERT INTO db_test VALUES ('testing123', 123)")
     cursor.execute("DROP TABLE IF EXISTS db_test")
     cursor.execute("DROP DATABASE IF EXISTS nupic_db_test")
-    return True
 
   except pymysql.err.OperationalError:
-    return False
+    print ("Couldn't connect to the database or you don't have the "
+           "permissions required to create databases and tables. "
+           "Please ensure you have MySQL\n installed, running, "
+           "accessible using the NuPIC configuration settings, "
+           "and the user specified has permission to create both "
+           "databases and tables.")
+    raise
 
 
 def dbValidator():
@@ -83,7 +88,7 @@ def dbValidator():
   host = Configuration.get("nupic.cluster.database.host")
   port = int(Configuration.get("nupic.cluster.database.port"))
   user = Configuration.get("nupic.cluster.database.user")
-  passwd = "*" * len(Configuration.get("nupic.cluster.database.passwd"))
+  passwd = Configuration.get("nupic.cluster.database.passwd")
 
 
   print "This script will validate that your MySQL is setup correctly for "
@@ -103,18 +108,11 @@ def dbValidator():
   print "    host   :    ", host
   print "    port   :    ", port
   print "    user   :    ", user
-  print "    passwd :    ", passwd
+  print "    passwd :    ", "*" * len(passwd)
 
 
-  if testDbConnection(host, port, user, passwd):
-    print "Connection successful!!"
-  else:
-    print ("Couldn't connect to the database or you don't have the "
-           "permissions required to create databases and tables. "
-           "Please ensure you have MySQL\n installed, running, "
-           "accessible using the NuPIC configuration settings, "
-           "and the user specified has permission to create both "
-           "databases and tables.")
+  testDbConnection(host, port, user, passwd)
+  print "Connection successful!!"
 
 if __name__ == "__main__":
   dbValidator()