don't use logging.basicConfig (#47)

* replace basicConfig with setLevel and addHandler

* avoid duplicate handlers

Author: kandersolar

cdsapi/api.py

@@ -271,9 +271,14 @@ def __init__(
             else:
                 level = logging.INFO
 
-            logging.basicConfig(
-                level=level, format="%(asctime)s %(levelname)s %(message)s"
-            )
+            self.logger.setLevel(level)
+
+            # avoid duplicate handlers when creating more than one Client
+            if not self.logger.handlers:
+                formatter = logging.Formatter("%(asctime)s %(levelname)s %(message)s")
+                handler = logging.StreamHandler()
+                handler.setFormatter(formatter)
+                self.logger.addHandler(handler)
 
         dotrc = os.environ.get("CDSAPI_RC", os.path.expanduser("~/.cdsapirc"))