Introduced log file option

Created by: stefanoborini

Allows to write a log file instead of relying to stdout/err.

force_bdss/cli/force_bdss.py

+import logging
 import click
 
 from ..bdss_application import BDSSApplication
@@ -10,12 +11,26 @@ push_exception_handler(reraise_exceptions=True)
 
 @click.command()
 @click.option("--evaluate", is_flag=True)
+@click.option("--logfile",
+              type=click.Path(exists=False),
+              help="If specified, the log filename. "
+                   " If unspecified, the log will be written to stdout.")
 @click.argument('workflow_filepath', type=click.Path(exists=True))
-def run(evaluate, workflow_filepath):
+def run(evaluate, logfile, workflow_filepath):
 
-    application = BDSSApplication(
-        evaluate=evaluate,
-        workflow_filepath=workflow_filepath
-    )
+    logging_config = {}
+    if logfile is not None:
+        logging_config["filename"] = logfile
 
-    application.run()
+    logging.basicConfig(**logging_config)
+    log = logging.getLogger(__name__)
+
+    try:
+        application = BDSSApplication(
+            evaluate=evaluate,
+            workflow_filepath=workflow_filepath
+        )
+
+        application.run()
+    except Exception as e:
+        log.exception(e)