Merge branch 'execute_prepare_fix' into 'master'

Prepare algorithm on execution

See merge request !21

beat/backend/python/scripts/execute.py

@@ -248,6 +248,20 @@ def main():
             s = process_traceback(tb, executor.prefix)
             raise UserError("%s%s: %s" % (s, type(e).__name__, e))
 
+        # Prepare the algorithm
+        try:
+            status = executor.prepare()
+            if not status:
+                raise UserError("Could not prepare algorithm (returned False)")
+        except (UserError, MemoryError):
+            raise
+        except Exception as e:
+            import traceback
+            exc_type, exc_value, exc_traceback = sys.exc_info()
+            tb = traceback.extract_tb(exc_traceback)
+            s = process_traceback(tb, executor.prefix)
+            raise UserError("%s%s: %s" % (s, type(e).__name__, e))
+
         # Execute the code
         try:
             status = executor.process()