handle missing known_hosts

Author: Snawoot

rsp/__main__.py

@@ -110,9 +110,15 @@ def ssh_options_from_args(args, known_hosts):
 
 async def amain(args, loop):  # pragma: no cover
     logger = logging.getLogger('MAIN')
-    known_hosts = asyncssh.read_known_hosts(args.hosts_file)
-    host_keys, ca_keys, _, x509_certs, _, x509_subjects, _ = \
-        known_hosts.match(args.dst_address, "", args.dst_port)
+
+    try:
+        known_hosts = asyncssh.read_known_hosts(args.hosts_file)
+    except Exception as exc:
+        logger.error("Host keys loading failed with error: %s", str(exc))
+        host_keys, ca_keys, x509_certs, x509_subjects = [], [], [], []
+    else:
+        host_keys, ca_keys, _, x509_certs, _, x509_subjects, _ = \
+            known_hosts.match(args.dst_address, "", args.dst_port)
     if not ( host_keys or ca_keys or x509_certs or x509_subjects ):
         logger.critical("Specified host is not found in known hosts. "
                         "Please run following command: "