frappy-cli: connect to servers on localhost by default

--scan option: specify where to scan if not on localhost

Change-Id: I51a694eb3cb045e7d18c19a332db8e6ba063009b

bin/frappy-cli

@@ -24,12 +24,14 @@
 
 import sys
 import argparse
+import socket
 from pathlib import Path
 
 # Add import path for inplace usage
 sys.path.insert(0, str(Path(__file__).absolute().parents[1]))
 
 from frappy.client.interactive import init, run, clientenv, interact
+from frappy.protocol.discovery import scan
 
 
 def parseArgv(argv):
@@ -37,6 +39,9 @@ def parseArgv(argv):
     parser.add_argument('-i', '--include',
                         help='file to execute after connecting to the clients', metavar='file',
                         type=Path, action='append', default=[])
+    parser.add_argument('-s', '--scan',
+                        help='hosts to scan for (-s subnet for all nodes in subnet)',
+                        action='append', default=[])
     parser.add_argument('-o', '--only-execute',
                         help='Do not go into interactive mode after executing files. \
                         Has no effect without --include.', action='store_true')
@@ -46,9 +51,38 @@ def parseArgv(argv):
     return parser.parse_args(argv)
 
 
+def own_ip():
+    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+    s.settimeout(0)
+    try:
+        # doesn't even have to be reachable
+        s.connect(('10.254.254.254', 1))
+        return s.getsockname()[0]
+    except Exception:
+        return '127.0.0.1'
+    finally:
+        s.close()
+
+
 args = parseArgv(sys.argv[1:])
 
-success = init(*args.node)
+nodes = args.node
+hosts = args.scan
+if not nodes and not hosts:
+    host = ['localhost']
+if hosts:
+    answers = []
+    for host in hosts:
+        ans = scan()
+        if host == 'subnet':  # all in subnet
+            answers.extend(ans)
+        else:  # filter by ip
+            ip = socket.gethostbyname(host)
+            if ip == '127.0.0.1':
+                ip = own_ip()
+            answers.extend(a for a in ans if a.address == ip)
+    nodes.extend(f'{h.hostname}:{h.port}' for h in answers)
+success = init(*nodes)
 
 run_error = ''
 file_success = False