Release 0.41.0: add is-local-tcp-port-opened script

setup.py

@@ -2,7 +2,7 @@ from setuptools import setup, find_packages
 import glob
 import os
 
-version = '0.40.4'
+version = '0.41.0'
 name = 'slapos.toolbox'
 long_description = open("README.txt").read() + "\n" + \
     open("CHANGES.txt").read() + "\n"
@@ -53,6 +53,7 @@ setup(name=name,
       entry_points={
         'console_scripts': [
           'agent = slapos.agent.agent:main [agent]',
+          'is-local-tcp-port-opened = slapos.promise.islocaltcpportopened:main',
           'clouddestroy = slapos.cloudmgr.destroy:main',
           'cloudgetprivatekey = slapos.cloudmgr.getprivatekey:main',
           'cloudgetpubliciplist = slapos.cloudmgr.getpubliciplist:main',

slapos/promise/islocaltcpportopened/__init__.py

+#!/usr/bin/env python
+
+"""
+Check if a specific ip address and port is listening.
+
+No connection establishment is done during the check.
+
+Uses:
+- /proc/net/tcp
+- /proc/net/tcp6
+"""
+
+import sys
+import socket
+import struct
+assert struct.calcsize('I') == 4
+
+def is_local_tcp_port_opened(ip_address, port):
+  family = socket.getaddrinfo(ip_address, 0)[0][0]
+  conf = {
+    socket.AF_INET6: (4, "/proc/net/tcp6"),
+    socket.AF_INET: (1, "/proc/net/tcp"),
+  }
+
+  int_count = conf[family][0]
+  tcp_path = conf[family][1]
+
+  ip_addr_hex = ('%08X' * int_count) % struct.unpack('I' * int_count, socket.inet_pton(family, ip_address))
+  full_addr_hex = ip_addr_hex + ":%04X" % port
+
+  return any(full_addr_hex == line.split()[1] for line in open(tcp_path).readlines())
+
+def main():
+  if is_local_tcp_port_opened(sys.argv[1], int(sys.argv[2])):
+    return 0
+  return 1
+
+if __name__ == "__main__":
+  sys.exit(main())