Adding customizable timeout support to the KMIP client

This change adds support for a customizable timeout option for the KMIP
client. The client will stop attempting connections or operations once
the timeout is exceeded instead of waiting for the default system
timeout. The default timeouts is 30 seconds.

kmip/core/config_helper.py

@@ -36,6 +36,9 @@ class ConfigHelper(object):
     DEFAULT_USERNAME = None
     DEFAULT_PASSWORD = None
 
+    # Timeout measured in seconds
+    DEFAULT_TIMEOUT = 30
+
     def __init__(self):
         self.logger = logging.getLogger(__name__)
 
@@ -78,6 +81,7 @@ class ConfigHelper(object):
                 return_value = default_value
                 self.logger.debug(DEFAULT_MSG.format(default_value,
                                                      config_option_name))
+        # TODO (peter-hamilton): Think about adding better value validation
         if return_value == self.NONE_VALUE:
             return None
         else:

kmip/kmipconfig.ini

@@ -10,6 +10,7 @@ do_handshake_on_connect=True
 suppress_ragged_eofs=True
 username=None
 password=None
+timeout=30
 
 [server]
 host=127.0.0.1

kmip/services/kmip_client.py

@@ -78,7 +78,7 @@ class KMIPProxy(KMIP):
                  cert_reqs=None, ssl_version=None, ca_certs=None,
                  do_handshake_on_connect=None,
                  suppress_ragged_eofs=None,
-                 username=None, password=None, config='client'):
+                 username=None, password=None, timeout=30, config='client'):
         super(KMIPProxy, self).__init__()
         self.logger = logging.getLogger(__name__)
         self.credential_factory = CredentialFactory()
@@ -87,7 +87,7 @@ class KMIPProxy(KMIP):
         self._set_variables(host, port, keyfile, certfile,
                             cert_reqs, ssl_version, ca_certs,
                             do_handshake_on_connect, suppress_ragged_eofs,
-                            username, password)
+                            username, password, timeout)
         self.batch_items = []
 
         self.conformance_clauses = [
@@ -217,7 +217,13 @@ class KMIPProxy(KMIP):
             suppress_ragged_eofs=self.suppress_ragged_eofs)
         self.protocol = KMIPProtocol(self.socket)
 
-        self.socket.connect((self.host, self.port))
+        self.socket.settimeout(self.timeout)
+
+        try:
+            self.socket.connect((self.host, self.port))
+        except socket.timeout as e:
+            self.logger.error("timeout occurred while connecting to appliance")
+            raise e
 
     def close(self):
         self.socket.shutdown(socket.SHUT_RDWR)
@@ -816,7 +822,7 @@ class KMIPProxy(KMIP):
     def _set_variables(self, host, port, keyfile, certfile,
                        cert_reqs, ssl_version, ca_certs,
                        do_handshake_on_connect, suppress_ragged_eofs,
-                       username, password):
+                       username, password, timeout):
         conf = ConfigHelper()
 
         self.host = conf.get_valid_value(
@@ -859,3 +865,12 @@ class KMIPProxy(KMIP):
 
         self.password = conf.get_valid_value(
             password, self.config, 'password', conf.DEFAULT_PASSWORD)
+
+        self.timeout = conf.get_valid_value(
+            timeout, self.config, 'timeout', conf.DEFAULT_TIMEOUT)
+        if self.timeout < 0:
+            self.logger.warning(
+                "Negative timeout value specified, "
+                "resetting to safe default of {0} seconds".format(
+                    conf.DEFAULT_TIMEOUT))
+            self.timeout = conf.DEFAULT_TIMEOUT