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authorPeter Mikus <pmikus@cisco.com>2018-05-09 13:40:12 +0200
committerPeter Mikus <pmikus@cisco.com>2018-05-11 12:38:08 +0000
commitefae5118e100d85938c8a69b974d3f45184f93c5 (patch)
treec191d73edfcf07ec54d75d137df3270cc7d7f84b /resources/libraries/python
parenta3d14e7cf128c5188a4e064042a64333ae64d191 (diff)
CSIT-1076 Improve SSH connection handling
Properly detect dropped connection via predicate is_active() to prevent using dropped connection. Change-Id: I9105622f28d2f7949675b8cee1dd4384a12f72a9 Signed-off-by: Peter Mikus <pmikus@cisco.com>
Diffstat (limited to 'resources/libraries/python')
-rw-r--r--resources/libraries/python/ssh.py61
1 files changed, 36 insertions, 25 deletions
diff --git a/resources/libraries/python/ssh.py b/resources/libraries/python/ssh.py
index 5ff1b2d769..b570003aa8 100644
--- a/resources/libraries/python/ssh.py
+++ b/resources/libraries/python/ssh.py
@@ -60,14 +60,27 @@ class SSH(object):
"""Connect to node prior to running exec_command or scp.
If there already is a connection to the node, this method reuses it.
+
+ :param node: Node in topology.
+ :param attempts: Number of reconnect attempts.
+ :type node: dict
+ :type attempts: int
+ :raises IOError: If cannot connect to host.
"""
- try:
- self._node = node
- node_hash = self._node_hash(node)
- if node_hash in SSH.__existing_connections:
- self._ssh = SSH.__existing_connections[node_hash]
- logger.debug('reusing ssh: {0}'.format(self._ssh))
+ self._node = node
+ node_hash = self._node_hash(node)
+ if node_hash in SSH.__existing_connections:
+ self._ssh = SSH.__existing_connections[node_hash]
+ if self._ssh.get_transport().is_active():
+ logger.debug('Reusing SSH: {ssh}'.format(ssh=self._ssh))
else:
+ if attempts > 0:
+ self._reconnect(attempts-1)
+ else:
+ raise IOError('Cannot connect to {host}'.
+ format(host=node['host']))
+ else:
+ try:
start = time()
pkey = None
if 'priv_key' in node:
@@ -84,19 +97,14 @@ class SSH(object):
self._ssh.get_transport().set_keepalive(10)
SSH.__existing_connections[node_hash] = self._ssh
-
- logger.trace('connect took {} seconds'.format(time() - start))
- logger.debug('new ssh: {0}'.format(self._ssh))
-
- logger.debug('Connect peer: {0}'.
- format(self._ssh.get_transport().getpeername()))
- logger.debug('Connections: {0}'.
- format(str(SSH.__existing_connections)))
- except:
- if attempts > 0:
- self._reconnect(attempts-1)
- else:
- raise
+ logger.debug('New SSH to {peer} took {total} seconds: {ssh}'.
+ format(
+ peer=self._ssh.get_transport().getpeername(),
+ total=(time() - start),
+ ssh=self._ssh))
+ except SSHException:
+ raise IOError('Cannot connect to {host}'.
+ format(host=node['host']))
def disconnect(self, node):
"""Close SSH connection to the node.
@@ -106,19 +114,22 @@ class SSH(object):
"""
node_hash = self._node_hash(node)
if node_hash in SSH.__existing_connections:
- logger.debug('Disconnecting peer: {}, {}'.
- format(node['host'], node['port']))
+ logger.debug('Disconnecting peer: {host}, {port}'.
+ format(host=node['host'], port=node['port']))
ssh = SSH.__existing_connections.pop(node_hash)
ssh.close()
def _reconnect(self, attempts=0):
- """Close the SSH connection and open it again."""
+ """Close the SSH connection and open it again.
+ :param attempts: Number of reconnect attempts.
+ :type attempts: int
+ """
node = self._node
self.disconnect(node)
self.connect(node, attempts)
- logger.debug('Reconnecting peer done: {}'.
- format(self._ssh.get_transport().getpeername()))
+ logger.debug('Reconnecting peer done: {host}, {port}'.
+ format(host=node['host'], port=node['port']))
def exec_command(self, cmd, timeout=10):
"""Execute SSH command on a new channel on the connected Node.
@@ -392,4 +403,4 @@ def exec_cmd_no_error(node, cmd, timeout=600, sudo=False):
(ret_code, stdout, stderr) = exec_cmd(node, cmd, timeout=timeout, sudo=sudo)
assert_equal(ret_code, 0, 'Command execution failed: "{}"\n{}'.
format(cmd, stderr))
- return stdout, stderr \ No newline at end of file
+ return stdout, stderr