Import of core OSM charm layers

[osm/SO.git] / charms / layers / sshproxy / lib / charms / sshproxy.py

diff --git a/charms/layers/sshproxy/lib/charms/sshproxy.py b/charms/layers/sshproxy/lib/charms/sshproxy.py
new file mode 100644 (file)
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+++ b/charms/layers/sshproxy/lib/charms/sshproxy.py
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+##
+# Copyright 2016 Canonical Ltd.
+# All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+##
+
+from charmhelpers.core.hookenv import (
+    config,
+)
+import io
+import paramiko
+
+from subprocess import (
+    Popen,
+    CalledProcessError,
+    PIPE,
+)
+
+
+def _run(cmd, env=None):
+    """ Run a command, either on the local machine or remotely via SSH. """
+    if isinstance(cmd, str):
+        cmd = cmd.split(' ') if ' ' in cmd else [cmd]
+
+    cfg = config()
+    if all(k in cfg for k in ['ssh-hostname', 'ssh-username',
+                              'ssh-password', 'ssh-private-key']):
+        host = cfg['ssh-hostname']
+        user = cfg['ssh-username']
+        passwd = cfg['ssh-password']
+        key = cfg['ssh-private-key']
+
+        if host and user and (passwd or key):
+            return ssh(cmd, host, user, passwd, key)
+
+    p = Popen(cmd,
+              env=env,
+              shell=True,
+              stdout=PIPE,
+              stderr=PIPE)
+    stdout, stderr = p.communicate()
+    retcode = p.poll()
+    if retcode > 0:
+        raise CalledProcessError(returncode=retcode,
+                                 cmd=cmd,
+                                 output=stderr.decode("utf-8").strip())
+    return (stdout.decode('utf-8').strip(), stderr.decode('utf-8').strip())
+
+
+def get_ssh_client(host, user, password=None, key=None):
+    """Return a connected Paramiko ssh object"""
+
+    client = paramiko.SSHClient()
+    client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
+
+    pkey = None
+    if key:
+        f = io.StringIO(key)
+        pkey = paramiko.RSAKey.from_private_key(f)
+
+    ###########################################################################
+    # There is a bug in some versions of OpenSSH 4.3 (CentOS/RHEL 5) where    #
+    # the server may not send the SSH_MSG_USERAUTH_BANNER message except when #
+    # responding to an auth_none request. For example, paramiko will attempt  #
+    # to use password authentication when a password is set, but the server   #
+    # could deny that, instead requesting keyboard-interactive. The hack to   #
+    # workaround this is to attempt a reconnect, which will receive the right #
+    # banner, and authentication can proceed. See the following for more info #
+    # https://github.com/paramiko/paramiko/issues/432                         #
+    # https://github.com/paramiko/paramiko/pull/438                           #
+    ###########################################################################
+
+    try:
+        client.connect(host, port=22, username=user,
+                       password=password, pkey=pkey)
+    except paramiko.ssh_exception.SSHException as e:
+        if 'Error reading SSH protocol banner' == str(e):
+            # Once more, with feeling
+            client.connect(host, port=22, username=user,
+                           password=password, pkey=pkey)
+            pass
+        else:
+            raise paramiko.ssh_exception.SSHException(e)
+
+    return client
+
+
+def sftp(local_file, remote_file, host, user, password=None, key=None):
+    """Copy a local file to a remote host"""
+    client = get_ssh_client(host, user, password, key)
+
+    # Create an sftp connection from the underlying transport
+    sftp = paramiko.SFTPClient.from_transport(client.get_transport())
+    sftp.put(local_file, remote_file)
+    client.close()
+
+
+def ssh(cmd, host, user, password=None, key=None):
+    """ Run an arbitrary command over SSH. """
+    client = get_ssh_client(host, user, password, key)
+
+    cmds = ' '.join(cmd)
+    stdin, stdout, stderr = client.exec_command(cmds, get_pty=True)
+    retcode = stdout.channel.recv_exit_status()
+    client.close()  # @TODO re-use connections
+    if retcode > 0:
+        output = stderr.read().strip()
+        raise CalledProcessError(returncode=retcode, cmd=cmd,
+                                 output=output)
+    return (
+        stdout.read().decode('utf-8').strip(),
+        stderr.read().decode('utf-8').strip()
+    )