turn off using blowfish for scp transfers - not available on a stock ubuntu-15.04...

[nepi.git] / src / nepi / util / sshfuncs.py

diff --git a/src/nepi/util/sshfuncs.py b/src/nepi/util/sshfuncs.py
index a88dc78..a01bded 100644 (file)
--- a/src/nepi/util/sshfuncs.py
+++ b/src/nepi/util/sshfuncs.py
@@ -3,9 +3,8 @@
 #    Copyright (C) 2013 INRIA
 #
 #    This program is free software: you can redistribute it and/or modify
 #    Copyright (C) 2013 INRIA
 #
 #    This program is free software: you can redistribute it and/or modify

-#    it under the terms of the GNU General Public License as published by
-#    the Free Software Foundation, either version 3 of the License, or
-#    (at your option) any later version.
+#    it under the terms of the GNU General Public License version 2 as
+#    published by the Free Software Foundation;

 #
 #    This program is distributed in the hope that it will be useful,
 #    but WITHOUT ANY WARRANTY; without even the implied warranty of
 #
 #    This program is distributed in the hope that it will be useful,
 #    but WITHOUT ANY WARRANTY; without even the implied warranty of


@@ -16,6 +15,9 @@
 #    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 # Author: Alina Quereilhac <alina.quereilhac@inria.fr>
 #    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 # Author: Alina Quereilhac <alina.quereilhac@inria.fr>

+#         Claudio Freire <claudio-daniel.freire@inria.fr>
+
+## TODO: This code needs reviewing !!!

 
 import base64
 import errno
 
 import base64
 import errno


@@ -32,6 +34,8 @@ import threading
 import time
 import tempfile
 
 import time
 import tempfile
 

+_re_inet = re.compile("\d+:\s+(?P<name>[a-z0-9_-]+)\s+inet6?\s+(?P<inet>[a-f0-9.:/]+)\s+(brd\s+[0-9.]+)?.*scope\s+global.*") 
+

 logger = logging.getLogger("sshfuncs")
 
 def log(msg, level, out = None, err = None):
 logger = logging.getLogger("sshfuncs")
 
 def log(msg, level, out = None, err = None):


@@ -43,7 +47,6 @@ def log(msg, level, out = None, err = None):
 
     logger.log(level, msg)
 
 
     logger.log(level, msg)
 

-

 if hasattr(os, "devnull"):
     DEV_NULL = os.devnull
 else:
 if hasattr(os, "devnull"):
     DEV_NULL = os.devnull
 else:


@@ -57,24 +60,36 @@ class STDOUT:
     redirect to whatever stdout was redirected to.
     """
 
     redirect to whatever stdout was redirected to.
     """
 

-class RUNNING:
-    """
-    Process is still running
-    """
-
-class FINISHED:
+class ProcStatus:

     """
     """

-    Process is finished
+    Codes for status of remote spawned process

     """
     """

+    # Process is still running
+    RUNNING = 1

 
 

-class NOT_STARTED:
-    """
-    Process hasn't started running yet (this should be very rare)
-    """
+    # Process is finished
+    FINISHED = 2
+    
+    # Process hasn't started running yet (this should be very rare)
+    NOT_STARTED = 3

 
 hostbyname_cache = dict()
 hostbyname_cache_lock = threading.Lock()
 
 
 hostbyname_cache = dict()
 hostbyname_cache_lock = threading.Lock()
 

+def resolve_hostname(host):
+    ip = None
+
+    if host in ["localhost", "127.0.0.1", "::1"]:
+        p = subprocess.Popen("ip -o addr list", shell=True,
+                stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        stdout, stderr = p.communicate()
+        m = _re_inet.findall(stdout)
+        ip = m[0][1].split("/")[0]
+    else:
+        ip = socket.gethostbyname(host)
+
+    return ip
+

 def gethostbyname(host):
     global hostbyname_cache
     global hostbyname_cache_lock
 def gethostbyname(host):
     global hostbyname_cache
     global hostbyname_cache_lock


@@ -82,7 +97,7 @@ def gethostbyname(host):
     hostbyname = hostbyname_cache.get(host)
     if not hostbyname:
         with hostbyname_cache_lock:
     hostbyname = hostbyname_cache.get(host)
     if not hostbyname:
         with hostbyname_cache_lock:

-            hostbyname = socket.gethostbyname(host)
+            hostbyname = resolve_hostname(host)

             hostbyname_cache[host] = hostbyname
 
             msg = " Added hostbyname %s - %s " % (host, hostbyname)
             hostbyname_cache[host] = hostbyname
 
             msg = " Added hostbyname %s - %s " % (host, hostbyname)


@@ -206,27 +221,29 @@ def eintr_retry(func):
     return rv
 
 def rexec(command, host, user, 
     return rv
 
 def rexec(command, host, user, 

-        port = None, 
+        port = None,
+        gwuser = None,
+        gw = None, 

         agent = True,
         sudo = False,
         agent = True,
         sudo = False,

-        stdin = None,

         identity = None,
         server_key = None,
         env = None,
         tty = False,
         identity = None,
         server_key = None,
         env = None,
         tty = False,

-        timeout = None,
-        retry = 3,
-        err_on_timeout = True,

         connect_timeout = 30,
         connect_timeout = 30,

+        retry = 3,

         persistent = True,
         forward_x11 = False,
         persistent = True,
         forward_x11 = False,

+        blocking = True,

         strict_host_checking = True):
     """
     Executes a remote command, returns ((stdout,stderr),process)
     """
         strict_host_checking = True):
     """
     Executes a remote command, returns ((stdout,stderr),process)
     """

-    
+

     tmp_known_hosts = None
     tmp_known_hosts = None

-    hostip = gethostbyname(host)
+    if not gw:
+        hostip = gethostbyname(host)
+    else: hostip = None

 
     args = ['ssh', '-C',
             # Don't bother with localhost. Makes test easier
 
     args = ['ssh', '-C',
             # Don't bother with localhost. Makes test easier


@@ -235,6 +252,7 @@ def rexec(command, host, user,
             '-o', 'ConnectionAttempts=3',
             '-o', 'ServerAliveInterval=30',
             '-o', 'TCPKeepAlive=yes',
             '-o', 'ConnectionAttempts=3',
             '-o', 'ServerAliveInterval=30',
             '-o', 'TCPKeepAlive=yes',

+            '-o', 'Batchmode=yes',

             '-l', user, hostip or host]
 
     if persistent and openssh_has_persist():
             '-l', user, hostip or host]
 
     if persistent and openssh_has_persist():


@@ -247,6 +265,10 @@ def rexec(command, host, user,
         # Do not check for Host key. Unsafe.
         args.extend(['-o', 'StrictHostKeyChecking=no'])
 
         # Do not check for Host key. Unsafe.
         args.extend(['-o', 'StrictHostKeyChecking=no'])
 

+    if gw:
+        proxycommand = _proxy_command(gw, gwuser, identity)
+        args.extend(['-o', proxycommand])
+

     if agent:
         args.append('-A')
 
     if agent:
         args.append('-A')
 


@@ -254,6 +276,7 @@ def rexec(command, host, user,
         args.append('-p%d' % port)
 
     if identity:
         args.append('-p%d' % port)
 
     if identity:

+        identity = os.path.expanduser(identity)

         args.extend(('-i', identity))
 
     if tty:
         args.extend(('-i', identity))
 
     if tty:


@@ -268,57 +291,30 @@ def rexec(command, host, user,
         tmp_known_hosts = make_server_key_args(server_key, host, port)
         args.extend(['-o', 'UserKnownHostsFile=%s' % (tmp_known_hosts.name,)])
 
         tmp_known_hosts = make_server_key_args(server_key, host, port)
         args.extend(['-o', 'UserKnownHostsFile=%s' % (tmp_known_hosts.name,)])
 

-    args.append(command)
-
-    for x in xrange(retry):
-        # connects to the remote host and starts a remote connection
-        proc = subprocess.Popen(args,
-                env = env,
-                stdout = subprocess.PIPE,
-                stdin = subprocess.PIPE, 
-                stderr = subprocess.PIPE)
-        
-        # attach tempfile object to the process, to make sure the file stays
-        # alive until the process is finished with it
-        proc._known_hosts = tmp_known_hosts
-    
-        try:
-            out, err = _communicate(proc, stdin, timeout, err_on_timeout)
-            msg = " rexec - host %s - command %s " % (host, " ".join(args))
-            log(msg, logging.DEBUG, out, err)
+    if sudo:
+        command = "sudo " + command

 
 

-            if proc.poll():
-                skip = False
+    args.append(command)

 
 

-                if err.strip().startswith('ssh: ') or err.strip().startswith('mux_client_hello_exchange: '):
-                    # SSH error, can safely retry
-                    skip = True 
-                elif retry:
-                    # Probably timed out or plain failed but can retry
-                    skip = True 
-                
-                if skip:
-                    t = x*2
-                    msg = "SLEEPING %d ... ATEMPT %d - host %s - command %s " % ( 
-                            t, x, host, " ".join(args))
-                    log(msg, logging.DEBUG)
+    log_msg = " rexec - host %s - command %s " % (str(host), " ".join(map(str, args))) 

 
 

-                    time.sleep(t)
-                    continue
-            break
-        except RuntimeError, e:
-            msg = " rexec EXCEPTION - host %s - command %s - TIMEOUT -> %s" % (host, " ".join(args), e.args)
-            log(msg, logging.DEBUG, out, err)
+    stdout = stderr = stdin = subprocess.PIPE
+    if forward_x11:
+        stdout = stderr = stdin = None

 
 

-            if retry <= 0:
-                raise
-            retry -= 1
-        
-    return ((out, err), proc)
+    return _retry_rexec(args, log_msg, 
+            stderr = stderr,
+            stdin = stdin,
+            stdout = stdout,
+            env = env, 
+            retry = retry, 
+            tmp_known_hosts = tmp_known_hosts,
+            blocking = blocking)

 
 def rcopy(source, dest,
 
 def rcopy(source, dest,

-        port = None, 
-        agent = True, 
+        port = None,
+        gwuser = None,
+        gw = None,

         recursive = False,
         identity = None,
         server_key = None,
         recursive = False,
         identity = None,
         server_key = None,


@@ -330,298 +326,135 @@ def rcopy(source, dest,
     Source and destination should have the user and host encoded
     as per scp specs.
     
     Source and destination should have the user and host encoded
     as per scp specs.
     

-    If source is a file object, a special mode will be used to
-    create the remote file with the same contents.
-    
-    If dest is a file object, the remote file (source) will be
-    read and written into dest.
-    
-    In these modes, recursive cannot be True.
-    
-    Source can be a list of files to copy to a single destination,
-    in which case it is advised that the destination be a folder.
+    Source can be a list of files to copy to a single destination, 
+    (in which case it is advised that the destination be a folder),
+    or a single file in a string.

     """
     """

-    
-    if isinstance(source, file) and source.tell() == 0:
-        source = source.name
-    elif hasattr(source, 'read'):
-        tmp = tempfile.NamedTemporaryFile()
-        while True:
-            buf = source.read(65536)
-            if buf:
-                tmp.write(buf)
-            else:
-                break
-        tmp.seek(0)
-        source = tmp.name
-    
-    if isinstance(source, file) or isinstance(dest, file) \
-            or hasattr(source, 'read')  or hasattr(dest, 'write'):
-        assert not recursive
-        
-        # Parse source/destination as <user>@<server>:<path>
-        if isinstance(dest, basestring) and ':' in dest:
-            remspec, path = dest.split(':',1)
-        elif isinstance(source, basestring) and ':' in source:
-            remspec, path = source.split(':',1)
-        else:
-            raise ValueError, "Both endpoints cannot be local"
-        user,host = remspec.rsplit('@',1)
-        
-        tmp_known_hosts = None
-        hostip = gethostbyname(host)
-        
-        args = ['ssh', '-l', user, '-C',
-                # Don't bother with localhost. Makes test easier
-                '-o', 'NoHostAuthenticationForLocalhost=yes',
-                '-o', 'ConnectTimeout=60',
-                '-o', 'ConnectionAttempts=3',
-                '-o', 'ServerAliveInterval=30',
-                '-o', 'TCPKeepAlive=yes',
-                hostip or host ]

 
 

-        if openssh_has_persist():
-            args.extend([
-                '-o', 'ControlMaster=auto',
-                '-o', 'ControlPath=%s' % (make_control_path(agent, False),),
-                '-o', 'ControlPersist=60' ])
-
-        if port:
-            args.append('-P%d' % port)
-
-        if identity:
-            args.extend(('-i', identity))
+    # Parse destination as <user>@<server>:<path>
+    if isinstance(dest, str) and ':' in dest:
+        remspec, path = dest.split(':',1)
+    elif isinstance(source, str) and ':' in source:
+        remspec, path = source.split(':',1)
+    else:
+        raise ValueError, "Both endpoints cannot be local"
+    user,host = remspec.rsplit('@',1)
+    
+    # plain scp
+    tmp_known_hosts = None

 
 

-        if server_key:
-            # Create a temporary server key file
-            tmp_known_hosts = make_server_key_args(server_key, host, port)
-            args.extend(['-o', 'UserKnownHostsFile=%s' % (tmp_known_hosts.name,)])
-        
-        if isinstance(source, file) or hasattr(source, 'read'):
-            args.append('cat > %s' % (shell_escape(path),))
-        elif isinstance(dest, file) or hasattr(dest, 'write'):
-            args.append('cat %s' % (shell_escape(path),))
-        else:
-            raise AssertionError, "Unreachable code reached! :-Q"
-        
-        # connects to the remote host and starts a remote connection
-        if isinstance(source, file):
-            proc = subprocess.Popen(args, 
-                    stdout = open('/dev/null','w'),
-                    stderr = subprocess.PIPE,
-                    stdin = source)
-            err = proc.stderr.read()
-            proc._known_hosts = tmp_known_hosts
-            eintr_retry(proc.wait)()
-            return ((None,err), proc)
-        elif isinstance(dest, file):
-            proc = subprocess.Popen(args, 
-                    stdout = open('/dev/null','w'),
-                    stderr = subprocess.PIPE,
-                    stdin = source)
-            err = proc.stderr.read()
-            proc._known_hosts = tmp_known_hosts
-            eintr_retry(proc.wait)()
-            return ((None,err), proc)
-        elif hasattr(source, 'read'):
-            # file-like (but not file) source
-            proc = subprocess.Popen(args, 
-                    stdout = open('/dev/null','w'),
-                    stderr = subprocess.PIPE,
-                    stdin = subprocess.PIPE)
-            
-            buf = None
-            err = []
-            while True:
-                if not buf:
-                    buf = source.read(4096)
-                if not buf:
-                    #EOF
-                    break
-                
-                rdrdy, wrdy, broken = select.select(
-                    [proc.stderr],
-                    [proc.stdin],
-                    [proc.stderr,proc.stdin])
-                
-                if proc.stderr in rdrdy:
-                    # use os.read for fully unbuffered behavior
-                    err.append(os.read(proc.stderr.fileno(), 4096))
-                
-                if proc.stdin in wrdy:
-                    proc.stdin.write(buf)
-                    buf = None
-                
-                if broken:
-                    break
-            proc.stdin.close()
-            err.append(proc.stderr.read())
-                
-            proc._known_hosts = tmp_known_hosts
-            eintr_retry(proc.wait)()
-            return ((None,''.join(err)), proc)
-        elif hasattr(dest, 'write'):
-            # file-like (but not file) dest
-            proc = subprocess.Popen(args, 
-                    stdout = subprocess.PIPE,
-                    stderr = subprocess.PIPE,
-                    stdin = open('/dev/null','w'))
+    args = ['scp', '-q', '-p', '-C',
+            # 2015-06-01 Thierry: I am commenting off blowfish
+            # as this is not available on a plain ubuntu 15.04 install
+            # this IMHO is too fragile, shoud be something the user
+            # decides explicitly (so he is at least aware of that dependency)
+            # Speed up transfer using blowfish cypher specification which is 
+            # faster than the default one (3des)
+            # '-c', 'blowfish',
+            # Don't bother with localhost. Makes test easier
+            '-o', 'NoHostAuthenticationForLocalhost=yes',
+            '-o', 'ConnectTimeout=60',
+            '-o', 'ConnectionAttempts=3',
+            '-o', 'ServerAliveInterval=30',
+            '-o', 'TCPKeepAlive=yes' ]

             
             

-            buf = None
-            err = []
-            while True:
-                rdrdy, wrdy, broken = select.select(
-                    [proc.stderr, proc.stdout],
-                    [],
-                    [proc.stderr, proc.stdout])
-                
-                if proc.stderr in rdrdy:
-                    # use os.read for fully unbuffered behavior
-                    err.append(os.read(proc.stderr.fileno(), 4096))
-                
-                if proc.stdout in rdrdy:
-                    # use os.read for fully unbuffered behavior
-                    buf = os.read(proc.stdout.fileno(), 4096)
-                    dest.write(buf)
-                    
-                    if not buf:
-                        #EOF
-                        break
-                
-                if broken:
-                    break
-            err.append(proc.stderr.read())
-                
-            proc._known_hosts = tmp_known_hosts
-            eintr_retry(proc.wait)()
-            return ((None,''.join(err)), proc)
-        else:
-            raise AssertionError, "Unreachable code reached! :-Q"
-    else:
-        # Parse destination as <user>@<server>:<path>
-        if isinstance(dest, basestring) and ':' in dest:
-            remspec, path = dest.split(':',1)
-        elif isinstance(source, basestring) and ':' in source:
-            remspec, path = source.split(':',1)
-        else:
-            raise ValueError, "Both endpoints cannot be local"
-        user,host = remspec.rsplit('@',1)
-        
-        # plain scp
-        tmp_known_hosts = None
-
-        args = ['scp', '-q', '-p', '-C',
-                # Don't bother with localhost. Makes test easier
-                '-o', 'NoHostAuthenticationForLocalhost=yes',
-                '-o', 'ConnectTimeout=60',
-                '-o', 'ConnectionAttempts=3',
-                '-o', 'ServerAliveInterval=30',
-                '-o', 'TCPKeepAlive=yes' ]
-                
-        if port:
-            args.append('-P%d' % port)
+    if port:
+        args.append('-P%d' % port)

 
 

-        if recursive:
-            args.append('-r')
+    if gw:
+        proxycommand = _proxy_command(gw, gwuser, identity)
+        args.extend(['-o', proxycommand])

 
 

-        if identity:
-            args.extend(('-i', identity))
+    if recursive:
+        args.append('-r')

 
 

-        if server_key:
-            # Create a temporary server key file
-            tmp_known_hosts = make_server_key_args(server_key, host, port)
-            args.extend(['-o', 'UserKnownHostsFile=%s' % (tmp_known_hosts.name,)])
+    if identity:
+        identity = os.path.expanduser(identity)
+        args.extend(('-i', identity))

 
 

-        if not strict_host_checking:
-            # Do not check for Host key. Unsafe.
-            args.extend(['-o', 'StrictHostKeyChecking=no'])
+    if server_key:
+        # Create a temporary server key file
+        tmp_known_hosts = make_server_key_args(server_key, host, port)
+        args.extend(['-o', 'UserKnownHostsFile=%s' % (tmp_known_hosts.name,)])

 
 

-        if isinstance(source,list):
-            args.extend(source)
-        else:
-            if openssh_has_persist():
-                args.extend([
-                    '-o', 'ControlMaster=auto',
-                    '-o', 'ControlPath=%s' % (make_control_path(agent, False),)
-                    ])
-            args.append(source)
+    if not strict_host_checking:
+        # Do not check for Host key. Unsafe.
+        args.extend(['-o', 'StrictHostKeyChecking=no'])
+    
+    if isinstance(source, list):
+        args.extend(source)
+    else:
+        if openssh_has_persist():
+            args.extend([
+                '-o', 'ControlMaster=auto',
+                '-o', 'ControlPath=%s' % (make_control_path(False, False),)
+                ])
+        args.append(source)

 
 

+    if isinstance(dest, list):
+        args.extend(dest)
+    else:

         args.append(dest)
 
         args.append(dest)
 

-        for x in xrange(retry):
-            # connects to the remote host and starts a remote connection
-            proc = subprocess.Popen(args,
-                    stdout = subprocess.PIPE,
-                    stdin = subprocess.PIPE, 
-                    stderr = subprocess.PIPE)
-            
-            # attach tempfile object to the process, to make sure the file stays
-            # alive until the process is finished with it
-            proc._known_hosts = tmp_known_hosts
-        
-            try:
-                (out, err) = proc.communicate()
-                eintr_retry(proc.wait)()
-                msg = " rcopy - host %s - command %s " % (host, " ".join(args))
-                log(msg, logging.DEBUG, out, err)
-
-                if proc.poll():
-                    t = x*2
-                    msg = "SLEEPING %d ... ATEMPT %d - host %s - command %s " % ( 
-                            t, x, host, " ".join(args))
-                    log(msg, logging.DEBUG)
-
-                    time.sleep(t)
-                    continue
-
-                break
-            except RuntimeError, e:
-                msg = " rcopy EXCEPTION - host %s - command %s - TIMEOUT -> %s" % (host, " ".join(args), e.args)
-                log(msg, logging.DEBUG, out, err)
-
-                if retry <= 0:
-                    raise
-                retry -= 1
-            
-        return ((out, err), proc)
+    log_msg = " rcopy - host %s - command %s " % (str(host), " ".join(map(str, args)))
+    
+    return _retry_rexec(args, log_msg, env = None, retry = retry, 
+            tmp_known_hosts = tmp_known_hosts,
+            blocking = True)

 
 def rspawn(command, pidfile, 
         stdout = '/dev/null', 
         stderr = STDOUT, 
 
 def rspawn(command, pidfile, 
         stdout = '/dev/null', 
         stderr = STDOUT, 

-        stdin = '/dev/null', 
+        stdin = '/dev/null',

         home = None, 
         create_home = False, 
         sudo = False,
         host = None, 
         port = None, 
         user = None, 
         home = None, 
         create_home = False, 
         sudo = False,
         host = None, 
         port = None, 
         user = None, 

+        gwuser = None,
+        gw = None,

         agent = None, 
         identity = None, 
         server_key = None,
         agent = None, 
         identity = None, 
         server_key = None,

-        tty = False):
+        tty = False,
+        strict_host_checking = True):

     """
     """

-    Spawn a remote command such that it will continue working asynchronously.
-    
-    Parameters:
-        command: the command to run - it should be a single line.
-        
-        pidfile: path of a (ideally unique to this task) pidfile for tracking the process.
-        
-        stdout: path of a file to redirect standard output to - must be a string.
-            Defaults to /dev/null
-        stderr: path of a file to redirect standard error to - string or the special STDOUT value
-            to redirect to the same file stdout was redirected to. Defaults to STDOUT.
-        stdin: path of a file with input to be piped into the command's standard input
-        
-        home: path of a folder to use as working directory - should exist, unless you specify create_home
-        
-        create_home: if True, the home folder will be created first with mkdir -p
+    Spawn a remote command such that it will continue working asynchronously in 
+    background. 
+
+        :param command: The command to run, it should be a single line.
+        :type command: str
+
+        :param pidfile: Path to a file where to store the pid and ppid of the 
+                        spawned process
+        :type pidfile: str
+
+        :param stdout: Path to file to redirect standard output. 
+                       The default value is /dev/null
+        :type stdout: str
+
+        :param stderr: Path to file to redirect standard error.
+                       If the special STDOUT value is used, stderr will 
+                       be redirected to the same file as stdout
+        :type stderr: str
+
+        :param stdin: Path to a file with input to be piped into the command's standard input
+        :type stdin: str
+
+        :param home: Path to working directory folder. 
+                    It is assumed to exist unless the create_home flag is set.
+        :type home: str
+
+        :param create_home: Flag to force creation of the home folder before 
+                            running the command
+        :type create_home: bool
+ 
+        :param sudo: Flag forcing execution with sudo user
+        :type sudo: bool

         
         

-        sudo: whether the command needs to be executed as root
-        
-        host/port/user/agent/identity: see rexec
-    
-    Returns:
+        :rtype: tuple
+

         (stdout, stderr), process
         
         Of the spawning process, which only captures errors at spawning time.
         (stdout, stderr), process
         
         Of the spawning process, which only captures errors at spawning time.


@@ -634,7 +467,7 @@ def rspawn(command, pidfile,
     else:
         stderr = ' ' + stderr
     
     else:
         stderr = ' ' + stderr
     

-    daemon_command = '{ { %(command)s  > %(stdout)s 2>%(stderr)s < %(stdin)s & } ; echo $! 1 > %(pidfile)s ; }' % {
+    daemon_command = '{ { %(command)s > %(stdout)s 2>%(stderr)s < %(stdin)s & } ; echo $! 1 > %(pidfile)s ; }' % {

         'command' : command,
         'pidfile' : shell_escape(pidfile),
         'stdout' : stdout,
         'command' : command,
         'pidfile' : shell_escape(pidfile),
         'stdout' : stdout,


@@ -655,10 +488,13 @@ def rspawn(command, pidfile,
         host = host,
         port = port,
         user = user,
         host = host,
         port = port,
         user = user,

+        gwuser = gwuser,
+        gw = gw,

         agent = agent,
         identity = identity,
         server_key = server_key,
         agent = agent,
         identity = identity,
         server_key = server_key,

-        tty = tty ,
+        tty = tty,
+        strict_host_checking = strict_host_checking ,

         )
     
     if proc.wait():
         )
     
     if proc.wait():


@@ -667,27 +503,32 @@ def rspawn(command, pidfile,
     return ((out, err), proc)
 
 @eintr_retry
     return ((out, err), proc)
 
 @eintr_retry

-def rcheckpid(pidfile,
+def rgetpid(pidfile,

         host = None, 
         port = None, 
         user = None, 
         host = None, 
         port = None, 
         user = None, 

+        gwuser = None,
+        gw = None,

         agent = None, 
         identity = None,
         agent = None, 
         identity = None,

-        server_key = None):
+        server_key = None,
+        strict_host_checking = True):

     """
     """

-    Check the pidfile of a process spawned with remote_spawn.
-    
-    Parameters:
-        pidfile: the pidfile passed to remote_span
+    Returns the pid and ppid of a process from a remote file where the 
+    information was stored.
+
+        :param home: Path to directory where the pidfile is located
+        :type home: str
+
+        :param pidfile: Name of file containing the pid information
+        :type pidfile: str

         
         

-        host/port/user/agent/identity: see rexec
-    
-    Returns:
+        :rtype: int

         
         

-        A (pid, ppid) tuple useful for calling remote_status and remote_kill,
-        or None if the pidfile isn't valid yet (maybe the process is still starting).
-    """
+        A (pid, ppid) tuple useful for calling rstatus and rkill,
+        or None if the pidfile isn't valid yet (can happen when process is staring up)

 
 

+    """

     (out,err),proc = rexec(
         "cat %(pidfile)s" % {
             'pidfile' : pidfile,
     (out,err),proc = rexec(
         "cat %(pidfile)s" % {
             'pidfile' : pidfile,


@@ -695,9 +536,12 @@ def rcheckpid(pidfile,
         host = host,
         port = port,
         user = user,
         host = host,
         port = port,
         user = user,

+        gwuser = gwuser,
+        gw = gw,

         agent = agent,
         identity = identity,
         agent = agent,
         identity = identity,

-        server_key = server_key
+        server_key = server_key,
+        strict_host_checking = strict_host_checking

         )
         
     if proc.wait():
         )
         
     if proc.wait():


@@ -715,22 +559,24 @@ def rstatus(pid, ppid,
         host = None, 
         port = None, 
         user = None, 
         host = None, 
         port = None, 
         user = None, 

+        gwuser = None,
+        gw = None,

         agent = None, 
         identity = None,
         agent = None, 
         identity = None,

-        server_key = None):
+        server_key = None,
+        strict_host_checking = True):

     """
     """

-    Check the status of a process spawned with remote_spawn.
+    Returns a code representing the the status of a remote process
+
+        :param pid: Process id of the process
+        :type pid: int
+
+        :param ppid: Parent process id of process
+        :type ppid: int

     
     

-    Parameters:
-        pid/ppid: pid and parent-pid of the spawned process. See remote_check_pid
-        
-        host/port/user/agent/identity: see rexec
+        :rtype: int (One of NOT_STARTED, RUNNING, FINISHED)

     
     

-    Returns:
-        
-        One of NOT_STARTED, RUNNING, FINISHED

     """
     """

-

     (out,err),proc = rexec(
         # Check only by pid. pid+ppid does not always work (especially with sudo) 
         " (( ps --pid %(pid)d -o pid | grep -c %(pid)d && echo 'wait')  || echo 'done' ) | tail -n 1" % {
     (out,err),proc = rexec(
         # Check only by pid. pid+ppid does not always work (especially with sudo) 
         " (( ps --pid %(pid)d -o pid | grep -c %(pid)d && echo 'wait')  || echo 'done' ) | tail -n 1" % {


@@ -740,13 +586,16 @@ def rstatus(pid, ppid,
         host = host,
         port = port,
         user = user,
         host = host,
         port = port,
         user = user,

+        gwuser = gwuser,
+        gw = gw,

         agent = agent,
         identity = identity,
         agent = agent,
         identity = identity,

-        server_key = server_key
+        server_key = server_key,
+        strict_host_checking = strict_host_checking

         )
     
     if proc.wait():
         )
     
     if proc.wait():

-        return NOT_STARTED
+        return ProcStatus.NOT_STARTED

     
     status = False
     if err:
     
     status = False
     if err:


@@ -755,37 +604,38 @@ def rstatus(pid, ppid,
     elif out:
         status = (out.strip() == 'wait')
     else:
     elif out:
         status = (out.strip() == 'wait')
     else:

-        return NOT_STARTED
-    return RUNNING if status else FINISHED
+        return ProcStatus.NOT_STARTED
+    return ProcStatus.RUNNING if status else ProcStatus.FINISHED

 
 @eintr_retry
 def rkill(pid, ppid,
         host = None, 
         port = None, 
         user = None, 
 
 @eintr_retry
 def rkill(pid, ppid,
         host = None, 
         port = None, 
         user = None, 

+        gwuser = None,
+        gw = None,

         agent = None, 
         sudo = False,
         identity = None, 
         server_key = None, 
         agent = None, 
         sudo = False,
         identity = None, 
         server_key = None, 

-        nowait = False):
+        nowait = False,
+        strict_host_checking = True):

     """
     """

-    Kill a process spawned with remote_spawn.
-    
+    Sends a kill signal to a remote process.
+

     First tries a SIGTERM, and if the process does not end in 10 seconds,
     it sends a SIGKILL.
     First tries a SIGTERM, and if the process does not end in 10 seconds,
     it sends a SIGKILL.

-    
-    Parameters:
-        pid/ppid: pid and parent-pid of the spawned process. See remote_check_pid
-        
-        sudo: whether the command was run with sudo - careful killing like this.
-        
-        host/port/user/agent/identity: see rexec
-    
-    Returns:
+ 
+        :param pid: Process id of process to be killed
+        :type pid: int
+
+        :param ppid: Parent process id of process to be killed
+        :type ppid: int
+
+        :param sudo: Flag indicating if sudo should be used to kill the process
+        :type sudo: bool

         
         

-        Nothing, should have killed the process

     """
     """

-    

     subkill = "$(ps --ppid %(pid)d -o pid h)" % { 'pid' : pid }
     cmd = """
 SUBKILL="%(subkill)s" ;
     subkill = "$(ps --ppid %(pid)d -o pid h)" % { 'pid' : pid }
     cmd = """
 SUBKILL="%(subkill)s" ;


@@ -819,9 +669,12 @@ fi
         host = host,
         port = port,
         user = user,
         host = host,
         port = port,
         user = user,

+        gwuser = gwuser,
+        gw = gw,

         agent = agent,
         identity = identity,
         agent = agent,
         identity = identity,

-        server_key = server_key
+        server_key = server_key,
+        strict_host_checking = strict_host_checking

         )
     
     # wait, don't leave zombies around
         )
     
     # wait, don't leave zombies around


@@ -829,33 +682,105 @@ fi
 
     return (out, err), proc
 
 
     return (out, err), proc
 

+def _retry_rexec(args,
+        log_msg,
+        stdout = subprocess.PIPE,
+        stdin = subprocess.PIPE, 
+        stderr = subprocess.PIPE,
+        env = None,
+        retry = 3,
+        tmp_known_hosts = None,
+        blocking = True):
+
+    for x in xrange(retry):
+        # connects to the remote host and starts a remote connection
+        proc = subprocess.Popen(args,
+                env = env,
+                stdout = stdout,
+                stdin = stdin, 
+                stderr = stderr)
+        
+        # attach tempfile object to the process, to make sure the file stays
+        # alive until the process is finished with it
+        proc._known_hosts = tmp_known_hosts
+    
+        # The argument block == False forces to rexec to return immediately, 
+        # without blocking 
+        try:
+            err = out = " "
+            if blocking:
+                #(out, err) = proc.communicate()
+                # The method communicate was re implemented for performance issues
+                # when using python subprocess communicate method the ssh commands 
+                # last one minute each
+                out, err = _communicate(proc, input=None)
+
+            elif stdout:
+                out = proc.stdout.read()
+                if proc.poll() and stderr:
+                    err = proc.stderr.read()
+
+            log(log_msg, logging.DEBUG, out, err)
+
+            if proc.poll():
+                skip = False
+
+                if err.strip().startswith('ssh: ') or err.strip().startswith('mux_client_hello_exchange: '):
+                    # SSH error, can safely retry
+                    skip = True 
+                elif retry:
+                    # Probably timed out or plain failed but can retry
+                    skip = True 
+                
+                if skip:
+                    t = x*2
+                    msg = "SLEEPING %d ... ATEMPT %d - command %s " % ( 
+                            t, x, " ".join(args))
+                    log(msg, logging.DEBUG)
+
+                    time.sleep(t)
+                    continue
+            break
+        except RuntimeError, e:
+            msg = " rexec EXCEPTION - TIMEOUT -> %s \n %s" % ( e.args, log_msg )
+            log(msg, logging.DEBUG, out, err)
+
+            if retry <= 0:
+                raise
+            retry -= 1
+
+    return ((out, err), proc)
+

 # POSIX
 # POSIX

-def _communicate(self, input, timeout=None, err_on_timeout=True):
+# Don't remove. The method communicate was re implemented for performance issues
+def _communicate(proc, input, timeout=None, err_on_timeout=True):

     read_set = []
     write_set = []
     stdout = None # Return
     stderr = None # Return
     read_set = []
     write_set = []
     stdout = None # Return
     stderr = None # Return

-    
+

     killed = False
     killed = False

-    
+

     if timeout is not None:
         timelimit = time.time() + timeout
         killtime = timelimit + 4
         bailtime = timelimit + 4
 
     if timeout is not None:
         timelimit = time.time() + timeout
         killtime = timelimit + 4
         bailtime = timelimit + 4
 

-    if self.stdin:
+    if proc.stdin:

         # Flush stdio buffer.  This might block, if the user has
         # been writing to .stdin in an uncontrolled fashion.
         # Flush stdio buffer.  This might block, if the user has
         # been writing to .stdin in an uncontrolled fashion.

-        self.stdin.flush()
+        proc.stdin.flush()

         if input:
         if input:

-            write_set.append(self.stdin)
+            write_set.append(proc.stdin)

         else:
         else:

-            self.stdin.close()
-    if self.stdout:
-        read_set.append(self.stdout)
+            proc.stdin.close()
+
+    if proc.stdout:
+        read_set.append(proc.stdout)

         stdout = []
         stdout = []

-    if self.stderr:
-        read_set.append(self.stderr)
+
+    if proc.stderr:
+        read_set.append(proc.stderr)

         stderr = []
 
     input_offset = 0
         stderr = []
 
     input_offset = 0


@@ -870,16 +795,16 @@ def _communicate(self, input, timeout=None, err_on_timeout=True):
                 else:
                     signum = signal.SIGTERM
                 # Lets kill it
                 else:
                     signum = signal.SIGTERM
                 # Lets kill it

-                os.kill(self.pid, signum)
+                os.kill(proc.pid, signum)

                 select_timeout = 0.5
             else:
                 select_timeout = timelimit - curtime + 0.1
         else:
             select_timeout = 1.0
                 select_timeout = 0.5
             else:
                 select_timeout = timelimit - curtime + 0.1
         else:
             select_timeout = 1.0

-        
+

         if select_timeout > 1.0:
             select_timeout = 1.0
         if select_timeout > 1.0:
             select_timeout = 1.0

-            
+

         try:
             rlist, wlist, xlist = select.select(read_set, write_set, [], select_timeout)
         except select.error,e:
         try:
             rlist, wlist, xlist = select.select(read_set, write_set, [], select_timeout)
         except select.error,e:


@@ -887,35 +812,37 @@ def _communicate(self, input, timeout=None, err_on_timeout=True):
                 raise
             else:
                 continue
                 raise
             else:
                 continue

-        
-        if not rlist and not wlist and not xlist and self.poll() is not None:
+
+        if not rlist and not wlist and not xlist and proc.poll() is not None:

             # timeout and process exited, say bye
             break
 
             # timeout and process exited, say bye
             break
 

-        if self.stdin in wlist:
+        if proc.stdin in wlist:

             # When select has indicated that the file is writable,
             # we can write up to PIPE_BUF bytes without risk
             # blocking.  POSIX defines PIPE_BUF >= 512
             # When select has indicated that the file is writable,
             # we can write up to PIPE_BUF bytes without risk
             # blocking.  POSIX defines PIPE_BUF >= 512

-            bytes_written = os.write(self.stdin.fileno(), buffer(input, input_offset, 512))
+            bytes_written = os.write(proc.stdin.fileno(),
+                    buffer(input, input_offset, 512))

             input_offset += bytes_written
             input_offset += bytes_written

+

             if input_offset >= len(input):
             if input_offset >= len(input):

-                self.stdin.close()
-                write_set.remove(self.stdin)
+                proc.stdin.close()
+                write_set.remove(proc.stdin)

 
 

-        if self.stdout in rlist:
-            data = os.read(self.stdout.fileno(), 1024)
+        if proc.stdout in rlist:
+            data = os.read(proc.stdout.fileno(), 1024)

             if data == "":
             if data == "":

-                self.stdout.close()
-                read_set.remove(self.stdout)
+                proc.stdout.close()
+                read_set.remove(proc.stdout)

             stdout.append(data)
 
             stdout.append(data)
 

-        if self.stderr in rlist:
-            data = os.read(self.stderr.fileno(), 1024)
+        if proc.stderr in rlist:
+            data = os.read(proc.stderr.fileno(), 1024)

             if data == "":
             if data == "":

-                self.stderr.close()
-                read_set.remove(self.stderr)
+                proc.stderr.close()
+                read_set.remove(proc.stderr)

             stderr.append(data)
             stderr.append(data)

-    
+

     # All data exchanged.  Translate lists into strings.
     if stdout is not None:
         stdout = ''.join(stdout)
     # All data exchanged.  Translate lists into strings.
     if stdout is not None:
         stdout = ''.join(stdout)


@@ -926,19 +853,49 @@ def _communicate(self, input, timeout=None, err_on_timeout=True):
     # object do the translation: It is based on stdio, which is
     # impossible to combine with select (unless forcing no
     # buffering).
     # object do the translation: It is based on stdio, which is
     # impossible to combine with select (unless forcing no
     # buffering).

-    if self.universal_newlines and hasattr(file, 'newlines'):
+    if proc.universal_newlines and hasattr(file, 'newlines'):

         if stdout:
         if stdout:

-            stdout = self._translate_newlines(stdout)
+            stdout = proc._translate_newlines(stdout)

         if stderr:
         if stderr:

-            stderr = self._translate_newlines(stderr)
+            stderr = proc._translate_newlines(stderr)

 
     if killed and err_on_timeout:
 
     if killed and err_on_timeout:

-        errcode = self.poll()
+        errcode = proc.poll()

         raise RuntimeError, ("Operation timed out", errcode, stdout, stderr)
     else:
         if killed:
         raise RuntimeError, ("Operation timed out", errcode, stdout, stderr)
     else:
         if killed:

-            self.poll()
+            proc.poll()

         else:
         else:

-            self.wait()
+            proc.wait()

         return (stdout, stderr)
 
         return (stdout, stderr)
 

+def _proxy_command(gw, gwuser, gwidentity):
+    """
+    Constructs the SSH ProxyCommand option to add to the SSH command to connect
+    via a proxy
+        :param gw: SSH proxy hostname
+        :type gw:  str 
+       
+        :param gwuser: SSH proxy username
+        :type gwuser:  str
+
+        :param gwidentity: SSH proxy identity file 
+        :type gwidentity:  str
+
+  
+        :rtype: str 
+        
+        returns the SSH ProxyCommand option.
+    """
+
+    proxycommand = 'ProxyCommand=ssh -q '
+    if gwidentity:
+        proxycommand += '-i %s ' % os.path.expanduser(gwidentity)
+    if gwuser:
+        proxycommand += '%s' % gwuser
+    else:
+        proxycommand += '%r'
+    proxycommand += '@%s -W %%h:%%p' % gw
+
+    return proxycommand
+