Add ssh-command setting

Patch by Lars Kruse.

3 files changed, 18 insertions, 2 deletions

diff --git a/NEWS b/NEWS
index 62e9a7ce..f400fb0c 100644
--- a/NEWS
+++ b/NEWS
@@ -25,6 +25,9 @@ Version 1.6, released UNRELEASED
   obey a new option, `--key-details`, to show the usernames
   attached to each public key. Patch by Lars Kruse.
 
+* New option `--ssh-command` to set the command Obnam runs
+  when invoking ssh. patch by Lars Kruse.
+
 Bug fixes:
 
 * Fix "obnam list-toplevels" so it doesn't give an error when it's
diff --git a/obnamlib/plugins/sftp_plugin.py b/obnamlib/plugins/sftp_plugin.py
index b0b6e08b..f185b05e 100644
--- a/obnamlib/plugins/sftp_plugin.py
+++ b/obnamlib/plugins/sftp_plugin.py
@@ -152,10 +152,12 @@ class SftpFS(obnamlib.VirtualFileSystem):
         self.chdir(self.path)
 
     def _connect_openssh(self):
-        args = ['ssh',
-                '-oForwardX11=no', '-oForwardAgent=no',
+        executable = 'ssh'
+        args = ['-oForwardX11=no', '-oForwardAgent=no',
                 '-oClearAllForwardings=yes', '-oProtocol=2',
                 '-s']
+        if self.settings and self.settings['ssh-command']:
+            executable = self.settings["ssh-command"]
         # default user/port from ssh (could be a per host configuration)
         if self.port:
             args += ['-p', str(self.port)]
@@ -171,6 +173,8 @@ class SftpFS(obnamlib.VirtualFileSystem):
                         self.settings['ssh-known-hosts']]
         args += [self.host, 'sftp']
 
+        # prepend the executable to the argument list
+        args.insert(0, executable)
         logging.debug('executing openssh: %s' % args)
         try:
             proc = subprocess.Popen(args,
@@ -623,6 +627,13 @@ class SftpPlugin(obnamlib.ObnamPlugin):
                                     os.path.expanduser('~/.ssh/known_hosts'),
                                  group=ssh_group)
 
+        self.app.settings.string(['ssh-command'],
+                                 'alternative executable to be used instead '
+                                    'of "ssh" (full path is allowed, no '
+                                    'arguments may be added)',
+                                 metavar='EXECUTABLE',
+                                 group=ssh_group)
+
         self.app.settings.boolean(['pure-paramiko'],
                                  'do not use openssh even if available, '
                                     'use paramiko only instead',
diff --git a/test-sftpfs b/test-sftpfs
index 52f7e369..6a7b9b93 100755
--- a/test-sftpfs
+++ b/test-sftpfs
@@ -49,6 +49,7 @@ class SftpTests(unittest.TestCase, obnamlib.VfsTests):
             'ssh-key': '',
             'strict-ssh-host-keys': False,
             'ssh-known-hosts': os.path.expanduser('~/.ssh/known_hosts'),
+            'ssh-command': None,
         }
         self.fs = obnamlib.plugins.sftp_plugin.SftpFS(baseurl,
                                                       settings=settings)
@@ -70,6 +71,7 @@ class SftpTests(unittest.TestCase, obnamlib.VfsTests):
             'ssh-key': '',
             'strict-ssh-host-keys': False,
             'ssh-known-hosts': os.path.expanduser('~/.ssh/known_hosts'),
+            'ssh-command': None,
         }
         fs = obnamlib.plugins.sftp_plugin.SftpFS(baseurl, settings=settings)
         fs.connect()