ssh: CompressionLevel is a v1-only option.

It's ignored by newer SSHes, which only pay attention to Compression.

docs/api.rst

@@ -596,7 +596,7 @@ Router Class
             :py:class:`mitogen.core.StreamError` to be raised, and that
             attributes of the stream match the actual behaviour of ``sudo``.
 
-    .. method:: ssh (hostname, username=None, ssh_path=None, port=None, check_host_keys=True, password=None, identity_file=None, compression_level=6, \**kwargs)
+    .. method:: ssh (hostname, username=None, ssh_path=None, port=None, check_host_keys=True, password=None, identity_file=None, compression=True, \**kwargs)
 
         Arrange for a context to be constructed over a ``ssh`` invocation. The
         ``ssh`` process is started in a newly allocated pseudo-terminal, and
@@ -628,10 +628,12 @@ Router Class
             the SSH client to perform authenticaion; agent authentication is
             automatically disabled, as is reading the default private key from
             ``~/.ssh/id_rsa``, or ``~/.ssh/id_dsa``.
-        :param int compression_level:
-            Integer 0-9 representing the zlib compression level to use on the
-            connection, with 0 indicating compression is disabled. Defaults to
-            6.
+        :param bool compression:
+            If :py:data:`True`, enable ``ssh`` compression support. Compression
+            has a minimal effect on the size of modules transmitted, as they
+            are already compressed, however it has a large effect on every
+            remaining message in the otherwise uncompressed stream protocol,
+            such as function call arguments and return values.
 
 
 Context Class

mitogen/ssh.py

@@ -61,7 +61,7 @@ class Stream(mitogen.parent.Stream):
 
     def construct(self, hostname, username=None, ssh_path=None, port=None,
                   check_host_keys=True, password=None, identity_file=None,
-                  compression_level=6, ssh_args=None, **kwargs):
+                  compression=True, ssh_args=None, **kwargs):
         super(Stream, self).construct(**kwargs)
         self.hostname = hostname
         self.username = username
@@ -69,7 +69,7 @@ class Stream(mitogen.parent.Stream):
         self.check_host_keys = check_host_keys
         self.password = password
         self.identity_file = identity_file
-        self.compression_level = compression_level
+        self.compression = compression
         if ssh_path:
             self.ssh_path = ssh_path
         if ssh_args:
@@ -87,11 +87,8 @@ class Stream(mitogen.parent.Stream):
             bits += ['-o', 'IdentitiesOnly yes']
         if self.identity_file:
             bits += ['-i', self.identity_file]
-        if self.compression_level:
-            bits += [
-                '-o', 'Compression yes',
-                '-o', 'CompressionLevel %d' % (self.compression_level,)
-            ]
+        if self.compression:
+            bits += ['-o', 'Compression yes']
         if not self.check_host_keys:
             bits += [
                 '-o', 'StrictHostKeyChecking no',