Merge pull request #418 from darko-poljak/ssh-mux-opts

ssh multiplexing options

docs/changelog

@@ -2,6 +2,7 @@ Changelog
 ---------
 
 next:
+	* Core: Add CDIST_REMOTE_COPY/EXEC env variables and multiplexing options for default scp/ssh (Darko Poljak)
 	* Types: Remove bashisms in scripts (Darko Poljak)
 	* Core: Fix bug in remote command with environment (Darko Poljak)
 	* Core: Fix bug in local code execution (Darko Poljak)

docs/man/cdist-reference.text.sh

@@ -249,6 +249,12 @@ CDIST_OVERRIDE::
 CDIST_ORDER_DEPENDENCY::
     Create dependencies based on the execution order (see cdist-manifest(7))
 
+CDIST_REMOTE_EXEC::
+    Use this command for remote execution (should behave like ssh)
+
+CDIST_REMOTE_COPY::
+    Use this command for remote copy (should behave like scp)
+
 SEE ALSO
 --------
 - cdist(1)

docs/man/man1/cdist.text

@@ -138,6 +138,11 @@ CDIST_LOCAL_SHELL::
 CDIST_REMOTE_SHELL::
     Selects shell for remote scirpt execution, defaults to /bin/sh
 
+CDIST_REMOTE_EXEC::
+    Use this command for remote execution (should behave like ssh)
+
+CDIST_REMOTE_COPY::
+    Use this command for remote copy (should behave like scp)
 
 EXIT STATUS
 -----------

scripts/cdist

@@ -2,6 +2,7 @@
 # -*- coding: utf-8 -*-
 #
 # 2010-2013 Nico Schottelius (nico-cdist at schottelius.org)
+# 2016 Darko Poljak (darko.poljak at gmail.com)
 #
 # This file is part of cdist.
 #
@@ -20,6 +21,28 @@
 #
 #
 
+def inspect_ssh_mux_opts(control_path_dir="~/.ssh/"):
+    """Inspect whether or not ssh supports multiplexing options"""
+    import subprocess
+    import os
+
+    control_path = os.path.join(control_path_dir, "cdist.master-%l-%r@%h:%p")
+    wanted_mux_opts = {
+        "ControlPath": control_path,
+        "ControlMaster": "auto",
+        "ControlPersist": "125",
+    }
+    mux_opts = " ".join([" -o {}={}".format(x,
+        wanted_mux_opts[x]) for x in wanted_mux_opts])
+    try:
+        subprocess.check_output("ssh {}".format(mux_opts),
+                stderr=subprocess.STDOUT, shell=True)
+    except subprocess.CalledProcessError as e:
+        subproc_output = e.output.decode().lower()
+        if "bad configuration option" in subproc_output:
+            return ""
+    return mux_opts
+
 def commandline():
     """Parse command line"""
     import argparse
@@ -27,6 +50,9 @@ def commandline():
     import cdist.banner
     import cdist.config
     import cdist.shell
+    import tempfile
+    import shutil
+    import os
 
     # Construct parser others can reuse
     parser = {}
@@ -73,14 +99,17 @@ def commandline():
     parser['config'].add_argument('-s', '--sequential',
          help='Operate on multiple hosts sequentially (default)',
          action='store_false', dest='parallel')
+    # remote-copy and remote-exec defaults are environment variables
+    # if set; if not then None - these will be futher handled after
+    # parsing to determine implementation default
     parser['config'].add_argument('--remote-copy',
          help='Command to use for remote copy (should behave like scp)',
          action='store', dest='remote_copy',
-         default=cdist.REMOTE_COPY)
+         default=os.environ.get('CDIST_REMOTE_COPY'))
     parser['config'].add_argument('--remote-exec',
          help='Command to use for remote execution (should behave like ssh)',
          action='store', dest='remote_exec',
-         default=cdist.REMOTE_EXEC)
+         default=os.environ.get('CDIST_REMOTE_EXEC'))
     parser['config'].set_defaults(func=cdist.config.Config.commandline)
 
     # Shell
@@ -101,6 +130,32 @@ def commandline():
         logging.root.setLevel(logging.INFO)
     if args.debug:
         logging.root.setLevel(logging.DEBUG)
+    args_dict = vars(args)
+    # if command with remote_copy and remote_exec params
+    if 'remote_copy' in args_dict and 'remote_exec' in args_dict:
+        # if out_path is not set then create temp dir here so
+        # Local uses it for base_path and ssh mux socket is
+        # created in it.
+        if args_dict['out_path'] is None:
+            args.out_path = tempfile.mkdtemp()
+            is_temp_dir = True
+        else:
+            is_temp_dir = False
+        # if remote-exec and/or remote-copy args are None then user
+        # didn't specify command line options nor env vars:
+        # inspect multiplexing options for default cdist.REMOTE_COPY/EXEC
+        if args_dict['remote_copy'] is None or args_dict['remote_exec'] is None:
+            control_path_dir = args.out_path
+            # only rmtree if it is temp directory;
+            # if user specifies out_path do not remove it
+            if is_temp_dir:
+                import atexit
+                atexit.register(lambda: shutil.rmtree(control_path_dir))
+            mux_opts = inspect_ssh_mux_opts(control_path_dir)
+            if args_dict['remote_exec'] is None:
+                args.remote_exec = cdist.REMOTE_EXEC + mux_opts
+            if args_dict['remote_copy'] is None:
+                args.remote_copy = cdist.REMOTE_COPY + mux_opts
 
     log.debug(args)
     log.info("version %s" % cdist.VERSION)