Add -f option for reading hosts from file or stdin.

cdist/config.py

@@ -53,6 +53,21 @@ class Config(object):
         self.local.create_files_dirs()
         self.remote.create_files_dirs()
 
+    @staticmethod
+    def hosts(source):
+        """Yield hosts from source.
+           Source can be a sequence or filename (stdin if \'-\').
+           In case of filename each line represents one host.
+        """
+        if isinstance(source, str):
+            import fileinput
+            for host in fileinput.input(files=(source)):
+                yield host.strip()  # remove leading and trailing whitespace
+        else:
+            for host in source:
+                yield host
+
+
     @classmethod
     def commandline(cls, args):
         """Configure remote system"""
@@ -61,6 +76,12 @@ class Config(object):
         # FIXME: Refactor relict - remove later
         log = logging.getLogger("cdist")
 
+        if args.manifest == '-' and args.hostfile == '-':
+            raise cdist.Error("Cannot read both, manifest and host file, from stdin")
+        # if no host source is specified then read hosts from stdin
+        if not (args.hostfile or args.host):
+            args.hostfile = '-'
+    
         initial_manifest_tempfile = None
         if args.manifest == '-':
             # read initial manifest from stdin
@@ -80,7 +101,14 @@ class Config(object):
         failed_hosts = []
         time_start = time.time()
 
-        for host in args.host:
+        hostcnt = 0
+        if args.host:
+            host_source = args.host
+        else:
+            host_source = args.hostfile
+    
+        for host in cls.hosts(host_source):
+            hostcnt += 1
             if args.parallel:
                 log.debug("Creating child process for %s", host)
                 process[host] = multiprocessing.Process(target=cls.onehost, args=(host, args, True))
@@ -101,7 +129,7 @@ class Config(object):
                     failed_hosts.append(host)
     
         time_end = time.time()
-        log.info("Total processing time for %s host(s): %s", len(args.host),
+        log.info("Total processing time for %s host(s): %s", hostcnt,
                     (time_end - time_start))
     
         if len(failed_hosts) > 0:

docs/man/man1/cdist.text

@@ -14,7 +14,7 @@ cdist [-h] [-d] [-v] [-V] {banner,config,shell} ...
 
 cdist banner [-h] [-d] [-v]
 
-cdist config [-h] [-d] [-V] [-c CONF_DIR] [-i MANIFEST] [-p] [-s] host [host ...]
+cdist config [-h] [-d] [-V] [-c CONF_DIR] [-f HOSTFILE] [-i MANIFEST] [-p] [-s] [host [host ...]]
 
 cdist shell [-h] [-d] [-v] [-s SHELL]
 
@@ -63,6 +63,11 @@ Configure one or more hosts
     --conf-dir argument have higher precedence over those set through the
     environment variable.
 
+-f HOSTFILE, --file HOSTFILE::
+    Read hosts to operate on from specified file or from stdin if '-'
+    (each host on separate line). If no host or host file is
+    specified then, by default, read hosts from stdin.
+
 -i MANIFEST, --initial-manifest MANIFEST::
     Path to a cdist manifest or - to read from stdin
 
@@ -105,6 +110,9 @@ EXAMPLES
     --remote-copy /path/to/my/remote/copy \
     -p ikq02.ethz.ch ikq03.ethz.ch ikq04.ethz.ch
 
+# Configure hosts in parallel by reading hosts from file loadbalancers
+% cdist config -f loadbalancers
+
 # Display banner
 cdist banner
 

scripts/cdist

@@ -67,12 +67,14 @@ def commandline():
         action='store_true', default=False)
 
     # Main subcommand parser
-    parser['main'] = argparse.ArgumentParser(description='cdist ' + cdist.VERSION,
+    parser['main'] = argparse.ArgumentParser(description='cdist '
+            + cdist.VERSION,
         parents=[parser['loglevel']])
     parser['main'].add_argument('-V', '--version',
         help='Show version', action='version',
         version='%(prog)s ' + cdist.VERSION)
-    parser['sub'] = parser['main'].add_subparsers(title="Commands")
+    parser['sub'] = parser['main'].add_subparsers(title="Commands",
+            dest="command")
 
     # Banner
     parser['banner'] = parser['sub'].add_parser('banner', 
@@ -82,11 +84,16 @@ def commandline():
     # Config
     parser['config'] = parser['sub'].add_parser('config',
         parents=[parser['loglevel']])
-    parser['config'].add_argument('host', nargs='+',
+    parser['config'].add_argument('host', nargs='*',
         help='one or more hosts to operate on')
     parser['config'].add_argument('-c', '--conf-dir',
-         help='Add configuration directory (can be repeated, last one wins)',
+         help=('Add configuration directory (can be repeated, '
-         action='append')
+             'last one wins)'), action='append')
+    parser['config'].add_argument('-f', '--file',
+         help=('Read hosts to operate on from specified file or from stdin '
+             'if \'-\' (each host on separate line). If no host or host '
+             'file is specified then, by default, read hosts from stdin.'),
+         dest='hostfile', required=False)
     parser['config'].add_argument('-i', '--initial-manifest', 
          help='Path to a cdist manifest or \'-\' to read from stdin.',
          dest='manifest', required=False)
@@ -108,7 +115,8 @@ def commandline():
          action='store', dest='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)',
+         help=('Command to use for remote execution '
+               '(should behave like ssh)'),
          action='store', dest='remote_exec',
          default=os.environ.get('CDIST_REMOTE_EXEC'))
     parser['config'].set_defaults(func=cdist.config.Config.commandline)
@@ -147,6 +155,11 @@ def commandline():
             if args_dict['remote_copy'] is None:
                 args.remote_copy = cdist.REMOTE_COPY + mux_opts
 
+    if args.command == 'config':
+        if args.manifest == '-' and args.hostfile == '-':
+            print('cdist config: error: cannot read both, manifest and host file, from stdin')
+            sys.exit(1)
+
     log.debug(args)
     log.info("version %s" % cdist.VERSION)