Add helpers for cdist config/install integration. (#551)

Implement simple integration API.

cdist/integration.py

@@ -0,0 +1,153 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+#
+# 2017 Darko Poljak (darko.poljak at gmail.com)
+#
+# This file is part of cdist.
+#
+# cdist 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.
+#
+# cdist is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with cdist. If not, see <http://www.gnu.org/licenses/>.
+#
+#
+
+import cdist
+# needed for cdist.argparse
+import cdist.banner
+import cdist.config
+import cdist.install
+import cdist.shell
+import cdist.inventory
+import cdist.argparse
+import cdist.log
+import cdist.config
+import cdist.install
+import sys
+import os
+import os.path
+import collections
+import uuid
+
+
+def find_cdist_exec_in_path():
+    """Search cdist executable in os.get_exec_path() entries.
+    """
+    for path in os.get_exec_path():
+        cdist_path = os.path.join(path, 'cdist')
+        if os.access(cdist_path, os.X_OK):
+            return cdist_path
+    return None
+
+
+_mydir = os.path.dirname(__file__)
+
+
+def find_cdist_exec():
+    """Search cdist executable starting from local lib directory.
+
+    Detect if ../scripts/cdist (from local lib direcotry) exists and
+    if it is executable. If not then try to find cdist exec path in
+    os.get_exec_path() entries. If no cdist path is found rasie
+    cdist.Error.
+    """
+    cdist_path = os.path.abspath(os.path.join(_mydir, '..', 'scripts',
+                                              'cdist'))
+    if os.access(cdist_path, os.X_OK):
+        return cdist_path
+    cdist_path = find_cdist_exec_in_path()
+    if not cdist_path:
+        raise cdist.Error('Cannot find cdist executable from local lib '
+                          'directory: {}, nor in PATH: {}.'.format(
+                              _mydir, os.environ.get('PATH')))
+    return cdist_path
+
+
+ACTION_CONFIG = 'config'
+ACTION_INSTALL = 'install'
+
+
+def _process_hosts_simple(action, host, manifest, verbose,
+                          cdist_path=None):
+    """Perform cdist action ('config' or 'install') on hosts with specified
+       manifest using default other cdist options. host parameter can be a
+       string or iterbale of hosts. verbose is a desired verbosity level
+       which defaults to VERBOSE_INFO. cdist_path is path to cdist executable,
+       if it is None then integration lib tries to find it.
+    """
+    if isinstance(host, str):
+        hosts = [host, ]
+    elif isinstance(host, collections.Iterable):
+        hosts = host
+    else:
+        raise cdist.Error('Invalid host argument: {}'.format(host))
+
+    # Setup sys.argv[0] since cdist relies on command line invocation.
+    if not cdist_path:
+        cdist_path = find_cdist_exec()
+    sys.argv[0] = cdist_path
+
+    cname = action.title()
+    module = getattr(cdist, action)
+    theclass = getattr(module, cname)
+
+    # Build argv for cdist and use argparse for argument parsing.
+    remote_out_dir_base = os.path.join('/', 'var', 'lib', 'cdist')
+    uid = str(uuid.uuid1())
+    out_dir = remote_out_dir_base + uid
+    cache_path_pattern = '%h-' + uid
+    argv = [action, '-i', manifest, '-r', out_dir, '-C', cache_path_pattern, ]
+    for i in range(verbose):
+        argv.append('-v')
+    for x in hosts:
+        argv.append(x)
+
+    parser, cfg = cdist.argparse.parse_and_configure(argv, singleton=False)
+    args = cfg.get_args()
+    configuration = cfg.get_config(section='GLOBAL')
+
+    theclass.construct_remote_exec_copy_patterns(args)
+    base_root_path = theclass.create_base_root_path(None)
+
+    for target_host in args.host:
+        host_base_path, hostdir = theclass.create_host_base_dirs(
+            target_host, base_root_path)
+        theclass.onehost(target_host, None, host_base_path, hostdir, args,
+                         parallel=False, configuration=configuration,
+                         remove_remote_files_dirs=True)
+
+
+def configure_hosts_simple(host, manifest,
+                           verbose=cdist.argparse.VERBOSE_INFO,
+                           cdist_path=None):
+    """Configure hosts with specified manifest using default other cdist
+       options. host parameter can be a string or iterbale of hosts. verbose
+       is a desired verbosity level which defaults to VERBOSE_INFO.
+       cdist_path is path to cdist executable, if it is None then integration
+       lib tries to find it.
+    """
+    _process_hosts_simple(action=ACTION_CONFIG, host=host,
+                          manifest=manifest, verbose=verbose,
+                          cdist_path=cdist_path)
+
+
+def install_hosts_simple(host, manifest,
+                         verbose=cdist.argparse.VERBOSE_INFO,
+                         cdist_path=None):
+    """Install hosts with specified manifest using default other cdist
+       options. host parameter can be a string or iterbale of hosts. verbose
+       is a desired verbosity level which defaults to VERBOSE_INFO.
+       cdist_path is path to cdist executable, if it is None then integration
+       lib tries to find it.
+    """
+    _process_hosts_simple(action=ACTION_INSTALL, host=host,
+                          manifest=manifest, verbose=verbose,
+                          cdist_path=cdist_path)