Implement preos

cdist/preos.py

@@ -0,0 +1,101 @@
+import os
+import os.path
+import sys
+import inspect
+import argparse
+import cdist
+import logging
+
+
+_PREOS_CALL = "commandline"
+_PREOS_NAME = "_preos_name"
+_PREOS_MARKER = "_cdist_preos"
+_PLUGINS_DIR = "preos"
+_PLUGINS_PATH = [os.path.join(os.path.dirname(__file__), _PLUGINS_DIR), ]
+cdist_home = cdist.home_dir()
+if cdist_home:
+    cdist_home_preos = os.path.join(cdist_home, "preos")
+    if os.path.isdir(cdist_home_preos):
+        _PLUGINS_PATH.append(cdist_home_preos)
+sys.path.extend(_PLUGINS_PATH)
+
+
+log = logging.getLogger("PreOS")
+
+
+def preos_plugin(obj):
+    """It is preos if _PREOS_MARKER is True and has _PREOS_CALL."""
+    if hasattr(obj, _PREOS_MARKER):
+        is_preos = getattr(obj, _PREOS_MARKER)
+    else:
+        is_preos = False
+
+    if is_preos and hasattr(obj, _PREOS_CALL):
+        yield obj
+
+
+def scan_preos_dir_plugins(dir):
+    for fname in os.listdir(dir):
+        if os.path.isfile(os.path.join(dir, fname)):
+            fname = os.path.splitext(fname)[0]
+        module_name = fname
+        try:
+            module = __import__(module_name)
+            yield from preos_plugin(module)
+            clsmembers = inspect.getmembers(module, inspect.isclass)
+            for cm in clsmembers:
+                c = cm[1]
+                yield from preos_plugin(c)
+        except ImportError as e:
+            log.warning("Cannot import '{}': {}".format(module_name, e))
+
+
+def find_preos_plugins():
+    for dir in _PLUGINS_PATH:
+        yield from scan_preos_dir_plugins(dir)
+
+
+def find_preoses():
+    preoses = {}
+    for preos in find_preos_plugins():
+        if hasattr(preos, _PREOS_NAME):
+            preos_name = getattr(preos, _PREOS_NAME)
+        else:
+            preos_name = preos.__name__.lower()
+        preoses[preos_name] = preos
+    return preoses
+
+
+def check_root():
+    if os.geteuid() != 0:
+        raise cdist.Error("Must be run with root privileges")
+
+
+class PreOS(object):
+    preoses = None
+
+    @classmethod
+    def commandline(cls, argv):
+
+        if not cls.preoses:
+            cls.preoses = find_preoses()
+
+        parser = argparse.ArgumentParser(
+            description="Create PreOS", prog="cdist preos")
+        parser.add_argument('preos', help='PreOS to create, one of: {}'.format(
+            set(cls.preoses)))
+        args = parser.parse_args(argv[1:2])
+
+        preos_name = args.preos
+        if preos_name in cls.preoses:
+            preos = cls.preoses[preos_name]
+            func = getattr(preos, _PREOS_CALL)
+            if inspect.ismodule(preos):
+                func_args = [preos, argv[2:], ]
+            else:
+                func_args = [argv[2:], ]
+            log.info("Running preos : {}".format(preos_name))
+            func(*func_args)
+        else:
+            log.error("Unknown preos: {}, available preoses: {}".format(
+                preos_name, set(cls.preoses.keys())))