initial code repo

[stor4nfv.git] / src / ceph / src / ceph-volume / ceph_volume / decorators.py

diff --git a/src/ceph/src/ceph-volume/ceph_volume/decorators.py b/src/ceph/src/ceph-volume/ceph_volume/decorators.py
new file mode 100644 (file)
index 0000000..d0be938
--- /dev/null
+++ b/src/ceph/src/ceph-volume/ceph_volume/decorators.py
@@ -0,0 +1,90 @@
+import os
+import sys
+from ceph_volume import terminal, exceptions
+from functools import wraps
+
+
+def needs_root(func):
+    """
+    Check for super user privileges on functions/methods. Raise
+    ``SuperUserError`` with a nice message.
+    """
+    @wraps(func)
+    def is_root(*a, **kw):
+        if not os.getuid() == 0:
+            raise exceptions.SuperUserError()
+        return func(*a, **kw)
+    return is_root
+
+
+def catches(catch=None, handler=None, exit=True):
+    """
+    Very simple decorator that tries any of the exception(s) passed in as
+    a single exception class or tuple (containing multiple ones) returning the
+    exception message and optionally handling the problem if it rises with the
+    handler if it is provided.
+
+    So instead of douing something like this::
+
+        def bar():
+            try:
+                some_call()
+                print "Success!"
+            except TypeError, exc:
+                print "Error while handling some call: %s" % exc
+                sys.exit(1)
+
+    You would need to decorate it like this to have the same effect::
+
+        @catches(TypeError)
+        def bar():
+            some_call()
+            print "Success!"
+
+    If multiple exceptions need to be catched they need to be provided as a
+    tuple::
+
+        @catches((TypeError, AttributeError))
+        def bar():
+            some_call()
+            print "Success!"
+    """
+    catch = catch or Exception
+
+    def decorate(f):
+
+        @wraps(f)
+        def newfunc(*a, **kw):
+            try:
+                return f(*a, **kw)
+            except catch as e:
+                import logging
+                logger = logging.getLogger('ceph_volume')
+                logger.exception('exception caught by decorator')
+                if os.environ.get('CEPH_VOLUME_DEBUG'):
+                    raise
+                if handler:
+                    return handler(e)
+                else:
+                    sys.stderr.write(make_exception_message(e))
+                    if exit:
+                        sys.exit(1)
+        return newfunc
+
+    return decorate
+
+#
+# Decorator helpers
+#
+
+
+def make_exception_message(exc):
+    """
+    An exception is passed in and this function
+    returns the proper string depending on the result
+    so it is readable enough.
+    """
+    if str(exc):
+        return '%s %s: %s\n' % (terminal.red_arrow, exc.__class__.__name__, exc)
+    else:
+        return '%s %s\n' % (terminal.red_arrow, exc.__class__.__name__)