backend (currently json).
"""
+# pylint: disable=C0103
+
+# C0103: Invalid name, since pylint doesn't see that Dump points to a
+# function and not a constant
-import simplejson
import re
-# Check whether the simplejson module supports indentation
-_JSON_INDENT = 2
-try:
- simplejson.dumps(1, indent=_JSON_INDENT)
-except TypeError:
- _JSON_INDENT = None
+# Python 2.6 and above contain a JSON module based on simplejson. Unfortunately
+# the standard library version is significantly slower than the external
+# module. While it should be better from at least Python 3.2 on (see Python
+# issue 7451), for now Ganeti needs to work well with older Python versions
+# too.
+import simplejson
+
+from ganeti import errors
+from ganeti import utils
+
-_RE_EOLSP = re.compile('[ \t]+$', re.MULTILINE)
+_RE_EOLSP = re.compile("[ \t]+$", re.MULTILINE)
def DumpJson(data):
"""Serialize a given object.
+ @param data: the data to serialize
+ @return: the string representation of data
+
"""
- if _JSON_INDENT is None:
- txt = simplejson.dumps(data)
- else:
- txt = simplejson.dumps(data, indent=_JSON_INDENT)
- txt = _RE_EOLSP.sub("", txt)
- if not txt.endswith('\n'):
- txt += '\n'
+ encoded = simplejson.dumps(data)
+
+ txt = _RE_EOLSP.sub("", encoded)
+ if not txt.endswith("\n"):
+ txt += "\n"
+
return txt
def LoadJson(txt):
"""Unserialize data from a string.
+ @param txt: the json-encoded form
+
+ @return: the original data
+
"""
return simplejson.loads(txt)
+def DumpSignedJson(data, key, salt=None, key_selector=None):
+ """Serialize a given object and authenticate it.
+
+ @param data: the data to serialize
+ @param key: shared hmac key
+ @param key_selector: name/id that identifies the key (in case there are
+ multiple keys in use, e.g. in a multi-cluster environment)
+ @return: the string representation of data signed by the hmac key
+
+ """
+ txt = DumpJson(data)
+ if salt is None:
+ salt = ""
+ signed_dict = {
+ "msg": txt,
+ "salt": salt,
+ }
+
+ if key_selector:
+ signed_dict["key_selector"] = key_selector
+ else:
+ key_selector = ""
+
+ signed_dict["hmac"] = utils.Sha1Hmac(key, txt, salt=salt + key_selector)
+
+ return DumpJson(signed_dict)
+
+
+def LoadSignedJson(txt, key):
+ """Verify that a given message was signed with the given key, and load it.
+
+ @param txt: json-encoded hmac-signed message
+ @param key: the shared hmac key or a callable taking one argument (the key
+ selector), which returns the hmac key belonging to the key selector.
+ Typical usage is to pass a reference to the get method of a dict.
+ @rtype: tuple of original data, string
+ @return: original data, salt
+ @raises errors.SignatureError: if the message signature doesn't verify
+
+ """
+ signed_dict = LoadJson(txt)
+ if not isinstance(signed_dict, dict):
+ raise errors.SignatureError("Invalid external message")
+ try:
+ msg = signed_dict["msg"]
+ salt = signed_dict["salt"]
+ hmac_sign = signed_dict["hmac"]
+ except KeyError:
+ raise errors.SignatureError("Invalid external message")
+
+ if callable(key):
+ # pylint: disable=E1103
+ key_selector = signed_dict.get("key_selector", None)
+ hmac_key = key(key_selector)
+ if not hmac_key:
+ raise errors.SignatureError("No key with key selector '%s' found" %
+ key_selector)
+ else:
+ key_selector = ""
+ hmac_key = key
+
+ if not utils.VerifySha1Hmac(hmac_key, msg, hmac_sign,
+ salt=salt + key_selector):
+ raise errors.SignatureError("Invalid Signature")
+
+ return LoadJson(msg), salt
+
+
+def LoadAndVerifyJson(raw, verify_fn):
+ """Parses and verifies JSON data.
+
+ @type raw: string
+ @param raw: Input data in JSON format
+ @type verify_fn: callable
+ @param verify_fn: Verification function, usually from L{ht}
+ @return: De-serialized data
+
+ """
+ try:
+ data = LoadJson(raw)
+ except Exception, err:
+ raise errors.ParseError("Can't parse input data: %s" % err)
+
+ if not verify_fn(data):
+ raise errors.ParseError("Data does not match expected format: %s" %
+ verify_fn)
+
+ return data
+
+
Dump = DumpJson
Load = LoadJson
+DumpSigned = DumpSignedJson
+LoadSigned = LoadSignedJson