core implementation
code bomb implementing the bulk of the osmo-gsm-tester
Change-Id: I53610becbf643ed51b90cfd9debc6992fe211ec9
diff --git a/src/osmo_gsm_tester/schema.py b/src/osmo_gsm_tester/schema.py
new file mode 100644
index 0000000..a10ddd1
--- /dev/null
+++ b/src/osmo_gsm_tester/schema.py
@@ -0,0 +1,144 @@
+# osmo_gsm_tester: validate dict structures
+#
+# Copyright (C) 2016-2017 by sysmocom - s.f.m.c. GmbH
+#
+# Author: Neels Hofmeyr <neels@hofmeyr.de>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program 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 Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+import re
+
+from . import log
+from .util import is_dict, is_list
+
+KEY_RE = re.compile('[a-zA-Z][a-zA-Z0-9_]*')
+IPV4_RE = re.compile('([0-9]{1,3}.){3}[0-9]{1,3}')
+HWADDR_RE = re.compile('([0-9a-fA-F]{2}:){5}[0-9a-fA-F]{2}')
+IMSI_RE = re.compile('[0-9]{6,15}')
+KI_RE = re.compile('[0-9a-fA-F]{32}')
+MSISDN_RE = re.compile('[0-9]{1,15}')
+
+def match_re(name, regex, val):
+ while True:
+ if not isinstance(val, str):
+ break;
+ if not regex.fullmatch(val):
+ break;
+ return
+ raise ValueError('Invalid %s: %r' % (name, val))
+
+def band(val):
+ if val in ('GSM-1800', 'GSM-1900'):
+ return
+ raise ValueError('Unknown GSM band: %r' % val)
+
+def ipv4(val):
+ match_re('IPv4 address', IPV4_RE, val)
+ els = [int(el) for el in val.split('.')]
+ if not all([el >= 0 and el <= 255 for el in els]):
+ raise ValueError('Invalid IPv4 address: %r' % val)
+
+def hwaddr(val):
+ match_re('hardware address', HWADDR_RE, val)
+
+def imsi(val):
+ match_re('IMSI', IMSI_RE, val)
+
+def ki(val):
+ match_re('KI', KI_RE, val)
+
+def msisdn(val):
+ match_re('MSISDN', MSISDN_RE, val)
+
+INT = 'int'
+STR = 'str'
+BAND = 'band'
+IPV4 = 'ipv4'
+HWADDR = 'hwaddr'
+IMSI = 'imsi'
+KI = 'ki'
+MSISDN = 'msisdn'
+SCHEMA_TYPES = {
+ INT: int,
+ STR: str,
+ BAND: band,
+ IPV4: ipv4,
+ HWADDR: hwaddr,
+ IMSI: imsi,
+ KI: ki,
+ MSISDN: msisdn,
+ }
+
+def validate(config, schema):
+ '''Make sure the given config dict adheres to the schema.
+ The schema is a dict of 'dict paths' in dot-notation with permitted
+ value type. All leaf nodes are validated, nesting dicts are implicit.
+
+ validate( { 'a': 123, 'b': { 'b1': 'foo', 'b2': [ 1, 2, 3 ] } },
+ { 'a': int,
+ 'b.b1': str,
+ 'b.b2[]': int } )
+
+ Raise a ValueError in case the schema is violated.
+ '''
+
+ def validate_item(path, value, schema):
+ want_type = schema.get(path)
+
+ if is_list(value):
+ if want_type:
+ raise ValueError('config item is a list, should be %r: %r' % (want_type, path))
+ path = path + '[]'
+ want_type = schema.get(path)
+
+ if not want_type:
+ if is_dict(value):
+ nest(path, value, schema)
+ return
+ if is_list(value) and value:
+ for list_v in value:
+ validate_item(path, list_v, schema)
+ return
+ raise ValueError('config item not known: %r' % path)
+
+ if want_type not in SCHEMA_TYPES:
+ raise ValueError('unknown type %r at %r' % (want_type, path))
+
+ if is_dict(value):
+ raise ValueError('config item is dict but should be a leaf node of type %r: %r'
+ % (want_type, path))
+
+ if is_list(value):
+ for list_v in value:
+ validate_item(path, list_v, schema)
+ return
+
+ with log.Origin(item=path):
+ type_validator = SCHEMA_TYPES.get(want_type)
+ type_validator(value)
+
+ def nest(parent_path, config, schema):
+ if parent_path:
+ parent_path = parent_path + '.'
+ else:
+ parent_path = ''
+ for k,v in config.items():
+ if not KEY_RE.fullmatch(k):
+ raise ValueError('invalid config key: %r' % k)
+ path = parent_path + k
+ validate_item(path, v, schema)
+
+ nest(None, config, schema)
+
+# vim: expandtab tabstop=4 shiftwidth=4