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import io
import ecdsa
import hashlib
import yaml
import base64
import sys
import configschema
def render_path(path):
if path:
return "'" + ", ".join(path) + "'"
else:
return "the top level"
import traceback
class ErrorHandlingDict(dict):
def __init__(self, filename, path, optionals):
self._filename = filename
self._path = path
self._optionals = optionals
dict.__init__({})
def get(self, key, default=None):
path = "/".join(self._path + [key])
if path in self._optionals:
return dict.get(self, key, default)
print >>sys.stderr, "error: read key", path, "optionally with default", default
traceback.print_stack()
sys.exit(1)
def __missing__(self, key):
path = render_path(self._path)
print >>sys.stderr, "error: could not find configuration key '%s' at %s in %s" % (key, path, self._filename)
sys.exit(1)
def errorhandlify(term, filename, optionals, path=[]):
if isinstance(term, basestring):
return term
elif isinstance(term, int):
return term
elif isinstance(term, dict):
result = ErrorHandlingDict(filename, path, optionals)
for k, v in term.items():
result[k] = errorhandlify(v, filename, optionals, path + [k])
return result
elif isinstance(term, list):
return [errorhandlify(e, filename, optionals, path + ["item %d" % i]) for i, e in enumerate(term, start=1)]
else:
print "unknown type", type(term)
sys.exit(1)
def verify_config(rawconfig, signature, publickey_base64, filename):
publickey = base64.decodestring(publickey_base64)
try:
vk = ecdsa.VerifyingKey.from_der(publickey)
vk.verify(signature, rawconfig, hashfunc=hashlib.sha256,
sigdecode=ecdsa.util.sigdecode_der)
except ecdsa.keys.BadSignatureError:
print >>sys.stderr, "error: configuration file %s did not have a correct signature" % (filename,)
sys.exit(1)
return common_read_config(io.BytesIO(rawconfig), filename, localconfig=False)
def verify_and_read_config(filename, publickey_base64):
rawconfig = open(filename).read()
signature = open(filename + ".sig").read()
return verify_config(rawconfig, signature, publickey_base64, filename)
def insert_schema_path(schema, path, datatype, highleveldatatype, extra):
if len(path) == 1:
schema[path[0]] = (datatype, highleveldatatype, extra)
else:
if path[0] not in schema:
schema[path[0]] = {}
insert_schema_path(schema[path[0]], path[1:], datatype, highleveldatatype, extra)
def transform_schema((in_schema, defaults, optionals)):
defaults_dict = dict(defaults)
schema = {}
for (rawpath, datatype, highleveldatatype) in in_schema:
path = rawpath.split("/")
extra = {}
extra["optional"] = rawpath in optionals
extra["default"] = defaults_dict.get(rawpath)
insert_schema_path(schema, path, datatype, highleveldatatype, extra)
return schema
def check_config_schema(config, schema):
transformed_schema = transform_schema(schema)
problems = check_config_schema_part(config, transformed_schema)
if problems:
haserrors = False
for problem in problems:
if problem.startswith("error:"):
haserrors = True
else:
assert(problem.startswith("WARNING:"))
print >>sys.stderr, problem
if haserrors:
sys.exit(1)
def check_config_schema_part(term, schema, path=[]):
joined_path = render_path(path)
problems = []
if isinstance(term, basestring):
(schema_lowlevel, schema_highlevel, extra) = schema
if schema_lowlevel != "string":
problems.append("error: expected %s at %s, not a string" % (schema_lowlevel, joined_path,))
elif isinstance(term, int):
(schema_lowlevel, schema_highlevel, extra) = schema
if schema_lowlevel != "integer":
problems.append("error: expected %s at %s, not an integer" % (schema_lowlevel, joined_path,))
elif isinstance(term, dict):
if not isinstance(schema, dict):
problems.append("error: expected %s at %s, not a key" % (schema, joined_path,))
for k, v in term.items():
schema_part = schema.get(k)
if schema_part == None and len(schema.keys()) == 1 and schema.keys()[0].startswith("*"):
schema_part = schema[schema.keys()[0]]
if schema_part == None:
problems.append("WARNING: configuration key '%s' at %s unknown" % (k, joined_path))
del term[k]
continue
problems.extend(check_config_schema_part(v, schema_part, path + [k]))
elif isinstance(term, list):
if not isinstance(schema, dict):
problems.append("error: expected %s at %s, not a list" % (schema, joined_path,))
schema_part = schema.get("[]")
if schema_part == None:
problems.append("error: expected dict at %s, not a list" % (joined_path,))
for i, e in enumerate(term, start=1):
problems.extend(check_config_schema_part(e, schema_part, path + ["item %d" % i]))
else:
print >>sys.stderr, "unknown type", type(term)
sys.exit(1)
return problems
def insert_defaults(config, configdefaults):
for (rawpath, value) in configdefaults:
path = rawpath.split("/")
node = config
for e in path[:-1]:
assert(e != "[]")
node = node[e]
lastelem = path[-1]
if lastelem not in node:
node[lastelem] = value
def common_read_config(f, filename, localconfig=True):
if localconfig:
schema = configschema.localconfigschema
configdefaults = configschema.localconfigdefaults
optionals = configschema.localconfigoptionals
else:
schema = configschema.globalconfigschema
configdefaults = configschema.globalconfigdefaults
optionals = configschema.globalconfigoptionals
config = yaml.load(f, yaml.SafeLoader)
insert_defaults(config, configdefaults)
check_config_schema(config, (schema, configdefaults, optionals))
return errorhandlify(config, filename, optionals)
def read_config(filename, localconfig=True):
return common_read_config(open(filename), filename, localconfig=localconfig)
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