Remove strict dependency on leap.common.

* Encapsulate leap_assert and leap_assert_type so Soledad works without them.
* Remove dependency on leap.common.files.mkdir_p().
* Encapsulate signaling.
* Add changes file.

6 files changed, 178 insertions, 76 deletions

diff --git a/changes/feature_remove-strict-dependency-on-leap.common b/changes/feature_remove-strict-dependency-on-leap.common
new file mode 100644
index 00000000..f25dcbf3
--- /dev/null
+++ b/changes/feature_remove-strict-dependency-on-leap.common
@@ -0,0 +1 @@
+  o Remove strict dependency on leap.common.
diff --git a/setup.py b/setup.py
index b1c0b9db..b016f124 100644
--- a/setup.py
+++ b/setup.py
@@ -26,7 +26,6 @@ from setuptools import (
 install_requirements = [
     'configparser',
     'couchdb',
-    'leap.common',
     'pysqlcipher',
     'simplejson',
     'twisted>=12.0.0',  # TODO: maybe we just want twisted-web?
@@ -45,6 +44,7 @@ tests_requirements = [
     'mock',
     'nose2',
     'testscenarios',
+    'leap.common',
 ]
 
 
@@ -89,4 +89,7 @@ setup(
     tests_require=tests_requirements,
     data_files=data_files,
     classifiers=trove_classifiers,
+    extras_require={
+        'signaling': ['leap.common'],
+    }
 )
diff --git a/src/leap/soledad/__init__.py b/src/leap/soledad/__init__.py
index fba275e3..ea3f676b 100644
--- a/src/leap/soledad/__init__.py
+++ b/src/leap/soledad/__init__.py
@@ -36,6 +36,7 @@ import scrypt
 import httplib
 import socket
 import ssl
+import errno
 
 
 from xdg import BaseDirectory
@@ -47,9 +48,92 @@ from u1db.remote.ssl_match_hostname import (  # noqa
 )
 
 
-from leap.common import events
-from leap.common.check import leap_assert
-from leap.common.files import mkdir_p
+#
+# Assert functions
+#
+
+def soledad_assert(condition, message):
+    """
+    Asserts the condition and displays the message if that's not
+    met.
+
+    @param condition: condition to check
+    @type condition: bool
+    @param message: message to display if the condition isn't met
+    @type message: str
+    """
+    assert condition, message
+
+
+# we want to use leap.common.check.leap_assert in case it is available,
+# because it also logs in a way other parts of leap can access log messages.
+try:
+    from leap.common.check import leap_assert
+    soledad_assert = leap_assert
+except ImportError:
+    pass
+
+
+def soledad_assert_type(var, expectedType):
+    """
+    Helper assert check for a variable's expected type
+
+    @param var: variable to check
+    @type var: any
+    @param expectedType: type to check agains
+    @type expectedType: type
+    """
+    soledad_assert(isinstance(var, expectedType),
+                   "Expected type %r instead of %r" %
+                   (expectedType, type(var)))
+
+try:
+    from leap.common.check import leap_assert_type
+    soledad_assert_type = leap_assert_type
+except ImportError:
+    pass
+
+
+#
+# Signaling function
+#
+
+# we define a fake signaling function and fake signal constants that will
+# allow for logging signaling attempts in case leap.common.events is not
+# available.
+
+def signal(signal, content=""):
+    logger.info("Would signal: %s - %s." % (str(signal), content))
+
+SOLEDAD_CREATING_KEYS = 'Creating keys...'
+SOLEDAD_DONE_CREATING_KEYS = 'Done creating keys.'
+SOLEDAD_DOWNLOADING_KEYS = 'Downloading keys...'
+SOLEDAD_DONE_DOWNLOADING_KEYS = 'Done downloading keys.'
+SOLEDAD_UPLOADING_KEYS = 'Uploading keys...'
+SOLEDAD_DONE_UPLOADING_KEYS = 'Done uploading keys.'
+SOLEDAD_NEW_DATA_TO_SYNC = 'New data available.'
+SOLEDAD_DONE_DATA_SYNC = 'Done data sync.'
+
+# we want to use leap.common.events to emits signals, if it is available.
+try:
+    from leap.common import events
+    # replace fake signaling function with real one
+    signal = events.signal
+    # replace fake string signals with real signals
+    SOLEDAD_CREATING_KEYS = events.events_pb2.SOLEDAD_CREATING_KEYS
+    SOLEDAD_DONE_CREATING_KEYS = events.events_pb2.SOLEDAD_DONE_CREATING_KEYS
+    SOLEDAD_DOWNLOADING_KEYS = events.events_pb2.SOLEDAD_DOWNLOADING_KEYS
+    SOLEDAD_DONE_DOWNLOADING_KEYS = \
+        events.events_pb2.SOLEDAD_DONE_DOWNLOADING_KEYS
+    SOLEDAD_UPLOADING_KEYS = events.events_pb2.SOLEDAD_UPLOADING_KEYS
+    SOLEDAD_DONE_UPLOADING_KEYS = \
+        events.events_pb2.SOLEDAD_DONE_UPLOADING_KEYS
+    SOLEDAD_NEW_DATA_TO_SYNC = events.events_pb2.SOLEDAD_NEW_DATA_TO_SYNC
+    SOLEDAD_DONE_DATA_SYNC = events.events_pb2.SOLEDAD_DONE_DATA_SYNC
+except ImportError:
+    pass
+
+
 from leap.soledad.backends import sqlcipher
 from leap.soledad.backends.leap_backend import (
     LeapDocument,
@@ -64,6 +148,10 @@ from leap.soledad.crypto import SoledadCrypto
 logger = logging.getLogger(name=__name__)
 
 
+#
+# Constants
+#
+
 SOLEDAD_CERT = None
 """
 Path to the certificate file used to certify the SSL connection between
@@ -226,7 +314,7 @@ class Soledad(object):
                 self.DEFAULT_PREFIX, self.LOCAL_DATABASE_FILE_NAME)
         # initialize server_url
         self._server_url = server_url
-        leap_assert(
+        soledad_assert(
             self._server_url is not None,
             'Missing URL for Soledad server.')
 
@@ -295,7 +383,13 @@ class Soledad(object):
             [self._local_db_path, self._secrets_path])
         for path in paths:
             logger.info('Creating directory: %s.' % path)
-            mkdir_p(path)
+            try:
+                os.makedirs(path)
+            except OSError as exc:
+                if exc.errno == errno.EEXIST and os.path.isdir(path):
+                    pass
+                else:
+                    raise
 
     def _init_db(self):
         """
@@ -439,8 +533,8 @@ class Soledad(object):
 
         This method emits the following signals:
 
-            * leap.common.events.events_pb2.SOLEDAD_CREATING_KEYS
-            * leap.common.events.events_pb2.SOLEDAD_DONE_CREATING_KEYS
+            * SOLEDAD_CREATING_KEYS
+            * SOLEDAD_DONE_CREATING_KEYS
 
         A secret has the following structure:
 
@@ -458,7 +552,7 @@ class Soledad(object):
         @return: The id of the generated secret.
         @rtype: str
         """
-        events.signal(events.events_pb2.SOLEDAD_CREATING_KEYS, self._uuid)
+        signal(SOLEDAD_CREATING_KEYS, self._uuid)
         # generate random secret
         secret = os.urandom(self.GENERATED_SECRET_LENGTH)
         secret_id = sha256(secret).hexdigest()
@@ -479,8 +573,7 @@ class Soledad(object):
                 str(iv), self.IV_SEPARATOR, binascii.b2a_base64(ciphertext)),
         }
         self._store_secrets()
-        events.signal(
-            events.events_pb2.SOLEDAD_DONE_CREATING_KEYS, self._uuid)
+        signal(SOLEDAD_DONE_CREATING_KEYS, self._uuid)
         return secret_id
 
     def _store_secrets(self):
@@ -543,15 +636,13 @@ class Soledad(object):
         @return: a document with encrypted key material in its contents
         @rtype: LeapDocument
         """
-        events.signal(
-            events.events_pb2.SOLEDAD_DOWNLOADING_KEYS, self._uuid)
+        signal(SOLEDAD_DOWNLOADING_KEYS, self._uuid)
         db = self._shared_db()
         if not db:
             logger.warning('No shared db found')
             return
         doc = db.get_doc(self._uuid_hash())
-        events.signal(
-            events.events_pb2.SOLEDAD_DONE_DOWNLOADING_KEYS, self._uuid)
+        signal(SOLEDAD_DONE_DOWNLOADING_KEYS, self._uuid)
         return doc
 
     def _put_secrets_in_shared_db(self):
@@ -563,7 +654,7 @@ class Soledad(object):
         Otherwise, upload keys to shared recovery database.
 
         """
-        leap_assert(
+        soledad_assert(
             self._has_secret(),
             'Tried to send keys to server but they don\'t exist in local '
             'storage.')
@@ -574,15 +665,13 @@ class Soledad(object):
         # fill doc with encrypted secrets
         doc.content = self.export_recovery_document(include_uuid=False)
         # upload secrets to server
-        events.signal(
-            events.events_pb2.SOLEDAD_UPLOADING_KEYS, self._uuid)
+        signal(SOLEDAD_UPLOADING_KEYS, self._uuid)
         db = self._shared_db()
         if not db:
             logger.warning('No shared db found')
             return
         db.put_doc(doc)
-        events.signal(
-            events.events_pb2.SOLEDAD_DONE_UPLOADING_KEYS, self._uuid)
+        signal(SOLEDAD_DONE_UPLOADING_KEYS, self._uuid)
 
     #
     # Document storage, retrieval and sync.
@@ -835,7 +924,7 @@ class Soledad(object):
         local_gen = self._db.sync(
             urlparse.urljoin(self.server_url, 'user-%s' % self._uuid),
             creds=self._creds, autocreate=True)
-        events.signal(events.events_pb2.SOLEDAD_DONE_DATA_SYNC, self._uuid)
+        signal(SOLEDAD_DONE_DATA_SYNC, self._uuid)
         return local_gen
 
     def need_sync(self, url):
@@ -852,8 +941,7 @@ class Soledad(object):
         info = target.get_sync_info(self._db._get_replica_uid())
         # compare source generation with target's last known source generation
         if self._db._get_generation() != info[4]:
-            events.signal(
-                events.events_pb2.SOLEDAD_NEW_DATA_TO_SYNC, self._uuid)
+            signal(SOLEDAD_NEW_DATA_TO_SYNC, self._uuid)
             return True
         return False
 
@@ -1005,3 +1093,6 @@ class VerifiedHTTPSConnection(httplib.HTTPSConnection):
 
 old__VerifiedHTTPSConnection = http_client._VerifiedHTTPSConnection
 http_client._VerifiedHTTPSConnection = VerifiedHTTPSConnection
+
+
+__all__ = ['soledad_assert', 'Soledad']
diff --git a/src/leap/soledad/backends/leap_backend.py b/src/leap/soledad/backends/leap_backend.py
index 18c64f97..4d92db37 100644
--- a/src/leap/soledad/backends/leap_backend.py
+++ b/src/leap/soledad/backends/leap_backend.py
@@ -33,11 +33,11 @@ from u1db.errors import BrokenSyncStream
 from u1db.remote.http_target import HTTPSyncTarget
 
 
+from leap.soledad import soledad_assert
 from leap.soledad.crypto import (
     EncryptionMethods,
     UnknownEncryptionMethod,
 )
-from leap.common.check import leap_assert
 from leap.soledad.auth import TokenBasedAuth
 
 
@@ -165,7 +165,7 @@ def encrypt_doc(crypto, doc):
         content.
     @rtype: str
     """
-    leap_assert(doc.is_tombstone() is False)
+    soledad_assert(doc.is_tombstone() is False)
     # encrypt content using AES-256 CTR mode
     iv, ciphertext = crypto.encrypt_sym(
         doc.get_json(),
@@ -218,12 +218,12 @@ def decrypt_doc(crypto, doc):
     @return: The JSON serialization of the decrypted content.
     @rtype: str
     """
-    leap_assert(doc.is_tombstone() is False)
-    leap_assert(ENC_JSON_KEY in doc.content)
-    leap_assert(ENC_SCHEME_KEY in doc.content)
-    leap_assert(ENC_METHOD_KEY in doc.content)
-    leap_assert(MAC_KEY in doc.content)
-    leap_assert(MAC_METHOD_KEY in doc.content)
+    soledad_assert(doc.is_tombstone() is False)
+    soledad_assert(ENC_JSON_KEY in doc.content)
+    soledad_assert(ENC_SCHEME_KEY in doc.content)
+    soledad_assert(ENC_METHOD_KEY in doc.content)
+    soledad_assert(MAC_KEY in doc.content)
+    soledad_assert(MAC_METHOD_KEY in doc.content)
     # verify MAC
     ciphertext = binascii.a2b_hex(  # content is stored as hex.
         doc.content[ENC_JSON_KEY])
@@ -239,7 +239,7 @@ def decrypt_doc(crypto, doc):
     if enc_scheme == EncryptionSchemes.SYMKEY:
         enc_method = doc.content[ENC_METHOD_KEY]
         if enc_method == EncryptionMethods.AES_256_CTR:
-            leap_assert(ENC_IV_KEY in doc.content)
+            soledad_assert(ENC_IV_KEY in doc.content)
             plainjson = crypto.decrypt_sym(
                 ciphertext,
                 crypto.doc_passphrase(doc.doc_id),
diff --git a/src/leap/soledad/crypto.py b/src/leap/soledad/crypto.py
index e3d2c30c..be83e4a2 100644
--- a/src/leap/soledad/crypto.py
+++ b/src/leap/soledad/crypto.py
@@ -26,9 +26,15 @@ import binascii
 import hmac
 import hashlib
 
+
 from Crypto.Cipher import AES
 from Crypto.Util import Counter
-from leap.common.check import leap_assert, leap_assert_type
+
+
+from leap.soledad import (
+    soledad_assert,
+    soledad_assert_type,
+)
 
 
 class EncryptionMethods(object):
@@ -85,13 +91,14 @@ class SoledadCrypto(object):
         @return: A tuple with the initial value and the encrypted data.
         @rtype: (long, str)
         """
-        leap_assert_type(key, str)
+        soledad_assert_type(key, str)
 
         # AES-256 in CTR mode
         if method == EncryptionMethods.AES_256_CTR:
-            leap_assert(
+            soledad_assert(
                 len(key) == 32,  # 32 x 8 = 256 bits.
-                'Wrong key size: %s bits (must be 256 bits long).' % (len(key)*8))
+                'Wrong key size: %s bits (must be 256 bits long).' %
+                (len(key) * 8))
             iv = os.urandom(8)
             ctr = Counter.new(64, prefix=iv)
             cipher = AES.new(key=key, mode=AES.MODE_CTR, counter=ctr)
@@ -119,15 +126,15 @@ class SoledadCrypto(object):
         @return: The decrypted data.
         @rtype: str
         """
-        leap_assert_type(key, str)
+        soledad_assert_type(key, str)
 
         # AES-256 in CTR mode
         if method == EncryptionMethods.AES_256_CTR:
             # assert params
-            leap_assert(
+            soledad_assert(
                 len(key) == 32,  # 32 x 8 = 256 bits.
                 'Wrong key size: %s (must be 256 bits long).' % len(key))
-            leap_assert(
+            soledad_assert(
                 'iv' in kwargs,
                 'AES-256-CTR needs an initial value given as.')
             ctr = Counter.new(64, prefix=binascii.a2b_base64(kwargs['iv']))
diff --git a/src/leap/soledad/tests/test_soledad.py b/src/leap/soledad/tests/test_soledad.py
index 09711f19..21d36771 100644
--- a/src/leap/soledad/tests/test_soledad.py
+++ b/src/leap/soledad/tests/test_soledad.py
@@ -165,7 +165,7 @@ class SoledadSignalingTestCase(BaseSoledadTest):
     def setUp(self):
         BaseSoledadTest.setUp(self)
         # mock signaling
-        soledad.events.signal = Mock()
+        soledad.signal = Mock()
 
     def tearDown(self):
         pass
@@ -179,54 +179,54 @@ class SoledadSignalingTestCase(BaseSoledadTest):
         """
         Test that a fresh soledad emits all bootstrap signals.
         """
-        soledad.events.signal.reset_mock()
+        soledad.signal.reset_mock()
         # get a fresh instance so it emits all bootstrap signals
         sol = self._soledad_instance(
             secrets_path='alternative.json',
             local_db_path='alternative.u1db')
         # reverse call order so we can verify in the order the signals were
         # expected
-        soledad.events.signal.mock_calls.reverse()
-        soledad.events.signal.call_args = \
-            soledad.events.signal.call_args_list[0]
-        soledad.events.signal.call_args_list.reverse()
+        soledad.signal.mock_calls.reverse()
+        soledad.signal.call_args = \
+            soledad.signal.call_args_list[0]
+        soledad.signal.call_args_list.reverse()
         # assert signals
-        soledad.events.signal.assert_called_with(
+        soledad.signal.assert_called_with(
             proto.SOLEDAD_DOWNLOADING_KEYS,
             ADDRESS,
         )
-        self._pop_mock_call(soledad.events.signal)
-        soledad.events.signal.assert_called_with(
+        self._pop_mock_call(soledad.signal)
+        soledad.signal.assert_called_with(
             proto.SOLEDAD_DONE_DOWNLOADING_KEYS,
             ADDRESS,
         )
-        self._pop_mock_call(soledad.events.signal)
-        soledad.events.signal.assert_called_with(
+        self._pop_mock_call(soledad.signal)
+        soledad.signal.assert_called_with(
             proto.SOLEDAD_CREATING_KEYS,
             ADDRESS,
         )
-        self._pop_mock_call(soledad.events.signal)
-        soledad.events.signal.assert_called_with(
+        self._pop_mock_call(soledad.signal)
+        soledad.signal.assert_called_with(
             proto.SOLEDAD_DONE_CREATING_KEYS,
             ADDRESS,
         )
-        self._pop_mock_call(soledad.events.signal)
-        soledad.events.signal.assert_called_with(
+        self._pop_mock_call(soledad.signal)
+        soledad.signal.assert_called_with(
             proto.SOLEDAD_DOWNLOADING_KEYS,
             ADDRESS,
         )
-        self._pop_mock_call(soledad.events.signal)
-        soledad.events.signal.assert_called_with(
+        self._pop_mock_call(soledad.signal)
+        soledad.signal.assert_called_with(
             proto.SOLEDAD_DONE_DOWNLOADING_KEYS,
             ADDRESS,
         )
-        self._pop_mock_call(soledad.events.signal)
-        soledad.events.signal.assert_called_with(
+        self._pop_mock_call(soledad.signal)
+        soledad.signal.assert_called_with(
             proto.SOLEDAD_UPLOADING_KEYS,
             ADDRESS,
         )
-        self._pop_mock_call(soledad.events.signal)
-        soledad.events.signal.assert_called_with(
+        self._pop_mock_call(soledad.signal)
+        soledad.signal.assert_called_with(
             proto.SOLEDAD_DONE_UPLOADING_KEYS,
             ADDRESS,
         )
@@ -235,32 +235,32 @@ class SoledadSignalingTestCase(BaseSoledadTest):
         """
         Test that an existent soledad emits some of the bootstrap signals.
         """
-        soledad.events.signal.reset_mock()
+        soledad.signal.reset_mock()
         # get an existent instance so it emits only some of bootstrap signals
         sol = self._soledad_instance()
         # reverse call order so we can verify in the order the signals were
         # expected
-        soledad.events.signal.mock_calls.reverse()
-        soledad.events.signal.call_args = \
-            soledad.events.signal.call_args_list[0]
-        soledad.events.signal.call_args_list.reverse()
+        soledad.signal.mock_calls.reverse()
+        soledad.signal.call_args = \
+            soledad.signal.call_args_list[0]
+        soledad.signal.call_args_list.reverse()
         # assert signals
-        soledad.events.signal.assert_called_with(
+        soledad.signal.assert_called_with(
             proto.SOLEDAD_DOWNLOADING_KEYS,
             ADDRESS,
         )
-        self._pop_mock_call(soledad.events.signal)
-        soledad.events.signal.assert_called_with(
+        self._pop_mock_call(soledad.signal)
+        soledad.signal.assert_called_with(
             proto.SOLEDAD_DONE_DOWNLOADING_KEYS,
             ADDRESS,
         )
-        self._pop_mock_call(soledad.events.signal)
-        soledad.events.signal.assert_called_with(
+        self._pop_mock_call(soledad.signal)
+        soledad.signal.assert_called_with(
             proto.SOLEDAD_UPLOADING_KEYS,
             ADDRESS,
         )
-        self._pop_mock_call(soledad.events.signal)
-        soledad.events.signal.assert_called_with(
+        self._pop_mock_call(soledad.signal)
+        soledad.signal.assert_called_with(
             proto.SOLEDAD_DONE_UPLOADING_KEYS,
             ADDRESS,
         )
@@ -269,7 +269,7 @@ class SoledadSignalingTestCase(BaseSoledadTest):
         """
         Test Soledad emits SOLEDAD_CREATING_KEYS signal.
         """
-        soledad.events.signal.reset_mock()
+        soledad.signal.reset_mock()
         # get a fresh instance so it emits all bootstrap signals
         sol = self._soledad_instance()
         # mock the actual db sync so soledad does not try to connect to the
@@ -278,7 +278,7 @@ class SoledadSignalingTestCase(BaseSoledadTest):
         # do the sync
         sol.sync()
         # assert the signal has been emitted
-        soledad.events.signal.assert_called_with(
+        soledad.signal.assert_called_with(
             proto.SOLEDAD_DONE_DATA_SYNC,
             ADDRESS,
         )
@@ -287,7 +287,7 @@ class SoledadSignalingTestCase(BaseSoledadTest):
         """
         Test Soledad emits SOLEDAD_CREATING_KEYS signal.
         """
-        soledad.events.signal.reset_mock()
+        soledad.signal.reset_mock()
         sol = self._soledad_instance()
         # mock the sync target
         LeapSyncTarget.get_sync_info = Mock(return_value=[0, 0, 0, 0, 2])
@@ -296,7 +296,7 @@ class SoledadSignalingTestCase(BaseSoledadTest):
         # check for new data to sync
         sol.need_sync('http://provider/userdb')
         # assert the signal has been emitted
-        soledad.events.signal.assert_called_with(
+        soledad.signal.assert_called_with(
             proto.SOLEDAD_NEW_DATA_TO_SYNC,
             ADDRESS,
         )