Add HBase storage

docs/user/usage.rst

@@ -114,14 +114,23 @@ Out of the box, Slack Machine provides 2 options for storage backend:
 
   *Class*: ``machine.storage.backends.redis.RedisStorage``
 
-So if, for example, you want to configure Slack Machine to use Redis as a storage backend, with your Redis 
+- **HBase**: this backend stores data in `HBase`_. HBase is a columnar store. This backend is for
+advanced users only. You should only use it if you already have a HBase cluster running and cannot
+use Redis for some reason. This backend requires 2 variables to be set in your ``local_settings.py``:
+``HBASE_URL`` and ``HBASE_TABLE``.
+
+    *Class*: ``machine.storage.backends.hbase.HBaseStorage``
+
+So if, for example, you want to configure Slack Machine to use Redis as a storage backend, with your Redis
 instance running on *localhost* on the default port, you would add this to your ``local_settings.py``:
 
 .. code-block:: python
-    
+
     STORAGE_BACKEND = 'machine.storage.backends.redis.RedisStorage'
     REDIS_URL = redis://localhost:6379'
 
 .. _Redis: https://redis.io/
 
+.. _HBase: https://hbase.apache.org/
+
 That's all there is to it!

machine/__about__.py

@@ -7,7 +7,7 @@
 __description__ = "A sexy, simple, yet powerful and extendable Slack bot"
 __uri__ = "https://github.com/DandyDev/slack-machine"
 
-__version_info__ = (0, 15, 0)
+__version_info__ = (0, 16, 0)
 __version__ = '.'.join(map(str, __version_info__))
 
 __author__ = "Daan Debie"

machine/storage/backends/hbase.py

@@ -0,0 +1,61 @@
+from datetime import datetime, timedelta
+
+from happybase import Connection
+from machine.storage.backends.base import MachineBaseStorage
+
+
+def bytes_to_float(byte_arr):
+    s = byte_arr.decode('utf-8')
+    return float(s)
+
+
+def float_to_bytes(i):
+    return bytes(str(i), 'utf-8')
+
+
+class HBaseStorage(MachineBaseStorage):
+
+    _VAL = b'values:value'
+    _EXP = b'values:expires_at'
+    _COLS = [_VAL, _EXP]
+
+    def __init__(self, settings):
+        super().__init__(settings)
+        hbase_host = settings['HBASE_HOST']
+        hbase_table = settings['HBASE_TABLE']
+        self._connection = Connection(hbase_host)
+        self._table = self._connection.table(hbase_table)
+
+    def _get_value(self, key):
+        row = self._table.row(key, self._COLS)
+        val = row.get(self._VAL)
+        if val:
+            exp = row.get(self._EXP)
+            if not exp:
+                return val
+            elif datetime.fromtimestamp(bytes_to_float(exp)) > datetime.utcnow():
+                return val
+            else:
+                self.delete(key)
+                return None
+        return None
+
+    def has(self, key):
+        val = self._get_value(key)
+        return bool(val)
+
+    def get(self, key):
+        return self._get_value(key)
+
+    def set(self, key, value, expires=None):
+        data = {self._VAL: value}
+        if expires:
+            expires_at = datetime.utcnow() + timedelta(seconds=expires)
+            data[self._EXP] = float_to_bytes(expires_at.timestamp())
+        self._table.put(key, data)
+
+    def delete(self, key):
+        self._table.delete(key)
+
+    def size(self):
+        return 0

requirements-dev.txt

@@ -10,4 +10,6 @@ coverage==4.5.1
 pytest-cov==2.6.0
 Sphinx==1.7.9
 sphinx-autobuild==0.7.1
-redis==2.10.6
+redis==2.10.6
+Cython==0.28.5
+happybase==1.1.0

setup.py

@@ -79,7 +79,8 @@ def run(self):
     install_requires=dependencies,
     python_requires='~=3.3',
     extras_require={
-        'redis': ['redis', 'hiredis']
+        'redis': ['redis', 'hiredis'],
+        'hbase': ['Cython==0.28.5', 'happybase']
     },
     classifiers=[
         "Development Status :: 3 - Alpha",

tests/test_hbase_storage.py

@@ -0,0 +1,46 @@
+import pytest
+from happybase import Table
+
+from machine.storage.backends.hbase import bytes_to_float, float_to_bytes, HBaseStorage
+
+_VAL = b'values:value'
+_EXP = b'values:expires_at'
+_COLS = [_VAL, _EXP]
+
+
+@pytest.fixture
+def table(mocker):
+    table = mocker.MagicMock(spec=Table)
+    ConnectionCls = mocker.patch('machine.storage.backends.hbase.Connection', autospec=True)
+    instance = ConnectionCls.return_value
+    instance.table.return_value = table
+    return table
+
+
+@pytest.fixture
+def hbase_storage(table):
+    return HBaseStorage({'HBASE_HOST': 'foo', 'HBASE_TABLE': 'bar'})
+
+
+def test_float_conversion():
+    assert bytes_to_float(float_to_bytes(3.14159265359)) == 3.14159265359
+
+
+def test_get(table, hbase_storage):
+    hbase_storage.get('key1')
+    table.row.assert_called_with('key1', _COLS)
+
+
+def test_has(table, hbase_storage):
+    hbase_storage.has('key1')
+    table.row.assert_called_with('key1', _COLS)
+
+
+def test_delete(table, hbase_storage):
+    hbase_storage.delete('key1')
+    table.delete.assert_called_with('key1')
+
+
+def test_set(table, hbase_storage):
+    hbase_storage.set('key1', 'val1')
+    table.put.assert_called_with('key1', {b'values:value': 'val1'})