From 2026320ae442a3e50fe5549e96333d7446a59d7f Mon Sep 17 00:00:00 2001
From: Jeong YunWon <jeong@youknowone.org>
Date: Mon, 8 Aug 2016 20:09:35 +0900
Subject: [PATCH] basic rings and storage

---
 .gitignore            | 14 +++++++++
 cachain/__init__.py   |  0
 cachain/ingredient.py | 73 +++++++++++++++++++++++++++++++++++++++++++
 cachain/storage.py    | 22 +++++++++++++
 tests/__init__.py     |  0
 tests/test_cachain.py | 26 +++++++++++++++
 6 files changed, 135 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 cachain/__init__.py
 create mode 100644 cachain/ingredient.py
 create mode 100644 cachain/storage.py
 create mode 100644 tests/__init__.py
 create mode 100644 tests/test_cachain.py

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..69ef6aa
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,14 @@
+
+dist
+.env
+*.pyc
+*.egg-info
+MANIFEST
+
+.cache
+.eggs
+.idea
+.tox
+.ropeproject
+/build
+setup.cfg
diff --git a/cachain/__init__.py b/cachain/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/cachain/ingredient.py b/cachain/ingredient.py
new file mode 100644
index 0000000..cc1bd5c
--- /dev/null
+++ b/cachain/ingredient.py
@@ -0,0 +1,73 @@
+
+
+class Key(object):
+
+    def __init__(self, key):
+        self.key = key
+
+    def build(self, args):
+        raise NotImplementedError
+
+
+class FormatKey(Key):
+
+    def build(self, args):
+        return self.key.format(**args)
+
+
+class CallableKey(Key):
+
+    def build(self, args):
+        return self.key(**args)
+
+
+class Ring(object):
+
+    def __init__(self, storage, key):
+        self.storage = storage
+        if not isinstance(key, Key):
+            if isinstance(key, (str, unicode)):
+                key = FormatKey(key)
+            elif callable(key):
+                key = CallableKey(key)
+            else:
+                raise TypeError
+        self.key = key
+
+    @staticmethod
+    def _key_args(args, kwargs):
+        if args and kwargs:
+            raise TypeError
+        if args and len(args) > 1:
+            raise TypeError
+        if args:
+            key = args[0]
+        else:
+            key = kwargs
+        return key
+
+    def get(self, *args, **kwargs):
+        key_args = self._key_args(args, kwargs)
+        return self.get_by_key(key_args)
+
+    def get_by_key(self, key_args):
+        built_key = self.key.build(key_args)
+        return self.storage.get(built_key)
+
+    def set(self, _value, *args, **kwargs):
+        key_args = self._key_args(args, kwargs)
+        if callable(_value):
+            _value = _value(**key_args)
+        return self.set_by_key(_value, key_args)
+
+    def set_by_key(self, value, key_args):
+        built_key = self.key.build(key_args)
+        return self.storage.set(built_key, value)
+
+    def get_or_set(self, _value, *args, **kwargs):
+        key_args = self._key_args(args, kwargs)
+        value = self.get_by_key(key_args)
+        if value is None:
+            value = _value(**key_args)
+            self.set_by_key(value, key_args)
+        return value
diff --git a/cachain/storage.py b/cachain/storage.py
new file mode 100644
index 0000000..f1c0c36
--- /dev/null
+++ b/cachain/storage.py
@@ -0,0 +1,22 @@
+
+
+class Storage(object):
+
+    def get(self, key):
+        raise NotImplementedError
+
+    def set(self, key, value, expire=None):
+        raise NotImplementedError
+
+
+class DictStorage(Storage):
+
+    def __init__(self, storage):
+        self.storage = storage
+
+    def get(self, key):
+        return self.storage.get(key)
+
+    def set(self, key, value, expire=None):
+        assert expire is None, 'expire is not supported'
+        return self.storage.update({key: value})
diff --git a/tests/__init__.py b/tests/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/test_cachain.py b/tests/test_cachain.py
new file mode 100644
index 0000000..99227cb
--- /dev/null
+++ b/tests/test_cachain.py
@@ -0,0 +1,26 @@
+
+from cachain.storage import DictStorage
+from cachain.ingredient import Ring
+
+
+import pytest
+
+
+@pytest.fixture
+def fx_ring():
+    storage = DictStorage({})
+    ring = Ring(storage, 'user_id:{user_id}')
+    return ring
+
+
+def test_ring_get_set(fx_ring):
+    assert fx_ring.get({'user_id': 1}) is None
+    fx_ring.set(lambda user_id: 100, {'user_id': 1})
+
+
+def test_ring_get_or_set(fx_ring):
+    assert fx_ring.get({'user_id': 1}) is None
+    assert fx_ring.get_or_set(lambda user_id: 100, {'user_id': 1}) == 100
+    assert fx_ring.get({'user_id': 1}) == 100
+
+