merging masterck-linkdocs

1 files changed, 24 insertions, 0 deletions

diff --git a/redis/crc.py b/redis/crc.py
new file mode 100644
index 0000000..7d2ee50
--- /dev/null
+++ b/redis/crc.py
@@ -0,0 +1,24 @@
+from binascii import crc_hqx
+
+# Redis Cluster's key space is divided into 16384 slots.
+# For more information see: https://github.com/redis/redis/issues/2576
+REDIS_CLUSTER_HASH_SLOTS = 16384
+
+__all__ = [
+    "key_slot",
+    "REDIS_CLUSTER_HASH_SLOTS"
+]
+
+
+def key_slot(key, bucket=REDIS_CLUSTER_HASH_SLOTS):
+    """Calculate key slot for a given key.
+    See Keys distribution model in https://redis.io/topics/cluster-spec
+    :param key - bytes
+    :param bucket - int
+    """
+    start = key.find(b"{")
+    if start > -1:
+        end = key.find(b"}", start + 1)
+        if end > -1 and end != start + 1:
+            key = key[start + 1: end]
+    return crc_hqx(key, 0) % bucket