diff grok_interview/consistent_hash.py @ 60:d64a8c189a77

Merged
author June Park <me@mrjunejune.com>
date Sat, 20 Dec 2025 13:56:01 -0500
parents 68fa88ac73fe
children
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line diff
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/grok_interview/consistent_hash.py	Sat Dec 20 13:56:01 2025 -0500
@@ -0,0 +1,32 @@
+# Write a function taht maps
+# Key string to one of N servers
+from bisect import bisect_left
+from hashlib import sha256
+
+class Server:
+
+    def __init__(self):
+        self.id = str(sha256())
+
+class ConsistentHash:
+    def __init__(self):
+        self.server = []
+        self.hash_key_to_server = {}
+        self.hash_range = 10000
+
+    def get_hash_pos(self, key: str) -> int:
+        x = sha256(bytes(key, "utf-8"))
+        return int.from_bytes(x.digest()[:8]) % self.hash_range
+
+    def add_server(self, server: Server):
+        self.server.append(server)
+        for i in range(len(self.server) + 1):
+            hash_key = self.get_hash_pos(server.id)
+            self.hash_key_to_server[hash_key] = i
+
+    def get_server(self, key):
+        hash_key = self.get_hash_pos(key)
+        return self.server[bisect_left(list(self.hash_key_to_server.keys()), hash_key)]
+
+    def remove_server(self, server):
+        hash_key = self.get_hash_pos(server.id)