CMO: disk-first plan on Kvrocks (#25)

tools/diskplan/diskplan.py

@@ -0,0 +1,37 @@
+#!/usr/bin/env python3
+"""Disk-first plan backed by Apache Kvrocks (plan item 25).
+
+For datasets bigger than RAM we offer a plan that runs Apache Kvrocks
+(Apache-2.0, RocksDB on NVMe, Redis protocol) instead of Valkey. We use the
+upstream image as-is; this module renders its config from a plan size and
+lists the commands that differ so the proxy can reject them clearly.
+"""
+import re
+
+PLANS = {  # disk GB -> (rocksdb block cache MB, worker threads)
+    50: (512, 4), 200: (2048, 8), 1000: (8192, 16),
+}
+# Valkey features Kvrocks does not support (proxy answers with a clear error).
+UNSUPPORTED = {"MODULE", "FUNCTION", "FT.CREATE", "FT.SEARCH", "JSON.SET", "BF.ADD", "WAITAOF", "SWAPDB"}
+
+
+def config(disk_gb, password_file="/run/secrets/kvrocks.conf", tls=True):
+    if disk_gb not in PLANS:
+        raise ValueError("plan sizes: %s" % sorted(PLANS))
+    cache, workers = PLANS[disk_gb]
+    lines = ["bind 0.0.0.0", "dir /data", "workers %d" % workers,
+             "rocksdb.block_cache_size %d" % cache,
+             "rocksdb.compression zstd",
+             "max-backup-to-keep 1",
+             "include %s" % password_file]  # holds `requirepass`; never inline secrets
+    lines += ["port 0", "tls-port 6380", "tls-cert-file /tls/server.crt",
+              "tls-key-file /tls/server.key", "tls-ca-cert-file /tls/ca.crt"] if tls else ["port 6379"]
+    return "\n".join(lines) + "\n"
+
+
+def check_command(argv):
+    """Return None if allowed on the disk plan, else an error string for the client."""
+    name = argv[0].upper() if argv else ""
+    if name in UNSUPPORTED or re.match(r"^(FT|JSON|BF|CF|TS)\.", name):
+        return "ERR %s is not available on the disk plan" % name
+    return None

tools/diskplan/test_diskplan.py

@@ -0,0 +1,25 @@
+import unittest
+import diskplan as D
+
+
+class T(unittest.TestCase):
+    def test_config(self):
+        c = D.config(200)
+        self.assertIn("rocksdb.block_cache_size 2048", c)
+        self.assertIn("tls-port 6380", c)
+        self.assertIn("port 0", c)
+        self.assertNotIn("requirepass", c)
+        self.assertIn("port 6379", D.config(50, tls=False))
+        with self.assertRaises(ValueError):
+            D.config(7)
+
+    def test_commands(self):
+        self.assertIsNone(D.check_command(["GET", "k"]))
+        self.assertIsNone(D.check_command(["hset", "h", "f", "v"]))
+        self.assertIn("not available", D.check_command(["ft.search", "i", "*"]))
+        self.assertIn("not available", D.check_command(["TS.ADD", "k", "*", "1"]))
+        self.assertIn("not available", D.check_command(["MODULE", "LIST"]))
+
+
+if __name__ == "__main__":
+    unittest.main()