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-rw-r--r--script/simulate_ring.py120
1 files changed, 120 insertions, 0 deletions
diff --git a/script/simulate_ring.py b/script/simulate_ring.py
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+++ b/script/simulate_ring.py
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+import hashlib
+import bisect
+import xxhash
+
+
+def walk_ring_from_pos(tokens, dcs, start, rep):
+ ret = []
+ ret_dcs = set()
+ delta = 0
+ while len(ret) < rep:
+ i = (start + delta) % len(tokens)
+ delta = delta + 1
+
+ (token_k, token_dc, token_node) = tokens[i]
+ if token_dc not in ret_dcs:
+ ret_dcs |= set([token_dc])
+ ret.append(token_node)
+ elif len(ret_dcs) == len(dcs) and token_node not in ret:
+ ret.append(token_node)
+ return ret
+
+def count_tokens_per_node(tokens):
+ tokens_of_node = {}
+ for _, _, token_node in tokens:
+ if token_node not in tokens_of_node:
+ tokens_of_node[token_node] = 0
+ tokens_of_node[token_node] += 1
+ print("#tokens per node:")
+ for node, ntok in sorted(list(tokens_of_node.items())):
+ print(node, ": ", ntok)
+
+def method1(nodes):
+ tokens = []
+ dcs = set()
+ for (node_id, dc, n_tokens) in nodes:
+ dcs |= set([dc])
+ for i in range(n_tokens):
+ token = hashlib.sha256(f"{node_id} {i}".encode('ascii')).hexdigest()
+ tokens.append((token, dc, node_id))
+ tokens.sort(key=lambda tok: tok[0])
+
+ count_tokens_per_node(tokens)
+
+ space_of_node = {}
+
+ def walk_ring(v, rep):
+ i = bisect.bisect_left([tok for tok, _, _ in tokens], hashlib.sha256(v).hexdigest())
+ return walk_ring_from_pos(tokens, dcs, i, rep)
+
+ return walk_ring
+
+
+def method2(nodes):
+ partition_bits = 10
+ partitions = list(range(2**partition_bits))
+ def partition_node(i):
+ h, hn, hndc = None, None, None
+ for (node_id, node_dc, n_tokens) in nodes:
+ for tok in range(n_tokens):
+ #hnode = hashlib.sha256(f"{i} {node_id} {tok}".encode('ascii')).hexdigest()
+ xxh = xxhash.xxh64()
+ xxh.update(f"partition {i} node {node_id} token {tok}".encode('ascii'))
+ hnode = xxh.digest()
+ if h is None or hnode < h:
+ h = hnode
+ hn = node_id
+ hndc = node_dc
+ return (i, hndc, hn)
+
+ partition_nodes = [partition_node(i) for i in partitions]
+ count_tokens_per_node(partition_nodes)
+
+ dcs = list(set(node_dc for _, node_dc, _ in nodes))
+
+
+ def walk_ring(v, rep):
+ vh = hashlib.sha256(v).digest()
+ i = (vh[0]<<8 | vh[1]) % (2**partition_bits)
+ return walk_ring_from_pos(partition_nodes, dcs, i, rep)
+
+ return walk_ring
+
+
+
+def evaluate_method(walk_ring):
+ node_data_counts = {}
+ for i in range(100000):
+ nodes = walk_ring(f"{i}".encode('ascii'), 3)
+ for n in nodes:
+ if n not in node_data_counts:
+ node_data_counts[n] = 0
+ node_data_counts[n] += 1
+ print("Number of data items per node:")
+ for n, v in sorted(list(node_data_counts.items())):
+ print(n, ": ", v)
+
+
+if __name__ == "__main__":
+
+ nodes = [('digitale', 'atuin', 10),
+ ('drosera', 'atuin', 10),
+ ('datura', 'atuin', 10),
+ ('io', 'jupiter', 20),
+ ('meta', 'pipo', 10),
+ ('mega', 'pipo', 10),
+ ('mina', 'pipo', 10),
+ #('moni', 'pipo', 10),
+ #('mimi', 'pipo', 10),
+ #('mesi', 'pipo', 10),
+ ]
+
+ print("------")
+ print("method 1")
+ method1_walk_ring = method1(nodes)
+ evaluate_method(method1_walk_ring)
+
+ print("------")
+ print("method 2")
+ method2_walk_ring = method2(nodes)
+ evaluate_method(method2_walk_ring)