зеркало из https://github.com/microsoft/CCF.git
77 строки
2.5 KiB
Python
77 строки
2.5 KiB
Python
# Copyright (c) Microsoft Corporation. All rights reserved.
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# Licensed under the Apache 2.0 License.
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import os
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import sys
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from random import randrange, choice, choices
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from itertools import combinations, count
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def fully_connected_scenario(nodes, steps):
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index = count(start=1)
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step_def = {
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0: lambda: "dispatch_all",
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# Most of the time, advance by a small periodic amount. Occasionally time out long enough to trigger an election
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1: lambda: "periodic_all,{}".format(
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choices([randrange(20), randrange(100, 500)], weights=[10, 1])[0]
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),
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2: lambda: "replicate,latest,{}".format(f"hello {next(index)}"),
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}
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# Define the nodes
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lines = ["nodes,{}".format(",".join(str(n) for n in range(nodes)))]
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for first, second in combinations(range(nodes), 2):
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lines.append("connect,{},{}".format(first, second))
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# Get past the initial election
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lines.append("periodic_one,0,110")
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lines.append("dispatch_all")
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lines.append("periodic_all,30")
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lines.append("dispatch_all")
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lines.append("state_all")
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for _ in range(steps):
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lines.append(step_def[choice(list(step_def.keys()))]())
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lines.append("state_all")
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# Allow the network to reconcile, and assert it reaches a stable state
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# It is likely this scenario has resulted in a lot of elections and very little commit advancement.
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# To reach a stable state, we need to give each node a chance to win an election and share their state.
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# In a real network, we expect this to arise from the randomised election timeouts, and it is sufficient
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# for one of a quorum of nodes to win and share their state. This exhaustive approach ensures convergence,
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# even in the pessimal case.
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for node in range(nodes):
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lines.append(f"periodic_one,{node},100")
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lines.append("dispatch_all")
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lines.append("periodic_all,10")
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lines.append("dispatch_all")
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lines.append("state_all")
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lines.append("assert_state_sync")
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return "\n".join(lines)
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def generate_scenarios(tgt_dir="."):
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NODES = 3
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SCENARIOS = 3
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STEPS = 25
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scenario_paths = []
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for scen_index in range(SCENARIOS):
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with open(
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os.path.join(tgt_dir, "scenario-{}".format(scen_index)),
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"w",
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encoding="utf-8",
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) as scen:
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scen.write(fully_connected_scenario(NODES, STEPS) + "\n")
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scenario_paths.append(os.path.realpath(scen.name))
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return scenario_paths
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if __name__ == "__main__":
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tgt_dir = sys.argv[1]
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generate_scenarios(tgt_dir)
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