Generate scenario from trace (#5875)

src/consensus/aft/test/driver.h

@@ -279,9 +279,7 @@ public:
 
       if (_nodes.find(node_id) == _nodes.end())
       {
-        throw std::runtime_error(fmt::format(
-          "Node {} does not exist yet. Use \"create_new_node, <node_id>\"",
-          node_id));
+        create_new_node(node_id_s);
       }
 
       configuration.try_emplace(node_id);
@@ -1053,7 +1051,8 @@ public:
              idx)
         << std::endl;
       throw std::runtime_error(fmt::format(
-        "Node not at expected commit idx ({}) on line {} : {}",
+        "Node {} not at expected commit idx ({}) on line {} : {}",
+        node_id,
         idx,
         std::to_string((int)lineno),
         _nodes.at(node_id).raft->get_committed_seqno()));

tla/trace2scen.py

@@ -0,0 +1,73 @@
+# Copyright (c) Microsoft Corporation. All rights reserved.
+# Licensed under the Apache 2.0 License.
+
+import sys
+import json
+import os
+
+def comment(action):
+    return f"# {action['name']} {action['location']['module']}:{action['location']['beginLine']}"
+
+def term(ctx, pre):
+    return str(pre["currentTerm"][ctx['i']])
+
+def noop(ctx, pre, post):
+    return ["# Noop"]
+
+MAP = {
+    "ClientRequest": lambda ctx, pre, post: ["replicate", term(ctx, pre), "42"],
+    "MCClientRequest": lambda ctx, pre, post: ["replicate", term(ctx, pre), "42"],
+    "CheckQuorum": lambda ctx, pre, post: ["periodic_one", ctx['i'], "110"],
+    "Timeout": lambda ctx, pre, post: ["periodic_one",  ctx['i'], "110"],
+    "MCTimeout": lambda ctx, pre, post: ["periodic_one",  ctx['i'], "110"],
+    "RequestVote": noop,
+    "AppendEntries": lambda _, __, ___: ["dispatch_all"],
+    "BecomeLeader": noop,
+    "SignCommittableMessages": lambda ctx, pre, post: ["emit_signature", term(ctx, pre)],
+    "MCSignCommittableMessages": lambda ctx, pre, post: ["emit_signature", term(ctx, pre)],
+    "ChangeConfigurationInt": lambda ctx, pre, post: ["replicate_new_configuration", term(ctx, pre), *ctx["newConfiguration"]],
+    "AdvanceCommitIndex": noop,
+    "HandleRequestVoteRequest": lambda _, __, ___: ["dispatch_all"],
+    "HandleRequestVoteResponse": noop,
+    "RejectAppendEntriesRequest": noop,
+    "ReturnToFollowerState": noop,
+    "AppendEntriesAlreadyDone": noop,
+    "RcvDropIgnoredMessage": noop,
+    "RcvUpdateTerm": noop,
+    "RcvRequestVoteRequest": noop,
+    "RcvRequestVoteResponse": noop,
+}
+
+def post_commit(post):
+    return [["assert_commit_idx", node, str(idx)] for node, idx in post["commitIndex"].items()]
+
+def post_state(post):
+    entries = []
+    for node, state in post["state"].items():
+        if state == "Leader":
+            entries.append(["assert_is_primary", node])
+        elif state == "Follower":
+            entries.append(["assert_is_backup", node])
+        elif state == "Candidate":
+            entries.append(["assert_is_candidate", node])
+    return entries
+
+def step_to_action(pre_state, action, post_state):
+    return os.linesep.join([
+        comment(action),
+        ','.join(MAP[action['name']](action['context'], pre_state[1], post_state[1]))])
+
+def asserts(pre_state, action, post_state, assert_gen):
+    return os.linesep.join([','.join(assertion) for assertion in assert_gen(post_state[1])])
+
+if __name__ == "__main__":
+    with open(sys.argv[1]) as trace:
+        steps = json.load(trace)["action"]
+        initial_state = steps[0][0][1]
+        initial_node, = [node for node, log in initial_state["log"].items() if log]
+        print(f"start_node,{initial_node}")
+        print(f"emit_signature,2")
+        for step in steps:
+            print(step_to_action(*step))
+            print(asserts(*step, post_state))
+        print(asserts(*steps[-1], post_commit))