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5e0b58b | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 | """Append-only audit records for external embodiment actions."""
from __future__ import annotations
import hashlib
import json
import os
from dataclasses import dataclass
from pathlib import Path
from time import time_ns
from typing import cast
from .models import ActionCommand, ActuatorResult, JSONValue
@dataclass(frozen=True, slots=True)
class ActionAuditRecord:
"""Immutable, hash-linked record of an attempted action."""
sequence: int
timestamp_ns: int
connection_id: str
command: ActionCommand
result: ActuatorResult
accepted: bool
reason: str
previous_digest: str
digest: str
class ActionAuditTrail:
"""In-memory append-only audit trail with tamper-evident chaining."""
def __init__(self, journal_path: Path | None = None) -> None:
self._records: list[ActionAuditRecord] = []
self._digest = "0" * 64
self._journal_path = journal_path
if journal_path is not None and journal_path.exists():
self._load(journal_path)
@property
def records(self) -> tuple[ActionAuditRecord, ...]:
return tuple(self._records)
def append(
self,
connection_id: str,
command: ActionCommand,
result: ActuatorResult,
*,
accepted: bool,
reason: str,
) -> ActionAuditRecord:
sequence = len(self._records)
timestamp_ns = time_ns()
payload = _payload(
sequence,
timestamp_ns,
connection_id,
command,
accepted,
reason,
self._digest,
)
digest = hashlib.sha256(
json.dumps(payload, sort_keys=True, separators=(",", ":")).encode()
).hexdigest()
record = ActionAuditRecord(
sequence,
timestamp_ns,
connection_id,
command,
result,
accepted,
reason,
self._digest,
digest,
)
self._records.append(record)
self._digest = digest
if self._journal_path is not None:
self._journal_path.parent.mkdir(parents=True, exist_ok=True)
with self._journal_path.open("a", encoding="utf-8") as stream:
stream.write(json.dumps(_record_json(record), sort_keys=True) + "\n")
stream.flush()
os.fsync(stream.fileno())
return record
def verify(self) -> bool:
previous = "0" * 64
for record in self._records:
if record.previous_digest != previous:
return False
payload = _payload(
record.sequence,
record.timestamp_ns,
record.connection_id,
record.command,
record.accepted,
record.reason,
previous,
)
if (
hashlib.sha256(
json.dumps(payload, sort_keys=True, separators=(",", ":")).encode()
).hexdigest()
!= record.digest
):
return False
previous = record.digest
return previous == self._digest
def _load(self, journal_path: Path) -> None:
try:
with journal_path.open(encoding="utf-8") as stream:
for line in stream:
raw = json.loads(line)
if not isinstance(raw, dict):
raise ValueError("action journal record must be an object")
decoded = cast(dict[str, object], raw)
command_raw = decoded["command"]
if not isinstance(command_raw, dict):
raise ValueError("action journal command must be an object")
command_data = cast(dict[str, object], command_raw)
command = ActionCommand(
str(command_data["actuator_id"]),
int(cast(str | int | float, command_data["tick"])),
str(command_data["action"]),
cast(JSONValue, command_data.get("payload")),
)
result = ActuatorResult(
bool(decoded["result_accepted"]),
str(decoded["result_message"]),
)
record = ActionAuditRecord(
int(cast(str | int | float, decoded["sequence"])),
int(cast(str | int | float, decoded["timestamp_ns"])),
str(decoded["connection_id"]),
command,
result,
bool(decoded["accepted"]),
str(decoded["reason"]),
str(decoded["previous_digest"]),
str(decoded["digest"]),
)
self._records.append(record)
self._digest = record.digest
except (OSError, KeyError, TypeError, ValueError, json.JSONDecodeError) as exc:
raise ValueError("invalid action journal") from exc
if not self.verify():
raise ValueError("action journal chain verification failed")
def _payload(
sequence: int,
timestamp_ns: int,
connection_id: str,
command: ActionCommand,
accepted: bool,
reason: str,
previous_digest: str,
) -> dict[str, JSONValue]:
return {
"sequence": sequence,
"timestamp_ns": timestamp_ns,
"connection_id": connection_id,
"command": {
"actuator_id": command.actuator_id,
"tick": command.tick,
"action": command.action,
"payload": command.payload,
},
"accepted": accepted,
"reason": reason,
"previous_digest": previous_digest,
}
def _record_json(record: ActionAuditRecord) -> dict[str, JSONValue]:
return {
**_payload(
record.sequence,
record.timestamp_ns,
record.connection_id,
record.command,
record.accepted,
record.reason,
record.previous_digest,
),
"result_accepted": record.result.accepted,
"result_message": record.result.message,
"digest": record.digest,
}
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