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| 1 | +"""Pure, bounded classifier for one immutable IB Gateway recovery epoch snapshot.""" |
| 2 | + |
| 3 | +from __future__ import annotations |
| 4 | + |
| 5 | +import argparse |
| 6 | +import re |
| 7 | +import sys |
| 8 | +from dataclasses import dataclass |
| 9 | +from datetime import datetime, timezone |
| 10 | +from enum import StrEnum |
| 11 | +from typing import Iterable, TextIO |
| 12 | + |
| 13 | + |
| 14 | +MAX_SNAPSHOT_EVENTS = 512 |
| 15 | +MAX_SNAPSHOT_BYTES = 256 * 1024 |
| 16 | +MAX_LINE_BYTES = 4096 |
| 17 | + |
| 18 | +DOCKER_TIMESTAMP = re.compile( |
| 19 | + r"^(?P<date>\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2})(?:\.(?P<fraction>\d{1,9}))?Z(?:\s|$)" |
| 20 | +) |
| 21 | +FILE_TIMESTAMP = re.compile( |
| 22 | + r"^(?P<date>\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2})(?:(?P<separator>[.,:])(?P<fraction>\d{1,9}))?(?:\s|$)" |
| 23 | +) |
| 24 | +TIMESTAMP_PREFIX = re.compile(r"^\d{4}-\d{2}-\d{2}[ T]") |
| 25 | +PROGRESS_MARKER = re.compile( |
| 26 | + r"IBC: (Starting Gateway|Login attempt|Second Factor Authentication|Login has completed|" |
| 27 | + r"Configuration tasks completed|Found Gateway main window|Getting config dialog|Getting main window)|" |
| 28 | + r"Authentication window found|Auto-fill submitted|Passed token authentication|" |
| 29 | + r"Authentication completed|Security code:", |
| 30 | + re.IGNORECASE, |
| 31 | +) |
| 32 | +AUTH_CONTEXT_MARKER = re.compile(r"login|authentication|security code|token authentication", re.IGNORECASE) |
| 33 | +EXPLICIT_TERMINAL_MARKER = re.compile( |
| 34 | + r"IBC closing because login has not completed|" |
| 35 | + r"(?:authentication|login).*(?:timed out|timeout|failed)|" |
| 36 | + r"(?:timed out|timeout|failed).*(?:authentication|login)", |
| 37 | + re.IGNORECASE, |
| 38 | +) |
| 39 | +GENERIC_DISCONNECT_MARKER = re.compile(r"connection reset by peer|server disconnected", re.IGNORECASE) |
| 40 | + |
| 41 | + |
| 42 | +class SnapshotError(ValueError): |
| 43 | + """The primitive event snapshot cannot be safely classified.""" |
| 44 | + |
| 45 | + |
| 46 | +class Decision(StrEnum): |
| 47 | + READY = "ready" |
| 48 | + TERMINAL = "terminal" |
| 49 | + PROGRESS = "progress" |
| 50 | + NONE = "none" |
| 51 | + INVALID = "invalid" |
| 52 | + |
| 53 | + |
| 54 | +@dataclass(frozen=True) |
| 55 | +class Epoch: |
| 56 | + container_id: str |
| 57 | + started_at: str |
| 58 | + old_container_id: str | None = None |
| 59 | + replacement_identity: bool = False |
| 60 | + |
| 61 | + def __post_init__(self) -> None: |
| 62 | + if not self.container_id: |
| 63 | + raise SnapshotError("missing epoch container identity") |
| 64 | + if self.replacement_identity and ( |
| 65 | + not self.old_container_id or self.old_container_id == self.container_id |
| 66 | + ): |
| 67 | + raise SnapshotError("invalid replacement identity") |
| 68 | + parse_rfc3339_nanos(self.started_at) |
| 69 | + |
| 70 | + @property |
| 71 | + def started_key(self) -> tuple[datetime, int]: |
| 72 | + return parse_rfc3339_nanos(self.started_at) |
| 73 | + |
| 74 | + |
| 75 | +@dataclass(frozen=True) |
| 76 | +class PrimitiveEvent: |
| 77 | + source: str |
| 78 | + container_id: str |
| 79 | + line: str |
| 80 | + |
| 81 | + |
| 82 | +@dataclass(frozen=True) |
| 83 | +class FrozenSnapshot: |
| 84 | + events: tuple[PrimitiveEvent, ...] |
| 85 | + |
| 86 | + |
| 87 | +@dataclass(frozen=True) |
| 88 | +class ParsedTimestamp: |
| 89 | + key: tuple[datetime, int] |
| 90 | + precision: str |
| 91 | + |
| 92 | + |
| 93 | +def parse_rfc3339_nanos(value: str) -> tuple[datetime, int]: |
| 94 | + match = re.fullmatch(r"(\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2})(?:\.(\d{1,9}))?Z", value) |
| 95 | + if match is None: |
| 96 | + raise SnapshotError("invalid epoch StartedAt") |
| 97 | + seconds = datetime.strptime(match.group(1), "%Y-%m-%dT%H:%M:%S").replace(tzinfo=timezone.utc) |
| 98 | + return seconds, _fraction_to_nanos(match.group(2)) |
| 99 | + |
| 100 | + |
| 101 | +def _fraction_to_nanos(fraction: str | None) -> int: |
| 102 | + if fraction is None: |
| 103 | + return 0 |
| 104 | + return int((fraction + "0" * 9)[:9]) |
| 105 | + |
| 106 | + |
| 107 | +def parse_event_timestamp(source: str, line: str) -> ParsedTimestamp | None: |
| 108 | + if source == "docker": |
| 109 | + match = DOCKER_TIMESTAMP.match(line) |
| 110 | + if match is None: |
| 111 | + return _reject_malformed_timestamp(line) |
| 112 | + seconds = datetime.strptime(match.group("date"), "%Y-%m-%dT%H:%M:%S").replace( |
| 113 | + tzinfo=timezone.utc |
| 114 | + ) |
| 115 | + return ParsedTimestamp((seconds, _fraction_to_nanos(match.group("fraction"))), "exact") |
| 116 | + if source == "file": |
| 117 | + match = FILE_TIMESTAMP.match(line) |
| 118 | + if match is None: |
| 119 | + return _reject_malformed_timestamp(line) |
| 120 | + seconds = datetime.strptime(match.group("date"), "%Y-%m-%d %H:%M:%S").replace( |
| 121 | + tzinfo=timezone.utc |
| 122 | + ) |
| 123 | + fraction = match.group("fraction") |
| 124 | + precision = "seconds" if fraction is None else "fractional" |
| 125 | + return ParsedTimestamp((seconds, _fraction_to_nanos(fraction)), precision) |
| 126 | + raise SnapshotError("unknown snapshot source") |
| 127 | + |
| 128 | + |
| 129 | +def _reject_malformed_timestamp(line: str) -> ParsedTimestamp | None: |
| 130 | + if TIMESTAMP_PREFIX.match(line): |
| 131 | + raise SnapshotError("malformed timestamp") |
| 132 | + return None |
| 133 | + |
| 134 | + |
| 135 | +def freeze_snapshot(events: Iterable[PrimitiveEvent]) -> FrozenSnapshot: |
| 136 | + frozen: list[PrimitiveEvent] = [] |
| 137 | + total_bytes = 0 |
| 138 | + for event in events: |
| 139 | + if event.source not in {"docker", "file"}: |
| 140 | + raise SnapshotError("unknown snapshot source") |
| 141 | + encoded_size = len(event.line.encode("utf-8", errors="replace")) |
| 142 | + if encoded_size > MAX_LINE_BYTES: |
| 143 | + raise SnapshotError("snapshot line exceeds limit") |
| 144 | + total_bytes += encoded_size |
| 145 | + if total_bytes > MAX_SNAPSHOT_BYTES: |
| 146 | + raise SnapshotError("snapshot exceeds byte limit") |
| 147 | + frozen.append(event) |
| 148 | + if len(frozen) > MAX_SNAPSHOT_EVENTS: |
| 149 | + raise SnapshotError("snapshot exceeds event limit") |
| 150 | + return FrozenSnapshot(tuple(frozen)) |
| 151 | + |
| 152 | + |
| 153 | +class RecoveryEpochMachine: |
| 154 | + """Sticky terminal state scoped to one explicit recovery attempt.""" |
| 155 | + |
| 156 | + def __init__(self, epoch: Epoch) -> None: |
| 157 | + self.epoch = epoch |
| 158 | + self._terminal = False |
| 159 | + |
| 160 | + def begin_new_attempt(self, epoch: Epoch) -> None: |
| 161 | + self.epoch = epoch |
| 162 | + self._terminal = False |
| 163 | + |
| 164 | + def classify(self, snapshot: FrozenSnapshot, *, stable_ready: bool = False) -> Decision: |
| 165 | + if stable_ready: |
| 166 | + return Decision.READY |
| 167 | + if self._terminal: |
| 168 | + return Decision.TERMINAL |
| 169 | + try: |
| 170 | + decision = self._classify_frozen_snapshot(snapshot) |
| 171 | + except SnapshotError: |
| 172 | + return Decision.INVALID |
| 173 | + if decision is Decision.TERMINAL: |
| 174 | + self._terminal = True |
| 175 | + return decision |
| 176 | + |
| 177 | + def _classify_frozen_snapshot(self, snapshot: FrozenSnapshot) -> Decision: |
| 178 | + progress_seen = False |
| 179 | + auth_context_seen = False |
| 180 | + generic_disconnect_seen = False |
| 181 | + |
| 182 | + for event in snapshot.events: |
| 183 | + if event.container_id == self.epoch.old_container_id: |
| 184 | + continue |
| 185 | + if event.container_id != self.epoch.container_id: |
| 186 | + continue |
| 187 | + timestamp = parse_event_timestamp(event.source, event.line) |
| 188 | + if timestamp is None or not self._is_in_epoch(timestamp): |
| 189 | + continue |
| 190 | + if EXPLICIT_TERMINAL_MARKER.search(event.line): |
| 191 | + return Decision.TERMINAL |
| 192 | + if PROGRESS_MARKER.search(event.line): |
| 193 | + progress_seen = True |
| 194 | + if AUTH_CONTEXT_MARKER.search(event.line): |
| 195 | + auth_context_seen = True |
| 196 | + if GENERIC_DISCONNECT_MARKER.search(event.line): |
| 197 | + generic_disconnect_seen = True |
| 198 | + |
| 199 | + if generic_disconnect_seen and auth_context_seen: |
| 200 | + return Decision.TERMINAL |
| 201 | + if progress_seen: |
| 202 | + return Decision.PROGRESS |
| 203 | + return Decision.NONE |
| 204 | + |
| 205 | + def _is_in_epoch(self, timestamp: ParsedTimestamp) -> bool: |
| 206 | + epoch_seconds, epoch_nanos = self.epoch.started_key |
| 207 | + event_seconds, event_nanos = timestamp.key |
| 208 | + if event_seconds > epoch_seconds: |
| 209 | + return True |
| 210 | + if event_seconds < epoch_seconds: |
| 211 | + return False |
| 212 | + if timestamp.precision == "seconds": |
| 213 | + # A replacement ID proves the file stream belongs to this attempt, |
| 214 | + # but a seconds-only line cannot be ordered against StartedAt nanos. |
| 215 | + # Include it conservatively; without that identity fail closed. |
| 216 | + if self.epoch.replacement_identity: |
| 217 | + return True |
| 218 | + raise SnapshotError("ambiguous same-second file event") |
| 219 | + return event_nanos >= epoch_nanos |
| 220 | + |
| 221 | + |
| 222 | +def parse_protocol_snapshot(stream: TextIO) -> FrozenSnapshot: |
| 223 | + events: list[PrimitiveEvent] = [] |
| 224 | + total_bytes = 0 |
| 225 | + protocol_line_limit = MAX_LINE_BYTES + 256 |
| 226 | + while True: |
| 227 | + raw_line = stream.readline(protocol_line_limit + 1) |
| 228 | + if not raw_line: |
| 229 | + break |
| 230 | + if len(raw_line) > protocol_line_limit or ( |
| 231 | + len(raw_line) == protocol_line_limit and not raw_line.endswith("\n") |
| 232 | + ): |
| 233 | + raise SnapshotError("snapshot protocol line exceeds limit") |
| 234 | + line = raw_line.rstrip("\n") |
| 235 | + if line.startswith("X\t"): |
| 236 | + raise SnapshotError("snapshot source failed") |
| 237 | + fields = line.split("\t", 2) |
| 238 | + if len(fields) != 3: |
| 239 | + raise SnapshotError("invalid snapshot protocol") |
| 240 | + source_code, container_id, message = fields |
| 241 | + source = {"D": "docker", "F": "file"}.get(source_code) |
| 242 | + if source is None: |
| 243 | + raise SnapshotError("unknown snapshot source") |
| 244 | + encoded_size = len(message.encode("utf-8", errors="replace")) |
| 245 | + if encoded_size > MAX_LINE_BYTES: |
| 246 | + raise SnapshotError("snapshot line exceeds limit") |
| 247 | + total_bytes += encoded_size |
| 248 | + if total_bytes > MAX_SNAPSHOT_BYTES: |
| 249 | + raise SnapshotError("snapshot exceeds byte limit") |
| 250 | + events.append(PrimitiveEvent(source=source, container_id=container_id, line=message)) |
| 251 | + if len(events) > MAX_SNAPSHOT_EVENTS: |
| 252 | + raise SnapshotError("snapshot exceeds event limit") |
| 253 | + return FrozenSnapshot(tuple(events)) |
| 254 | + |
| 255 | + |
| 256 | +def main() -> int: |
| 257 | + parser = argparse.ArgumentParser(description=__doc__) |
| 258 | + parser.add_argument("--epoch-container-id", required=True) |
| 259 | + parser.add_argument("--epoch-started-at", required=True) |
| 260 | + parser.add_argument("--old-container-id") |
| 261 | + parser.add_argument("--replacement-identity", action="store_true") |
| 262 | + args = parser.parse_args() |
| 263 | + try: |
| 264 | + epoch = Epoch( |
| 265 | + container_id=args.epoch_container_id, |
| 266 | + started_at=args.epoch_started_at, |
| 267 | + old_container_id=args.old_container_id, |
| 268 | + replacement_identity=args.replacement_identity, |
| 269 | + ) |
| 270 | + snapshot = parse_protocol_snapshot(sys.stdin) |
| 271 | + print(RecoveryEpochMachine(epoch).classify(snapshot).value) |
| 272 | + except SnapshotError: |
| 273 | + print(Decision.INVALID.value) |
| 274 | + return 0 |
| 275 | + |
| 276 | + |
| 277 | +if __name__ == "__main__": |
| 278 | + raise SystemExit(main()) |
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