Phase 1/3 of DEBT-039. Adds the Python emitter-side counterpart to
auth-helper.c's sd_escape + base64 logic so service templates can
emit the universal credential SD shape with a single spread:
_log("auth_attempt", principal=user, **encode_secret(password))
secret_printable mirrors the C helper's [0x20, 0x7f) → '?' contract;
secret_b64 preserves the ORIGINAL utf-8 bytes losslessly so non-ASCII
or control-byte payloads survive as fingerprinting signal even when
the printable form sanitizes them.
The canonical syslog_bridge.py is what _sync_logging_helper()
propagates into per-template build contexts at deploy time, so any
service that imports its local syslog_bridge picks this up
automatically on next rebuild.
Phase 2 migrates the six cred-emitting service templates (FTP, POP3,
IMAP, SMTP, Redis, LDAP) onto this helper. Phase 3 deletes the
ingester's legacy adapter once nothing emits the old shape.
117 lines
4.1 KiB
Python
117 lines
4.1 KiB
Python
#!/usr/bin/env python3
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"""
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Shared RFC 5424 syslog helper used by service containers.
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Services call syslog_line() to format an RFC 5424 message, then
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write_syslog_file() to emit it to stdout — the container runtime
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captures it, and the host-side collector streams it into the log file.
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RFC 5424 structure:
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<PRI>1 TIMESTAMP HOSTNAME APP-NAME PROCID MSGID [SD-ELEMENT] MSG
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Facility: local0 (16). SD element ID uses PEN 55555.
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"""
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import base64
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from datetime import datetime, timezone
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from typing import Any
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# ─── Constants ────────────────────────────────────────────────────────────────
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_FACILITY_LOCAL0 = 16
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_SD_ID = "relay@55555"
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_NILVALUE = "-"
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SEVERITY_EMERG = 0
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SEVERITY_ALERT = 1
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SEVERITY_CRIT = 2
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SEVERITY_ERROR = 3
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SEVERITY_WARNING = 4
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SEVERITY_NOTICE = 5
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SEVERITY_INFO = 6
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SEVERITY_DEBUG = 7
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_MAX_HOSTNAME = 255
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_MAX_APPNAME = 48
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_MAX_MSGID = 32
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# ─── Formatter ────────────────────────────────────────────────────────────────
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def _sd_escape(value: str) -> str:
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"""Escape SD-PARAM-VALUE per RFC 5424 §6.3.3."""
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return value.replace("\\", "\\\\").replace('"', '\\"').replace("]", "\\]")
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def _sd_element(fields: dict[str, Any]) -> str:
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if not fields:
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return _NILVALUE
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params = " ".join(f'{k}="{_sd_escape(str(v))}"' for k, v in fields.items())
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return f"[{_SD_ID} {params}]"
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def syslog_line(
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service: str,
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hostname: str,
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event_type: str,
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severity: int = SEVERITY_INFO,
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timestamp: datetime | None = None,
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msg: str | None = None,
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**fields: Any,
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) -> str:
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"""
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Return a single RFC 5424-compliant syslog line (no trailing newline).
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Args:
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service: APP-NAME (e.g. "http", "mysql")
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hostname: HOSTNAME (node name)
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event_type: MSGID (e.g. "request", "login_attempt")
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severity: Syslog severity integer (default: INFO=6)
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timestamp: UTC datetime; defaults to now
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msg: Optional free-text MSG
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**fields: Encoded as structured data params
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"""
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pri = f"<{_FACILITY_LOCAL0 * 8 + severity}>"
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ts = (timestamp or datetime.now(timezone.utc)).isoformat()
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host = (hostname or _NILVALUE)[:_MAX_HOSTNAME]
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appname = (service or _NILVALUE)[:_MAX_APPNAME]
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msgid = (event_type or _NILVALUE)[:_MAX_MSGID]
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sd = _sd_element(fields)
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message = f" {msg}" if msg else ""
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return f"{pri}1 {ts} {host} {appname} {_NILVALUE} {msgid} {sd}{message}"
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def encode_secret(secret: str) -> dict[str, str]:
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"""Standardized credential-secret encoding for the universal SD-block shape.
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Returns ``{'secret_printable': ..., 'secret_b64': ...}`` ready to spread
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into a :func:`syslog_line` / ``_log`` call::
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_log("auth_attempt", principal=user, **encode_secret(password))
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``secret_printable`` mirrors auth-helper.c's sd_escape: bytes outside
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``[0x20, 0x7f)`` collapse to ``'?'`` so the field is always parser-safe
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RFC 5424 ASCII. ``secret_b64`` preserves the *original* utf-8 bytes —
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NUL/0xff/control/non-utf8 sequences all survive losslessly, useful as
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a fingerprinting signal even when the printable form sanitizes them.
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The decnet web ingester's native-shape branch keys off ``secret_b64``
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being present, so any service emitter calling this helper lands its
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cred attempt directly in the :class:`Credential` table.
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"""
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raw = secret.encode("utf-8", errors="replace")
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printable = "".join(chr(b) if 0x20 <= b < 0x7f else "?" for b in raw)
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return {
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"secret_printable": printable,
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"secret_b64": base64.b64encode(raw).decode("ascii"),
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}
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def write_syslog_file(line: str) -> None:
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"""Emit a syslog line to stdout for container log capture."""
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print(line, flush=True)
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def forward_syslog(line: str, log_target: str) -> None:
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"""No-op stub. TCP forwarding is handled by rsyslog, not by service containers."""
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pass
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