Files
DECNET/decnet/canary/instrumenters/plain.py
anti 6d8c90777d chore: remove vulture-flagged dead code, add whitelist
- plain.py: drop `or True` short-circuit + unreachable return; drop now-unused _HASH_HINTS
- ingester.py: drop unused `current_position` param from _flush_batch
- vulture_whitelist.py: document remaining false positives (FastAPI Depends side-effects, IMAP uid_mode where UID==seq)
2026-04-28 14:30:12 -04:00

80 lines
2.8 KiB
Python

"""Plain-text / config-file instrumenter.
Two embedding strategies, picked in order:
1. **Token substitution.** If the blob contains the literal
placeholder ``{{CANARY_URL}}`` or ``{{CANARY_HOST}}``, replace it.
This gives operators full control over where the slug lands —
they can pre-edit the file with placeholders before uploading.
2. **Append.** Otherwise, append a comment line that mentions the
callback URL. The comment style adapts to the file's apparent
syntax (``#`` for shell/yaml/python/dockerfile, ``//`` for json5/
javascript-ish, ``;`` for ini).
Operators who want neither behavior should upload the file as
``passthrough``.
"""
from __future__ import annotations
from decnet.canary.base import CanaryArtifact, CanaryContext, CanaryInstrumenter
_SLASH_HINTS = (b"//", b"function ", b"const ", b"let ", b"var ")
_SEMI_HINTS = (b"[default]", b"[section]", b"\n[")
def _comment_prefix(blob: bytes) -> bytes:
head = blob[:512]
if any(h in head for h in _SEMI_HINTS):
return b"; "
if any(h in head for h in _SLASH_HINTS):
return b"// "
# Default to # — the most common comment glyph across config files
# we'd plausibly canary.
return b"# "
class PlainInstrumenter(CanaryInstrumenter):
name = "plain"
mime_prefixes = ("text/", "application/json", "application/yaml", "application/toml")
def instrument(
self, blob: bytes, ctx: CanaryContext, *, target_path: str,
) -> CanaryArtifact:
base = ctx.http_base.rstrip("/")
callback_url = f"{base}/c/{ctx.callback_token}".encode()
callback_host = (
f"{ctx.callback_token}.{ctx.dns_zone}".encode()
if ctx.dns_zone else b""
)
notes: list[str] = []
out = blob
if b"{{CANARY_URL}}" in blob:
out = out.replace(b"{{CANARY_URL}}", callback_url)
notes.append(f"substituted {{{{CANARY_URL}}}} -> {callback_url.decode()}")
if b"{{CANARY_HOST}}" in blob and callback_host:
out = out.replace(b"{{CANARY_HOST}}", callback_host)
notes.append(f"substituted {{{{CANARY_HOST}}}} -> {callback_host.decode()}")
if not notes:
# No placeholders — append a comment line at the end.
prefix = _comment_prefix(blob)
tail = (
b"\n" + prefix + b"see " + callback_url
+ b" for the latest version\n"
)
out = (out if out.endswith(b"\n") else out + b"\n") + tail
notes.append(
f"appended comment line carrying {callback_url.decode()}"
)
return CanaryArtifact(
path=target_path,
content=out,
mode=0o644,
mtime_offset=-86400 * 7,
instrumenter=self.name,
notes=notes,
)