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2
.gitignore
vendored
2
.gitignore
vendored
@ -5,4 +5,4 @@ dist/
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build/
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.venv/
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.pytest_cache/
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CLAUDE.md
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.claude/
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50
README.md
50
README.md
@ -13,25 +13,27 @@ authorization system and the key-document schema; the crypto primitives live in
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## Install
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```
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envelope_authorizer @ git+ssh://git@git.rethinkstudios.io/rethink-public/envelope_authorizer.git@v0.1.0
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envelope_authorizer @ git+ssh://git@git.rethinkstudios.io/rethink-public/envelope_authorizer.git@v0.1.2
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```
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Direct:
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```bash
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pip install "envelope_authorizer @ git+ssh://git@git.rethinkstudios.io/rethink-public/envelope_authorizer.git@v0.1.0"
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pip install "envelope_authorizer @ git+ssh://git@git.rethinkstudios.io/rethink-public/envelope_authorizer.git@v0.1.2"
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```
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The base install uses a local JSON file for storage (stdlib only). For shared
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dev→server storage, install the mongo extra:
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```bash
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pip install "envelope_authorizer[mongo] @ git+ssh://git@git.rethinkstudios.io/rethink-public/envelope_authorizer.git@v0.1.0"
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pip install "envelope_authorizer[mongo] @ git+ssh://git@git.rethinkstudios.io/rethink-public/envelope_authorizer.git@v0.1.2"
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```
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Installing pulls `envelope_crypto` (and `mongo` with the extra). After install,
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the `authorizer` command is on your PATH; `python -m envelope_authorizer` also works.
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Drop the `@v0.1.2` suffix from the line above to install the latest unpinned.
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## Trust model (read this)
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There is one shared **AES data-encryption key (DEK)** per project. Each key doc
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@ -47,12 +49,39 @@ Each key carries an **encrypted capability flag** — `meta.authorizer` =
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- **Servers** are authorized with `allowed: False` → they can boot and use the DEK
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(decrypt project data) but **cannot authorize anything else**.
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The flag is GCM-sealed under the DEK on purpose: a server **cannot flip its own
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flag in the database to escalate**, because forging a valid flag requires already
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holding the DEK, and editing the stored ciphertext breaks the auth tag. The
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guarantee is precisely: *you cannot grant yourself authority without already
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having it.* (A legitimate authorizer can of course mint new flags — that is its
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job. This stops passive DB tampering, not an authorizer.)
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The flag is GCM-sealed under the DEK on purpose. What that buys, stated honestly:
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- **Without the DEK, the flag is inert.** A stolen database at rest cannot be
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escalated — the flags are ciphertext, unforgeable and unflippable without the key
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(editing the stored ciphertext breaks the GCM auth tag). This stops passive DB
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tampering.
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- **It does not defend against a party that already holds the DEK and can write
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storage.** The flag is sealed under the *shared* DEK and is **not bound to key
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identity**, so such a party can copy a valid sealed `True` flag from an
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authorizer's doc onto its own and self-grant authority. This is **out of scope by
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design**: the trust model assumes DEK-holders are trusted. A DEK-holder already
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has full data access (DEK + write access is game over), so self-granting authority
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exposes no additional data. We deliberately do not add per-key signing to prevent
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it — the residual is handled operationally (below).
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So the precise boundary is: **the capability flag is unforgeable without the DEK; it
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is not a defense against a malicious DEK-holder.** (A legitimate authorizer can of
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course mint new flags — that is its job.)
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### Operational guidance (the residual control)
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Because the DEK-holder case above is **not** prevented cryptographically in the
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shared-DEK model, the intended mitigation is **detection, not crypto**. Consumers
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should periodically audit the authorization state in storage:
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- enumerate every key doc's capability flag (`list` shows authorizer status),
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- compare the set of `allowed: True` keys against a known-good list of expected
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authorizers,
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- alert on any unexpected authorizer.
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An unexpected `allowed: True` appearing in storage is the signal that a DEK-holder
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self-granted — catch it by review, then revoke and re-authorize from a trusted
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machine.
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`revoke` is **bookkeeping, not rotation**: it deletes the record so the key can no
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longer unwrap at boot, but it does not rotate the DEK or scrub it from a machine
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@ -195,5 +224,4 @@ Owned by this lib (not `envelope_crypto`):
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## Versioning
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Tagged `vX.Y.Z`. Pin the tag. `envelope_crypto` is pinned at `v0.1.0` in
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`pyproject.toml`; to change it, edit the pin and re-test.
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Releases are tagged `vX.Y.Z`. The install line above pins a release; drop the `@vX.Y.Z` suffix to install the latest unpinned. Pin deliberately for reproducible installs.
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@ -4,7 +4,7 @@ build-backend = "hatchling.build"
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[project]
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name = "envelope_authorizer"
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version = "0.1.0"
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version = "0.1.2"
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description = "CLI key-authorization manager for envelope_crypto"
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requires-python = ">=3.10"
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dependencies = [
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@ -1 +1 @@
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__version__ = "0.1.0"
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__version__ = "0.1.2"
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@ -9,6 +9,8 @@ command loads config and resolves a storage backend first. expected failures
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import argparse
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import sys
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from cryptography.exceptions import InvalidTag
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from . import __version__
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from .config import ConfigError, load_config
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from .commands import CommandError, authorize, config_init, init, list_keys, revoke, verify
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@ -70,7 +72,9 @@ def main() -> int:
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try:
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config_init.run(None, None, args)
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return 0
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except CommandError as error:
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except (CommandError, OSError) as error:
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# config_init writes a file (cwd may be read-only, full, or gone) — an
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# OSError must print a clean [✘] line, not a raw traceback
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return _fail(str(error))
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parser.parse_args(["config", "--help"])
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return 0
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@ -88,7 +92,12 @@ def main() -> int:
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storage = resolve(config)
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handlers[args.cmd](config, storage, args)
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return 0
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except (ConfigError, CommandError, RuntimeError, ValueError, FileNotFoundError) as error:
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except InvalidTag:
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return _fail("capability flag failed authentication — tampered or wrong DEK")
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except (ConfigError, CommandError, RuntimeError, ValueError, OSError, KeyError, TypeError) as error:
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# OSError covers the FileNotFoundError/PermissionError/IsADirectoryError family;
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# KeyError/TypeError cover a structurally-malformed flag/doc (unguarded indexing
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# of ['iv']/['meta']['authorizer']/['key']) — all print a clean [✘] line, not a traceback
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return _fail(str(error))
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@ -22,7 +22,11 @@ def make_flag(crypto: EnvelopeCrypto, allowed: bool) -> dict:
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def read_flag(crypto: EnvelopeCrypto, blob: dict) -> bool:
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"""decrypt a capability flag; return the `allowed` bool"""
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"""decrypt a capability flag; return the `allowed` bool
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fails closed: a non-dict / unexpected plaintext reads as not-allowed rather than
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raising — a privilege gate must default to deny on a malformed flag.
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"""
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data = crypto.decrypt_data(blob)
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return bool(data.get("allowed", False)) if isinstance(data, dict) else False
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@ -11,7 +11,14 @@ from . import CommandError, build_doc, find_by_friendly, make_flag
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def run(config, storage, args) -> None:
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"""initialize the key system on this machine as the first authorizer"""
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"""initialize the key system on this machine as the first authorizer
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the already-initialized / duplicate-friendly checks are non-atomic (a check-then-act
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TOCTOU under two concurrent CLIs), but this is a one-shot human admin tool and `save`
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upserts by `_id`, so key material can never collide — the worst case is a cosmetic
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double-init under a race, which carries no security consequence in the trusted-
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DEK-holder threat model. left non-atomic by design.
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"""
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if storage.get_all():
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raise CommandError(
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"already initialized; use `authorizer list` to see existing keys"
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@ -11,7 +11,12 @@ from . import boot_local, read_flag
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def _can_authorize(crypto, doc) -> str:
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"""decrypted authority of a doc as Yes/No, or `?` if not readable here"""
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"""decrypted authority of a doc as Yes/No, or `?` if not readable here
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`?` means the flag could not be read for ANY reason — the local key can't unwrap it,
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or the doc is missing/malformed — so the table always renders rather than crashing on
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one bad row. it is not specifically a corruption signal.
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"""
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try:
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return "Yes" if read_flag(crypto, doc["meta"]["authorizer"]) else "No"
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except Exception:
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@ -19,11 +24,16 @@ def _can_authorize(crypto, doc) -> str:
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def _created(doc) -> str:
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"""format created_at as a UTC timestamp string, or '-' if absent"""
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"""format created_at as a UTC timestamp string, or '-' if absent/unparseable"""
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raw = doc.get("meta", {}).get("created_at")
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if not raw:
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return "-"
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return datetime.fromtimestamp(int(raw), tz=timezone.utc).strftime("%Y-%m-%d %H:%M:%S")
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try:
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return datetime.fromtimestamp(int(raw), tz=timezone.utc).strftime("%Y-%m-%d %H:%M:%S")
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except (TypeError, ValueError, OverflowError, OSError):
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# one hand-edited/legacy doc with a bad created_at shouldn't abort the
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# whole table render
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return "-"
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def run(config, storage, args) -> None:
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@ -18,11 +18,18 @@ _WARNING = (
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def _find_by_fingerprint(storage, prefix: str):
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"""return the doc whose `_id` starts with the given prefix, or None"""
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for doc in storage.get_all():
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if doc.get("_id", "").startswith(prefix):
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return doc
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return None
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"""return the single doc whose `_id` starts with the given prefix, or None
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rejects an empty prefix (which would match every key) and an ambiguous prefix
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that matches more than one key, rather than silently revoking the first match.
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"""
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if not prefix:
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raise CommandError("fingerprint prefix must not be empty")
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matches = [doc for doc in storage.get_all() if doc.get("_id", "").startswith(prefix)]
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if len(matches) > 1:
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ids = ", ".join(d["_id"][:16] for d in matches)
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raise CommandError(f"fingerprint prefix '{prefix}' is ambiguous; matches: {ids}")
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return matches[0] if matches else None
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def run(config, storage, args) -> None:
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@ -8,6 +8,7 @@ setups; for dev->server flows across machines, use the mongo backend.
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import json
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import os
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import tempfile
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from pathlib import Path
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from typing import List, Optional
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@ -34,13 +35,36 @@ class JsonStore(StorageBackend):
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return data
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def _write(self, docs: List[dict]) -> None:
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"""atomically write the docs list (temp file then replace)"""
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"""atomically write the docs list (unique temp file then replace)
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the temp name is unique per write (tempfile.mkstemp in the same dir) so two
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concurrent writers can't clobber a shared `.tmp`; os.replace is atomic on the
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same filesystem. the temp is cleaned up if the write fails before replace.
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"""
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self.path.parent.mkdir(parents=True, exist_ok=True)
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tmp = self.path.with_suffix(self.path.suffix + ".tmp")
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with open(tmp, "w", encoding="utf-8") as handle:
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json.dump(docs, handle, indent=2)
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handle.write("\n")
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os.replace(tmp, self.path)
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fd, tmp = tempfile.mkstemp(
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dir=self.path.parent, prefix=self.path.name + ".", suffix=".tmp"
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)
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wrapped = False
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try:
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with os.fdopen(fd, "w", encoding="utf-8") as handle:
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wrapped = True # fdopen took ownership of fd; its close() handles it
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json.dump(docs, handle, indent=2)
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handle.write("\n")
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os.replace(tmp, self.path)
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except BaseException:
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if not wrapped:
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# fdopen raised before taking ownership — close the raw fd ourselves so
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# it isn't leaked (the `with` only closes once fdopen returns a file object)
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try:
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os.close(fd)
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except OSError:
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pass
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try:
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os.unlink(tmp)
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except OSError:
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pass
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raise
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def get(self, fingerprint: str) -> Optional[dict]:
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"""return the doc whose `_id` matches, or None"""
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@ -6,6 +6,14 @@ self-contained per call. no module-level client and no shared event loop, so it
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never collides with a running loop. a per-call connect is an accepted tradeoff
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for a one-shot admin CLI. requires envelope_authorizer[mongo]; without it every
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method raises a clear RuntimeError.
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fail-loud: operations go through the mongo lib's RAW collection escape hatch
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(`db.collection(name)`, the motor collection — which raises) rather than the
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swallow-and-return-default wrapped methods. this is an auth backend; conflating
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a backend error with "no document / not initialized" in the thing that gates
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authority is the worst place for the swallow anti-pattern, so a driver error
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propagates and a no-op upsert raises instead of silently reporting success.
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`close()` is synchronous on the mongo lib (motor's close is sync) — not awaited.
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"""
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import asyncio
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@ -36,33 +44,38 @@ class MongoStore(StorageBackend):
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async def _get(self, fingerprint: str) -> Optional[dict]:
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db = Mongo(self.uri, self.database)
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try:
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return await db.get_document(self.collection, {"_id": fingerprint})
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return await db.collection(self.collection).find_one({"_id": fingerprint})
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finally:
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await db.close()
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db.close()
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async def _get_all(self) -> List[dict]:
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db = Mongo(self.uri, self.database)
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try:
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return await db.get_documents(self.collection, {})
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cursor = db.collection(self.collection).find({})
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return await cursor.to_list(length=None)
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finally:
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await db.close()
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db.close()
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async def _save(self, doc: dict) -> None:
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db = Mongo(self.uri, self.database)
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try:
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await db.update_document(
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self.collection, {"_id": doc["_id"]}, doc, do_upsert=True
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result = await db.collection(self.collection).replace_one(
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{"_id": doc["_id"]}, doc, upsert=True
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)
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if not (result.matched_count or result.upserted_id):
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raise RuntimeError(
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f"mongo upsert affected no document for _id={doc['_id']!r}"
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)
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finally:
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await db.close()
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db.close()
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async def _delete(self, fingerprint: str) -> bool:
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db = Mongo(self.uri, self.database)
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try:
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removed = await db.delete_document(self.collection, {"_id": fingerprint})
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return bool(removed)
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result = await db.collection(self.collection).delete_one({"_id": fingerprint})
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return result.deleted_count > 0
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finally:
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await db.close()
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db.close()
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def get(self, fingerprint: str) -> Optional[dict]:
|
||||
"""return the key doc with this `_id`, or None"""
|
||||
|
||||
Loading…
Reference in New Issue
Block a user