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| """ | |
| File: /_naming.py | |
| Project: postgresql | |
| Helpers for converting a `brain_id` (which can be a UUID, name_key, or any | |
| arbitrary string) into a deterministic Postgres-safe database identifier. | |
| Postgres identifiers must be at most 63 bytes (NAMEDATALEN - 1) and, when | |
| unquoted, can only contain `[a-z][a-z0-9_]*`. We always lowercase + sanitize | |
| to ASCII `[a-z0-9_]`. If the resulting name exceeds the length budget we | |
| truncate the human-readable tail and append a SHA-256 prefix so the mapping | |
| stays stable and collision-resistant. | |
| """ | |
| from __future__ import annotations | |
| import hashlib | |
| import re | |
| __all__ = ["brain_db_name", "brain_id_from_db_name", "BRAIN_DB_PREFIX", "is_internal_brain_db_suffix"] | |
| BRAIN_DB_PREFIX = "brain_" | |
| _MAX_DBNAME_LEN = 63 | |
| _HASH_SUFFIX_LEN = 12 | |
| _SANITIZE_RE = re.compile(r"[^a-z0-9_]+") | |
| def brain_db_name(brain_id: str) -> str: | |
| """Return the Postgres database name that hosts `brain_id`. | |
| Always lowercase, ASCII, and stable across runs for the same `brain_id`. | |
| """ | |
| if not brain_id: | |
| raise ValueError("brain_id must be a non-empty string") | |
| sanitized = _SANITIZE_RE.sub("_", brain_id.lower()).strip("_") | |
| if not sanitized: | |
| sanitized = "x" | |
| candidate = f"{BRAIN_DB_PREFIX}{sanitized}" | |
| if len(candidate) <= _MAX_DBNAME_LEN: | |
| return candidate | |
| digest = hashlib.sha256(brain_id.encode("utf-8")).hexdigest()[:_HASH_SUFFIX_LEN] | |
| head_budget = _MAX_DBNAME_LEN - len(BRAIN_DB_PREFIX) - len(digest) - 1 | |
| head = sanitized[:head_budget].rstrip("_") | |
| return f"{BRAIN_DB_PREFIX}{head}_{digest}" | |
| def brain_id_from_db_name(db_name: str) -> str | None: | |
| if not db_name.startswith(BRAIN_DB_PREFIX): | |
| return None | |
| suffix = db_name[len(BRAIN_DB_PREFIX) :] | |
| return suffix or None | |
| def is_internal_brain_db_suffix(suffix: str) -> bool: | |
| compact = suffix.replace("_", "") | |
| if len(compact) < 32: | |
| return False | |
| return all(ch in "0123456789abcdef" for ch in compact) | |