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v0.1.3
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49e8de3b1a
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1ae280e5c3 |
@@ -10,18 +10,18 @@ a sibling of the `mongo` lib. Class is **`PsqlDB`**.
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`requirements.txt`:
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```
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psql @ git+ssh://git@git.rethinkstudios.io/rethink-public/psql.git@v0.1.3
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psql @ git+ssh://git@git.rethinkstudios.io/rethink-public/psql.git@v0.1.7
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```
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Direct:
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```bash
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pip install "psql @ git+ssh://git@git.rethinkstudios.io/rethink-public/psql.git@v0.1.3"
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pip install "psql @ git+ssh://git@git.rethinkstudios.io/rethink-public/psql.git@v0.1.7"
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```
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Pulls `asyncpg`.
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Drop the `@v0.1.3` suffix from the line above to install the latest unpinned.
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Drop the `@v0.1.7` suffix from the line above to install the latest unpinned.
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## The two-layer API
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@@ -63,6 +63,12 @@ async with PsqlDB(database="app", user="postgres") as db:
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await db.insert("events", {"kind": "login"})
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```
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`host`/`port` default to `None`, not `"localhost"`/`5432` — asyncpg only reads a `dsn`'s
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embedded host/port when the `host`/`port` kwargs are falsy, so passing `dsn=...` in
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`pool_kwargs` (with no `host`/`port` of your own) lets the dsn's server reach asyncpg
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instead of being silently overridden. The no-dsn path above still defaults to
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`localhost:5432` when you don't pass `host`.
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### Layer 2 — raw SQL for the complex queries
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```python
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+1
-1
@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
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[project]
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name = "psql"
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version = "0.1.3"
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version = "1.0.0"
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description = "async postgres wrapper over asyncpg: two-layer API (friendly verbs + raw escape hatch), fail-loud, config-free"
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requires-python = ">=3.10"
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dependencies = [
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@@ -1,3 +1,10 @@
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from importlib.metadata import PackageNotFoundError, version
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from .psql import PsqlDB
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__all__ = ["PsqlDB"]
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try:
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__version__ = version("psql")
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except PackageNotFoundError:
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__version__ = "0.0.0+unknown"
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+81
-57
@@ -1,5 +1,5 @@
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"""
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async postgres wrapper over asyncpg — two-layer API (friendly verbs + raw escape hatch)
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async postgres wrapper over asyncpg - two-layer API (friendly verbs + raw escape hatch)
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object pattern (one pool per process), attach to the app:
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from psql import PsqlDB
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@@ -13,39 +13,33 @@ context manager:
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async with PsqlDB(database="app", user="postgres") as db:
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await db.execute("CREATE TABLE ...")
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lifecycle:
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construction is sync and opens no socket. connect() builds the asyncpg pool and
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validates it with `SELECT 1` so a bad host/credentials fails loud immediately rather
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than on the first real op, and returns self. close() closes the pool.
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dsn:
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host/port default to None, not "localhost"/5432 - asyncpg only reads a dsn's embedded
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host/port when the host/port kwargs are falsy, so a hardcoded default would silently
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shadow the dsn's server. pass dsn=... in pool_kwargs alone (no host/port) to let the
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dsn's own host/port reach asyncpg; the no-dsn path still defaults to localhost:5432.
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two-layer API:
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LAYER 1 — friendly, portable verbs for simple single-table CRUD. these hide the
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dialect and are byte-for-byte identical to the `mysql` lib, so a dev swaps psql<->mysql
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with zero call-site changes: create_database, create_table, drop, insert, get,
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get_one, delete, exists, upsert.
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LAYER 2 — raw escape hatch for the complex ~20% (joins, aggregates, CTEs, window
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functions): execute, fetch, fetchone, fetchval, transaction. you write the SQL with
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`$1, $2` placeholders (asyncpg style) + params; the wrapper still gives pooling,
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parameterization, fail-loud errors, and row->dict conversion. raw SQL is psql-specific.
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there is deliberately NOTHING in between — no query builder / ORM. a join goes through
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raw fetch(), never a chainable .where()/.join().
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rows:
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layer 1 and fetch/fetchone return plain dicts ({column: value}), not asyncpg Record
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objects — identical shape to the mysql lib.
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LAYER 1 - friendly, portable verbs for simple single-table CRUD, byte-for-byte
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identical to the `mysql` lib (zero call-site changes swapping psql<->mysql):
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create_database, create_table, drop, insert, get, get_one, delete, exists, upsert.
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LAYER 2 - raw escape hatch for the complex ~20% (joins, aggregates, CTEs, window
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functions): execute, fetch, fetchone, fetchval, transaction, using `$1, $2`
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placeholders (asyncpg style). deliberately nothing in between - no query builder/ORM.
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placeholders / injection safety:
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values are ALWAYS parameterized — layer 1 builds `$1, $2` internally; layer 2 takes
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values are ALWAYS parameterized - layer 1 builds `$1, $2` internally; layer 2 takes
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your `$1` placeholders + *params. never f-string/format a value into SQL. only
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identifiers (table/column names) are interpolated, and they are quoted.
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errors (FAIL LOUD — unlike the mongo lib's swallow-and-default):
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errors (FAIL LOUD - unlike the mongo lib's swallow-and-default):
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every method catches the driver error (asyncpg.PostgresError / InterfaceError, OSError
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on connection loss), logs via getLogger(__name__), and re-raises. a None/[] return is
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only ever a real result (no row, empty table) — never a swallowed failure. for anything
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only ever a real result (no row, empty table) - never a swallowed failure. for anything
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not wrapped, use the raw `.pool` property (the asyncpg.Pool).
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"""
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import asyncio
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import logging
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from typing import Any, Dict, List, Optional, Sequence
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@@ -59,7 +53,7 @@ _DRIVER_ERRORS = (asyncpg.PostgresError, asyncpg.InterfaceError, OSError)
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def _quote_ident(identifier: str) -> str:
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"""quote a sql identifier (table/column), escaping embedded double-quotes
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identifiers can't be parameterized, so they are interpolated — quoting + doubling any
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identifiers can't be parameterized, so they are interpolated - quoting + doubling any
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embedded quote is the postgres-safe way to do that for caller-supplied names.
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"""
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return '"' + identifier.replace('"', '""') + '"'
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@@ -75,8 +69,8 @@ class PsqlDB:
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def __init__(
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self,
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host: str = "localhost",
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port: int = 5432,
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host: Optional[str] = None,
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port: Optional[int] = None,
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database: Optional[str] = None,
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user: Optional[str] = None,
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password: Optional[str] = None,
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@@ -91,7 +85,18 @@ class PsqlDB:
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host/port/database/user/password/min_size/max_size/command_timeout are injected by
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the caller. extra pool_kwargs pass through to asyncpg.create_pool (ssl, server_
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settings, dsn, etc). `host` may be a unix socket directory as well as a hostname.
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host/port default to None here (not "localhost"/5432): asyncpg only reads a dsn's
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embedded host/port when the host/port kwargs are falsy, so a hardcoded default
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would silently shadow the dsn's server. no dsn -> host/port fall back to
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localhost:5432; dsn passed -> host/port stay None (letting the dsn's own reach
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asyncpg) unless the caller explicitly overrides them.
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"""
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if "dsn" not in pool_kwargs:
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if host is None:
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host = "localhost"
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if port is None:
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port = 5432
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self._config = dict(
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host=host,
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port=port,
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@@ -104,6 +109,7 @@ class PsqlDB:
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**pool_kwargs,
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)
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self._pool: Optional[asyncpg.Pool] = None
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self._connect_lock = asyncio.Lock()
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async def connect(self) -> "PsqlDB":
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"""build the pool and validate it with SELECT 1; fail loud on bad config
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@@ -111,25 +117,42 @@ class PsqlDB:
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returns self so callers can write `db = await PsqlDB(...).connect()`. if called
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again on an already-connected instance the previous pool is closed first (no
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orphaned pool); if the SELECT-1 validation fails the freshly-built pool is torn
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down before re-raising, so a failed connect() never leaks a live pool.
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down before re-raising, so a failed connect() never leaks a live pool. guarded by
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an internal lock so concurrent connect() calls build exactly one pool instead of
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each racing to create + orphan their own.
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"""
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if self._pool is not None:
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await self.close()
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pool = await asyncpg.create_pool(**self._config)
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try:
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await pool.fetchval("SELECT 1")
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except _DRIVER_ERRORS:
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log.exception("psql.connect() validation failed")
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await pool.close()
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raise
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except BaseException:
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await pool.close()
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raise
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self._pool = pool
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return self
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async with self._connect_lock:
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if self._pool is not None:
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await self._close_locked()
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pool = None
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try:
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pool = await asyncpg.create_pool(**self._config)
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await pool.fetchval("SELECT 1")
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except _DRIVER_ERRORS:
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log.exception("psql.connect() failed")
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if pool is not None:
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await pool.close()
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raise
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except BaseException:
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if pool is not None:
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await pool.close()
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raise
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self._pool = pool
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return self
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async def close(self) -> None:
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"""close the pool on shutdown"""
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"""close the pool on shutdown and null the reference (so pool/connected checks
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report not-connected against a dead pool)
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guarded by the same lock as connect() - a close() racing an in-flight connect()
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waits for it rather than no-opping against a not-yet-installed pool and leaving
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the just-built one live.
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"""
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async with self._connect_lock:
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await self._close_locked()
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async def _close_locked(self) -> None:
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"""close the pool and null the reference; caller must hold `_connect_lock`"""
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if self._pool is None:
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return
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try:
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@@ -137,31 +160,33 @@ class PsqlDB:
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except _DRIVER_ERRORS:
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log.exception("psql.close()")
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raise
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finally:
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self._pool = None
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async def __aenter__(self) -> "PsqlDB":
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"""enter: connect() and return self"""
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return await self.connect()
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async def __aexit__(self, exc_type, exc, tb) -> None:
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"""exit: close(), ignoring exc_type/exc/tb"""
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await self.close()
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@property
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def pool(self) -> asyncpg.Pool:
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"""raw asyncpg.Pool escape hatch; full driver surface, raises
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use for copy/prepare/listen-notify/cursors and anything not wrapped.
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"""
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"""raw asyncpg.Pool escape hatch for copy/prepare/listen-notify/cursors and
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anything not wrapped; full driver surface, raises"""
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if self._pool is None:
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raise RuntimeError("psql: not connected; call await db.connect() first")
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return self._pool
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# -------------------------------------------------------------------------
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# layer 2 — raw escape hatch (you write the SQL, $1 placeholders)
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# layer 2 - raw escape hatch (you write the SQL, $1 placeholders)
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async def execute(self, query: str, *params: Any) -> str:
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"""run a statement (INSERT/UPDATE/DELETE/DDL); return asyncpg's status string
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the status string is e.g. "INSERT 0 1" / "UPDATE 3" / "DELETE 2" — parse it or use
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the layer-1 verbs (insert/delete) which return structured values instead.
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e.g. "INSERT 0 1" / "UPDATE 3" / "DELETE 2" - parse it, or use the layer-1 verbs
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(insert/delete) which return structured values instead.
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"""
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try:
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return await self.pool.execute(query, *params)
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@@ -181,8 +206,7 @@ class PsqlDB:
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async def fetchone(self, query: str, *params: Any) -> Optional[dict]:
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"""run a query and return the first row as a dict, or None if no rows
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named fetchone (not asyncpg's fetchrow) to match the mysql lib's layer-2 surface;
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maps to the driver's fetchrow internally.
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named fetchone (not asyncpg's fetchrow) to match the mysql lib's layer-2 surface.
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"""
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try:
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row = await self.pool.fetchrow(query, *params)
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@@ -207,15 +231,15 @@ class PsqlDB:
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await conn.execute("INSERT ...", a)
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await conn.execute("UPDATE ...", b)
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commits on clean exit, rolls back and re-raises on any error. `conn` is a raw
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asyncpg connection (use its $1-placeholder execute/fetch/... directly).
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asyncpg connection ($1-placeholder execute/fetch/... directly).
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"""
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return _Transaction(self.pool)
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# -------------------------------------------------------------------------
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# layer 1 — friendly portable verbs (identical across psql/mysql)
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# layer 1 - friendly portable verbs (identical across psql/mysql)
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async def create_database(self, name: str) -> None:
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"""CREATE DATABASE name (raises if it already exists — postgres has no IF NOT
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"""CREATE DATABASE name (raises if it already exists - postgres has no IF NOT
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EXISTS for CREATE DATABASE; catch the duplicate error or check first)"""
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try:
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await self.pool.execute(f"CREATE DATABASE {_quote_ident(name)}")
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@@ -251,7 +275,7 @@ class PsqlDB:
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"""INSERT one row from {column: value}; return the inserted rowcount (1)
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values are parameterized ($1, $2, ...). returns the number of rows inserted (1 on
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success) — the portable return shape shared with the mysql lib.
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success) - the portable return shape shared with the mysql lib.
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"""
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cols = list(values.keys())
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placeholders = ", ".join(f"${i + 1}" for i in range(len(cols)))
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@@ -267,7 +291,7 @@ class PsqlDB:
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async def get(self, table: str, conditions: Optional[Dict[str, Any]] = None) -> List[dict]:
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"""SELECT * rows matching equality `conditions` (col = val AND ...) as dicts
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conditions=None/{} returns all rows. simple equality only — anything more complex
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conditions=None/{} returns all rows. simple equality only - anything more complex
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goes through raw fetch().
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"""
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where, params = _where(conditions)
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@@ -315,7 +339,7 @@ class PsqlDB:
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raise
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async def upsert(self, table: str, values: Dict[str, Any], conflict: Sequence[str]) -> int:
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"""INSERT ... ON CONFLICT (conflict_cols) DO UPDATE — insert or update on key clash
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"""INSERT ... ON CONFLICT (conflict_cols) DO UPDATE - insert or update on key clash
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`conflict` is the list of columns forming the unique/pk constraint to upsert on.
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the wrapper emits ON CONFLICT here (the mysql lib emits ON DUPLICATE KEY UPDATE for
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@@ -353,7 +377,7 @@ class _Transaction:
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await self._tx.start()
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except BaseException:
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# start() (or transaction()) failing after acquire would otherwise leak the
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# pooled connection — __aexit__ is not called when __aenter__ raises. release
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# pooled connection - __aexit__ is not called when __aenter__ raises. release
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# it and reset so a failed transaction start never burns a pool slot.
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await self._pool.release(self._conn)
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self._conn = None
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Reference in New Issue
Block a user