mirror of
https://github.com/sprockets/sprockets-postgres.git
synced 2024-09-21 10:10:57 +00:00
WIP refactor
This commit is contained in:
Gavin M. Roy
parent
b9c9495545
commit
611dfd1ec7
2 changed files with 277 additions and 159 deletions
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@ -1,24 +1,16 @@
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"""
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:class:`sprockets.http.app.Application` mixin for handling the connection to
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Postgres and exporting functions for querying the database, getting the status,
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and proving a cursor.
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Automatically creates and shuts down :class:`aio.pool.Pool` on startup
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and shutdown.
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"""
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import asyncio
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import contextlib
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import functools
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import dataclasses
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import logging
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import os
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import time
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import typing
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from distutils import util
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import aiopg
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import psycopg2
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from aiopg import pool
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from psycopg2 import errors, extensions, extras
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from psycopg2 import errors, extras
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from tornado import ioloop, web
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LOGGER = logging.getLogger('sprockets-postgres')
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@ -30,13 +22,115 @@ DEFAULT_POSTGRES_JSON = 'FALSE'
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DEFAULT_POSTGRES_MAX_POOL_SIZE = 0
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DEFAULT_POSTGRES_MIN_POOL_SIZE = 1
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DEFAULT_POSTGRES_QUERY_TIMEOUT = 120
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DEFAULT_POSTGRES_URL = 'postgresql://localhost:5432'
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DEFAULT_POSTGRES_UUID = 'TRUE'
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QueryParameters = typing.Union[list, tuple, None]
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Timeout = typing.Union[int, float, None]
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@dataclasses.dataclass
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class QueryResult:
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row_count: int
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row: typing.Optional[dict]
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rows: typing.Optional[typing.List[dict]]
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class PostgresConnector:
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def __init__(self,
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cursor: aiopg.Cursor,
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on_error: typing.Callable,
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record_duration: typing.Optional[typing.Callable] = None,
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timeout: Timeout = None):
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self.cursor = cursor
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self._on_error = on_error
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self._record_duration = record_duration
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self._timeout = timeout or int(
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os.environ.get(
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'POSTGRES_QUERY_TIMEOUT',
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DEFAULT_POSTGRES_QUERY_TIMEOUT))
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async def callproc(self,
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name: str,
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parameters: QueryParameters = None,
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metric_name: str = '',
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*,
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timeout: Timeout = None) -> QueryResult:
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return await self._query(
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self.cursor.callproc,
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metric_name,
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procname=name,
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parameters=parameters,
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timeout=timeout)
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async def execute(self,
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sql: str,
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parameters: QueryParameters = None,
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metric_name: str = '',
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*,
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timeout: Timeout = None) -> QueryResult:
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return await self._query(
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self.cursor.execute,
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metric_name,
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operation=sql,
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parameters=parameters,
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timeout=timeout)
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@contextlib.asynccontextmanager
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async def transaction(self) \
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-> typing.AsyncContextManager['PostgresConnector']:
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async with self.cursor.begin():
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yield self
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async def _query(self,
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method: typing.Callable,
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metric_name: str,
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**kwargs):
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if kwargs['timeout'] is None:
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kwargs['timeout'] = self._timeout
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start_time = time.monotonic()
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try:
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await method(**kwargs)
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except (asyncio.TimeoutError, psycopg2.Error) as err:
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LOGGER.error('Caught %r', err)
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exc = self._on_error(metric_name, err)
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if exc:
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raise exc
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finally:
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if self._record_duration:
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self._record_duration(
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metric_name, time.monotonic() - start_time)
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return await self._query_results()
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async def _query_results(self) -> QueryResult:
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row, rows = None, None
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if self.cursor.rowcount == 1:
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try:
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row = dict(await self.cursor.fetchone())
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except psycopg2.ProgrammingError:
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pass
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elif self.cursor.rowcount > 1:
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try:
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rows = [dict(row) for row in await self.cursor.fetchall()]
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except psycopg2.ProgrammingError:
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pass
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return QueryResult(self.cursor.rowcount, row, rows)
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class ConnectionException(Exception):
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"""Raised when the connection to Postgres can not be established"""
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class ApplicationMixin:
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"""Application mixin for setting up the PostgreSQL client pool"""
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"""
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:class:`sprockets.http.app.Application` mixin for handling the connection
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to Postgres and exporting functions for querying the database,
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getting the status, and proving a cursor.
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Automatically creates and shuts down :class:`aio.pool.Pool` on startup
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and shutdown.
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"""
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POSTGRES_STATUS_TIMEOUT = 3
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def __init__(self, *args, **kwargs):
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@ -46,155 +140,57 @@ class ApplicationMixin:
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self.runner_callbacks['shutdown'].append(self._postgres_shutdown)
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@contextlib.asynccontextmanager
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async def postgres_cursor(self,
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timeout: typing.Optional[int] = None,
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raise_http_error: bool = True) \
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-> typing.AsyncContextManager[extensions.cursor]:
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"""Return a Postgres cursor for the pool"""
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async def postgres_connector(self,
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on_error: typing.Callable,
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record_duration: typing.Optional[
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typing.Callable] = None,
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timeout: Timeout = None) \
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-> typing.AsyncContextManager[PostgresConnector]:
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try:
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async with self._postgres_pool.acquire() as conn:
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async with conn.cursor(
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cursor_factory=extras.RealDictCursor,
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timeout=self._postgres_query_timeout(timeout)) as pgc:
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yield pgc
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except (asyncio.TimeoutError,
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psycopg2.OperationalError,
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psycopg2.Error) as error:
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LOGGER.critical('Error connecting to Postgres: %s', error)
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if raise_http_error:
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raise web.HTTPError(503, 'Database Unavailable')
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raise
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async def postgres_callproc(self,
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name: str,
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params: typing.Union[list, tuple, None] = None,
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timeout: typing.Optional[int] = None) \
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-> typing.Union[dict, list, None]:
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"""Execute a stored procedure, specifying the name, SQL, passing in
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optional parameters.
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:param name: The stored-proc to call
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:param params: Optional parameters to pass into the function
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:param timeout: Optional timeout to override the default query timeout
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"""
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async with self.postgres_cursor(timeout) as cursor:
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return await self._postgres_query(
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cursor, cursor.callproc, name, name, params)
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async def postgres_execute(self, name: str, sql: str,
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*args,
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timeout: typing.Optional[int] = None) \
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-> typing.Union[dict, list, None]:
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"""Execute a query, specifying a name for the query, the SQL statement,
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and optional positional arguments to pass in with the query.
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Parameters may be provided as sequence or mapping and will be
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bound to variables in the operation. Variables are specified
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either with positional ``%s`` or named ``%({name})s`` placeholders.
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:param name: The stored-proc to call
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:param sql: The SQL statement to execute
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:param timeout: Optional timeout to override the default query timeout
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"""
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async with self.postgres_cursor(timeout) as cursor:
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return await self._postgres_query(
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cursor, cursor.execute, name, sql, args)
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timeout=timeout) as cursor:
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yield PostgresConnector(
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cursor, on_error, record_duration, timeout)
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except (asyncio.TimeoutError, psycopg2.Error) as err:
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on_error('postgres_connector', ConnectionException(str(err)))
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async def postgres_status(self) -> dict:
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"""Invoke from the ``/status`` RequestHandler to check that there is
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a Postgres connection handler available and return info about the
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pool.
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"""
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available = True
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try:
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async with self.postgres_cursor(
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self.POSTGRES_STATUS_TIMEOUT, False) as cursor:
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await cursor.execute('SELECT 1')
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except (asyncio.TimeoutError, psycopg2.OperationalError):
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available = False
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"""
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query_error = asyncio.Event()
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def on_error(_metric_name, _exc) -> None:
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query_error.set()
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return None
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async with self.postgres_connector(
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on_error,
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timeout=self.POSTGRES_STATUS_TIMEOUT) as connector:
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await connector.execute('SELECT 1')
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return {
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'available': available,
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'available': not query_error.is_set(),
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'pool_size': self._postgres_pool.size,
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'pool_free': self._postgres_pool.freesize
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}
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async def _postgres_query(self,
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cursor: aiopg.Cursor,
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method: typing.Callable,
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name: str,
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sql: str,
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parameters: typing.Union[dict, list, tuple]) \
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-> typing.Union[dict, list, None]:
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"""Execute a query, specifying the name, SQL, passing in
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"""
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try:
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await method(sql, parameters)
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except asyncio.TimeoutError as err:
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LOGGER.error('Query timeout for %s: %s',
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name, str(err).split('\n')[0])
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raise web.HTTPError(500, reason='Query Timeout')
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except errors.UniqueViolation as err:
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LOGGER.error('Database error for %s: %s',
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name, str(err).split('\n')[0])
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raise web.HTTPError(409, reason='Unique Violation')
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except psycopg2.Error as err:
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LOGGER.error('Database error for %s: %s',
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name, str(err).split('\n')[0])
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raise web.HTTPError(500, reason='Database Error')
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try:
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return await self._postgres_query_results(cursor)
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except psycopg2.ProgrammingError:
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return
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@staticmethod
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async def _postgres_query_results(cursor: aiopg.Cursor) \
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-> typing.Union[dict, list, None]:
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"""Invoked by self.postgres_query to return all of the query results
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as either a ``dict`` or ``list`` depending on the quantity of rows.
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This can raise a ``psycopg2.ProgrammingError`` for an INSERT/UPDATE
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without RETURNING or a DELETE. That exception is caught by the caller.
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:raises psycopg2.ProgrammingError: when there are no rows to fetch
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even though the rowcount is > 0
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"""
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if cursor.rowcount == 1:
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return await cursor.fetchone()
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elif cursor.rowcount > 1:
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return await cursor.fetchall()
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return None
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@functools.lru_cache(2)
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def _postgres_query_timeout(self,
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timeout: typing.Optional[int] = None) -> int:
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"""Return query timeout, either from the specified value or
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``POSTGRES_QUERY_TIMEOUT`` environment variable, if set.
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Defaults to sprockets_postgres.DEFAULT_POSTGRES_QUERY_TIMEOUT.
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"""
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return timeout if timeout else int(
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os.environ.get(
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'POSTGRES_QUERY_TIMEOUT',
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DEFAULT_POSTGRES_QUERY_TIMEOUT))
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async def _postgres_setup(self,
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_app: web.Application,
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_ioloop: ioloop.IOLoop) -> None:
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loop: ioloop.IOLoop) -> None:
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"""Setup the Postgres pool of connections and log if there is an error.
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This is invoked by the Application on start callback mechanism.
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"""
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url = os.environ.get('POSTGRES_URL', DEFAULT_POSTGRES_URL)
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LOGGER.debug('Connecting to PostgreSQL: %s', url)
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if 'POSTGRES_URL' not in os.environ:
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LOGGER.critical('Missing POSTGRES_URL environment variable')
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return self.stop(loop)
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self._postgres_pool = pool.Pool(
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url,
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os.environ['POSTGRES_URL'],
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minsize=int(
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os.environ.get(
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'POSTGRES_MIN_POOL_SIZE',
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@ -236,3 +232,90 @@ class ApplicationMixin:
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"""
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self._postgres_pool.close()
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await self._postgres_pool.wait_closed()
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class RequestHandlerMixin:
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"""
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RequestHandler mixin class exposing functions for querying the database,
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recording the duration to either `sprockets-influxdb` or
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`sprockets.mixins.metrics`, and handling exceptions.
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"""
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async def postgres_callproc(self,
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name: str,
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parameters: QueryParameters = None,
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metric_name: str = '',
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*,
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timeout: Timeout = None) -> QueryResult:
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async with self._postgres_connector(timeout) as connector:
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return await connector.callproc(
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name, parameters, metric_name, timeout=timeout)
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async def postgres_execute(self,
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sql: str,
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parameters: QueryParameters = None,
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metric_name: str = '',
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*,
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timeout: Timeout = None) -> QueryResult:
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"""Execute a query, specifying a name for the query, the SQL statement,
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and optional positional arguments to pass in with the query.
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Parameters may be provided as sequence or mapping and will be
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bound to variables in the operation. Variables are specified
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either with positional ``%s`` or named ``%({name})s`` placeholders.
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"""
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async with self._postgres_connector(timeout) as connector:
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return await connector.execute(
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sql, parameters, metric_name, timeout=timeout)
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@contextlib.asynccontextmanager
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async def postgres_transaction(self, timeout: Timeout = None) \
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-> typing.AsyncContextManager[PostgresConnector]:
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"""Yields a :class:`PostgresConnector` instance in a transaction.
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Will automatically commit or rollback based upon exception.
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"""
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async with self._postgres_connector(timeout) as connector:
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async with connector.transaction():
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yield connector
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@contextlib.asynccontextmanager
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async def _postgres_connector(self, timeout: Timeout = None) \
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-> typing.AsyncContextManager[PostgresConnector]:
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async with self.application.postgres_connector(
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self.__on_postgres_error,
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self.__on_postgres_timing,
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timeout) as connector:
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yield connector
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def __on_postgres_error(self,
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metric_name: str,
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exc: Exception) -> typing.Optional[Exception]:
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"""Override for different error handling behaviors"""
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LOGGER.error('%s in %s for %s (%s)',
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exc.__class__.__name__,
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self.__class__.__name__,
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metric_name,
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str(exc).split('\n')[0])
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if isinstance(exc, ConnectionException):
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raise web.HTTPError(503, reason='Database Connection Error')
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elif isinstance(exc, asyncio.TimeoutError):
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raise web.HTTPError(500, reason='Query Timeout')
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elif isinstance(exc, errors.UniqueViolation):
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raise web.HTTPError(409, reason='Unique Violation')
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elif isinstance(exc, psycopg2.Error):
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raise web.HTTPError(500, reason='Database Error')
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return exc
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def __on_postgres_timing(self,
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metric_name: str,
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duration: float) -> None:
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"""Override for custom metric recording"""
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if hasattr(self, 'influxdb'): # sprockets-influxdb
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self.influxdb.set_field(metric_name, duration)
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elif hasattr(self, 'record_timing'): # sprockets.mixins.metrics
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self.record_timing(metric_name, duration)
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else:
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LOGGER.debug('Postgres query %s duration: %s',
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metric_name, duration)
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|
|
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75
tests.py
75
tests.py
|
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@ -12,40 +12,46 @@ from tornado import web
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import sprockets_postgres
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class CallprocRequestHandler(web.RequestHandler):
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class CallprocRequestHandler(sprockets_postgres.RequestHandlerMixin,
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web.RequestHandler):
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async def get(self):
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result = await self.application.postgres_callproc('uuid_generate_v4')
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await self.finish({'value': str(result['uuid_generate_v4'])})
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result = await self.postgres_callproc(
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'uuid_generate_v4', metric_name='uuid')
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await self.finish({'value': str(result.row['uuid_generate_v4'])})
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class ExecuteRequestHandler(web.RequestHandler):
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class ExecuteRequestHandler(sprockets_postgres.RequestHandlerMixin,
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web.RequestHandler):
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GET_SQL = 'SELECT %s::TEXT AS value;'
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async def get(self):
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result = await self.application.postgres_execute(
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'get', self.GET_SQL, self.get_argument('value'))
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await self.finish({'value': result['value'] if result else None})
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result = await self.postgres_execute(
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self.GET_SQL, [self.get_argument('value')], 'get')
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await self.finish({
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'value': result.row['value'] if result.row else None})
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class MultiRowRequestHandler(web.RequestHandler):
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class MultiRowRequestHandler(sprockets_postgres.RequestHandlerMixin,
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web.RequestHandler):
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|
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GET_SQL = 'SELECT * FROM information_schema.enabled_roles;'
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async def get(self):
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rows = await self.application.postgres_execute('get', self.GET_SQL)
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await self.finish({'rows': [row['role_name'] for row in rows]})
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result = await self.postgres_execute(self.GET_SQL)
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await self.finish({'rows': [row['role_name'] for row in result.rows]})
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class NoRowRequestHandler(web.RequestHandler):
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class NoRowRequestHandler(sprockets_postgres.RequestHandlerMixin,
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web.RequestHandler):
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GET_SQL = """\
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SELECT * FROM information_schema.tables WHERE table_schema = 'public';"""
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|
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async def get(self):
|
||||
rows = await self.application.postgres_execute('get', self.GET_SQL)
|
||||
await self.finish({'rows': rows})
|
||||
result = await self.postgres_execute(self.GET_SQL)
|
||||
await self.finish({'rows': result.rows})
|
||||
|
||||
|
||||
class StatusRequestHandler(web.RequestHandler):
|
||||
|
|
@ -62,7 +68,7 @@ class Application(sprockets_postgres.ApplicationMixin,
|
|||
pass
|
||||
|
||||
|
||||
class ExecuteTestCase(testing.SprocketsHttpTestCase):
|
||||
class TestCase(testing.SprocketsHttpTestCase):
|
||||
|
||||
@classmethod
|
||||
def setUpClass(cls):
|
||||
|
|
@ -143,15 +149,44 @@ class ExecuteTestCase(testing.SprocketsHttpTestCase):
|
|||
self.assertEqual(response.code, 500)
|
||||
self.assertIn(b'Database Error', response.body)
|
||||
|
||||
def test_postgres_programming_error(self):
|
||||
with mock.patch.object(self.app, '_postgres_query_results') as pqr:
|
||||
pqr.side_effect = psycopg2.ProgrammingError()
|
||||
response = self.fetch('/execute?value=1')
|
||||
self.assertEqual(response.code, 200)
|
||||
self.assertIsNone(json.loads(response.body)['value'])
|
||||
@mock.patch('aiopg.cursor.Cursor.fetchone')
|
||||
def test_postgres_programming_error(self, fetchone):
|
||||
fetchone.side_effect = psycopg2.ProgrammingError()
|
||||
response = self.fetch('/execute?value=1')
|
||||
self.assertEqual(response.code, 200)
|
||||
self.assertIsNone(json.loads(response.body)['value'])
|
||||
|
||||
@mock.patch('aiopg.connection.Connection.cursor')
|
||||
def test_postgres_cursor_raises(self, cursor):
|
||||
cursor.side_effect = asyncio.TimeoutError()
|
||||
response = self.fetch('/execute?value=1')
|
||||
self.assertEqual(response.code, 503)
|
||||
|
||||
"""
|
||||
class MissingURLTestCase(testing.SprocketsHttpTestCase):
|
||||
|
||||
@classmethod
|
||||
def setUpClass(cls):
|
||||
with open('build/test-environment') as f:
|
||||
for line in f:
|
||||
if line.startswith('export '):
|
||||
line = line[7:]
|
||||
name, _, value = line.strip().partition('=')
|
||||
if name != 'POSTGRES_URL':
|
||||
os.environ[name] = value
|
||||
if 'POSTGRES_URL' in os.environ:
|
||||
del os.environ['POSTGRES_URL']
|
||||
|
||||
def setUp(self):
|
||||
self.stop_mock = None
|
||||
super().setUp()
|
||||
|
||||
def get_app(self):
|
||||
self.app = Application()
|
||||
self.stop_mock = mock.Mock(
|
||||
wraps=self.app.stop, side_effect=RuntimeError)
|
||||
return self.app
|
||||
|
||||
def test_that_stop_is_invoked(self):
|
||||
self.stop_mock.assert_called_once_with(self.io_loop)
|
||||
"""
|
||||
|
|
|
|||
Loading…
Reference in a new issue