55 lines
2.3 KiB
Python
55 lines
2.3 KiB
Python
"""Direct PostgreSQL implementation of the DWH port."""
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from tht.config import DatabaseConfig
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from sqlalchemy.exc import OperationalError, SQLAlchemyError
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from tht.db import execute, sampling
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from tht.db.connection import can_create_in_schema, make_engine, ping, writable_tables
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from tht.db.introspect import introspect
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from tht.execute import ExecResult, PlanSummary
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from tht.mschema.models import PhysicalSchema
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from tht.ports.dwh import DistinctValues, DwhCapabilities, DwhHealth
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class PostgresDwhAdapter:
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capabilities = DwhCapabilities()
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def __init__(self, config: DatabaseConfig, *, statement_timeout_ms: int = 30_000):
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self._config = config
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self._engine = make_engine(config)
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self._statement_timeout_ms = statement_timeout_ms
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def health(self) -> DwhHealth:
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try:
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ping(self._engine)
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except OperationalError as exc:
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return DwhHealth(ok=False, detail=str(exc.orig), error_kind="connection")
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except SQLAlchemyError as exc:
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return DwhHealth(ok=False, detail=str(exc), error_kind="connection")
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writable = tuple(writable_tables(self._engine, self._config.db_schema))
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can_create = can_create_in_schema(self._engine, self._config.db_schema)
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return DwhHealth(ok=True, database=self._config.database, schema=self._config.db_schema,
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read_only=not writable and not can_create,
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writable_tables=writable, can_create=can_create)
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def introspect(self) -> PhysicalSchema:
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return introspect(self._engine, self._config.database, self._config.db_schema)
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def run_query(self, sql: str, *, limit: int) -> ExecResult:
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return execute.run_query(
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self._engine, sql, limit=limit, timeout_ms=self._statement_timeout_ms
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)
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def explain(self, sql: str) -> PlanSummary:
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return execute.explain(self._engine, sql, timeout_ms=self._statement_timeout_ms)
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def sample_column(self, table: str, column: str, *, limit: int) -> list[object]:
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return sampling.sample_column(
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self._engine, self._config.db_schema, table, column, limit=limit
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)
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def distinct_values(self, table: str, column: str, *, limit: int) -> DistinctValues:
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return sampling.distinct_values(
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self._engine, self._config.db_schema, table, column, max_values=limit
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)
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