from typing import Any, Dict, Iterable, List, Optional, Sequence, Union
from uuid import UUID
import sqlalchemy.exc
from sqlalchemy import asc, bindparam, desc, select, text
from sqlalchemy.orm.exc import MultipleResultsFound, NoResultFound
from sqlalchemy.sql import func
from eventsourcing.exceptions import OperationalError, ProgrammingError
from eventsourcing.infrastructure.base import (
BaseRecordManager,
SQLRecordManager,
TrackingKwargs,
)
[docs]class SQLAlchemyRecordManager(SQLRecordManager):
_where_application_name_tmpl = (
" WHERE application_name=:application_name AND pipeline_id=:pipeline_id"
)
[docs] def __init__(self, session: Any, *args: Any, **kwargs: Any):
super(SQLAlchemyRecordManager, self).__init__(*args, **kwargs)
self.session = session
[docs] def _prepare_insert(
self,
tmpl: Any,
record_class: type,
field_names: List[str],
placeholder_for_id: bool = False,
) -> Any:
"""
With transaction isolation level of "read committed" this should
generate records with a contiguous sequence of integer IDs, assumes
an indexed ID column, the database-side SQL max function, the
insert-select-from form, and optimistic concurrency control.
"""
statement = super()._prepare_insert(
tmpl, record_class, field_names, placeholder_for_id
)
statement = text(statement)
# Define bind parameters with explicit types taken from record column types.
bindparams = []
for col_name in field_names:
column_type = getattr(record_class, col_name).type
bindparams.append(bindparam(col_name, type_=column_type))
# Redefine statement with explicitly typed bind parameters.
statement = statement.bindparams(*bindparams)
return statement
[docs] def make_placeholder(self, field_name: str) -> str:
return ":{}".format(field_name)
[docs] def write_records(
self,
records: Iterable[Any],
tracking_kwargs: Optional[TrackingKwargs] = None,
orm_objs_pending_save: Optional[Sequence[Any]] = None,
orm_objs_pending_delete: Optional[Sequence[Any]] = None,
) -> None:
all_params = []
statement = None
if not isinstance(records, list):
records = list(records)
if records:
# Prepare to insert event and notification records.
statement = self.insert_values
if self.notification_id_name:
all_ids = set((getattr(r, self.notification_id_name) for r in records))
if None in all_ids:
if len(all_ids) > 1:
# Either all or zero records must have IDs.
raise ProgrammingError("Only some records have IDs")
elif self.contiguous_record_ids:
# Do an "insert select max" from existing.
statement = self.insert_select_max
elif hasattr(self.record_class, "application_name"):
# Can't allow auto-incrementing ID if table has field
# application_name. We need values and don't have them.
raise ProgrammingError("record ID not set when required")
for record in records:
# Params for stored item itself (e.g. event).
params = {name: getattr(record, name) for name in self.field_names}
# Params for application partition (bounded context).
if hasattr(self.record_class, "application_name"):
params["application_name"] = self.application_name
# Params for notification log.
if self.notification_id_name:
notification_id = getattr(record, self.notification_id_name)
if notification_id == "event-not-notifiable":
params[self.notification_id_name] = None
else:
params[self.notification_id_name] = notification_id
if hasattr(self.record_class, "pipeline_id"):
if notification_id == "event-not-notifiable":
params["pipeline_id"] = None
else:
params["pipeline_id"] = self.pipeline_id
if hasattr(record, "causal_dependencies"):
params["causal_dependencies"] = record.causal_dependencies
all_params.append(params)
try:
nothing_to_commit = True
# Commit custom ORM objects.
if orm_objs_pending_save:
for orm_obj in orm_objs_pending_save:
self.session.add(orm_obj)
nothing_to_commit = False
if orm_objs_pending_delete:
for orm_obj in orm_objs_pending_delete:
self.session.delete(orm_obj)
nothing_to_commit = False
# Insert tracking record.
if tracking_kwargs:
self.session.execute(self.insert_tracking_record, tracking_kwargs)
nothing_to_commit = False
# Bulk insert event records.
if all_params:
self.session.execute(statement, all_params)
nothing_to_commit = False
if nothing_to_commit:
return
self.session.commit()
except sqlalchemy.exc.IntegrityError as e:
self.session.rollback()
self.raise_record_integrity_error(e)
except sqlalchemy.exc.DBAPIError as e:
self.session.rollback()
self.raise_operational_error(e)
except:
self.session.rollback()
raise
finally:
self.session.close()
[docs] def get_records(
self,
sequence_id: UUID,
gt: Optional[int] = None,
gte: Optional[int] = None,
lt: Optional[int] = None,
lte: Optional[int] = None,
limit: Optional[int] = None,
query_ascending: bool = True,
results_ascending: bool = True,
) -> Sequence[Any]:
assert limit is None or limit >= 1, limit
try:
# Filter by sequence_id.
filter_kwargs: Dict[str, Union[UUID, str]] = {
self.field_names.sequence_id: sequence_id
}
# Optionally, filter by application_name.
if hasattr(self.record_class, "application_name"):
assert self.application_name
filter_kwargs["application_name"] = self.application_name
query = self.filter_by(**filter_kwargs)
# Filter and order by position.
position_field = getattr(self.record_class, self.field_names.position)
if query_ascending:
query = query.order_by(asc(position_field))
else:
query = query.order_by(desc(position_field))
if gt is not None:
query = query.filter(position_field > gt)
if gte is not None:
query = query.filter(position_field >= gte)
if lt is not None:
query = query.filter(position_field < lt)
if lte is not None:
query = query.filter(position_field <= lte)
# Limit the results.
if limit is not None:
query = query.limit(limit)
# Get the results.
results = list(query.all())
except sqlalchemy.exc.OperationalError as e:
raise OperationalError(e)
finally:
self.session.close()
# Reverse if necessary.
if results_ascending != query_ascending:
# This code path is under test, but not otherwise used ATM.
results.reverse()
return results
[docs] def get_notification_records(
self,
start: Optional[int] = None,
stop: Optional[int] = None,
*args: Any,
**kwargs: Any
) -> Iterable:
try:
query = self.orm_query()
query = self.filter_for_application_name(query)
query = self.filter_for_pipeline_id(query)
if self.notification_id_name:
query = query.order_by(asc(self.notification_id_name))
# NB '+1' because record IDs start from 1.
notification_id_col = getattr(
self.record_class, self.notification_id_name
)
if start is not None:
query = query.filter(notification_id_col >= start + 1)
if stop is not None:
query = query.filter(notification_id_col < stop + 1)
# Todo: Should some tables with an ID not be ordered by ID?
# Todo: Which order do other tables have?
return list(query.all())
except sqlalchemy.exc.OperationalError as e:
raise OperationalError(e)
finally:
self.session.close()
[docs] def get_record(self, sequence_id: UUID, position: int) -> Any:
"""
Gets record at position in sequence.
"""
try:
filter_args = {self.field_names.sequence_id: sequence_id}
query = self.filter_by(**filter_args)
query = self.filter_for_application_name(query)
position_field = getattr(self.record_class, self.field_names.position)
query = query.filter(position_field == position)
return query.one()
except (NoResultFound, MultipleResultsFound):
raise IndexError(self.application_name, sequence_id, position)
def filter_for_application_name(self, query: Any) -> Any:
try:
application_name_field = getattr(self.record_class, "application_name")
except AttributeError:
pass
else:
query = query.filter(application_name_field == self.application_name)
return query
def filter_for_pipeline_id(self, query: Any) -> Any:
try:
pipeline_id_field = getattr(self.record_class, "pipeline_id")
except AttributeError:
pass
else:
query = query.filter(pipeline_id_field == self.pipeline_id)
return query
def filter_by(self, **kwargs: Any) -> Any:
return self.orm_query().filter_by(**kwargs)
def orm_query(self) -> Any:
return self.session.query(self.record_class)
[docs] def get_max_notification_id(self) -> int:
try:
notification_id_col = getattr(self.record_class, self.notification_id_name)
query = self.session.query(func.max(notification_id_col))
query = self.filter_for_application_name(query)
query = self.filter_for_pipeline_id(query)
return query.scalar() or 0
finally:
self.session.close()
[docs] def get_max_tracking_record_id(self, upstream_application_name: str) -> int:
assert self.tracking_record_class is not None
application_name_field = (
self.tracking_record_class.application_name # type: ignore
)
upstream_app_name_field = (
self.tracking_record_class.upstream_application_name # type: ignore
)
pipeline_id_field = self.tracking_record_class.pipeline_id # type: ignore
notification_id_field = (
self.tracking_record_class.notification_id # type: ignore
)
query = self.session.query(func.max(notification_id_field))
query = query.filter(application_name_field == self.application_name)
query = query.filter(upstream_app_name_field == upstream_application_name)
query = query.filter(pipeline_id_field == self.pipeline_id)
value = query.scalar() or 0
return value
[docs] def has_tracking_record(
self, upstream_application_name: str, pipeline_id: int, notification_id: int
) -> bool:
query = self.session.query(self.tracking_record_class)
application_name_field = (
self.tracking_record_class.application_name # type: ignore
)
upstream_name_field = (
self.tracking_record_class.upstream_application_name # type: ignore
)
pipeline_id_field = self.tracking_record_class.pipeline_id # type: ignore
notification_id_field = (
self.tracking_record_class.notification_id # type: ignore
)
query = query.filter(application_name_field == self.application_name)
query = query.filter(upstream_name_field == upstream_application_name)
query = query.filter(pipeline_id_field == pipeline_id)
query = query.filter(notification_id_field == notification_id)
try:
query.one()
except (MultipleResultsFound, NoResultFound):
return False
else:
return True
[docs] def all_sequence_ids(self) -> Iterable[UUID]:
c = self.record_class.__table__.c # type: ignore
sequence_id_col = getattr(c, self.field_names.sequence_id)
expr = select([sequence_id_col], distinct=True)
if hasattr(self.record_class, "application_name"):
expr = expr.where(c.application_name == self.application_name)
try:
for row in self.session.query(expr):
yield row[0]
finally:
self.session.close()
[docs] def delete_record(self, record: Any) -> None:
"""
Permanently removes record from table.
"""
try:
self.session.delete(record)
self.session.commit()
except Exception as e:
self.session.rollback()
raise ProgrammingError(e)
finally:
self.session.close()
[docs] def get_record_table_name(self, record_class: type) -> str:
return record_class.__table__.name # type: ignore
def clone(
self, application_name: str, pipeline_id: int, **kwargs: Any
) -> BaseRecordManager:
return super().clone(
application_name=application_name,
pipeline_id=pipeline_id,
session=self.session,
**kwargs
)