The Database Layer

The cinder.db.api Module

Defines interface for DB access.

The underlying driver is loaded as a LazyPluggable.

Functions in this module are imported into the cinder.db namespace. Call these functions from cinder.db namespace, not the cinder.db.api namespace.

All functions in this module return objects that implement a dictionary-like interface. Currently, many of these objects are sqlalchemy objects that implement a dictionary interface. However, a future goal is to have all of these objects be simple dictionaries.

Related Flags

backend:string to lookup in the list of LazyPluggable backends. sqlalchemy is the only supported backend right now.
connection:string specifying the sqlalchemy connection to use, like: sqlite:///var/lib/cinder/cinder.sqlite.
enable_new_services:
 when adding a new service to the database, is it in the pool of available hardware (Default: True)
backup_create(context, values)

Create a backup from the values dictionary.

backup_destroy(context, backup_id)

Destroy the backup or raise if it does not exist.

backup_get(context, backup_id)

Get a backup or raise if it does not exist.

backup_get_all(context, filters=None)

Get all backups.

backup_get_all_by_host(context, host)

Get all backups belonging to a host.

backup_get_all_by_project(context, project_id, filters=None)

Get all backups belonging to a project.

backup_update(context, backup_id, values)

Set the given properties on a backup and update it.

Raises NotFound if backup does not exist.

cgsnapshot_create(context, values)

Create a cgsnapshot from the values dictionary.

cgsnapshot_destroy(context, cgsnapshot_id)

Destroy the cgsnapshot or raise if it does not exist.

cgsnapshot_get(context, cgsnapshot_id)

Get a cgsnapshot or raise if it does not exist.

cgsnapshot_get_all(context)

Get all cgsnapshots.

cgsnapshot_get_all_by_group(context, group_id)

Get all cgsnapshots belonging to a consistency group.

cgsnapshot_get_all_by_host(context, host)

Get all cgsnapshots belonging to a host.

cgsnapshot_get_all_by_project(context, project_id)

Get all cgsnapshots belonging to a project.

cgsnapshot_update(context, cgsnapshot_id, values)

Set the given properties on a cgsnapshot and update it.

Raises NotFound if cgsnapshot does not exist.

consistencygroup_create(context, values)

Create a consistencygroup from the values dictionary.

consistencygroup_destroy(context, consistencygroup_id)

Destroy the consistencygroup or raise if it does not exist.

consistencygroup_get(context, consistencygroup_id)

Get a consistencygroup or raise if it does not exist.

consistencygroup_get_all(context)

Get all consistencygroups.

consistencygroup_get_all_by_host(context, host)

Get all consistencygroups belonging to a host.

consistencygroup_get_all_by_project(context, project_id)

Get all consistencygroups belonging to a project.

consistencygroup_update(context, consistencygroup_id, values)

Set the given properties on a consistencygroup and update it.

Raises NotFound if consistencygroup does not exist.

finish_volume_migration(context, src_vol_id, dest_vol_id)

Perform database updates upon completion of volume migration.

iscsi_target_count_by_host(context, host)

Return count of export devices.

iscsi_target_create_safe(context, values)

Create an iscsi_target from the values dictionary.

The device is not returned. If the create violates the unique constraints because the iscsi_target and host already exist, no exception is raised.

qos_specs_associate(context, qos_specs_id, type_id)

Associate qos_specs from volume type.

qos_specs_associations_get(context, qos_specs_id)

Get all associated volume types for a given qos_specs.

qos_specs_create(context, values)

Create a qos_specs.

qos_specs_delete(context, qos_specs_id)

Delete the qos_specs.

qos_specs_disassociate(context, qos_specs_id, type_id)

Disassociate qos_specs from volume type.

qos_specs_disassociate_all(context, qos_specs_id)

Disassociate qos_specs from all entities.

qos_specs_get(context, qos_specs_id)

Get all specification for a given qos_specs.

qos_specs_get_all(context, inactive=False, filters=None)

Get all qos_specs.

qos_specs_get_by_name(context, name)

Get all specification for a given qos_specs.

qos_specs_item_delete(context, qos_specs_id, key)

Delete specified key in the qos_specs.

qos_specs_update(context, qos_specs_id, specs)

Update qos specs.

This adds or modifies the key/value pairs specified in the specs dict argument for a given qos_specs.

quota_class_create(context, class_name, resource, limit)

Create a quota class for the given name and resource.

quota_class_destroy(context, class_name, resource)

Destroy the quota class or raise if it does not exist.

quota_class_destroy_all_by_name(context, class_name)

Destroy all quotas associated with a given quota class.

quota_class_get(context, class_name, resource)

Retrieve a quota class or raise if it does not exist.

quota_class_get_all_by_name(context, class_name)

Retrieve all quotas associated with a given quota class.

quota_class_get_default(context)

Retrieve all default quotas.

quota_class_update(context, class_name, resource, limit)

Update a quota class or raise if it does not exist.

quota_create(context, project_id, resource, limit)

Create a quota for the given project and resource.

quota_destroy(context, project_id, resource)

Destroy the quota or raise if it does not exist.

quota_destroy_all_by_project(context, project_id)

Destroy all quotas associated with a given project.

quota_get(context, project_id, resource)

Retrieve a quota or raise if it does not exist.

quota_get_all_by_project(context, project_id)

Retrieve all quotas associated with a given project.

quota_reserve(context, resources, quotas, deltas, expire, until_refresh, max_age, project_id=None)

Check quotas and create appropriate reservations.

quota_update(context, project_id, resource, limit)

Update a quota or raise if it does not exist.

quota_usage_get(context, project_id, resource)

Retrieve a quota usage or raise if it does not exist.

quota_usage_get_all_by_project(context, project_id)

Retrieve all usage associated with a given resource.

reservation_commit(context, reservations, project_id=None)

Commit quota reservations.

reservation_expire(context)

Roll back any expired reservations.

reservation_rollback(context, reservations, project_id=None)

Roll back quota reservations.

service_create(context, values)

Create a service from the values dictionary.

service_destroy(context, service_id)

Destroy the service or raise if it does not exist.

service_get(context, service_id)

Get a service or raise if it does not exist.

service_get_all(context, disabled=None)

Get all services.

service_get_all_by_host(context, host)

Get all services for a given host.

service_get_all_by_topic(context, topic, disabled=None)

Get all services for a given topic.

service_get_all_volume_sorted(context)

Get all volume services sorted by volume count.

Returns:a list of (Service, volume_count) tuples.
service_get_by_args(context, host, binary)

Get the state of an service by node name and binary.

service_get_by_host_and_topic(context, host, topic)

Get a service by host it’s on and topic it listens to.

service_update(context, service_id, values)

Set the given properties on an service and update it.

Raises NotFound if service does not exist.

snapshot_create(context, values)

Create a snapshot from the values dictionary.

snapshot_data_get_for_project(context, project_id, volume_type_id=None)

Get count and gigabytes used for snapshots for specified project.

snapshot_destroy(context, snapshot_id)

Destroy the snapshot or raise if it does not exist.

snapshot_get(context, snapshot_id)

Get a snapshot or raise if it does not exist.

snapshot_get_active_by_window(context, begin, end=None, project_id=None)

Get all the snapshots inside the window.

Specifying a project_id will filter for a certain project.

snapshot_get_all(context)

Get all snapshots.

snapshot_get_all_by_project(context, project_id)

Get all snapshots belonging to a project.

snapshot_get_all_for_cgsnapshot(context, project_id)

Get all snapshots belonging to a cgsnapshot.

snapshot_get_all_for_volume(context, volume_id)

Get all snapshots for a volume.

snapshot_metadata_delete(context, snapshot_id, key)

Delete the given metadata item.

snapshot_metadata_get(context, snapshot_id)

Get all metadata for a snapshot.

snapshot_metadata_update(context, snapshot_id, metadata, delete)

Update metadata if it exists, otherwise create it.

snapshot_update(context, snapshot_id, values)

Set the given properties on an snapshot and update it.

Raises NotFound if snapshot does not exist.

transfer_accept(context, transfer_id, user_id, project_id)

Accept a volume transfer.

transfer_create(context, values)

Create an entry in the transfers table.

transfer_destroy(context, transfer_id)

Destroy a record in the volume transfer table.

transfer_get(context, transfer_id)

Get a volume transfer record or raise if it does not exist.

transfer_get_all(context)

Get all volume transfer records.

transfer_get_all_by_project(context, project_id)

Get all volume transfer records for specified project.

volume_admin_metadata_delete(context, volume_id, key)

Delete the given metadata item.

volume_admin_metadata_get(context, volume_id)

Get all administration metadata for a volume.

volume_admin_metadata_update(context, volume_id, metadata, delete)

Update metadata if it exists, otherwise create it.

volume_allocate_iscsi_target(context, volume_id, host)

Atomically allocate a free iscsi_target from the pool.

volume_attached(context, volume_id, instance_id, host_name, mountpoint)

Ensure that a volume is set as attached.

volume_create(context, values)

Create a volume from the values dictionary.

volume_data_get_for_host(context, host, count_only=False)

Get (volume_count, gigabytes) for project.

volume_data_get_for_project(context, project_id)

Get (volume_count, gigabytes) for project.

volume_destroy(context, volume_id)

Destroy the volume or raise if it does not exist.

volume_detached(context, volume_id)

Ensure that a volume is set as detached.

volume_encryption_metadata_get(context, volume_id, session=None)
volume_get(context, volume_id)

Get a volume or raise if it does not exist.

volume_get_active_by_window(context, begin, end=None, project_id=None)

Get all the volumes inside the window.

Specifying a project_id will filter for a certain project.

volume_get_all(context, marker, limit, sort_key, sort_dir, filters=None)

Get all volumes.

volume_get_all_by_group(context, group_id)

Get all volumes belonging to a consistency group.

volume_get_all_by_host(context, host)

Get all volumes belonging to a host.

volume_get_all_by_project(context, project_id, marker, limit, sort_key, sort_dir, filters=None)

Get all volumes belonging to a project.

volume_get_iscsi_target_num(context, volume_id)

Get the target num (tid) allocated to the volume.

volume_glance_metadata_copy_from_volume_to_volume(context, src_volume_id, volume_id)

Update the Glance metadata for a volume by copying all of the key:value pairs from the originating volume.

This is so that a volume created from the volume (clone) will retain the original metadata.

volume_glance_metadata_copy_to_snapshot(context, snapshot_id, volume_id)

Update the Glance metadata for a snapshot.

This will copy all of the key:value pairs from the originating volume, to ensure that a volume created from the snapshot will retain the original metadata.

volume_glance_metadata_copy_to_volume(context, volume_id, snapshot_id)

Update the Glance metadata from a volume (created from a snapshot).

This will copy all of the key:value pairs from the originating snapshot, to ensure that the Glance metadata from the original volume is retained.

volume_glance_metadata_create(context, volume_id, key, value)

Update the Glance metadata for the specified volume.

volume_glance_metadata_delete_by_snapshot(context, snapshot_id)

Delete the glance metadata for a snapshot.

volume_glance_metadata_delete_by_volume(context, volume_id)

Delete the glance metadata for a volume.

volume_glance_metadata_get(context, volume_id)

Return the glance metadata for a volume.

volume_glance_metadata_get_all(context)

Return the glance metadata for all volumes.

volume_metadata_delete(context, volume_id, key)

Delete the given metadata item.

volume_metadata_get(context, volume_id)

Get all metadata for a volume.

volume_metadata_update(context, volume_id, metadata, delete)

Update metadata if it exists, otherwise create it.

volume_snapshot_glance_metadata_get(context, snapshot_id)

Return the Glance metadata for the specified snapshot.

volume_type_create(context, values)

Create a new volume type.

volume_type_destroy(context, id)

Delete a volume type.

volume_type_encryption_create(context, volume_type_id, encryption_specs)
volume_type_encryption_delete(context, volume_type_id)
volume_type_encryption_get(context, volume_type_id, session=None)
volume_type_encryption_update(context, volume_type_id, encryption_specs)
volume_type_encryption_volume_get(context, volume_type_id, session=None)
volume_type_extra_specs_delete(context, volume_type_id, key)

Delete the given extra specs item.

volume_type_extra_specs_get(context, volume_type_id)

Get all extra specs for a volume type.

volume_type_extra_specs_update_or_create(context, volume_type_id, extra_specs)

Create or update volume type extra specs. This adds or modifies the key/value pairs specified in the extra specs dict argument

volume_type_get(context, id, inactive=False)

Get volume type by id.

volume_type_get_all(context, inactive=False)

Get all volume types.

volume_type_get_by_name(context, name)

Get volume type by name.

volume_type_qos_associate(context, type_id, qos_specs_id)

Associate a volume type with specific qos specs.

volume_type_qos_associations_get(context, qos_specs_id, inactive=False)

Get volume types that are associated with specific qos specs.

volume_type_qos_disassociate(context, qos_specs_id, type_id)

Disassociate a volume type from specific qos specs.

volume_type_qos_disassociate_all(context, qos_specs_id)

Disassociate all volume types from specific qos specs.

volume_type_qos_specs_get(context, type_id)

Get all qos specs for given volume type.

volume_types_get_by_name_or_id(context, volume_type_list)

Get volume types by name or id.

volume_update(context, volume_id, values)

Set the given properties on an volume and update it.

Raises NotFound if volume does not exist.

The Sqlalchemy Driver

The cinder.db.sqlalchemy.api Module

Implementation of SQLAlchemy backend.

The cinder.db.sqlalchemy.models Module

SQLAlchemy models for cinder data.

class Backup(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, cinder.db.sqlalchemy.models.CinderBase

Represents a backup of a volume to Swift.

Backup.availability_zone
Backup.container
Backup.created_at
Backup.deleted
Backup.deleted_at
Backup.display_description
Backup.display_name
Backup.fail_reason
Backup.host
Backup.id
Backup.name
Backup.object_count
Backup.project_id
Backup.service
Backup.service_metadata
Backup.size
Backup.status
Backup.updated_at
Backup.user_id
Backup.validate_fail_reason(key, fail_reason)
Backup.volume_id
class Cgsnapshot(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, cinder.db.sqlalchemy.models.CinderBase

Represents a cgsnapshot.

Cgsnapshot.consistencygroup
Cgsnapshot.consistencygroup_id
Cgsnapshot.created_at
Cgsnapshot.deleted
Cgsnapshot.deleted_at
Cgsnapshot.description
Cgsnapshot.id
Cgsnapshot.name
Cgsnapshot.project_id
Cgsnapshot.status
Cgsnapshot.updated_at
Cgsnapshot.user_id
class CinderBase

Bases: oslo.db.sqlalchemy.models.TimestampMixin, oslo.db.sqlalchemy.models.ModelBase

Base class for Cinder Models.

CinderBase.delete(session)

Delete this object.

CinderBase.deleted = Column(None, Boolean(), table=None, default=ColumnDefault(False))
CinderBase.deleted_at = Column(None, DateTime(), table=None)
CinderBase.metadata = None
class ConsistencyGroup(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, cinder.db.sqlalchemy.models.CinderBase

Represents a consistencygroup.

ConsistencyGroup.availability_zone
ConsistencyGroup.created_at
ConsistencyGroup.deleted
ConsistencyGroup.deleted_at
ConsistencyGroup.description
ConsistencyGroup.host
ConsistencyGroup.id
ConsistencyGroup.name
ConsistencyGroup.project_id
ConsistencyGroup.status
ConsistencyGroup.updated_at
ConsistencyGroup.user_id
ConsistencyGroup.volume_type_id
class Encryption(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, cinder.db.sqlalchemy.models.CinderBase

Represents encryption requirement for a volume type.

Encryption here is a set of performance characteristics describing cipher, provider, and key_size for a certain volume type.

Encryption.cipher
Encryption.control_location
Encryption.created_at
Encryption.deleted
Encryption.deleted_at
Encryption.key_size
Encryption.provider
Encryption.updated_at
Encryption.volume_type
Encryption.volume_type_id
class IscsiTarget(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, cinder.db.sqlalchemy.models.CinderBase

Represents an iscsi target for a given host.

IscsiTarget.created_at
IscsiTarget.deleted
IscsiTarget.deleted_at
IscsiTarget.host
IscsiTarget.id
IscsiTarget.target_num
IscsiTarget.updated_at
IscsiTarget.volume
IscsiTarget.volume_id
class QualityOfServiceSpecs(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, cinder.db.sqlalchemy.models.CinderBase

Represents QoS specs as key/value pairs.

QoS specs is standalone entity that can be associated/disassociated with volume types (one to many relation). Adjacency list relationship pattern is used in this model in order to represent following hierarchical data with in flat table, e.g, following structure

qos-specs-1 ‘Rate-Limit’

+——> consumer = ‘front-end’ +——> total_bytes_sec = 1048576 +——> total_iops_sec = 500

qos-specs-2 ‘QoS_Level1’

+——> consumer = ‘back-end’ +——> max-iops = 1000 +——> min-iops = 200

is represented by:

id specs_id key value

—— ——– ————- —– UUID-1 NULL QoSSpec_Name Rate-Limit UUID-2 UUID-1 consumer front-end UUID-3 UUID-1 total_bytes_sec 1048576 UUID-4 UUID-1 total_iops_sec 500 UUID-5 NULL QoSSpec_Name QoS_Level1 UUID-6 UUID-5 consumer back-end UUID-7 UUID-5 max-iops 1000 UUID-8 UUID-5 min-iops 200

QualityOfServiceSpecs.created_at
QualityOfServiceSpecs.deleted
QualityOfServiceSpecs.deleted_at
QualityOfServiceSpecs.id
QualityOfServiceSpecs.key
QualityOfServiceSpecs.specs
QualityOfServiceSpecs.specs_id
QualityOfServiceSpecs.updated_at
QualityOfServiceSpecs.value
QualityOfServiceSpecs.vol_types
class Quota(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, cinder.db.sqlalchemy.models.CinderBase

Represents a single quota override for a project.

If there is no row for a given project id and resource, then the default for the quota class is used. If there is no row for a given quota class and resource, then the default for the deployment is used. If the row is present but the hard limit is Null, then the resource is unlimited.

Quota.created_at
Quota.deleted
Quota.deleted_at
Quota.hard_limit
Quota.id
Quota.project_id
Quota.resource
Quota.updated_at
class QuotaClass(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, cinder.db.sqlalchemy.models.CinderBase

Represents a single quota override for a quota class.

If there is no row for a given quota class and resource, then the default for the deployment is used. If the row is present but the hard limit is Null, then the resource is unlimited.

QuotaClass.class_name
QuotaClass.created_at
QuotaClass.deleted
QuotaClass.deleted_at
QuotaClass.hard_limit
QuotaClass.id
QuotaClass.resource
QuotaClass.updated_at
class QuotaUsage(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, cinder.db.sqlalchemy.models.CinderBase

Represents the current usage for a given resource.

QuotaUsage.created_at
QuotaUsage.deleted
QuotaUsage.deleted_at
QuotaUsage.id
QuotaUsage.in_use
QuotaUsage.project_id
QuotaUsage.reserved
QuotaUsage.resource
QuotaUsage.total
QuotaUsage.until_refresh
QuotaUsage.updated_at
class Reservation(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, cinder.db.sqlalchemy.models.CinderBase

Represents a resource reservation for quotas.

Reservation.created_at
Reservation.deleted
Reservation.deleted_at
Reservation.delta
Reservation.expire
Reservation.id
Reservation.project_id
Reservation.resource
Reservation.updated_at
Reservation.usage
Reservation.usage_id
Reservation.uuid
class Service(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, cinder.db.sqlalchemy.models.CinderBase

Represents a running service on a host.

Service.availability_zone
Service.binary
Service.created_at
Service.deleted
Service.deleted_at
Service.disabled
Service.disabled_reason
Service.host
Service.id
Service.report_count
Service.topic
Service.updated_at
class Snapshot(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, cinder.db.sqlalchemy.models.CinderBase

Represents a snapshot of volume.

Snapshot.cgsnapshot
Snapshot.cgsnapshot_id
Snapshot.created_at
Snapshot.deleted
Snapshot.deleted_at
Snapshot.display_description
Snapshot.display_name
Snapshot.encryption_key_id
Snapshot.id
Snapshot.name
Snapshot.progress
Snapshot.project_id
Snapshot.provider_location
Snapshot.status
Snapshot.updated_at
Snapshot.user_id
Snapshot.volume
Snapshot.volume_id
Snapshot.volume_name
Snapshot.volume_size
Snapshot.volume_type_id
class SnapshotMetadata(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, cinder.db.sqlalchemy.models.CinderBase

Represents a metadata key/value pair for a snapshot.

SnapshotMetadata.created_at
SnapshotMetadata.deleted
SnapshotMetadata.deleted_at
SnapshotMetadata.id
SnapshotMetadata.key
SnapshotMetadata.snapshot
SnapshotMetadata.snapshot_id
SnapshotMetadata.updated_at
SnapshotMetadata.value
class Transfer(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, cinder.db.sqlalchemy.models.CinderBase

Represents a volume transfer request.

Transfer.created_at
Transfer.crypt_hash
Transfer.deleted
Transfer.deleted_at
Transfer.display_name
Transfer.expires_at
Transfer.id
Transfer.salt
Transfer.updated_at
Transfer.volume
Transfer.volume_id
class Volume(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, cinder.db.sqlalchemy.models.CinderBase

Represents a block storage device that can be attached to a vm.

Volume.attach_status
Volume.attach_time
Volume.attached_host
Volume.availability_zone
Volume.bootable
Volume.consistencygroup
Volume.consistencygroup_id
Volume.created_at
Volume.deleted
Volume.deleted_at
Volume.display_description
Volume.display_name
Volume.ec2_id
Volume.encryption_key_id
Volume.host
Volume.id
Volume.instance_uuid
Volume.launched_at
Volume.migration_status
Volume.mountpoint
Volume.name
Volume.name_id
Volume.project_id
Volume.provider_auth
Volume.provider_geometry
Volume.provider_location
Volume.replication_driver_data
Volume.replication_extended_status
Volume.replication_status
Volume.scheduled_at
Volume.size
Volume.snapshot_id
Volume.source_volid
Volume.status
Volume.terminated_at
Volume.updated_at
Volume.user_id
Volume.volume_type_id
class VolumeAdminMetadata(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, cinder.db.sqlalchemy.models.CinderBase

Represents an administrator metadata key/value pair for a volume.

VolumeAdminMetadata.created_at
VolumeAdminMetadata.deleted
VolumeAdminMetadata.deleted_at
VolumeAdminMetadata.id
VolumeAdminMetadata.key
VolumeAdminMetadata.updated_at
VolumeAdminMetadata.value
VolumeAdminMetadata.volume
VolumeAdminMetadata.volume_id
class VolumeGlanceMetadata(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, cinder.db.sqlalchemy.models.CinderBase

Glance metadata for a bootable volume.

VolumeGlanceMetadata.created_at
VolumeGlanceMetadata.deleted
VolumeGlanceMetadata.deleted_at
VolumeGlanceMetadata.id
VolumeGlanceMetadata.key
VolumeGlanceMetadata.snapshot_id
VolumeGlanceMetadata.updated_at
VolumeGlanceMetadata.value
VolumeGlanceMetadata.volume
VolumeGlanceMetadata.volume_id
class VolumeMetadata(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, cinder.db.sqlalchemy.models.CinderBase

Represents a metadata key/value pair for a volume.

VolumeMetadata.created_at
VolumeMetadata.deleted
VolumeMetadata.deleted_at
VolumeMetadata.id
VolumeMetadata.key
VolumeMetadata.updated_at
VolumeMetadata.value
VolumeMetadata.volume
VolumeMetadata.volume_id
class VolumeTypeExtraSpecs(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, cinder.db.sqlalchemy.models.CinderBase

Represents additional specs as key/value pairs for a volume_type.

VolumeTypeExtraSpecs.created_at
VolumeTypeExtraSpecs.deleted
VolumeTypeExtraSpecs.deleted_at
VolumeTypeExtraSpecs.id
VolumeTypeExtraSpecs.key
VolumeTypeExtraSpecs.updated_at
VolumeTypeExtraSpecs.value
VolumeTypeExtraSpecs.volume_type
VolumeTypeExtraSpecs.volume_type_id
class VolumeTypes(**kwargs)

Bases: sqlalchemy.ext.declarative.api.Base, cinder.db.sqlalchemy.models.CinderBase

Represent possible volume_types of volumes offered.

VolumeTypes.created_at
VolumeTypes.deleted
VolumeTypes.deleted_at
VolumeTypes.id
VolumeTypes.name
VolumeTypes.qos_specs_id
VolumeTypes.updated_at
VolumeTypes.volumes
register_models()

Register Models and create metadata.

Called from cinder.db.sqlalchemy.__init__ as part of loading the driver, it will never need to be called explicitly elsewhere unless the connection is lost and needs to be reestablished.

relationship(argument, secondary=None, primaryjoin=None, secondaryjoin=None, foreign_keys=None, uselist=None, order_by=False, backref=None, back_populates=None, post_update=False, cascade=False, extension=None, viewonly=False, lazy=True, collection_class=None, passive_deletes=False, passive_updates=True, remote_side=None, enable_typechecks=True, join_depth=None, comparator_factory=None, single_parent=False, innerjoin=False, distinct_target_key=None, doc=None, active_history=False, cascade_backrefs=True, load_on_pending=False, strategy_class=None, _local_remote_pairs=None, query_class=None, info=None)

Provide a relationship between two mapped classes.

This corresponds to a parent-child or associative table relationship. The constructed class is an instance of RelationshipProperty.

A typical relationship(), used in a classical mapping:

mapper(Parent, properties={
  'children': relationship(Child)
})

Some arguments accepted by relationship() optionally accept a callable function, which when called produces the desired value. The callable is invoked by the parent Mapper at “mapper initialization” time, which happens only when mappers are first used, and is assumed to be after all mappings have been constructed. This can be used to resolve order-of-declaration and other dependency issues, such as if Child is declared below Parent in the same file:

mapper(Parent, properties={
    "children":relationship(lambda: Child,
                        order_by=lambda: Child.id)
})

When using the declarative_toplevel extension, the Declarative initializer allows string arguments to be passed to relationship(). These string arguments are converted into callables that evaluate the string as Python code, using the Declarative class-registry as a namespace. This allows the lookup of related classes to be automatic via their string name, and removes the need to import related classes at all into the local module space:

from sqlalchemy.ext.declarative import declarative_base

Base = declarative_base()

class Parent(Base):
    __tablename__ = 'parent'
    id = Column(Integer, primary_key=True)
    children = relationship("Child", order_by="Child.id")

See also

relationship_config_toplevel - Full introductory and reference documentation for relationship().

orm_tutorial_relationship - ORM tutorial introduction.

Parameters:
  • argument

    a mapped class, or actual Mapper instance, representing the target of the relationship.

    :paramref:`~.relationship.argument` may also be passed as a callable function which is evaluated at mapper initialization time, and may be passed as a Python-evaluable string when using Declarative.

    See also

    declarative_configuring_relationships - further detail on relationship configuration when using Declarative.

  • secondary

    for a many-to-many relationship, specifies the intermediary table, and is typically an instance of Table. In less common circumstances, the argument may also be specified as an Alias construct, or even a Join construct.

    :paramref:`~.relationship.secondary` may also be passed as a callable function which is evaluated at mapper initialization time. When using Declarative, it may also be a string argument noting the name of a Table that is present in the MetaData collection associated with the parent-mapped Table.

    The :paramref:`~.relationship.secondary` keyword argument is typically applied in the case where the intermediary Table is not otherwise exprssed in any direct class mapping. If the “secondary” table is also explicitly mapped elsewhere (e.g. as in association_pattern), one should consider applying the :paramref:`~.relationship.viewonly` flag so that this relationship() is not used for persistence operations which may conflict with those of the association object pattern.

    See also

    relationships_many_to_many - Reference example of “many to many”.

    orm_tutorial_many_to_many - ORM tutorial introduction to many-to-many relationships.

    self_referential_many_to_many - Specifics on using many-to-many in a self-referential case.

    declarative_many_to_many - Additional options when using Declarative.

    association_pattern - an alternative to :paramref:`~.relationship.secondary` when composing association table relationships, allowing additional attributes to be specified on the association table.

    composite_secondary_join - a lesser-used pattern which in some cases can enable complex relationship() SQL conditions to be used.

    New in version 0.9.2: :paramref:`~.relationship.secondary` works more effectively when referring to a Join instance.

  • active_history=False – When True, indicates that the “previous” value for a many-to-one reference should be loaded when replaced, if not already loaded. Normally, history tracking logic for simple many-to-ones only needs to be aware of the “new” value in order to perform a flush. This flag is available for applications that make use of attributes.get_history() which also need to know the “previous” value of the attribute.
  • backref

    indicates the string name of a property to be placed on the related mapper’s class that will handle this relationship in the other direction. The other property will be created automatically when the mappers are configured. Can also be passed as a backref() object to control the configuration of the new relationship.

    See also

    relationships_backref - Introductory documentation and examples.

    :paramref:`~.relationship.back_populates` - alternative form of backref specification.

    backref() - allows control over relationship() configuration when using :paramref:`~.relationship.backref`.

  • back_populates

    Takes a string name and has the same meaning as :paramref:`~.relationship.backref`, except the complementing property is not created automatically, and instead must be configured explicitly on the other mapper. The complementing property should also indicate :paramref:`~.relationship.back_populates` to this relationship to ensure proper functioning.

    See also

    relationships_backref - Introductory documentation and examples.

    :paramref:`~.relationship.backref` - alternative form of backref specification.

  • cascade

    a comma-separated list of cascade rules which determines how Session operations should be “cascaded” from parent to child. This defaults to False, which means the default cascade should be used - this default cascade is "save-update, merge".

    The available cascades are save-update, merge, expunge, delete, delete-orphan, and refresh-expire. An additional option, all indicates shorthand for "save-update, merge, refresh-expire, expunge, delete", and is often used as in "all, delete-orphan" to indicate that related objects should follow along with the parent object in all cases, and be deleted when de-associated.

    See also

    unitofwork_cascades - Full detail on each of the available cascade options.

    tutorial_delete_cascade - Tutorial example describing a delete cascade.

  • cascade_backrefs=True

    a boolean value indicating if the save-update cascade should operate along an assignment event intercepted by a backref. When set to False, the attribute managed by this relationship will not cascade an incoming transient object into the session of a persistent parent, if the event is received via backref.

    See also

    backref_cascade - Full discussion and examples on how the :paramref:`~.relationship.cascade_backrefs` option is used.

  • collection_class

    a class or callable that returns a new list-holding object. will be used in place of a plain list for storing elements.

    See also

    custom_collections - Introductory documentation and examples.

  • comparator_factory

    a class which extends RelationshipProperty.Comparator which provides custom SQL clause generation for comparison operations.

    See also

    PropComparator - some detail on redefining comparators at this level.

    custom_comparators - Brief intro to this feature.

  • distinct_target_key=None

    Indicate if a “subquery” eager load should apply the DISTINCT keyword to the innermost SELECT statement. When left as None, the DISTINCT keyword will be applied in those cases when the target columns do not comprise the full primary key of the target table. When set to True, the DISTINCT keyword is applied to the innermost SELECT unconditionally.

    It may be desirable to set this flag to False when the DISTINCT is reducing performance of the innermost subquery beyond that of what duplicate innermost rows may be causing.

    New in version 0.8.3: - :paramref:`~.relationship.distinct_target_key` allows the subquery eager loader to apply a DISTINCT modifier to the innermost SELECT.

    Changed in version 0.9.0: - :paramref:`~.relationship.distinct_target_key` now defaults to None, so that the feature enables itself automatically for those cases where the innermost query targets a non-unique key.

    See also

    loading_toplevel - includes an introduction to subquery eager loading.

  • doc – docstring which will be applied to the resulting descriptor.
  • extension

    an AttributeExtension instance, or list of extensions, which will be prepended to the list of attribute listeners for the resulting descriptor placed on the class.

    Deprecated since version 0.7: Please see AttributeEvents.

  • foreign_keys

    a list of columns which are to be used as “foreign key” columns, or columns which refer to the value in a remote column, within the context of this relationship() object’s :paramref:`~.relationship.primaryjoin` condition. That is, if the :paramref:`~.relationship.primaryjoin` condition of this relationship() is a.id == b.a_id, and the values in b.a_id are required to be present in a.id, then the “foreign key” column of this relationship() is b.a_id.

    In normal cases, the :paramref:`~.relationship.foreign_keys` parameter is not required. relationship() will automatically determine which columns in the :paramref:`~.relationship.primaryjoin` conditition are to be considered “foreign key” columns based on those Column objects that specify ForeignKey, or are otherwise listed as referencing columns in a ForeignKeyConstraint construct. :paramref:`~.relationship.foreign_keys` is only needed when:

    1. There is more than one way to construct a join from the local table to the remote table, as there are multiple foreign key references present. Setting foreign_keys will limit the relationship() to consider just those columns specified here as “foreign”.

      Changed in version 0.8: A multiple-foreign key join ambiguity can be resolved by setting the :paramref:`~.relationship.foreign_keys` parameter alone, without the need to explicitly set :paramref:`~.relationship.primaryjoin` as well.

    2. The Table being mapped does not actually have ForeignKey or ForeignKeyConstraint constructs present, often because the table was reflected from a database that does not support foreign key reflection (MySQL MyISAM).
    3. The :paramref:`~.relationship.primaryjoin` argument is used to construct a non-standard join condition, which makes use of columns or expressions that do not normally refer to their “parent” column, such as a join condition expressed by a complex comparison using a SQL function.

    The relationship() construct will raise informative error messages that suggest the use of the :paramref:`~.relationship.foreign_keys` parameter when presented with an ambiguous condition. In typical cases, if relationship() doesn’t raise any exceptions, the :paramref:`~.relationship.foreign_keys` parameter is usually not needed.

    :paramref:`~.relationship.foreign_keys` may also be passed as a callable function which is evaluated at mapper initialization time, and may be passed as a Python-evaluable string when using Declarative.

    See also

    relationship_foreign_keys

    relationship_custom_foreign

    foreign() - allows direct annotation of the “foreign” columns within a :paramref:`~.relationship.primaryjoin` condition.

    New in version 0.8: The foreign() annotation can also be applied directly to the :paramref:`~.relationship.primaryjoin` expression, which is an alternate, more specific system of describing which columns in a particular :paramref:`~.relationship.primaryjoin` should be considered “foreign”.

  • info

    Optional data dictionary which will be populated into the MapperProperty.info attribute of this object.

    New in version 0.8.

  • innerjoin=False

    when True, joined eager loads will use an inner join to join against related tables instead of an outer join. The purpose of this option is generally one of performance, as inner joins generally perform better than outer joins.

    This flag can be set to True when the relationship references an object via many-to-one using local foreign keys that are not nullable, or when the reference is one-to-one or a collection that is guaranteed to have one or at least one entry.

    If the joined-eager load is chained onto an existing LEFT OUTER JOIN, innerjoin=True will be bypassed and the join will continue to chain as LEFT OUTER JOIN so that the results don’t change. As an alternative, specify the value "nested". This will instead nest the join on the right side, e.g. using the form “a LEFT OUTER JOIN (b JOIN c)”.

    New in version 0.9.4: Added innerjoin="nested" option to support nesting of eager “inner” joins.

    See also

    what_kind_of_loading - Discussion of some details of various loader options.

    :paramref:`.joinedload.innerjoin` - loader option version

  • join_depth

    when non-None, an integer value indicating how many levels deep “eager” loaders should join on a self-referring or cyclical relationship. The number counts how many times the same Mapper shall be present in the loading condition along a particular join branch. When left at its default of None, eager loaders will stop chaining when they encounter a the same target mapper which is already higher up in the chain. This option applies both to joined- and subquery- eager loaders.

    See also

    self_referential_eager_loading - Introductory documentation and examples.

  • lazy=’select’

    specifies how the related items should be loaded. Default value is select. Values include:

    • select - items should be loaded lazily when the property is first accessed, using a separate SELECT statement, or identity map fetch for simple many-to-one references.
    • immediate - items should be loaded as the parents are loaded, using a separate SELECT statement, or identity map fetch for simple many-to-one references.
    • joined - items should be loaded “eagerly” in the same query as that of the parent, using a JOIN or LEFT OUTER JOIN. Whether the join is “outer” or not is determined by the :paramref:`~.relationship.innerjoin` parameter.
    • subquery - items should be loaded “eagerly” as the parents are loaded, using one additional SQL statement, which issues a JOIN to a subquery of the original statement, for each collection requested.
    • noload - no loading should occur at any time. This is to support “write-only” attributes, or attributes which are populated in some manner specific to the application.
    • dynamic - the attribute will return a pre-configured Query object for all read operations, onto which further filtering operations can be applied before iterating the results. See the section dynamic_relationship for more details.
    • True - a synonym for ‘select’
    • False - a synonym for ‘joined’
    • None - a synonym for ‘noload’

    See also

    /orm/loading - Full documentation on relationship loader configuration.

    dynamic_relationship - detail on the dynamic option.

  • load_on_pending=False

    Indicates loading behavior for transient or pending parent objects.

    When set to True, causes the lazy-loader to issue a query for a parent object that is not persistent, meaning it has never been flushed. This may take effect for a pending object when autoflush is disabled, or for a transient object that has been “attached” to a Session but is not part of its pending collection.

    The :paramref:`~.relationship.load_on_pending` flag does not improve behavior when the ORM is used normally - object references should be constructed at the object level, not at the foreign key level, so that they are present in an ordinary way before a flush proceeds. This flag is not not intended for general use.

    See also

    Session.enable_relationship_loading() - this method establishes “load on pending” behavior for the whole object, and also allows loading on objects that remain transient or detached.

  • order_by

    indicates the ordering that should be applied when loading these items. :paramref:`~.relationship.order_by` is expected to refer to one of the Column objects to which the target class is mapped, or the attribute itself bound to the target class which refers to the column.

    :paramref:`~.relationship.order_by` may also be passed as a callable function which is evaluated at mapper initialization time, and may be passed as a Python-evaluable string when using Declarative.

  • passive_deletes=False

    Indicates loading behavior during delete operations.

    A value of True indicates that unloaded child items should not be loaded during a delete operation on the parent. Normally, when a parent item is deleted, all child items are loaded so that they can either be marked as deleted, or have their foreign key to the parent set to NULL. Marking this flag as True usually implies an ON DELETE <CASCADE|SET NULL> rule is in place which will handle updating/deleting child rows on the database side.

    Additionally, setting the flag to the string value ‘all’ will disable the “nulling out” of the child foreign keys, when there is no delete or delete-orphan cascade enabled. This is typically used when a triggering or error raise scenario is in place on the database side. Note that the foreign key attributes on in-session child objects will not be changed after a flush occurs so this is a very special use-case setting.

    See also

    passive_deletes - Introductory documentation and examples.

  • passive_updates=True

    Indicates loading and INSERT/UPDATE/DELETE behavior when the source of a foreign key value changes (i.e. an “on update” cascade), which are typically the primary key columns of the source row.

    When True, it is assumed that ON UPDATE CASCADE is configured on the foreign key in the database, and that the database will handle propagation of an UPDATE from a source column to dependent rows. Note that with databases which enforce referential integrity (i.e. PostgreSQL, MySQL with InnoDB tables), ON UPDATE CASCADE is required for this operation. The relationship() will update the value of the attribute on related items which are locally present in the session during a flush.

    When False, it is assumed that the database does not enforce referential integrity and will not be issuing its own CASCADE operation for an update. The relationship() will issue the appropriate UPDATE statements to the database in response to the change of a referenced key, and items locally present in the session during a flush will also be refreshed.

    This flag should probably be set to False if primary key changes are expected and the database in use doesn’t support CASCADE (i.e. SQLite, MySQL MyISAM tables).

    See also

    passive_updates - Introductory documentation and examples.

    :paramref:`.mapper.passive_updates` - a similar flag which takes effect for joined-table inheritance mappings.

  • post_update

    this indicates that the relationship should be handled by a second UPDATE statement after an INSERT or before a DELETE. Currently, it also will issue an UPDATE after the instance was UPDATEd as well, although this technically should be improved. This flag is used to handle saving bi-directional dependencies between two individual rows (i.e. each row references the other), where it would otherwise be impossible to INSERT or DELETE both rows fully since one row exists before the other. Use this flag when a particular mapping arrangement will incur two rows that are dependent on each other, such as a table that has a one-to-many relationship to a set of child rows, and also has a column that references a single child row within that list (i.e. both tables contain a foreign key to each other). If a flush operation returns an error that a “cyclical dependency” was detected, this is a cue that you might want to use :paramref:`~.relationship.post_update` to “break” the cycle.

    See also

    post_update - Introductory documentation and examples.

  • primaryjoin

    a SQL expression that will be used as the primary join of this child object against the parent object, or in a many-to-many relationship the join of the primary object to the association table. By default, this value is computed based on the foreign key relationships of the parent and child tables (or association table).

    :paramref:`~.relationship.primaryjoin` may also be passed as a callable function which is evaluated at mapper initialization time, and may be passed as a Python-evaluable string when using Declarative.

    See also

    relationship_primaryjoin

  • remote_side

    used for self-referential relationships, indicates the column or list of columns that form the “remote side” of the relationship.

    :paramref:`.relationship.remote_side` may also be passed as a callable function which is evaluated at mapper initialization time, and may be passed as a Python-evaluable string when using Declarative.

    Changed in version 0.8: The remote() annotation can also be applied directly to the primaryjoin expression, which is an alternate, more specific system of describing which columns in a particular primaryjoin should be considered “remote”.

    See also

    self_referential - in-depth explanation of how :paramref:`~.relationship.remote_side` is used to configure self-referential relationships.

    remote() - an annotation function that accomplishes the same purpose as :paramref:`~.relationship.remote_side`, typically when a custom :paramref:`~.relationship.primaryjoin` condition is used.

  • query_class

    a Query subclass that will be used as the base of the “appender query” returned by a “dynamic” relationship, that is, a relationship that specifies lazy="dynamic" or was otherwise constructed using the orm.dynamic_loader() function.

    See also

    dynamic_relationship - Introduction to “dynamic” relationship loaders.

  • secondaryjoin

    a SQL expression that will be used as the join of an association table to the child object. By default, this value is computed based on the foreign key relationships of the association and child tables.

    :paramref:`~.relationship.secondaryjoin` may also be passed as a callable function which is evaluated at mapper initialization time, and may be passed as a Python-evaluable string when using Declarative.

    See also

    relationship_primaryjoin

  • single_parent

    when True, installs a validator which will prevent objects from being associated with more than one parent at a time. This is used for many-to-one or many-to-many relationships that should be treated either as one-to-one or one-to-many. Its usage is optional, except for relationship() constructs which are many-to-one or many-to-many and also specify the delete-orphan cascade option. The relationship() construct itself will raise an error instructing when this option is required.

    See also

    unitofwork_cascades - includes detail on when the :paramref:`~.relationship.single_parent` flag may be appropriate.

  • uselist

    a boolean that indicates if this property should be loaded as a list or a scalar. In most cases, this value is determined automatically by relationship() at mapper configuration time, based on the type and direction of the relationship - one to many forms a list, many to one forms a scalar, many to many is a list. If a scalar is desired where normally a list would be present, such as a bi-directional one-to-one relationship, set :paramref:`~.relationship.uselist` to False.

    The :paramref:`~.relationship.uselist` flag is also available on an existing relationship() construct as a read-only attribute, which can be used to determine if this relationship() deals with collections or scalar attributes:

    >>> User.addresses.property.uselist
    True
    

    See also

    relationships_one_to_one - Introduction to the “one to one” relationship pattern, which is typically when the :paramref:`~.relationship.uselist` flag is needed.

  • viewonly=False – when set to True, the relationship is used only for loading objects, and not for any persistence operation. A relationship() which specifies :paramref:`~.relationship.viewonly` can work with a wider range of SQL operations within the :paramref:`~.relationship.primaryjoin` condition, including operations that feature the use of a variety of comparison operators as well as SQL functions such as cast(). The :paramref:`~.relationship.viewonly` flag is also of general use when defining any kind of relationship() that doesn’t represent the full set of related objects, to prevent modifications of the collection from resulting in persistence operations.

The cinder.db.sqlalchemy.session Module

Tests

Tests are lacking for the db api layer and for the sqlalchemy driver. Failures in the drivers would be detected in other test cases, though.