swh.objstorage.backends.winery.roshard module#

exception swh.objstorage.backends.winery.roshard.ShardNotMapped[source]#

Bases: Exception

swh.objstorage.backends.winery.roshard.record_shard_mapped(base: SharedBase, shard_name: str)[source]#

Record a shard as mapped, bailing out after a few attempts.

Multiple attempts are used to handle a race condition when two hosts attempt to record the shard as mapped at the same time. In this situation, one of the two hosts will succeed and the other one will fail, the sleep delay can be kept short and linear.

swh.objstorage.backends.winery.roshard.manage_images(pool: Pool, base_dsn: str, manage_rw_images: bool, wait_for_image: Callable[[int], None], stop_running: Callable[[], bool], only_prefix: str | None = None, application_name: str | None = None) → None[source]#

Manage RBD image creation and mapping automatically.

Parameters:

  • base_dsn – the DSN of the connection to the SharedBase

  • manage_rw_images – whether RW images should be created and mapped

  • wait_for_image – function which is called at each loop iteration, with an attempt number, if no images had to be mapped recently

  • stop_running – callback that returns True when the manager should stop running

  • only_prefix – only map images with the given name prefix

  • application_name – the application name sent to PostgreSQL

class swh.objstorage.backends.winery.roshard.ROShard(name, pool)[source]#

Bases: object

open()[source]#
get(key)[source]#
close()[source]#
static delete(pool, shard_name, obj_id)[source]#
class swh.objstorage.backends.winery.roshard.ROShardCreator(name: str, count: int, pool: ~swh.objstorage.backends.winery.pools.Pool, rbd_create_images: bool = True, rbd_wait_for_image: ~typing.Callable[[int], None] = <function sleep_exponential.<locals>.sleep>, **kwargs)[source]#

Bases: object

Helper for Read-Only shard creation.

Parameters:

  • name – Name of the shard to be initialized

  • count – Number of objects to provision in the shard

  • rbd_create_images – whether the ROShardCreator should create the rbd image, or delegate to the rbd_shard_manager

  • rbd_wait_for_image – function called when waiting for a shard to be mapped

  • shard_max_size – the size of the shard, passed to Pool

  • rbd_* – other RBD-related Pool arguments

zero_image_if_needed()[source]#

Check whether the image is empty, and zero it out if it’s not.

We really check only the first 1kB, as we assume that the SWHShard marker will have been written at the beginning of the image under all circumstances if the RO Shard creation has been interrupted.

add(content, obj_id)[source]#