buildgrid.server.cas.storage.with_cache module

WithCacheStorage

A storage provider that first checks a cache, then tries a slower fallback provider.

To ensure clients can reliably store blobs in CAS, only get_blob calls are cached – has_blob and missing_blobs will always query the fallback.

class buildgrid.server.cas.storage.with_cache.WithCacheStorage(cache: StorageABC, fallback: StorageABC, defer_fallback_writes: bool = False, fallback_writer_threads: int = 20)

Bases: StorageABC

TYPE: str = 'WithCache'

start() → None

stop() → None

has_blob(digest: Digest) → bool

Return True if the blob with the given instance/digest exists.

get_blob(digest: Digest) → IO[bytes] | None

Return a file-like object containing the blob. Most implementations will read the entire file into memory and return a BytesIO object. Eventually this should be corrected to handle files which cannot fit into memory.

The file-like object must be readable and seekable.

If the blob isn’t present in storage, return None.

delete_blob(digest: Digest) → None

Delete the blob from storage if it’s present.

bulk_delete(digests: list[Digest]) → list[str]

Delete a list of blobs from storage.

commit_write(digest: Digest, write_session: IO[bytes]) → None

Store the contents for a digest.

The storage object is not responsible for verifying that the data written to the write_session actually matches the digest. The caller must do that.

missing_blobs(digests: list[Digest]) → list[Digest]

Return a container containing the blobs not present in CAS.

bulk_update_blobs(blobs: list[tuple[Digest, bytes]]) → list[Status]

Given a container of (digest, value) tuples, add all the blobs to CAS. Return a list of Status objects corresponding to the result of uploading each of the blobs.

The storage object is not responsible for verifying that the data for each blob actually matches the digest. The caller must do that.

bulk_read_blobs(digests: list[Digest]) → dict[str, bytes]

Given an iterable container of digests, return a {hash: file-like object} dictionary corresponding to the blobs represented by the input digests.

Each file-like object must be readable and seekable.