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strands.storage.in_memory_storage

In-memory storage implementation.

InMemoryStorage

Section titled “InMemoryStorage”
class InMemoryStorage()

Defined in: src/strands/storage/in_memory_storage.py:19

Map-backed storage for testing and short-lived processes.

Content does not survive process restarts. The store is unbounded — consumers manage eviction themselves.

Example:

from strands.storage import InMemoryStorage


storage = InMemoryStorage()
await storage.write("sessions/abc/state.json", b'\{"messages": []}')
data = await storage.read("sessions/abc/state.json")

__init__

Section titled “__init__”
def __init__(
        *,
        search_strategy: SearchStrategy[InMemoryStorage] | None = None
) -> None

Defined in: src/strands/storage/in_memory_storage.py:37

Initialize an empty in-memory store.

Arguments:

  • search_strategy - Optional search strategy. When set, write() automatically indexes entries and search() delegates to the strategy instead of the default keyword scan.

write

Section titled “write”
async def write(key: str, data: bytes) -> None

Defined in: src/strands/storage/in_memory_storage.py:51

Store data under key, overwriting any existing value.

Arguments:

  • key - Opaque string key identifying the value.
  • data - Raw bytes to persist.

Raises:

  • StorageError - If the key is invalid.

read

Section titled “read”
async def read(key: str) -> bytes | None

Defined in: src/strands/storage/in_memory_storage.py:71

Retrieve the bytes previously stored under key.

Arguments:

  • key - The key to read.

Returns:

The stored bytes, or None if no value exists for key.

Raises:

  • StorageError - If the key is invalid.

delete

Section titled “delete”
async def delete(key: str) -> None

Defined in: src/strands/storage/in_memory_storage.py:88

Delete the value stored under key. A no-op if the key does not exist.

Arguments:

  • key - The key to delete.

Raises:

  • StorageError - If the key is invalid.

list

Section titled “list”
async def list(query: str = "") -> builtins.list[str]

Defined in: src/strands/storage/in_memory_storage.py:101

List keys matching the given prefix.

Arguments:

  • query - A prefix string to filter keys. Empty string matches all.

Returns:

Matching keys sorted ascending.

Raises:

  • StorageError - If the prefix is invalid.
Section titled “search”
async def search(query: str) -> builtins.list[StorageSearchResult]

Defined in: src/strands/storage/in_memory_storage.py:118

Search stored content using the configured strategy.

Delegates to the search strategy when one is set, otherwise falls back to keyword token-overlap scoring.

Arguments:

  • query - Natural-language search query.

Returns:

All matches with relevance scores, ranked best-first.

namespace

Section titled “namespace”
def namespace(prefix: str) -> InMemoryStorage

Defined in: src/strands/storage/in_memory_storage.py:134

Return an InMemoryStorage scoped to prefix.

The scoped instance shares this instance’s entries and search strategy. Unlike a generic _NamespacedStorage wrapper, its search() only sees entries under the prefix and scores keys without it, so a query never matches every entry just because it contains a word from the prefix.

The shared search strategy receives the scoped instance and keys relative to the prefix. A strategy that keeps its own index must not key it by those relative keys alone; see SearchStrategy.index.

Arguments:

  • prefix - Prefix to prepend to all keys.

Returns:

An InMemoryStorage scoped to the prefix.

clear

Section titled “clear”
def clear() -> None

Defined in: src/strands/storage/in_memory_storage.py:161

Remove all entries visible to this instance.

That is every entry under its namespace, or every entry when not namespaced.