perf: Intern string constants

libs/langgraph/langgraph/constants.py

@@ -1,5 +1,6 @@
+import sys
 from types import MappingProxyType
-from typing import Any, Mapping
+from typing import Any, Literal, Mapping, cast
 
 from langgraph.types import Interrupt, Send  # noqa: F401
 
@@ -11,67 +12,69 @@
 EMPTY_SEQ: tuple[str, ...] = tuple()
 
 # --- Public constants ---
-TAG_HIDDEN = "langsmith:hidden"
+TAG_HIDDEN = sys.intern("langsmith:hidden")
 # tag to hide a node/edge from certain tracing/streaming environments
-START = "__start__"
+START = sys.intern("__start__")
 # the first (maybe virtual) node in graph-style Pregel
-END = "__end__"
+END = sys.intern("__end__")
 # the last (maybe virtual) node in graph-style Pregel
 
 # --- Reserved write keys ---
-INPUT = "__input__"
+INPUT = sys.intern("__input__")
 # for values passed as input to the graph
-INTERRUPT = "__interrupt__"
+INTERRUPT = sys.intern("__interrupt__")
 # for dynamic interrupts raised by nodes
-ERROR = "__error__"
+ERROR = sys.intern("__error__")
 # for errors raised by nodes
-NO_WRITES = "__no_writes__"
+NO_WRITES = sys.intern("__no_writes__")
 # marker to signal node didn't write anything
-SCHEDULED = "__scheduled__"
+SCHEDULED = sys.intern("__scheduled__")
 # marker to signal node was scheduled (in distributed mode)
-TASKS = "__pregel_tasks"
+TASKS = sys.intern("__pregel_tasks")
 # for Send objects returned by nodes/edges, corresponds to PUSH below
 
 # --- Reserved config.configurable keys ---
-CONFIG_KEY_SEND = "__pregel_send"
+CONFIG_KEY_SEND = sys.intern("__pregel_send")
 # holds the `write` function that accepts writes to state/edges/reserved keys
-CONFIG_KEY_READ = "__pregel_read"
+CONFIG_KEY_READ = sys.intern("__pregel_read")
 # holds the `read` function that returns a copy of the current state
-CONFIG_KEY_CHECKPOINTER = "__pregel_checkpointer"
+CONFIG_KEY_CHECKPOINTER = sys.intern("__pregel_checkpointer")
 # holds a `BaseCheckpointSaver` passed from parent graph to child graphs
-CONFIG_KEY_STREAM = "__pregel_stream"
+CONFIG_KEY_STREAM = sys.intern("__pregel_stream")
 # holds a `StreamProtocol` passed from parent graph to child graphs
-CONFIG_KEY_STREAM_WRITER = "__pregel_stream_writer"
+CONFIG_KEY_STREAM_WRITER = sys.intern("__pregel_stream_writer")
 # holds a `StreamWriter` for stream_mode=custom
-CONFIG_KEY_STORE = "__pregel_store"
+CONFIG_KEY_STORE = sys.intern("__pregel_store")
 # holds a `BaseStore` made available to managed values
-CONFIG_KEY_RESUMING = "__pregel_resuming"
+CONFIG_KEY_RESUMING = sys.intern("__pregel_resuming")
 # holds a boolean indicating if subgraphs should resume from a previous checkpoint
-CONFIG_KEY_TASK_ID = "__pregel_task_id"
+CONFIG_KEY_TASK_ID = sys.intern("__pregel_task_id")
 # holds the task ID for the current task
-CONFIG_KEY_DEDUPE_TASKS = "__pregel_dedupe_tasks"
+CONFIG_KEY_DEDUPE_TASKS = sys.intern("__pregel_dedupe_tasks")
 # holds a boolean indicating if tasks should be deduplicated (for distributed mode)
-CONFIG_KEY_ENSURE_LATEST = "__pregel_ensure_latest"
+CONFIG_KEY_ENSURE_LATEST = sys.intern("__pregel_ensure_latest")
 # holds a boolean indicating whether to assert the requested checkpoint is the latest
 # (for distributed mode)
-CONFIG_KEY_DELEGATE = "__pregel_delegate"
+CONFIG_KEY_DELEGATE = sys.intern("__pregel_delegate")
 # holds a boolean indicating whether to delegate subgraphs (for distributed mode)
-CONFIG_KEY_CHECKPOINT_MAP = "checkpoint_map"
+CONFIG_KEY_CHECKPOINT_MAP = sys.intern("checkpoint_map")
 # holds a mapping of checkpoint_ns -> checkpoint_id for parent graphs
-CONFIG_KEY_CHECKPOINT_ID = "checkpoint_id"
+CONFIG_KEY_CHECKPOINT_ID = sys.intern("checkpoint_id")
 # holds the current checkpoint_id, if any
-CONFIG_KEY_CHECKPOINT_NS = "checkpoint_ns"
+CONFIG_KEY_CHECKPOINT_NS = sys.intern("checkpoint_ns")
 # holds the current checkpoint_ns, "" for root graph
 
 # --- Other constants ---
-PUSH = "__pregel_push"
+PUSH = sys.intern("__pregel_push")
 # denotes push-style tasks, ie. those created by Send objects
-PULL = "__pregel_pull"
+PULL = sys.intern("__pregel_pull")
 # denotes pull-style tasks, ie. those triggered by edges
-NS_SEP = "|"
+NS_SEP = sys.intern("|")
 # for checkpoint_ns, separates each level (ie. graph|subgraph|subsubgraph)
-NS_END = ":"
+NS_END = sys.intern(":")
 # for checkpoint_ns, for each level, separates the namespace from the task_id
+CONF = cast(Literal["configurable"], sys.intern("configurable"))
+# key for the configurable dict in RunnableConfig
 
 RESERVED = {
     TAG_HIDDEN,
@@ -103,4 +106,5 @@
     PULL,
     NS_SEP,
     NS_END,
+    CONF,
 }

libs/langgraph/langgraph/managed/shared_value.py

@@ -13,7 +13,7 @@
 from langchain_core.runnables import RunnableConfig
 from typing_extensions import NotRequired, Required, Self
 
-from langgraph.constants import CONFIG_KEY_STORE
+from langgraph.constants import CONF, CONFIG_KEY_STORE
 from langgraph.errors import InvalidUpdateError
 from langgraph.managed.base import (
     ChannelKeyPlaceholder,
@@ -83,10 +83,10 @@ def __init__(
                 raise ValueError("SharedValue must be a dict")
         self.scope = scope
         self.value: Value = {}
-        self.store = cast(BaseStore, config["configurable"].get(CONFIG_KEY_STORE))
+        self.store = cast(BaseStore, config[CONF].get(CONFIG_KEY_STORE))
         if self.store is None:
             pass
-        elif scope_value := config["configurable"].get(self.scope):
+        elif scope_value := config[CONF].get(self.scope):
             self.ns = f"scoped:{scope}:{key}:{scope_value}"
         else:
             raise ValueError(