refactor: move workflow package to dify_graph (#32844)

api/dify_graph/runtime/graph_runtime_state_protocol.py

@@ -0,0 +1,83 @@
+from collections.abc import Mapping, Sequence
+from typing import Any, Protocol
+
+from core.model_runtime.entities.llm_entities import LLMUsage
+from dify_graph.system_variable import SystemVariableReadOnlyView
+from dify_graph.variables.segments import Segment
+
+
+class ReadOnlyVariablePool(Protocol):
+    """Read-only interface for VariablePool."""
+
+    def get(self, selector: Sequence[str], /) -> Segment | None:
+        """Get a variable value (read-only)."""
+        ...
+
+    def get_all_by_node(self, node_id: str) -> Mapping[str, object]:
+        """Get all variables for a node (read-only)."""
+        ...
+
+    def get_by_prefix(self, prefix: str) -> Mapping[str, object]:
+        """Get all variables stored under a given node prefix (read-only)."""
+        ...
+
+
+class ReadOnlyGraphRuntimeState(Protocol):
+    """
+    Read-only view of GraphRuntimeState for layers.
+
+    This protocol defines a read-only interface that prevents layers from
+    modifying the graph runtime state while still allowing observation.
+    All methods return defensive copies to ensure immutability.
+    """
+
+    @property
+    def system_variable(self) -> SystemVariableReadOnlyView: ...
+
+    @property
+    def variable_pool(self) -> ReadOnlyVariablePool:
+        """Get read-only access to the variable pool."""
+        ...
+
+    @property
+    def start_at(self) -> float:
+        """Get the start time (read-only)."""
+        ...
+
+    @property
+    def total_tokens(self) -> int:
+        """Get the total tokens count (read-only)."""
+        ...
+
+    @property
+    def llm_usage(self) -> LLMUsage:
+        """Get a copy of LLM usage info (read-only)."""
+        ...
+
+    @property
+    def outputs(self) -> dict[str, Any]:
+        """Get a defensive copy of outputs (read-only)."""
+        ...
+
+    @property
+    def node_run_steps(self) -> int:
+        """Get the node run steps count (read-only)."""
+        ...
+
+    @property
+    def ready_queue_size(self) -> int:
+        """Get the number of nodes currently in the ready queue."""
+        ...
+
+    @property
+    def exceptions_count(self) -> int:
+        """Get the number of node execution exceptions recorded."""
+        ...
+
+    def get_output(self, key: str, default: Any = None) -> Any:
+        """Get a single output value (returns a copy)."""
+        ...
+
+    def dumps(self) -> str:
+        """Serialize the runtime state into a JSON snapshot (read-only)."""
+        ...