feat(box): add sandbox_exec tool loop for local-agent calculations

tests/unit_tests/box/test_box_service.py

@@ -0,0 +1,104 @@
+from __future__ import annotations
+
+import datetime as dt
+from types import SimpleNamespace
+from unittest.mock import Mock
+
+import pytest
+
+import langbot_plugin.api.entities.builtin.pipeline.query as pipeline_query
+
+from langbot.pkg.box.backend import BaseSandboxBackend
+from langbot.pkg.box.errors import BoxBackendUnavailableError
+from langbot.pkg.box.models import BoxExecutionResult, BoxExecutionStatus, BoxNetworkMode, BoxSessionInfo, BoxSpec
+from langbot.pkg.box.runtime import BoxRuntime
+from langbot.pkg.box.service import BoxService
+
+
+class FakeBackend(BaseSandboxBackend):
+    def __init__(self, logger: Mock, available: bool = True):
+        super().__init__(logger)
+        self.name = 'fake'
+        self.available = available
+        self.start_calls: list[str] = []
+        self.exec_calls: list[tuple[str, str]] = []
+        self.stop_calls: list[str] = []
+
+    async def is_available(self) -> bool:
+        return self.available
+
+    async def start_session(self, spec: BoxSpec) -> BoxSessionInfo:
+        self.start_calls.append(spec.session_id)
+        now = dt.datetime.now(dt.UTC)
+        return BoxSessionInfo(
+            session_id=spec.session_id,
+            backend_name=self.name,
+            backend_session_id=f'backend-{spec.session_id}',
+            image=spec.image,
+            network=spec.network,
+            created_at=now,
+            last_used_at=now,
+        )
+
+    async def exec(self, session: BoxSessionInfo, spec: BoxSpec) -> BoxExecutionResult:
+        self.exec_calls.append((session.session_id, spec.cmd))
+        return BoxExecutionResult(
+            session_id=session.session_id,
+            backend_name=self.name,
+            status=BoxExecutionStatus.COMPLETED,
+            exit_code=0,
+            stdout=f'executed: {spec.cmd}',
+            stderr='',
+            duration_ms=12,
+        )
+
+    async def stop_session(self, session: BoxSessionInfo):
+        self.stop_calls.append(session.session_id)
+
+
+def make_query(query_id: int = 42) -> pipeline_query.Query:
+    return pipeline_query.Query.model_construct(query_id=query_id)
+
+
+@pytest.mark.asyncio
+async def test_box_runtime_reuses_request_session():
+    logger = Mock()
+    backend = FakeBackend(logger)
+    runtime = BoxRuntime(logger=logger, backends=[backend], session_ttl_sec=300)
+    await runtime.initialize()
+
+    first = BoxSpec.model_validate({'cmd': 'echo first', 'session_id': 'req-1'})
+    second = BoxSpec.model_validate({'cmd': 'echo second', 'session_id': 'req-1'})
+
+    await runtime.execute(first)
+    await runtime.execute(second)
+
+    assert backend.start_calls == ['req-1']
+    assert backend.exec_calls == [('req-1', 'echo first'), ('req-1', 'echo second')]
+
+
+@pytest.mark.asyncio
+async def test_box_service_defaults_session_id_from_query():
+    logger = Mock()
+    backend = FakeBackend(logger)
+    runtime = BoxRuntime(logger=logger, backends=[backend], session_ttl_sec=300)
+    service = BoxService(SimpleNamespace(logger=logger), runtime=runtime)
+    await service.initialize()
+
+    result = await service.execute_sandbox_tool({'cmd': 'pwd', 'network': BoxNetworkMode.OFF.value}, make_query(7))
+
+    assert result['session_id'] == '7'
+    assert result['ok'] is True
+    assert backend.start_calls == ['7']
+
+
+@pytest.mark.asyncio
+async def test_box_service_fails_closed_when_backend_unavailable():
+    logger = Mock()
+    backend = FakeBackend(logger, available=False)
+    runtime = BoxRuntime(logger=logger, backends=[backend], session_ttl_sec=300)
+    service = BoxService(SimpleNamespace(logger=logger), runtime=runtime)
+    await service.initialize()
+
+    with pytest.raises(BoxBackendUnavailableError):
+        await service.execute_sandbox_tool({'cmd': 'echo hello'}, make_query(9))