Allow an action to get a copy of the logs raised during the action.

src/labthings_fastapi/actions.py

@@ -44,7 +44,7 @@
 from .base_descriptor import BaseDescriptor
 from .logs import add_thing_log_destination
 from .utilities import model_to_dict, wrap_plain_types_in_rootmodel
-from .invocations import InvocationModel, InvocationStatus, LogRecordModel
+from .invocations import InvocationModel, InvocationStatus
 from .dependencies.invocation import NonWarningInvocationID
 from .exceptions import (
     InvocationCancelledError,
@@ -154,7 +154,7 @@
             return self._return_value
 
     @property
-    def log(self) -> list[LogRecordModel]:
+    def log(self) -> list[logging.LogRecord]:
         """A list of log items generated by the Action."""
         with self._status_lock:
             return list(self._log)
@@ -505,8 +505,8 @@
             with self._invocations_lock:
                 try:
                     invocation: Any = self._invocations[id]
                 except KeyError as e:
                     raise HTTPException(
                         status_code=404,
                         detail="No action invocation found with ID {id}",
                     ) from e
@@ -519,7 +519,7 @@
                     invocation.output.response
                 ):
                     # TODO: honour "accept" header
                     return invocation.output.response()
                 return invocation.output
 
         @app.delete(
@@ -544,8 +544,8 @@
             with self._invocations_lock:
                 try:
                     invocation: Any = self._invocations[id]
                 except KeyError as e:
                     raise HTTPException(
                         status_code=404,
                         detail="No action invocation found with ID {id}",
                     ) from e
@@ -670,7 +670,7 @@
         """
         super().__set_name__(owner, name)
         if self.name != self.func.__name__:
             raise ValueError(
                 f"Action name '{self.name}' does not match function name "
                 f"'{self.func.__name__}'",
             )
@@ -814,14 +814,14 @@
         try:
             responses[200]["model"] = self.output_model
             pass
         except AttributeError:
             print(f"Failed to generate response model for action {self.name}")
         # Add an additional media type if we may return a file
         if hasattr(self.output_model, "media_type"):
             responses[200]["content"][self.output_model.media_type] = {}
         # Now we can add the endpoint to the app.
         if thing.path is None:
             raise NotConnectedToServerError(
                 "Can't add the endpoint without thing.path!"
             )
         app.post(
@@ -869,7 +869,7 @@
         """
         path = path or thing.path
         if path is None:
             raise NotConnectedToServerError("Can't generate forms without a path!")
         forms = [
             Form[ActionOp](href=path + self.name, op=[ActionOp.invokeaction]),
         ]

src/labthings_fastapi/thing.py

@@ -30,7 +30,7 @@
 from .websockets import websocket_endpoint
 from .exceptions import PropertyNotObservableError
 from .thing_server_interface import ThingServerInterface
-
+from .invocation_contexts import get_invocation_id
 
 if TYPE_CHECKING:
     from .server import ThingServer
@@ -249,13 +249,13 @@
         the settings file every time.
         """
         if self._disable_saving_settings:
             return
         if self._settings is not None:
             setting_dict = {}
             for name in self._settings.keys():
                 value = getattr(self, name)
                 if isinstance(value, BaseModel):
                     value = value.model_dump()
                 setting_dict[name] = value
             # Dumpy to string before writing so if this fails the file isn't overwritten
             setting_json = json.dumps(setting_dict, indent=4)
@@ -383,3 +383,26 @@
             raise KeyError(f"{action_name} is not an LabThings Action")
         observers = action._observers_set(self)
         observers.add(stream)
+
+    def get_logs(self) -> list[logging.LogRecord]:
+        """Get the log records for an on going action.
+
+        This is useful if an action wishes to save its logs alongside any data.
+
+        Note that only the last 1000 logs are returned so for long running tasks that
+        log frequently this may want to be read periodically.
+
+        This will error if it is called outside an action invocation.
+
+        :return: a list of all logs from this action.
+
+        :raises RuntimeError: If the server cannot be retrieved. This should never
+            happen.
+        """
+        inv_id = get_invocation_id()
+        server = self._thing_server_interface._server()
+        if server is None:
+            raise RuntimeError("Could not get server from thing_server_interface")
+        action_manager = server.action_manager
+        this_invocation = action_manager.get_invocation(inv_id)
+        return this_invocation.log

tests/test_logs.py

@@ -10,6 +10,7 @@
 from types import EllipsisType
 import pytest
 from uuid import UUID, uuid4
+from fastapi.testclient import TestClient
 from labthings_fastapi import logs
 from labthings_fastapi.invocation_contexts import (
     fake_invocation_context,
@@ -19,13 +20,29 @@
 from labthings_fastapi.exceptions import LogConfigurationError
 from labthings_fastapi.testing import create_thing_without_server
 
+from .temp_client import poll_task
+
 
 class ThingThatLogs(lt.Thing):
     @lt.action
     def log_a_message(self, msg: str):
         """Log a message to the thing's logger."""
         self.logger.info(msg)
 
+    @lt.action
+    def log_and_capture(self, msg: str) -> str:
+        """Log a message to the thing's logger."""
+        self.logger.info(msg)
+        self.logger.warning(msg)
+        self.logger.error(msg)
+        logs = self.get_logs()
+        logging_str = ""
+        for record in logs:
+            level = record.levelname
+            msg = record.getMessage()
+            logging_str += f"[{level}] {msg}\n"
+        return logging_str
+
 
 def reset_thing_logger():
     """Remove all handlers from the THING_LOGGER to reset it."""
@@ -176,3 +193,15 @@ def test_add_thing_log_destination():
         thing.log_a_message("Test Message.")
     assert len(dest) == 1
     assert dest[0].getMessage() == "Test Message."
+
+
+def test_action_can_get_logs():
+    """Check that an action can get a copy of its own logs."""
+    server = lt.ThingServer({"logging_thing": ThingThatLogs})
+    with TestClient(server.app) as client:
+        response = client.post("/logging_thing/log_and_capture", json={"msg": "foobar"})
+    response.raise_for_status()
+    invocation = poll_task(client, response.json())
+    assert invocation["status"] == "completed"
+    expected_message = "[INFO] foobar\n[WARNING] foobar\n[ERROR] foobar\n"
+    assert invocation["output"] == expected_message