Feature:3963 Step HeartBeat components

src/zenml/constants.py

@@ -439,6 +439,7 @@ def handle_int_env_var(var: str, default: int = 0) -> int:
 STATUS = "/status"
 STEP_CONFIGURATION = "/step-configuration"
 STEPS = "/steps"
+HEARTBEAT = "/heartbeat"
 STOP = "/stop"
 TAGS = "/tags"
 TAG_RESOURCES = "/tag_resources"

src/zenml/models/__init__.py

@@ -346,7 +346,8 @@
     StepRunResponse,
     StepRunResponseBody,
     StepRunResponseMetadata,
-    StepRunResponseResources
+    StepRunResponseResources,
+    StepHeartbeatResponse,
 )
 from zenml.models.v2.core.tag import (
     TagFilter,
@@ -908,4 +909,5 @@
     "StepRunIdentifier",
     "ArtifactVersionIdentifier",
     "ModelVersionIdentifier",
+    "StepHeartbeatResponse",
 ]

src/zenml/models/v2/core/step_run.py

@@ -26,7 +26,7 @@
 )
 from uuid import UUID
 
-from pydantic import ConfigDict, Field
+from pydantic import BaseModel, ConfigDict, Field
 
 from zenml.config.step_configurations import StepConfiguration, StepSpec
 from zenml.constants import STR_FIELD_MAX_LENGTH, TEXT_FIELD_MAX_LENGTH
@@ -210,6 +210,10 @@ class StepRunResponseBody(ProjectScopedResponseBody):
         title="The end time of the step run.",
         default=None,
     )
+    latest_heartbeat: Optional[datetime] = Field(
+        title="The latest heartbeat of the step run.",
+        default=None,
+    )
     model_version_id: Optional[UUID] = Field(
         title="The ID of the model version that was "
         "configured by this step run explicitly.",
@@ -589,6 +593,15 @@ def end_time(self) -> Optional[datetime]:
         """
         return self.get_body().end_time
 
+    @property
+    def latest_heartbeat(self) -> Optional[datetime]:
+        """The `latest_heartbeat` property.
+
+        Returns:
+            the value of the property.
+        """
+        return self.get_body().latest_heartbeat
+
     @property
     def logs(self) -> Optional["LogsResponse"]:
         """The `logs` property.
@@ -795,3 +808,14 @@ def get_custom_filters(
             custom_filters.append(cache_expiration_filter)
 
         return custom_filters
+
+
+# ------------------ Heartbeat Model ---------------
+
+
+class StepHeartbeatResponse(BaseModel):
+    """Light-weight model for Step Heartbeat responses."""
+
+    id: UUID
+    status: str
+    latest_heartbeat: datetime

src/zenml/orchestrators/step_launcher.py

@@ -43,7 +43,9 @@
 from zenml.orchestrators import utils as orchestrator_utils
 from zenml.orchestrators.step_runner import StepRunner
 from zenml.stack import Stack
+from zenml.steps import StepHeartBeatTerminationException, StepHeartbeatWorker
 from zenml.utils import env_utils, exception_utils, string_utils
+from zenml.utils.exception_utils import ContextReraise
 from zenml.utils.time_utils import utc_now
 
 if TYPE_CHECKING:
@@ -167,7 +169,6 @@ def signal_handler(signum: int, frame: Any) -> None:
 
             try:
                 client = Client()
-                pipeline_run = None
 
                 if self._step_run:
                     pipeline_run = client.get_pipeline_run(
@@ -443,35 +444,58 @@ def _run_step(
         )
 
         start_time = time.time()
-        try:
-            if self._step.config.step_operator:
-                step_operator_name = None
-                if isinstance(self._step.config.step_operator, str):
-                    step_operator_name = self._step.config.step_operator
-
-                self._run_step_with_step_operator(
-                    step_operator_name=step_operator_name,
-                    step_run_info=step_run_info,
+
+        # To have a cross-platform compatible handling of main thread termination
+        # we use Python's interrupt_main instead of termination signals (not Windows supported).
+        # Since interrupt_main raises KeyboardInterrupt we want in this context to capture it
+        # and handle it as a custom exception.
+
+        with ContextReraise(
+            source_exceptions=[KeyboardInterrupt],
+            target_exception=StepHeartBeatTerminationException,
+            message=f"Step {self._invocation_id} has been remotely stopped - terminating",
+            propagate_traceback=False,
+        ) as ctx_reraise:
+
+            logger.info(f"Initiating heartbeat for step {self._invocation_id}")
+
+            StepHeartbeatWorker(step_id=step_run.id).start()
+
+            try:
+                if self._step.config.step_operator:
+                    step_operator_name = None
+                    if isinstance(self._step.config.step_operator, str):
+                        step_operator_name = self._step.config.step_operator
+
+                    self._run_step_with_step_operator(
+                        step_operator_name=step_operator_name,
+                        step_run_info=step_run_info,
+                    )
+                else:
+                    self._run_step_without_step_operator(
+                        pipeline_run=pipeline_run,
+                        step_run=step_run,
+                        step_run_info=step_run_info,
+                        input_artifacts=step_run.regular_inputs,
+                        output_artifact_uris=output_artifact_uris,
+                    )
+            except StepHeartBeatTerminationException:
+                logger.info(ctx_reraise.message)
+                output_utils.remove_artifact_dirs(
+                    artifact_uris=list(output_artifact_uris.values())
                 )
-            else:
-                self._run_step_without_step_operator(
-                    pipeline_run=pipeline_run,
-                    step_run=step_run,
-                    step_run_info=step_run_info,
-                    input_artifacts=step_run.regular_inputs,
-                    output_artifact_uris=output_artifact_uris,
+                raise
+            except:  # noqa: E722
+                output_utils.remove_artifact_dirs(
+                    artifact_uris=list(output_artifact_uris.values())
                 )
-        except:  # noqa: E722
-            output_utils.remove_artifact_dirs(
-                artifact_uris=list(output_artifact_uris.values())
-            )
-            raise
+                raise
 
-        duration = time.time() - start_time
-        logger.info(
-            f"Step `{self._invocation_id}` has finished in "
-            f"`{string_utils.get_human_readable_time(duration)}`."
-        )
+            duration = time.time() - start_time
+            logger.info(
+                f"Step `{self._invocation_id}` has finished in "
+                f"`{string_utils.get_human_readable_time(duration)}`."
+            )
 
     def _run_step_with_step_operator(
         self,

src/zenml/steps/__init__.py

@@ -28,6 +28,7 @@
 
 from zenml.steps.base_step import BaseStep
 from zenml.config.resource_settings import ResourceSettings
+from zenml.steps.heartbeat import StepHeartbeatWorker, StepHeartBeatTerminationException
 from zenml.steps.step_context import StepContext, get_step_context
 from zenml.steps.step_decorator import step
 
@@ -36,5 +37,7 @@
     "ResourceSettings",
     "StepContext",
     "step",
-    "get_step_context"
+    "get_step_context",
+    "StepHeartbeatWorker",
+    "StepHeartBeatTerminationException",
 ]

src/zenml/steps/heartbeat.py

@@ -0,0 +1,158 @@
+#  Copyright (c) ZenML GmbH 2022. All Rights Reserved.
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at:
+#
+#       https://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+#  or implied. See the License for the specific language governing
+#  permissions and limitations under the License.
+"""ZenML Step HeartBeat functionality."""
+
+import _thread
+import logging
+import threading
+import time
+from uuid import UUID
+
+from zenml.enums import ExecutionStatus
+
+logger = logging.getLogger(__name__)
+
+
+class StepHeartBeatTerminationException(Exception):
+    """Custom exception class for heartbeat termination."""
+
+    pass
+
+
+class StepHeartbeatWorker:
+    """Worker class implementing heartbeat polling and remote termination."""
+
+    STEP_HEARTBEAT_INTERVAL_SECONDS = 30
+
+    def __init__(self, step_id: UUID):
+        """Heartbeat worker constructor.
+
+        Args:
+            options: Parameter group - polling interval, step id, etc.
+        """
+
+        self._step_id = step_id
+
+        self._thread: threading.Thread | None = None
+        self._running: bool = False
+        self._terminated: bool = (
+            False  # one-shot guard to avoid repeated interrupts
+        )
+
+    # properties
+
+    @property
+    def interval(self) -> int:
+        """Property function for heartbeat interval.
+
+        Returns:
+            The heartbeat polling interval value.
+        """
+        return self.STEP_HEARTBEAT_INTERVAL_SECONDS
+
+    @property
+    def name(self) -> str:
+        """Property function for heartbeat worker name.
+
+        Returns:
+            The name of the heartbeat worker.
+        """
+        return f"HeartBeatWorker-{self.step_id}"
+
+    @property
+    def step_id(self) -> UUID:
+        """Property function for heartbeat worker step ID.
+
+        Returns:
+            The id of the step heartbeat is running for.
+        """
+        return self.step_id
+
+    # public functions
+
+    def start(self) -> None:
+        """Start the heartbeat worker on a background thread."""
+        if self._thread and self._thread.is_alive():
+            logger.info("%s already running; start() is a no-op", self.name)
+            return
+
+        self._running = True
+        self._terminated = False
+        self._thread = threading.Thread(
+            target=self._run, name=self.name, daemon=True
+        )
+        self._thread.start()
+        logger.info(
+            "Daemon thread %s started (interval=%s)", self.name, self.interval
+        )
+
+    def stop(self) -> None:
+        """Stops the heartbeat worker."""
+        if not self._running:
+            return
+        self._running = False
+        logger.info("%s stop requested", self.name)
+
+    def is_alive(self) -> bool:
+        """Liveness of the heartbeat worker thread.
+
+        Returns:
+            True if the heartbeat worker thread is alive, False otherwise.
+        """
+        t = self._thread
+        return bool(t and t.is_alive())
+
+    def _run(self) -> None:
+        logger.info("%s run() loop entered", self.name)
+        try:
+            while self._running:
+                try:
+                    self._heartbeat()
+                except StepHeartBeatTerminationException:
+                    # One-shot: signal the main thread and stop the loop.
+                    if not self._terminated:
+                        self._terminated = True
+                        logger.info(
+                            "%s received HeartBeatTerminationException; "
+                            "interrupting main thread",
+                            self.name,
+                        )
+                        _thread.interrupt_main()  # raises KeyboardInterrupt in main thread
+                    # Ensure we stop our own loop as well.
+                    self._running = False
+                except Exception:
+                    # Log-and-continue policy for all other errors.
+                    logger.exception(
+                        "%s heartbeat() failed; continuing", self.name
+                    )
+                # Sleep after each attempt (even after errors, unless stopped).
+                if self._running:
+                    time.sleep(self.interval)
+        finally:
+            logger.info("%s run() loop exiting", self.name)
+
+    def _heartbeat(self) -> None:
+        from zenml.config.global_config import GlobalConfiguration
+
+        store = GlobalConfiguration().zen_store
+
+        response = store.update_step_heartbeat(step_run_id=self.step_id)
+
+        if response.status in {
+            ExecutionStatus.STOPPED,
+            ExecutionStatus.STOPPING,
+        }:
+            raise StepHeartBeatTerminationException(
+                f"Step {self.step_id} remotely stopped with status {response.status}."
+            )