vdk-jobs-troubleshooting: Add thread-dump utility

This change adds the implementation of a thread-dump utility to the
vdk-jobs-troubleshooting plugin.

The utility uses an http server, through which an administrator is able
to force a stacktrace dump of all threads used by the python process of
the data job. The server is bound to a port on the localhost, so to get
the stacktrace, one needs to be attached to the data job pod.

Testing Done: Added unit tests for the utility registry, and tested the
plugin itself locally by running a simple data job and examining the
execution logs.

Signed-off-by: Andon Andonov <[email protected]>

projects/vdk-plugins/vdk-jobs-troubleshooting/src/vdk/plugin/jobs_troubleshoot/jobs_troubleshoot_plugin.py

@@ -5,21 +5,59 @@
 """
 import logging
 from typing import List
+from typing import Optional
 
 from vdk.api.plugin.hook_markers import hookimpl
 from vdk.api.plugin.plugin_registry import IPluginRegistry
+from vdk.internal.builtin_plugins.run.job_context import JobContext
 from vdk.internal.core.config import ConfigurationBuilder
+from vdk.plugin.jobs_troubleshoot.api.troubleshoot_utility import ITroubleshootUtility
 from vdk.plugin.jobs_troubleshoot.troubleshoot_configuration import add_definitions
+from vdk.plugin.jobs_troubleshoot.troubleshoot_utilities.utilities_registry import (
+    get_utilities_to_use,
+)
 
 log = logging.getLogger(__name__)
 
 
 class JobTroubleshootingPlugin:
+    def __init__(self):
+        self.troubleshooting_utils: Optional[List[ITroubleshootUtility]] = []
+
     @staticmethod
     @hookimpl
     def vdk_configure(config_builder: ConfigurationBuilder) -> None:
         add_definitions(config_builder=config_builder)
 
+    @hookimpl
+    def initialize_job(self, context: JobContext) -> None:
+        self.troubleshooting_utils = get_utilities_to_use(
+            job_config=context.core_context.configuration
+        )
+        try:
+            for util in self.troubleshooting_utils:
+                util.start()
+        except Exception as e:
+            log.info(
+                f"""
+                An exception occurred while processing a troubleshooting
+                utility. The error was: {e}
+                """
+            )
+
+    @hookimpl
+    def finalize_job(self, context: JobContext) -> None:
+        try:
+            for util in self.troubleshooting_utils:
+                util.stop()
+        except Exception as e:
+            log.info(
+                f"""
+                An exception occurred while processing a troubleshooting
+                utility. The error was: {e}
+                """
+            )
+
 
 @hookimpl
 def vdk_start(plugin_registry: IPluginRegistry, command_line_args: List) -> None:

projects/vdk-plugins/vdk-jobs-troubleshooting/src/vdk/plugin/jobs_troubleshoot/troubleshoot_utilities/healthcheck_server.py

@@ -0,0 +1,30 @@
+# Copyright 2021 VMware, Inc.
+# SPDX-License-Identifier: Apache-2.0
+from http.server import HTTPServer
+from http.server import SimpleHTTPRequestHandler
+from threading import Thread
+from typing import Any
+
+
+class HealthCheckServer:
+    def __init__(self, port: int, handler: Any = None):
+        if handler:
+            self._server = HTTPServer(("", port), handler)
+        else:
+            self._server = HTTPServer(("", port), SimpleHTTPRequestHandler)
+        self._thread = Thread(target=self._server.serve_forever)
+
+    def __enter__(self):
+        self.start()
+        return self
+
+    def __exit__(self, typ, value, traceback):
+        self.stop()
+
+    def start(self):
+        self._thread.start()
+
+    def stop(self):
+        self._server.shutdown()
+        self._server.server_close()
+        self._thread.join()

projects/vdk-plugins/vdk-jobs-troubleshooting/src/vdk/plugin/jobs_troubleshoot/troubleshoot_utilities/thread_dump.py

@@ -0,0 +1,63 @@
+# Copyright 2021 VMware, Inc.
+# SPDX-License-Identifier: Apache-2.0
+import json
+import logging
+import sys
+import threading
+import traceback
+from http.server import BaseHTTPRequestHandler
+
+from vdk.internal.core.config import Configuration
+from vdk.plugin.jobs_troubleshoot.api.troubleshoot_utility import ITroubleshootUtility
+from vdk.plugin.jobs_troubleshoot.troubleshoot_configuration import (
+    TROUBLESHOOT_PORT_TO_USE,
+)
+from vdk.plugin.jobs_troubleshoot.troubleshoot_utilities.healthcheck_server import (
+    HealthCheckServer,
+)
+
+log = logging.getLogger(__name__)
+
+
+class ThreadDumpHandler(BaseHTTPRequestHandler):
+    def do_GET(self):
+        if self.path == "/threads":
+            self.send_response(200)
+            self.wfile.write(b"making a thread dump")
+            log.info("Dumping threads")
+            self._log_thread_dump()
+        else:
+            self.send_error(404)
+
+    @staticmethod
+    def _log_thread_dump():
+        try:
+            for t in threading.enumerate():
+                log.info(
+                    f"Thread:{t.getName()} alive:{t.is_alive()} daemon:{t.isDaemon()}"
+                )
+            log.info("--------------------------------------------------------------")
+            log.info("Dumping threads stacks:")
+            code = []
+            for threadId, stack in sys._current_frames().items():
+                code.append("\n# ThreadID: %s" % threadId)
+                for filename, lineno, name, line in traceback.extract_stack(stack):
+                    code.append('File: "%s", line %d, in %s' % (filename, lineno, name))
+                    if line:
+                        code.append("  %s" % (line.strip()))
+            log.info(f"Threads stacks:{json.dumps(code)}")
+            log.info("--------------------------------------------------------------")
+        except Exception as e:
+            log.exception(f"test_reporter_thread exception:{e}", exc_info=True)
+
+
+class ThreadDumpUtility(ITroubleshootUtility):
+    def __init__(self, job_configuration: Configuration):
+        self.port_to_use = job_configuration.get_value(TROUBLESHOOT_PORT_TO_USE)
+        self.server = HealthCheckServer(self.port_to_use, ThreadDumpHandler)
+
+    def start(self):
+        self.server.start()
+
+    def stop(self):
+        self.server.stop()

projects/vdk-plugins/vdk-jobs-troubleshooting/src/vdk/plugin/jobs_troubleshoot/troubleshoot_utilities/utilities_registry.py

@@ -0,0 +1,65 @@
+# Copyright 2021 VMware, Inc.
+# SPDX-License-Identifier: Apache-2.0
+import logging
+from typing import Any
+from typing import Dict
+from typing import List
+from typing import Optional
+
+from vdk.internal.core.config import Configuration
+from vdk.plugin.jobs_troubleshoot.api.troubleshoot_utility import ITroubleshootUtility
+from vdk.plugin.jobs_troubleshoot.troubleshoot_configuration import (
+    TROUBLESHOOT_UTILITIES_TO_USE,
+)
+from vdk.plugin.jobs_troubleshoot.troubleshoot_utilities.thread_dump import (
+    ThreadDumpUtility,
+)
+
+
+log = logging.getLogger(__name__)
+
+
+def utilities_registry(job_config: Configuration) -> Dict[str, Any]:
+    """
+    The troubleshooting utilities registry is where all utility objects are to
+    be initialized.
+    TODO: Come up with a more elegant approach to register utilities.
+
+    :param job_config: The data job configuration.
+    :return: A dictionary with all available troubleshooting utilities.
+    """
+    registered_utilities: Dict[str, Any] = {}
+    registered_utilities["thread-dump"] = ThreadDumpUtility(
+        job_configuration=job_config
+    )
+
+    return registered_utilities
+
+
+def get_utilities_to_use(
+    job_config: Configuration,
+) -> Optional[List[ITroubleshootUtility]]:
+    """
+    Get a list of the initialized troubleshooting utilities that are specified
+    by the VDK_TROUBLESHOOT_UTILITIES_TO_USE configuration variable.
+    :param job_config: Data Job configuration
+    :return: A list of utility objects that are to be used.
+    """
+    utilities: Optional[List[ITroubleshootUtility]] = []
+    selected_utilities: str = job_config.get_value(TROUBLESHOOT_UTILITIES_TO_USE)
+    registered_utilities: Dict = utilities_registry(job_config=job_config)
+
+    for util in selected_utilities.split(","):
+        registered_util = registered_utilities.get(util)
+        if registered_util:
+            utilities.append(registered_util)
+        else:
+            log.info(
+                f"""
+                Utility {util} is not in the list of available troubleshooting
+                utilities.
+                Available utilities: {registered_utilities.keys()}
+                """
+            )
+
+    return utilities

projects/vdk-plugins/vdk-jobs-troubleshooting/tests/test_utilities_registry.py

@@ -0,0 +1,39 @@
+# Copyright 2021 VMware, Inc.
+# SPDX-License-Identifier: Apache-2.0
+from typing import List
+
+from vdk.internal.core.config import ConfigurationBuilder
+from vdk.plugin.jobs_troubleshoot.troubleshoot_configuration import (
+    TROUBLESHOOT_PORT_TO_USE,
+)
+from vdk.plugin.jobs_troubleshoot.troubleshoot_configuration import (
+    TROUBLESHOOT_UTILITIES_TO_USE,
+)
+from vdk.plugin.jobs_troubleshoot.troubleshoot_utilities.utilities_registry import (
+    get_utilities_to_use,
+)
+
+
+def test_get_utilities_to_use():
+    config_builder = ConfigurationBuilder()
+    config_builder.set_value(key=TROUBLESHOOT_UTILITIES_TO_USE, value="thread-dump")
+    config_builder.set_value(key=TROUBLESHOOT_PORT_TO_USE, value=8783)
+    configuration = config_builder.build()
+
+    utility = get_utilities_to_use(configuration)
+
+    assert isinstance(utility, List)
+    assert len(utility) == 1
+
+
+def test_get_utilities_to_use__nonexistent_utility():
+    config_builder = ConfigurationBuilder()
+    config_builder.set_value(
+        key=TROUBLESHOOT_UTILITIES_TO_USE, value="non-existent-utility"
+    )
+    config_builder.set_value(key=TROUBLESHOOT_PORT_TO_USE, value=8783)
+    configuration = config_builder.build()
+
+    utility = get_utilities_to_use(configuration)
+
+    assert len(utility) == 0