Remove watchman. (pantsbuild#10114)

[ci skip-jvm-tests]

3rdparty/python/requirements.txt

@@ -26,7 +26,6 @@ psutil==5.7.0
 Pygments==2.6.1
 pystache==0.5.4
 python-Levenshtein==0.12.1
-pywatchman==1.4.1
 PyYAML>=5.3.1,<5.4
 py_zipkin==0.20.0
 requests[security]>=2.20.1

src/docs/architecture_pantsd.md

@@ -38,7 +38,7 @@ Services
 
 A Pants Daemon process has several services that it polls in order. Every service runs in a separate thread, and can be paused, resumed or terminated. Services can communicate with each other.
 
-Examples of services are [`FSEventService`](https://github.com/pantsbuild/pants/blob/master/src/python/pants/pantsd/service/fs_event_service.py#14), which takes care of listening for watchman events, [`SchedulerService`](https://github.com/pantsbuild/pants/blob/master/src/python/pants/pantsd/service/scheduler_service.py#21), which takes care of listening responding to those events to keep a warm `Graph`, and [`PailgunService`](https://github.com/pantsbuild/pants/blob/master/src/python/pants/pantsd/service/pailgun_service.py#15), which listens to `SchedulerService` and manages the lifetime of a `PailgunServer` responsible for spawning pants runs when requested by clients, it takes a `DaemonPantsRunner` as one of its arguments, to use as a template to spawn pants runs when requested by the clients.
+Examples of services are [`SchedulerService`](https://github.com/pantsbuild/pants/blob/master/src/python/pants/pantsd/service/scheduler_service.py#21), which takes care of listening responding to those events to keep a warm `Graph`, and [`PailgunService`](https://github.com/pantsbuild/pants/blob/master/src/python/pants/pantsd/service/pailgun_service.py#15), which listens to `SchedulerService` and manages the lifetime of a `PailgunServer` responsible for spawning pants runs when requested by clients, it takes a `DaemonPantsRunner` as one of its arguments, to use as a template to spawn pants runs when requested by the clients.
 
 ### PailgunService
 

src/python/pants/core_tasks/register.py

@@ -58,8 +58,7 @@ def register_goals():
     # Pantsd.
     kill_pantsd = task(name="kill-pantsd", action=PantsDaemonKill)
     kill_pantsd.install()
-    # Kill pantsd/watchman first, so that they're not using any files
-    # in .pants.d at the time of removal.
+    # Kill pantsd first so that it's not using any files in .pants.d at the time of removal.
     kill_pantsd.install("clean-all", first=True)
 
     # Reporting server.

src/python/pants/option/global_options.py

@@ -666,83 +666,6 @@ def register_bootstrap_options(cls, register):
             "Pants' own code, plugins, and `--pants-config-files` are inherently invalidated.",
         )
 
-        # Watchman options.
-        register(
-            "--watchman-enable",
-            type=bool,
-            advanced=True,
-            default=False,
-            removal_version="1.31.0.dev0",
-            removal_hint=(
-                "The native watcher is now sufficient to monitor for filesystem "
-                "changes, so watchman is being removed."
-            ),
-            help="Use the watchman daemon filesystem event watcher to watch for changes "
-            "in the buildroot in addition to the built in watcher.",
-        )
-        register(
-            "--watchman-version",
-            advanced=True,
-            default="4.9.0-pants1",
-            removal_version="1.31.0.dev0",
-            removal_hint=(
-                "The native watcher is now sufficient to monitor for filesystem "
-                "changes, so watchman is being removed."
-            ),
-            help="Watchman version.",
-        )
-        register(
-            "--watchman-supportdir",
-            advanced=True,
-            default="bin/watchman",
-            removal_version="1.31.0.dev0",
-            removal_hint=(
-                "The native watcher is now sufficient to monitor for filesystem "
-                "changes, so watchman is being removed."
-            ),
-            help="Find watchman binaries under this dir. Used as part of the path to lookup "
-            "the binary with --binaries-baseurls and --pants-bootstrapdir.",
-        )
-        register(
-            "--watchman-startup-timeout",
-            type=float,
-            advanced=True,
-            default=60.0,
-            removal_version="1.31.0.dev0",
-            removal_hint=(
-                "The native watcher is now sufficient to monitor for filesystem "
-                "changes, so watchman is being removed."
-            ),
-            help="The watchman socket timeout (in seconds) for the initial `watch-project` command. "
-            "This may need to be set higher for larger repos due to watchman startup cost.",
-        )
-        register(
-            "--watchman-socket-timeout",
-            type=float,
-            advanced=True,
-            default=0.1,
-            removal_version="1.31.0.dev0",
-            removal_hint=(
-                "The native watcher is now sufficient to monitor for filesystem "
-                "changes, so watchman is being removed."
-            ),
-            help="The watchman client socket timeout in seconds. Setting this to too high a "
-            "value can negatively impact the latency of runs forked by pantsd.",
-        )
-        register(
-            "--watchman-socket-path",
-            type=str,
-            advanced=True,
-            default=None,
-            removal_version="1.31.0.dev0",
-            removal_hint=(
-                "The native watcher is now sufficient to monitor for filesystem "
-                "changes, so watchman is being removed."
-            ),
-            help="The path to the watchman UNIX socket. This can be overridden if the default "
-            "absolute path length exceeds the maximum allowed by the OS.",
-        )
-
         register(
             "--build-file-prelude-globs",
             advanced=True,

src/python/pants/pantsd/BUILD

@@ -29,7 +29,6 @@ python_library(
     '3rdparty/python:setproctitle',
     ':pants_daemon_core',
     ':process_manager',
-    ':watchman_launcher',
     'src/python/pants/base:build_environment',
     'src/python/pants/base:exception_sink',
     'src/python/pants/base:exiter',
@@ -40,7 +39,6 @@ python_library(
     'src/python/pants/init',
     'src/python/pants/option',
     'src/python/pants/option:options_bootstrapper',
-    'src/python/pants/pantsd/service:fs_event_service',
     'src/python/pants/pantsd/service:scheduler_service',
     'src/python/pants/pantsd/service:store_gc_service',
     'src/python/pants/util:contextutil',
@@ -61,36 +59,3 @@ python_library(
   ],
   tags = {"partially_type_checked"},
 )
-
-python_library(
-  name = 'watchman',
-  sources = ['watchman.py'],
-  dependencies = [
-    'src/python/pants/util:dirutil',
-    'src/python/pants/util:retry',
-    ':process_manager',
-    ':watchman_client'
-  ],
-  tags = {"partially_type_checked"},
-)
-
-python_library(
-  name = 'watchman_client',
-  sources = ['watchman_client.py'],
-  dependencies = [
-    '3rdparty/python:pywatchman'
-  ],
-  tags = {"partially_type_checked"},
-)
-
-python_library(
-  name = 'watchman_launcher',
-  sources = ['watchman_launcher.py'],
-  dependencies = [
-    ':watchman',
-    'src/python/pants/binaries',
-    'src/python/pants/util:logging',
-    'src/python/pants/util:memo',
-  ],
-  tags = {"partially_type_checked"},
-)

src/python/pants/pantsd/pants_daemon.py

@@ -22,11 +22,9 @@
 from pants.option.options_bootstrapper import OptionsBootstrapper
 from pants.pantsd.pants_daemon_core import PantsDaemonCore
 from pants.pantsd.process_manager import PantsDaemonProcessManager
-from pants.pantsd.service.fs_event_service import FSEventService
 from pants.pantsd.service.pants_service import PantsServices
 from pants.pantsd.service.scheduler_service import SchedulerService
 from pants.pantsd.service.store_gc_service import StoreGCService
-from pants.pantsd.watchman_launcher import WatchmanLauncher
 from pants.util.contextutil import stdio_as
 from pants.util.logging import LogLevel
 from pants.util.strutil import ensure_text
@@ -129,24 +127,11 @@ def _setup_services(
         """
         build_root = get_buildroot()
 
-        # TODO: https://github.com/pantsbuild/pants/issues/3479
-        watchman_launcher = WatchmanLauncher.create(bootstrap_options)
-        watchman_launcher.maybe_launch()
-        watchman = watchman_launcher.watchman
-        fs_event_service = (
-            FSEventService(
-                watchman, scheduler=legacy_graph_scheduler.scheduler, build_root=build_root
-            )
-            if bootstrap_options.watchman_enable
-            else None
-        )
-
         invalidation_globs = OptionsInitializer.compute_pantsd_invalidation_globs(
             build_root, bootstrap_options,
         )
 
         scheduler_service = SchedulerService(
-            fs_event_service=fs_event_service,
             legacy_graph_scheduler=legacy_graph_scheduler,
             build_root=build_root,
             invalidation_globs=invalidation_globs,
@@ -158,14 +143,7 @@ def _setup_services(
         )
 
         store_gc_service = StoreGCService(legacy_graph_scheduler.scheduler)
-
-        return PantsServices(
-            services=tuple(
-                service
-                for service in (fs_event_service, scheduler_service, store_gc_service,)
-                if service is not None
-            ),
-        )
+        return PantsServices(services=(scheduler_service, store_gc_service))
 
     def __init__(
         self,

src/python/pants/pantsd/service/BUILD

@@ -11,16 +11,6 @@ python_library(
   tags = {"partially_type_checked"},
 )
 
-python_library(
-  name = 'fs_event_service',
-  sources = ['fs_event_service.py'],
-  dependencies = [
-    ':pants_service',
-    'src/python/pants/pantsd:watchman'
-  ],
-  tags = {"partially_type_checked"},
-)
-
 python_library(
   name = 'scheduler_service',
   sources = ['scheduler_service.py'],

src/python/pants/pantsd/service/scheduler_service.py

@@ -10,14 +10,14 @@
 from pants.engine.fs import PathGlobs, Snapshot
 from pants.engine.internals.scheduler import ExecutionTimeoutError
 from pants.init.engine_initializer import LegacyGraphScheduler
-from pants.pantsd.service.fs_event_service import FSEventService
 from pants.pantsd.service.pants_service import PantsService
 
 
 class SchedulerService(PantsService):
     """The pantsd scheduler service.
 
-    This service holds an online Scheduler instance that is primed via watchman filesystem events.
+    This service uses the scheduler to watch the filesystem and determine whether pantsd needs to
+    restart in order to reload its state.
     """
 
     # The interval on which we will long-poll the invalidation globs. If a glob changes, the poll
@@ -30,7 +30,6 @@ class SchedulerService(PantsService):
     def __init__(
         self,
         *,
-        fs_event_service: Optional[FSEventService],
         legacy_graph_scheduler: LegacyGraphScheduler,
         build_root: str,
         invalidation_globs: List[str],
@@ -39,7 +38,6 @@ def __init__(
         max_memory_usage_in_bytes: int,
     ) -> None:
         """
-        :param fs_event_service: An unstarted FSEventService instance for setting up filesystem event handlers.
         :param legacy_graph_scheduler: The LegacyGraphScheduler instance for graph construction.
         :param build_root: The current build root.
         :param invalidation_globs: A list of `globs` that when encountered in filesystem event
@@ -51,7 +49,6 @@ def __init__(
                                           shut down if it observes more than this amount in use.
         """
         super().__init__()
-        self._fs_event_service = fs_event_service
         self._graph_helper = legacy_graph_scheduler
         self._build_root = build_root