pw_watch: Remove deps to enable running watch in other environments

- Remove pw_build dependency from the pw_watch library. pw_build
  transitively depends on pigweed.json, which means pw_watch cannot run
  unless projects have a pigweed.json integrated into their build.
  Remove pw_build and other deps from core pw_watch functionality.
- Move UI code into pw_watch/run.py to simplify things and remove a
  dependency on pw_presubmit, which transitively depends on pw_build.

Change-Id: Ie4a2728fac546500905973bd496d47c9fad1729c
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/259693
Docs-Not-Needed: Wyatt Hepler <[email protected]>
Presubmit-Verified: CQ Bot Account <[email protected]>
Commit-Queue: Auto-Submit <[email protected]>
Reviewed-by: Dave Roth <[email protected]>
Pigweed-Auto-Submit: Wyatt Hepler <[email protected]>
Lint: Lint 🤖 <[email protected]>

pw_presubmit/py/pw_presubmit/presubmit.py

@@ -96,7 +96,7 @@ def run_the_build():
 
 _LEFT = 7
 _RIGHT = 11
-BOX_CENTER_WIDTH = WIDTH - _LEFT - _RIGHT - 4
+_CENTER = WIDTH - _LEFT - _RIGHT - 4
 
 
 def _title(msg, style=_SUMMARY_BOX) -> str:
@@ -120,7 +120,7 @@ def _box(
         section1=left + ('' if left.endswith(' ') else ' '),
         width1=_LEFT,
         section2=' ' + middle,
-        width2=BOX_CENTER_WIDTH,
+        width2=_CENTER,
         section3=right + ' ',
         width3=_RIGHT,
     )
@@ -147,12 +147,14 @@ def color(value):
         return padding + color(self.value) + padding
 
 
-def step_header(left: str, middle: str, right: str) -> str:
-    return _box(_CHECK_UPPER, left, middle, right)
+def _step_header(count: int, total: int, name: str, num_paths: int) -> str:
+    return _box(
+        _CHECK_UPPER, f'{count}/{total}', name, plural(num_paths, "file")
+    )
 
 
-def step_footer(left: str, middle: str, right: str) -> str:
-    return _box(_CHECK_LOWER, left, middle, right)
+def _step_footer(result: PresubmitResult, name: str, timestamp: str) -> str:
+    return _box(_CHECK_LOWER, result.colorized(_LEFT), name, timestamp)
 
 
 class Program(collections.abc.Sequence):
@@ -921,13 +923,7 @@ def run(
     ) -> PresubmitResult:
         """Runs the presubmit check on the provided paths."""
 
-        _print_ui(
-            step_header(
-                f'{count}/{total}',
-                self.name,
-                plural(ctx.paths, "file"),
-            )
-        )
+        _print_ui(_step_header(count, total, self.name, len(ctx.paths)))
 
         substep_part = f'.{substep}' if substep else ''
         _LOG.debug(
@@ -951,7 +947,7 @@ def run(
         if ctx.dry_run:
             log_check_traces(ctx)
 
-        _print_ui(step_footer(result.colorized(_LEFT), self.name, time_str))
+        _print_ui(_step_footer(result, self.name, time_str))
         _LOG.debug('%s duration:%s', self.name, time_str)
 
         return result

pw_watch/py/BUILD.bazel

@@ -27,24 +27,27 @@ py_library(
         "pw_watch/common.py",
         "pw_watch/debounce.py",
         "pw_watch/run.py",
-        "pw_watch/watch.py",
-        "pw_watch/watch_app.py",
     ],
     imports = ["."],
     deps = [
-        "//pw_build/py:pw_project_builder",
         "//pw_cli/py:pw_cli",
-        "//pw_config_loader/py:pw_config_loader",
-        "//pw_console/py:pw_console",
-        "@python_packages//prompt_toolkit",
         "@python_packages//watchdog",
     ],
 )
 
 pw_py_binary(
     name = "watch",
-    srcs = ["pw_watch/watch.py"],
-    deps = [":pw_watch"],
+    srcs = [
+        "pw_watch/watch.py",
+        "pw_watch/watch_app.py",
+    ],
+    deps = [
+        ":pw_watch",
+        "//pw_build/py:pw_project_builder",
+        "//pw_config_loader/py:pw_config_loader",
+        "//pw_console/py:pw_console",
+        "@python_packages//prompt_toolkit",
+    ],
 )
 
 pw_py_binary(

pw_watch/py/pw_watch/debounce.py

@@ -16,12 +16,9 @@
 import enum
 import logging
 import threading
+from typing import Any, Callable
 from abc import ABC, abstractmethod
 
-from pw_build.project_builder_context import get_project_builder_context
-
-BUILDER_CONTEXT = get_project_builder_context()
-
 _LOG = logging.getLogger('pw_build.watch')
 
 
@@ -60,12 +57,25 @@ class State(enum.Enum):
     RERUN = 6  # ------- Transistions to: IDLE (but triggers a press)
 
 
+def _flush_and_log(event_description: str) -> None:
+    # Surround the error message with newlines to make it stand out.
+    print('\n', flush=True)
+    _LOG.warning('Event while running: %s', event_description)
+    print('', flush=True)
+
+
 class Debouncer:
     """Run an interruptable, cancellable function with debouncing"""
 
-    def __init__(self, function: DebouncedFunction) -> None:
+    def __init__(
+        self,
+        function: DebouncedFunction,
+        *,
+        log_event: Callable[[str], Any] = _flush_and_log,
+    ) -> None:
         super().__init__()
         self.function = function
+        self._log_event = log_event
 
         self.state = State.IDLE
 
@@ -101,17 +111,7 @@ def _press_unlocked(self, event_description: str) -> None:
             # When the function is already running but we get an incoming
             # event, go into the INTERRUPTED state to signal that we should
             # re-try running afterwards.
-            error_message = ['Event while running: %s', event_description]
-            if BUILDER_CONTEXT.using_progress_bars():
-                _LOG.warning(*error_message)
-            else:
-                # Push an empty line to flush ongoing I/O in subprocess.
-                print('')
-
-                # Surround the error message with newlines to make it stand out.
-                print('')
-                _LOG.warning(*error_message)
-                print('')
+            self._log_event(event_description)
 
             self.function.cancel()
             self._transition(State.INTERRUPTED)

pw_watch/py/pw_watch/run.py

@@ -28,7 +28,7 @@
 
 .. code-block:: sh
 
-   # Run a `cowsay`, then `cowthink`, when files change.
+   # Run `cowsay` then `cowthink` when watched files change.
    run.py cowsay "Hey, how are you?" , cowthink Not in moood to talk
 
 The Bazel build's ``//pw_watch/py:bazel`` watch entrypoint invokes
@@ -53,14 +53,25 @@
 import pw_cli.env
 import pw_cli.log
 from pw_cli.plural import plural
-from pw_presubmit import presubmit
 
 from pw_watch import common
 from pw_watch.debounce import DebouncedFunction, Debouncer
 
 _LOG = logging.getLogger('pw_watch')
 _COLOR = pw_cli.color.colors()
 
+_WIDTH = 80
+_STEP_START = '━' * (_WIDTH - 1) + '┓'
+_STEP_FINISH = '━' * (_WIDTH - 1) + '┛'
+
+
+def _format_time(time_s: float) -> str:
+    minutes, seconds = divmod(time_s, 60)
+    if minutes < 60:
+        return f' {int(minutes)}:{seconds:04.1f}'
+    hours, minutes = divmod(minutes, 60)
+    return f'{int(hours):d}:{int(minutes):02}:{int(seconds):02}'
+
 
 class Watcher(FileSystemEventHandler, DebouncedFunction):
     """Process filesystem events and run commands on changes."""
@@ -114,9 +125,9 @@ def run(self) -> None:
         print('\033c', end='', flush=True)  # clear the screen
 
         for i, command in enumerate(self.commands, 1):
-            count = f'{i}/{len(self.commands)}'
+            count = f' {i}/{len(self.commands)}   '
             print(
-                presubmit.step_header(count, shlex.join(command), ''),
+                f'{_STEP_START}\n{count}{shlex.join(command)}\n',
                 flush=True,
             )
             start = time.time()
@@ -125,19 +136,17 @@ def run(self) -> None:
 
             if code == 0:
                 result = _COLOR.bold_green('PASSED')
+                msg = ''
             else:
-                result = f'{_COLOR.bold_red("FAILED")} with exit code {code}'
+                result = _COLOR.bold_red('FAILED')
+                msg = f' with exit code {code}'
 
+            remaining_width = _WIDTH - len(count) - 6 - len(msg) - 2
+            timestamp = _format_time(total_time).rjust(remaining_width)
             print(
-                presubmit.step_footer(
-                    count,
-                    # Pad the result to account for the ANSI escape codes.
-                    result.ljust(presubmit.BOX_CENTER_WIDTH + 13),
-                    presubmit.format_time(total_time),
-                ),
+                f'\n{count}{result}{msg}{timestamp}\n{_STEP_FINISH}\n',
                 flush=True,
             )
-            print(flush=True)
 
             if code and not self.keep_going and i < len(self.commands):
                 _LOG.info(

pw_watch/py/pw_watch/watch.py

@@ -89,6 +89,15 @@
 BUILDER_CONTEXT = get_project_builder_context()
 
 
+def _log_event(event_description: str) -> None:
+    if BUILDER_CONTEXT.using_progress_bars():
+        _LOG.warning('Event while running: %s', event_description)
+    else:
+        print('\n')
+        _LOG.warning('Event while running: %s', event_description)
+        print('')
+
+
 class PigweedBuildWatcher(FileSystemEventHandler, DebouncedFunction):
     """Process filesystem events and launch builds if necessary."""
 
@@ -125,7 +134,7 @@ def __init__(  # pylint: disable=too-many-arguments
         if self.parallel_workers > 1:
             self.separate_logfiles = True
 
-        self.debouncer = Debouncer(self)
+        self.debouncer = Debouncer(self, log_event=_log_event)
 
         # Track state of a build. These need to be members instead of locals
         # due to the split between dispatch(), run(), and on_complete().