Examples of using that keystroke reader thing.

examples/stopwatch/stopwatch.py

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+#!/usr/bin/env python3
+
+"""
+A (unix terminal)  stopwatch utility.
+"""
+
+import logging
+import sys
+import time
+
+from pyutils import bootstrap, config, input_utils
+
+logger = logging.getLogger(__name__)
+args = config.add_commandline_args(f'({__file__})', f'Args related to {__file__}')
+args.add_argument("--start", action="store_true", help="Start as soon as possible.")
+
+
+class Stopwatch:
+    def __init__(self):
+        self.running = False
+        self.start_time = 0.0
+        self.elapsed_time = 0.0
+
+    def start(self):
+        if not self.running:
+            self.start_time = time.time()
+            self.running = True
+
+    def pause(self):
+        if self.running:
+            self.elapsed_time += time.time() - self.start_time
+            self.running = False
+
+    def reset(self):
+        self.running = False
+        self.start_time = 0
+        self.elapsed_time = 0
+
+    def get_elapsed_time(self) -> float:
+        if self.running:
+            return self.elapsed_time + time.time() - self.start_time
+        else:
+            return self.elapsed_time
+
+
+@bootstrap.initialize
+def main():
+    print("Stopwatch...  [space]=stop/start, [l]ap, [r]eset, [q]uit (or ^C)")
+    stopwatch = Stopwatch()
+    if config.config["start"]:
+        stopwatch.start()
+
+    with input_utils.KeystrokeReader() as get_keystroke:
+        while True:
+            # Check / parse any keys.
+            key = get_keystroke(timeout_seconds=0.01)
+            if key:
+                if key == ' ':
+                    if not stopwatch.running:
+                        stopwatch.start()
+                    else:
+                        stopwatch.pause()
+                elif key == 'r':
+                    print(" " * 50, end='\r')
+                    stopwatch.reset()
+                elif key == 'l':
+                    print(f"Lap: {stopwatch.get_elapsed_time():.5f}", end="\r\n")
+                elif key == 'q' or key == chr(3):
+                    print()
+                    return
+
+            # Update display.
+            print(f"Elapsed time: {stopwatch.get_elapsed_time():0.4f}", end="\r")
+            sys.stdout.flush()
+    return None
+
+
+if __name__ == "__main__":
+    main()

examples/timer/timer.py

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+#!/usr/bin/env python3
+
+"""
+A (unix terminal) countdown timer utility.
+"""
+
+import logging
+import sys
+import time
+from typing import Optional
+
+from pyutils import argparse_utils, bootstrap, config, input_utils
+
+logger = logging.getLogger(__name__)
+args = config.add_commandline_args(f'({__file__})', f'Args related to {__file__}')
+args.add_argument(
+    "time_limit",
+    type=argparse_utils.valid_duration,
+    help="The time limit of the countdown timer.",
+)
+args.add_argument(
+    "--infinite",
+    action="store_true",
+    help="After the timer expires, reset and start again forever.",
+)
+args.add_argument(
+    "--pause_between",
+    action="store_true",
+    help="Should we pause between adjacent timer runs.",
+)
+
+
+class Timer:
+    def __init__(self, duration: float):
+        self.running = True
+        self.start = time.time()
+        self.original_duration = duration
+        self.duration = duration
+        self.run_number = 1
+        self.elapsed_before_pause = 0.0
+
+    def get_remaining_time(self) -> float:
+        return self.original_duration - self.get_elapsed_time()
+
+    def get_elapsed_time(self) -> float:
+        if self.running:
+            now = time.time()
+            return now - self.start + self.elapsed_before_pause
+        else:
+            return self.elapsed_before_pause
+
+    def is_expired(self):
+        elapsed = self.get_elapsed_time()
+        return elapsed >= self.original_duration
+
+    def reset(self):
+        self.run_number += 1
+        self.start = time.time()
+        self.duration = self.original_duration
+        self.elapsed_before_pause = 0
+        self.running = True
+
+    def reset_and_pause(self):
+        self.run_number += 1
+        self.start = time.time()
+        self.duration = self.original_duration
+        self.elapsed_before_pause = 0
+        self.running = False
+
+    def pause(self):
+        self.elapsed_before_pause = self.get_elapsed_time()
+        self.running = False
+
+    def unpause(self):
+        self.start = time.time()
+        self.duration = self.original_duration - self.elapsed_before_pause
+        self.running = True
+
+
+@bootstrap.initialize
+def main() -> Optional[int]:
+    duration = config.config["time_limit"]
+    timer = Timer(duration.seconds)
+    print("Countdown timer... [space]=pause/unpause, [r]eset, [q]uit (or ^C).")
+
+    with input_utils.KeystrokeReader() as get_keystroke:
+        while True:
+
+            # Check for input / parse any.
+            key = get_keystroke(timeout_seconds=0.01)
+            if key:
+                if key == ' ':
+                    if timer.running:
+                        timer.pause()
+                    else:
+                        timer.unpause()
+                elif key == 'r':
+                    print(end="\r\n")
+                    timer.reset()
+                elif key == 'q' or key == chr(3):
+                    sys.exit(0)
+
+            # Display remaining countdown.
+            remaining = timer.get_remaining_time()
+            print(f"{remaining:0.2f}  ", end='\r')
+
+            # Done?
+            if timer.is_expired():
+                if not config.config["infinite"]:
+                    print("Beep, beep, beep!", end="\r\n")
+                    sys.exit(0)
+
+                print(
+                    f"Run number {timer.run_number} expired... Beep, beep, beep!",
+                    end="\r\n",
+                )
+                if config.config["pause_between"]:
+                    timer.reset_and_pause()
+                else:
+                    timer.reset()
+    return None
+
+
+if __name__ == '__main__':
+    main()