test(build): expire old cache files before building

should not be kept indefinitely, since sources may've been changed already
ci cache dir is expected to only survive for the current build session,
prefer similar behaviour for local build tests

Author: mcspr

code/scripts/test_build.py

@@ -38,6 +38,14 @@
 CACHE_PATH = TEST_PATH / "cache"
 BUILD_PATH = ROOT_PATH / ".pio" / "build"
 
+CACHE_TIMEDELTA = datetime.timedelta(days=1)
+TIMEDELTA_PARAM = {
+    "d": "days",
+    "h": "hours",
+    "m": "minutes",
+    "s": "seconds",
+}
+
 
 def bold(string: str):
     return clr(Color.BOLD, string)
@@ -54,7 +62,46 @@ def pluralize(string: str, length: int):
     return string
 
 
+def make_timedelta(string: str) -> datetime.timedelta:
+    if not string:
+        return datetime.timedelta(seconds=0)
+
+    if string.isdigit():
+        suffix = "d"
+    else:
+        suffix = string[-1]
+        string = string[:-1]
+
+    param = TIMEDELTA_PARAM[suffix]
+    value = int(string, 10)
+
+    return datetime.timedelta(**{param: value})
+
+
+def cache_cleanup(cache_path: pathlib.Path, offset: datetime.timedelta):
+    now = datetime.datetime.now()
+
+    for pair in cache_path.iterdir():
+        # {CACHE_DIR} / AA / AA...rest of the hash...
+        if not pair.is_dir():
+            continue
+
+        for f in pair.iterdir():
+            mtime_raw = f.stat().st_mtime
+            mtime_dt = datetime.datetime.fromtimestamp(mtime_raw)
+
+            if now - mtime_dt > offset:
+                f.unlink()
+
+        if not any(pair.iterdir()):
+            pair.rmdir()
+
+
 def build_configurations(args: argparse.Namespace, configurations: list[pathlib.Path]):
+    cache_path = args.cache_path.resolve()
+
+    cache_cleanup(cache_path, args.expire_cache)
+
     cmd = ["platformio", "run"]
     if args.silent:
         cmd.extend(["-s"])
@@ -67,7 +114,7 @@ def build_configurations(args: argparse.Namespace, configurations: list[pathlib.
         log.info("%s contents\n%s", bold(cfg.name), cfg.read_text())
 
         os_env = os.environ.copy()
-        os_env["PLATFORMIO_BUILD_CACHE_DIR"] = args.cache_path.resolve().as_posix()
+        os_env["PLATFORMIO_BUILD_CACHE_DIR"] = cache_path.resolve().as_posix()
         if args.single_source:
             os_env["ESPURNA_BUILD_SINGLE_SOURCE"] = "1"
 
@@ -99,7 +146,10 @@ def build_configurations(args: argparse.Namespace, configurations: list[pathlib.
 
         log.info(
             "%s finished in %s, %s is %s bytes",
-            *(bold(str(x)) for x in (cfg, diff, firmware_bin, firmware_bin.stat().st_size)),
+            *(
+                bold(str(x))
+                for x in (cfg, diff, firmware_bin, firmware_bin.stat().st_size)
+            ),
         )
 
         build_time += diff
@@ -211,6 +261,13 @@ def main(args: argparse.Namespace):
         help="PlatformIO build path",
     )
 
+    parser.add_argument(
+        "--expire-cache",
+        default=CACHE_TIMEDELTA,
+        type=make_timedelta,
+        help="PlatformIO cache expiration time (NUMBER or NUMBER{d,h,m,s} for days, hours, minutes or seconds respectively)}",
+    )
+
     parser.add_argument(
         "configurations",
         nargs="*",