v0.34.0_p1

scripts/tests/cache_age_policy_034_model.py

@@ -0,0 +1,62 @@
+#!/usr/bin/env python3
+"""Deterministic oracle for HTTP Age / local freshness-cap algebra.
+No binary execution, no claim of measured throughput. Run with Python 3 only.
+"""
+import json
+import random
+from pathlib import Path
+
+
+def old_freshness(max_age, header_age, apparent_age, response_delay, local_limit):
+    age = max(header_age, apparent_age) + response_delay
+    return max(0, min(max_age, local_limit) - age)
+
+
+def new_freshness(max_age, header_age, apparent_age, response_delay, local_limit):
+    # RFC 9111 corrected_initial_age = max(apparent_age, age_value + response_delay)
+    age = max(apparent_age, header_age + response_delay)
+    lifetime = min(max_age, age + local_limit)
+    return max(0, lifetime - age)
+
+
+def run():
+    cases = [
+        ('user_cdn_example', 2_592_000, 1_553_483, 0, 0, 86_400),
+        ('user_cdn_example_7d', 2_592_000, 1_553_483, 0, 0, 604_800),
+        ('origin_nearly_stale', 2_592_000, 2_591_990, 0, 0, 86_400),
+        ('origin_stale', 2_592_000, 2_592_010, 0, 0, 86_400),
+        ('normal_small', 3_600, 0, 0, 0, 86_400),
+        ('date_is_older', 3_600, 10, 600, 2, 86_400),
+        ('rfc_delay_case', 3_600, 3, 10, 2, 86_400),
+    ]
+    report = {'reference': 'RFC 9111 4.2.3 (Age) and 4.2.1 (freshness lifetime)',
+              'kind': 'algebra simulation; not RustProxy RPS benchmark',
+              'scenarios': [], 'randomized_checks': 0, 'false_miss_cases_old': 0}
+    for name, max_age, age, apparent, delay, local in cases:
+        old = old_freshness(max_age, age, apparent, delay, local)
+        new = new_freshness(max_age, age, apparent, delay, local)
+        report['scenarios'].append({'scenario': name, 'origin_max_age_seconds': max_age,
+                                    'received_age_seconds': age, 'apparent_age_seconds': apparent,
+                                    'response_delay_seconds': delay, 'local_max_ttl_seconds': local,
+                                    'old_freshness_seconds': old, 'new_freshness_seconds': new})
+    rng = random.Random(0x3400)
+    for _ in range(100_000):
+        origin = rng.randrange(0, 1 << 24)
+        header_age = rng.randrange(0, 1 << 24)
+        apparent = rng.randrange(0, 1 << 24)
+        delay = rng.randrange(0, 300)
+        local = rng.randrange(0, 604_801)
+        corrected_age = max(apparent, header_age + delay)
+        new = new_freshness(origin, header_age, apparent, delay, local)
+        expected = min(max(0, origin - corrected_age), local)
+        assert new == expected, (origin, header_age, apparent, delay, local, new, expected)
+        assert new <= local and new <= max(0, origin - corrected_age)
+        old = old_freshness(origin, header_age, apparent, delay, local)
+        report['false_miss_cases_old'] += old == 0 < new
+        report['randomized_checks'] += 1
+    return report
+
+
+if __name__ == '__main__':
+    report = run()
+    print(json.dumps(report, ensure_ascii=False, indent=2))