bug 1849352: add throttler rule for Firefox ESR Windows <= 8.1

This adds a throttler rule to accept only 25% of Firefox, ESR, Windows
<= 8.1 crash reports.

antenna/throttler.py

@@ -11,6 +11,7 @@
 
 import datetime
 import importlib
+import json
 import logging
 import random
 import re
@@ -281,6 +282,40 @@ def match_old_buildid(throttler, data):
     return buildid_date < (now - datetime.timedelta(days=730))
 
 
+WINDOWS_8_1_BUILD_NUMBER = 9600
+
+
+def match_unsupported_windows(throttler, data):
+    """Match Windows versions we don't support."""
+    telemetry_environment = safe_get(data, "TelemetryEnvironment")
+    if not telemetry_environment:
+        return False
+
+    try:
+        telemetry_environment_data = json.loads(telemetry_environment)
+    except (json.decoder.JSONDecodeError, UnicodeDecodeError):
+        return False
+
+    system_data = telemetry_environment_data.get("system")
+    if not system_data or not isinstance(system_data, dict):
+        return False
+
+    os_data = system_data.get("os")
+    if not os_data or not isinstance(os_data, dict):
+        return False
+
+    os_name = os_data.get("name")
+    if not os_name or os_name != "Windows_NT":
+        return False
+
+    windows_build_number = os_data.get("windowsBuildNumber")
+    if not windows_build_number or not isinstance(windows_build_number, int):
+        return False
+
+    # At this point, we should have a windowsBuildNumber with a valid value.
+    return windows_build_number <= WINDOWS_8_1_BUILD_NUMBER
+
+
 #: This accepts crash reports for all products
 ALL_PRODUCTS = []
 
@@ -372,6 +407,19 @@ def match_old_buildid(throttler, data):
         condition=lambda throttler, x: x == "ShutDownKill",
         result=(10, CONTINUE, REJECT),
     ),
+    # Accept 25% crash reports from Firefox ESR Windows <= 8.1
+    Rule(
+        rule_name="is_firefox_esr_unsupported_windows",
+        key="*",
+        condition=(
+            lambda throttler, data: (
+                safe_get(data, "ProductName") == "Firefox"
+                and safe_get(data, "ReleaseChannel") == "esr"
+                and match_unsupported_windows(throttler, data)
+            )
+        ),
+        result=(25, CONTINUE, REJECT),
+    ),
     # Accept crash reports in ReleaseChannel=aurora, beta, esr channels
     Rule(
         rule_name="is_alpha_beta_esr",

tests/unittest/test_throttler.py

@@ -2,6 +2,7 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at https://mozilla.org/MPL/2.0/.
 
+import json
 import logging
 
 from everett.manager import ConfigManager
@@ -16,6 +17,7 @@
     Throttler,
     match_infobar_true,
     match_old_buildid,
+    match_unsupported_windows,
 )
 
 
@@ -91,7 +93,7 @@ def test_ruleset(self):
         )
 
 
-class Testmatch_infobar_true:
+class Test_match_infobar_true:
     @pytest.mark.parametrize(
         "version, expected",
         [
@@ -186,7 +188,57 @@ def test_buildid(self, throttler):
         assert match_infobar_true(throttler, raw_crash) is False
 
 
-class Testmatch_old_buildid:
+class Test_match_unsupported_windows:
+    @pytest.mark.parametrize(
+        "data",
+        [
+            {},
+            {"TelemetryEnvironment": "{}"},
+            {"TelemetryEnvironment": '{"system":{}}'},
+            {"TelemetryEnvironment": '{"system":{"os":{}}}'},
+            {"TelemetryEnvironment": '{"system":{"os":{"name":""}}}'},
+            {"TelemetryEnvironment": '{"system":{"os":{"name":"Windows_NT"}}}'},
+            {
+                "TelemetryEnvironment": '{"system":{"os":{"name":"Windows_NT","windowsBuildNumber":""}}}'
+            },
+            {
+                "TelemetryEnvironment": '{"system":{"os":{"name":"Windows_NT","windowsBuildNumber":null}}}'
+            },
+        ],
+    )
+    def test_missing_data(self, throttler, data):
+        assert match_unsupported_windows(throttler, data) is False
+
+    @pytest.mark.parametrize(
+        "version, expected",
+        [
+            # Windows 7
+            (7601, True),
+            # Windows 8
+            (9200, True),
+            # Windows 8.1
+            (9600, True),
+            # Windows 10
+            (10240, False),
+        ],
+    )
+    def test_windows_versions(self, throttler, version, expected):
+        data = {
+            "TelemetryEnvironment": json.dumps(
+                {
+                    "system": {
+                        "os": {
+                            "name": "Windows_NT",
+                            "windowsBuildNumber": version,
+                        },
+                    },
+                }
+            )
+        }
+        assert match_unsupported_windows(throttler, data) is expected
+
+
+class Test_match_old_buildid:
     def test_no_buildid(self, throttler):
         assert match_old_buildid(throttler, {}) is False
 
@@ -373,6 +425,33 @@ def test_is_shutdownkill(self, throttler, randommock):
             raw_crash = {"ProductName": "Test", "ipc_channel_error": "ShutDownKill"}
             assert throttler.throttle(raw_crash) == (ACCEPT, "accept_everything", 100)
 
+    def test_is_firefox_esr_unsupported_windows(self, throttler, randommock):
+        tel_env = json.dumps(
+            {
+                "system": {
+                    "os": {
+                        "name": "Windows_NT",
+                        "windowsBuildNumber": 9600,
+                    },
+                },
+            }
+        )
+        raw_crash = {
+            "ProductName": "Firefox",
+            "ReleaseChannel": "esr",
+            "TelemetryEnvironment": tel_env,
+        }
+        with randommock(0.30):
+            assert throttler.throttle(raw_crash) == (
+                REJECT,
+                "is_firefox_esr_unsupported_windows",
+                25,
+            )
+
+        # If it returns CONTINUE, then it will trigger another rule
+        with randommock(0.20):
+            assert throttler.throttle(raw_crash) == (ACCEPT, "is_alpha_beta_esr", 100)
+
     @pytest.mark.parametrize("channel", ["aurora", "beta", "esr"])
     def test_is_alpha_beta_esr(self, throttler, channel):
         raw_crash = {"ProductName": "Test", "ReleaseChannel": channel}