1 files changed, 47 insertions, 0 deletions
diff --git a/taskcluster/gecko_taskgraph/optimize/backstop.py b/taskcluster/gecko_taskgraph/optimize/backstop.py
new file mode 100644
index 0000000000..7b0c86222b
--- /dev/null
+++ b/taskcluster/gecko_taskgraph/optimize/backstop.py
@@ -0,0 +1,47 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+from taskgraph.optimize.base import All, OptimizationStrategy, register_strategy
+
+from gecko_taskgraph.util.backstop import BACKSTOP_PUSH_INTERVAL
+
+
+@register_strategy("skip-unless-backstop")
+class SkipUnlessBackstop(OptimizationStrategy):
+    """Always removes tasks except on backstop pushes."""
+
+    def should_remove_task(self, task, params, _):
+        return not params["backstop"]
+
+
+class SkipUnlessPushInterval(OptimizationStrategy):
+    """Always removes tasks except every N pushes.
+
+    Args:
+        push_interval (int): Number of pushes
+    """
+
+    def __init__(self, push_interval, remove_on_projects=None):
+        self.push_interval = push_interval
+
+    @property
+    def description(self):
+        return f"skip-unless-push-interval-{self.push_interval}"
+
+    def should_remove_task(self, task, params, _):
+        # On every Nth push, want to run all tasks.
+        return int(params["pushlog_id"]) % self.push_interval != 0
+
+
+# Strategy to run tasks on "expanded" pushes, currently defined as pushes that
+# are half the backstop interval. The 'All' composite strategy means that the
+# "backstop" strategy will prevent "expanded" from applying on backstop pushes.
+register_strategy(
+    "skip-unless-expanded",
+    args=(
+        "skip-unless-backstop",
+        SkipUnlessPushInterval(BACKSTOP_PUSH_INTERVAL / 2),
+    ),
+)(All)