feat(caches): support opting into or out of specific name caches

Bug: 1526028

Author: ahal

src/taskgraph/transforms/run/common.py

@@ -9,6 +9,7 @@
 
 import hashlib
 import json
+import re
 
 from taskgraph.util.taskcluster import get_artifact_prefix
 
@@ -31,7 +32,11 @@ def add_cache(task, taskdesc, name, mount_point, skip_untrusted=False):
         skip_untrusted (bool): Whether cache is used in untrusted environments
             (default: False). Only applies to docker-worker.
     """
-    if not task["run"].get("use-caches", True):
+    use_caches = task["run"].get("use-caches", True)
+    if isinstance(use_caches, list):
+        use_caches = any(re.match(pattern, name) for pattern in use_caches)
+
+    if not use_caches:
         return
 
     worker = task["worker"]

src/taskgraph/transforms/run/run_task.py

@@ -28,8 +28,10 @@
         # tend to hide their caches.  This cache is never added for level-1 tasks.
         # TODO Once bug 1526028 is fixed, this and 'use-caches' should be merged.
         Required("cache-dotcache"): bool,
-        # Whether or not to use caches.
-        Optional("use-caches"): bool,
+        # Whether or not to use caches. If a boolean, all caches will be
+        # enabled or disabled. If a list, entries are regexes. Only cache names
+        # that match one of the listed regexes are enabled.
+        Optional("use-caches"): Any(bool, [str]),
         # if true (the default), perform a checkout on the worker
         Required("checkout"): Any(bool, {str: dict}),
         Optional(

test/test_transforms_run.py

@@ -109,6 +109,18 @@ def test_caches_generic_worker(run_caches):
     ]
 
 
+def test_caches_regex(run_caches):
+    task = {
+        "run": {
+            "use-caches": ["cache[^1]"],
+        },
+        "worker-type": "t-win",
+    }
+    caches = run_caches(task)
+    assert len(caches) == 1
+    assert caches[0]["cache-name"] == "cache2"
+
+
 @pytest.mark.parametrize("worker_type", ("t-linux", "t-win"))
 def test_caches_disabled(run_caches, worker_type):
     assert (