Use wall-time for credential helper invalidation

Previously we were using time intervals which excluded time spent with the system sleeping, which is not appropriate for expiring tokens which expire based on wall-time duration.

Closes #18301.

PiperOrigin-RevId: 529340767
Change-Id: I15e74e7bc87284f8ba53aedace955b29bd52df8e

Author: illicitonion

src/main/java/com/google/devtools/build/lib/authandtls/credentialhelper/BUILD

@@ -13,7 +13,10 @@ filegroup(
 
 java_library(
     name = "credential_module",
-    srcs = ["CredentialModule.java"],
+    srcs = [
+        "CredentialModule.java",
+        "SystemMillisTicker.java",
+    ],
     deps = [
         "//src/main/java/com/google/devtools/build/lib:runtime",
         "//src/main/java/com/google/devtools/build/lib/authandtls",
@@ -26,7 +29,10 @@ java_library(
     name = "credentialhelper",
     srcs = glob(
         ["*.java"],
-        exclude = ["CredentialModule.java"],
+        exclude = [
+            "CredentialModule.java",
+            "SystemMillisTicker.java",
+        ],
     ),
     deps = [
         "//src/main/java/com/google/devtools/build/lib/events",

src/main/java/com/google/devtools/build/lib/authandtls/credentialhelper/CredentialModule.java

@@ -27,7 +27,10 @@
 /** A module whose sole purpose is to hold the credential cache which is shared by other modules. */
 public class CredentialModule extends BlazeModule {
   private final Cache<URI, ImmutableMap<String, ImmutableList<String>>> credentialCache =
-      Caffeine.newBuilder().expireAfterWrite(Duration.ZERO).build();
+      Caffeine.newBuilder()
+          .expireAfterWrite(Duration.ZERO)
+          .ticker(SystemMillisTicker.INSTANCE)
+          .build();
 
   /** Returns the credential cache. */
   public Cache<URI, ImmutableMap<String, ImmutableList<String>>> getCredentialCache() {

src/main/java/com/google/devtools/build/lib/authandtls/credentialhelper/SystemMillisTicker.java

@@ -0,0 +1,35 @@
+// Copyright 2023 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.devtools.build.lib.authandtls.credentialhelper;
+
+import com.github.benmanes.caffeine.cache.Ticker;
+
+/**
+ * SystemMillisTicker is a Ticker which uses the unix epoch as its fixed reference point.
+ *
+ * <p>It is preferable to com.github.benmanes.caffeine.cache.Ticker.SystemTicker because that class
+ * doesn't increment its time-source while the system is asleep, which isn't appropriate when
+ * expiring tokens which have wall-time-based expiry policies.
+ */
+public class SystemMillisTicker implements Ticker {
+  public static final SystemMillisTicker INSTANCE = new SystemMillisTicker();
+
+  private SystemMillisTicker() {}
+
+  @Override
+  public long read() {
+    return System.currentTimeMillis() * 1_000_000;
+  }
+}