From e7a23602da63627f8b30e094bc41469c301891dd Mon Sep 17 00:00:00 2001
From: Tor Brede Vekterli <vekterli@vespa.ai>
Date: Mon, 4 Dec 2023 13:46:05 +0100
Subject: Use fake ZooKeeper database implementation for subset of CC tests

The fake impl acts "as if" a single-node ZK quorum is present, so it
cannot be directly used with most multi-node tests that require
multiple nodes to actually participate in leader elections.
---
 .../core/FakeZooKeeperDatabase.java                | 136 +++++++++++++++++++++
 1 file changed, 136 insertions(+)
 create mode 100644 clustercontroller-core/src/test/java/com/yahoo/vespa/clustercontroller/core/FakeZooKeeperDatabase.java

(limited to 'clustercontroller-core/src/test/java/com/yahoo/vespa/clustercontroller/core/FakeZooKeeperDatabase.java')

diff --git a/clustercontroller-core/src/test/java/com/yahoo/vespa/clustercontroller/core/FakeZooKeeperDatabase.java b/clustercontroller-core/src/test/java/com/yahoo/vespa/clustercontroller/core/FakeZooKeeperDatabase.java
new file mode 100644
index 00000000000..057d137650f
--- /dev/null
+++ b/clustercontroller-core/src/test/java/com/yahoo/vespa/clustercontroller/core/FakeZooKeeperDatabase.java
@@ -0,0 +1,136 @@
+// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.clustercontroller.core;
+
+import com.yahoo.vdslib.state.Node;
+import com.yahoo.vdslib.state.NodeState;
+import com.yahoo.vespa.clustercontroller.core.database.Database;
+import com.yahoo.vespa.clustercontroller.core.database.DatabaseFactory;
+
+import java.util.Map;
+import java.util.TreeMap;
+
+/**
+ * Memory-backed fake DB implementation that tries to mirror the semantics of the
+ * (synchronous) ZooKeeper DB implementation. By itself this fake acts as if a quorum
+ * with a _single_, local ZK instance has been configured. This DB instance cannot be
+ * used across multiple cluster controller instances.
+ *
+ * Threading note: we expect all invocations on this instance to happen from the
+ * main cluster controller thread (i.e. "as-if" single threaded), but we wrap everything
+ * in a mutex to stay on the safe side since this isn't explicitly documented as
+ * part of the API,
+ */
+public class FakeZooKeeperDatabase extends Database {
+
+    public static class Factory implements DatabaseFactory {
+        private final FleetControllerContext context;
+        public Factory(FleetControllerContext context) {
+            this.context = context;
+        }
+        @Override
+        public Database create(Params params) {
+            return new FakeZooKeeperDatabase(context, params.listener);
+        }
+    }
+
+    private final FleetControllerContext context;
+    private final Database.DatabaseListener listener;
+
+    private final Object mutex = new Object();
+    private boolean closed = false;
+    private Integer persistedLatestStateVersion = null;
+    private Map<Integer, Integer> persistedLeaderVotes = new TreeMap<>();
+    private Map<Node, NodeState> persistedWantedStates = new TreeMap<>();
+    private Map<Node, Long> persistedStartTimestamps = new TreeMap<>();
+    private ClusterStateBundle persistedBundle = ClusterStateBundle.ofBaselineOnly(AnnotatedClusterState.emptyState());
+
+    public FakeZooKeeperDatabase(FleetControllerContext context, DatabaseListener listener) {
+        this.context = context;
+        this.listener = listener;
+    }
+
+    @Override
+    public void close() {
+        synchronized (mutex) {
+            closed = true;
+        }
+    }
+
+    @Override
+    public boolean isClosed() {
+        synchronized (mutex) {
+            return closed;
+        }
+    }
+
+    @Override
+    public boolean storeMasterVote(int voteForNode) {
+        Map<Integer, Integer> voteState;
+        synchronized (mutex) {
+            persistedLeaderVotes.put(context.id().index(), voteForNode);
+            voteState = Map.copyOf(persistedLeaderVotes);
+        }
+        listener.handleMasterData(voteState);
+        return true;
+    }
+
+    @Override
+    public boolean storeLatestSystemStateVersion(int version) {
+        synchronized (mutex) {
+            persistedLatestStateVersion = version;
+            return true;
+        }
+    }
+
+    @Override
+    public Integer retrieveLatestSystemStateVersion() {
+        synchronized (mutex) {
+            return persistedLatestStateVersion;
+        }
+    }
+
+    @Override
+    public boolean storeWantedStates(Map<Node, NodeState> states) {
+        synchronized (mutex) {
+            persistedWantedStates = Map.copyOf(states);
+        }
+        return true;
+    }
+
+    @Override
+    public Map<Node, NodeState> retrieveWantedStates() {
+        synchronized (mutex) {
+            return Map.copyOf(persistedWantedStates);
+        }
+    }
+
+    @Override
+    public boolean storeStartTimestamps(Map<Node, Long> timestamps) {
+        synchronized (mutex) {
+            persistedStartTimestamps = Map.copyOf(timestamps);
+            return true;
+        }
+    }
+
+    @Override
+    public Map<Node, Long> retrieveStartTimestamps() {
+        synchronized (mutex) {
+            return Map.copyOf(persistedStartTimestamps);
+        }
+    }
+
+    @Override
+    public boolean storeLastPublishedStateBundle(ClusterStateBundle stateBundle) {
+        synchronized (mutex) {
+            persistedBundle = stateBundle;
+            return true;
+        }
+    }
+
+    @Override
+    public ClusterStateBundle retrieveLastPublishedStateBundle() {
+        synchronized (mutex) {
+            return persistedBundle;
+        }
+    }
+}
-- 
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