Store scaling events in ZooKeeper

4 files changed, 74 insertions, 0 deletions

diff --git a/config-provisioning/src/main/java/com/yahoo/config/provision/ActivationContext.java b/config-provisioning/src/main/java/com/yahoo/config/provision/ActivationContext.java
new file mode 100644
index 00000000000..6cc7ec4c5bc
--- /dev/null
+++ b/config-provisioning/src/main/java/com/yahoo/config/provision/ActivationContext.java
@@ -0,0 +1,20 @@
+// Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.config.provision;
+
+/**
+ * The context passed to the node repo when activating a node.
+ *
+ * @author bratseth
+ */
+public class ActivationContext {
+
+    private final long generation;
+
+    public ActivationContext(long generation) {
+        this.generation = generation;
+    }
+
+    /** Returns the application config generation we are activating */
+    public long generation() { return generation; }
+
+}
diff --git a/config-provisioning/src/main/java/com/yahoo/config/provision/ApplicationTransaction.java b/config-provisioning/src/main/java/com/yahoo/config/provision/ApplicationTransaction.java
new file mode 100644
index 00000000000..d21f7cfe5ae
--- /dev/null
+++ b/config-provisioning/src/main/java/com/yahoo/config/provision/ApplicationTransaction.java
@@ -0,0 +1,44 @@
+// Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.config.provision;
+
+import com.yahoo.transaction.Mutex;
+import com.yahoo.transaction.NestedTransaction;
+
+import java.io.Closeable;
+import java.util.Objects;
+
+/**
+ * A transaction which exists while holding the application provision lock.
+ *
+ * @author bratseth
+ */
+public class ApplicationTransaction implements Closeable {
+
+    private final ProvisionLock lock;
+    private final NestedTransaction transaction;
+
+    public ApplicationTransaction(ProvisionLock lock, NestedTransaction transaction) {
+        this.lock = Objects.requireNonNull(lock);
+        this.transaction = Objects.requireNonNull(transaction);
+    }
+
+    public ApplicationId application() { return lock.application(); }
+
+    /** Returns the lock held by this */
+    // Usage of this might indicate we are writing changes directly (outside of the transaction) and should probably be avoided
+    public ProvisionLock lock() { return lock; }
+
+    /** Returns the NestedTransaction of this */
+    public NestedTransaction nested() { return transaction; }
+
+    @Override
+    public void close() {
+        try {
+            transaction.commit();
+        }
+        finally {
+            lock.close();
+        }
+    }
+
+}
diff --git a/config-provisioning/src/main/java/com/yahoo/config/provision/ClusterResources.java b/config-provisioning/src/main/java/com/yahoo/config/provision/ClusterResources.java
index 9aaf0d365cd..f1c86485a64 100644
--- a/config-provisioning/src/main/java/com/yahoo/config/provision/ClusterResources.java
+++ b/config-provisioning/src/main/java/com/yahoo/config/provision/ClusterResources.java
@@ -1,6 +1,7 @@
 // Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.config.provision;
 
+import java.util.List;
 import java.util.Objects;
 
 /**
diff --git a/config-provisioning/src/main/java/com/yahoo/config/provision/Provisioner.java b/config-provisioning/src/main/java/com/yahoo/config/provision/Provisioner.java
index 1eb2c1e61b2..9e75e9278e8 100644
--- a/config-provisioning/src/main/java/com/yahoo/config/provision/Provisioner.java
+++ b/config-provisioning/src/main/java/com/yahoo/config/provision/Provisioner.java
@@ -41,8 +41,12 @@ public interface Provisioner {
      * @param hosts       a set of {@link HostSpec}.
      * @param lock        A provision lock for the relevant application. This must be held when calling this.
      */
+    // TODO: Remove after November 2020
     void activate(NestedTransaction transaction, Collection<HostSpec> hosts, ProvisionLock lock);
 
+    /** Activates the allocation of nodes to this application captured in the hosts argument. */
+    void activate(Collection<HostSpec> hosts, ActivationContext context, ApplicationTransaction transaction);
+
     /**
      * Transactionally remove this application.
      *
@@ -58,8 +62,13 @@ public interface Provisioner {
      * @param transaction Transaction with operations to commit together with any operations done within the provisioner.
      * @param lock        A provision lock for the relevant application. This must be held when calling this.
      */
+    // TODO: Remove after November 2020
     void remove(NestedTransaction transaction, ProvisionLock lock);
 
+    /** Transactionally remove an application under lock. */
+    // TODO: Remove after November 2020
+    void remove(ApplicationTransaction transaction);
+
     /**
      * Requests a restart of the services of the given application
      *