Acquire provision lock for transactional writes

2 files changed, 54 insertions, 0 deletions

diff --git a/config-provisioning/src/main/java/com/yahoo/config/provision/ProvisionLock.java b/config-provisioning/src/main/java/com/yahoo/config/provision/ProvisionLock.java
new file mode 100644
index 00000000000..633c8520e72
--- /dev/null
+++ b/config-provisioning/src/main/java/com/yahoo/config/provision/ProvisionLock.java
@@ -0,0 +1,32 @@
+// 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 java.util.Objects;
+
+/**
+ * A type-safe wrapper for an application's provision lock.
+ *
+ * @author mpolden
+ */
+public class ProvisionLock implements AutoCloseable {
+
+    private final ApplicationId application;
+    private final Mutex lock;
+
+    public ProvisionLock(ApplicationId application, Mutex lock) {
+        this.application = Objects.requireNonNull(application);
+        this.lock = Objects.requireNonNull(lock);
+    }
+
+    public ApplicationId application() {
+        return application;
+    }
+
+    @Override
+    public void close() {
+        lock.close();
+    }
+
+}
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 2a1528f5368..1eb2c1e61b2 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
@@ -31,17 +31,36 @@ public interface Provisioner {
      * @param application The {@link ApplicationId} that was activated.
      * @param hosts a set of {@link HostSpec}.
      */
+    // TODO(mpolden): Remove
     void activate(NestedTransaction transaction, ApplicationId application, Collection<HostSpec> hosts);
 
     /**
+     * Activates the allocation of nodes to this application captured in the hosts argument.
+     *
+     * @param transaction Transaction with operations to commit together with any operations done within the provisioner.
+     * @param hosts       a set of {@link HostSpec}.
+     * @param lock        A provision lock for the relevant application. This must be held when calling this.
+     */
+    void activate(NestedTransaction transaction, Collection<HostSpec> hosts, ProvisionLock lock);
+
+    /**
      * Transactionally remove this application.
      *
      * @param transaction Transaction with operations to commit together with any operations done within the provisioner.
      * @param application the application to remove
      */
+    // TODO(mpolden): Remove
     void remove(NestedTransaction transaction, ApplicationId application);
 
     /**
+     * Transactionally remove application guarded by given lock.
+     *
+     * @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.
+     */
+    void remove(NestedTransaction transaction, ProvisionLock lock);
+
+    /**
      * Requests a restart of the services of the given application
      *
      * @param application the application to restart
@@ -49,4 +68,7 @@ public interface Provisioner {
      */
     void restart(ApplicationId application, HostFilter filter);
 
+    /** Returns a provision lock for the given application */
+    ProvisionLock lock(ApplicationId application);
+
 }