Quotas in the configuration server (#14088)

* Create a quota JSON encoded parameter

* Propagate quota from PrepareParams to ModelContext.Properties

* Persist quota and read it back

* Check maxClusterSize quota in Validator step

* Default to Quota.empty() in TestProperties

* Javadoc and authors

* Fix parameter type after it was changed on master

Co-authored-by: Andreas Eriksen <andreer@verizonmedia.com>

2 files changed, 77 insertions, 0 deletions

diff --git a/config-model-api/src/main/java/com/yahoo/config/model/api/ModelContext.java b/config-model-api/src/main/java/com/yahoo/config/model/api/ModelContext.java
index 64a2906b1be..413a7dbc62e 100644
--- a/config-model-api/src/main/java/com/yahoo/config/model/api/ModelContext.java
+++ b/config-model-api/src/main/java/com/yahoo/config/model/api/ModelContext.java
@@ -121,6 +121,11 @@ public interface ModelContext {
 
         // TODO(bjorncs): Temporary feature flag
         default double feedCoreThreadPoolSizeFactor() { return 1.0; }
+
+        default Quota quota() {
+            return Quota.empty();
+        }
+
     }
 
 }
diff --git a/config-model-api/src/main/java/com/yahoo/config/model/api/Quota.java b/config-model-api/src/main/java/com/yahoo/config/model/api/Quota.java
new file mode 100644
index 00000000000..cb600bc0a5e
--- /dev/null
+++ b/config-model-api/src/main/java/com/yahoo/config/model/api/Quota.java
@@ -0,0 +1,72 @@
+// Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.config.model.api;
+
+import com.yahoo.slime.Inspector;
+import com.yahoo.slime.Slime;
+import com.yahoo.slime.SlimeUtils;
+
+import java.util.Objects;
+import java.util.Optional;
+
+/**
+ * Quota for the application deployed.  If the application exceeds this quota, deployment will fail.
+ *
+ * @author ogronnesby
+ */
+public class Quota {
+    private final Optional<Integer> maxClusterSize;
+    private final Optional<Integer> budget;
+
+    public Quota(Optional<Integer> maybeClusterSize, Optional<Integer> budget) {
+        this.maxClusterSize = maybeClusterSize;
+        this.budget = budget;
+    }
+
+    public static Quota fromSlime(Inspector inspector) {
+        var clusterSize = SlimeUtils.optionalLong(inspector.field("clusterSize"));
+        var budget = SlimeUtils.optionalLong(inspector.field("budget"));
+        return new Quota(clusterSize.map(Long::intValue), budget.map(Long::intValue));
+    }
+
+    public Slime toSlime() {
+        var slime = new Slime();
+        var root = slime.setObject();
+        maxClusterSize.ifPresent(clusterSize -> root.setLong("clusterSize", clusterSize));
+        budget.ifPresent(b -> root.setLong("budget", b));
+        return slime;
+    }
+
+    public static Quota empty() {
+        return new Quota(Optional.empty(), Optional.empty());
+    }
+
+    public Optional<Integer> maxClusterSize() {
+        return maxClusterSize;
+    }
+
+    public Optional<Integer> budget() {
+        return budget;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        Quota quota = (Quota) o;
+        return Objects.equals(maxClusterSize, quota.maxClusterSize) &&
+                Objects.equals(budget, quota.budget);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(maxClusterSize, budget);
+    }
+
+    @Override
+    public String toString() {
+        return "Quota{" +
+                "maxClusterSize=" + maxClusterSize +
+                ", budget=" + budget +
+                '}';
+    }
+}