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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.vespa.hosted.provision.lb;
import com.yahoo.vespa.applicationmodel.InfrastructureApplication;
import com.yahoo.vespa.hosted.provision.maintenance.LoadBalancerExpirer;
import java.time.Instant;
import java.util.Objects;
import java.util.Optional;
import java.util.Set;
/**
* Represents a load balancer for an application's cluster. This is immutable.
*
* @author mpolden
*/
public class LoadBalancer {
private final LoadBalancerId id;
private final Optional<LoadBalancerInstance> instance;
private final State state;
private final Instant changedAt;
public LoadBalancer(LoadBalancerId id, Optional<LoadBalancerInstance> instance, State state, Instant changedAt) {
this.id = Objects.requireNonNull(id, "id must be non-null");
this.instance = Objects.requireNonNull(instance, "instance must be non-null");
this.state = Objects.requireNonNull(state, "state must be non-null");
this.changedAt = Objects.requireNonNull(changedAt, "changedAt must be non-null");
if (state == State.active && instance.isEmpty()) {
throw new IllegalArgumentException("Load balancer instance is required in state " + state);
}
if (id.application().equals(InfrastructureApplication.CONFIG_SERVER.id()) &&
Set.of(State.inactive, State.removable).contains(state)) {
throw new IllegalArgumentException("The config server load balancer is managed by Terraform - therefore the state cannot be '" + state + "'");
}
}
/** An identifier for this load balancer. The ID is unique inside the zone */
public LoadBalancerId id() {
return id;
}
/** The instance associated with this */
public Optional<LoadBalancerInstance> instance() {
return instance;
}
/** The current state of this */
public State state() {
return state;
}
/** Returns when this was last changed */
public Instant changedAt() {
return changedAt;
}
/** Returns a copy of this with state set to given state */
public LoadBalancer with(State state, Instant changedAt) {
if (changedAt.isBefore(this.changedAt)) {
throw new IllegalArgumentException("Invalid changeAt: '" + changedAt + "' is before existing value '" +
this.changedAt + "'");
}
if (this.state != State.reserved && state == State.reserved) {
throw new IllegalArgumentException("Invalid state transition: " + this.state + " -> " + state);
}
return new LoadBalancer(id, instance, state, changedAt);
}
/** Returns a copy of this with instance set to given instance */
public LoadBalancer with(LoadBalancerInstance instance) {
return new LoadBalancer(id, Optional.of(instance), state, changedAt);
}
public enum State {
/** The load balancer has been provisioned and reserved for an application */
reserved,
/**
* The load balancer has been deactivated and is ready to be removed. Inactive load balancers are eventually
* removed by {@link LoadBalancerExpirer}. Inactive load balancers may be reactivated if a deleted cluster is
* redeployed.
*/
inactive,
/** The load balancer is in active use by an application */
active,
/** The load balancer should be removed immediately by {@link LoadBalancerExpirer} */
removable,
}
}
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