Method add_replica_to_instance

src/compute-client/src/controller.rs:700–751

Adds replicas of an instance.

(
        &mut self,
        instance_id: ComputeInstanceId,
        replica_id: ReplicaId,
        location: ClusterReplicaLocation,
        config: ComputeReplicaConfig,
    )

    /// Adds replicas of an instance.
    pub fn add_replica_to_instance(
        &mut self,
        instance_id: ComputeInstanceId,
        replica_id: ReplicaId,
        location: ClusterReplicaLocation,
        config: ComputeReplicaConfig,
    ) -> Result<(), ReplicaCreationError> {
        use ReplicaCreationError::*;

        let instance = self.instance(instance_id)?;

        // Validation
        if instance.replicas.contains(&replica_id) {
            return Err(ReplicaExists(replica_id));
        }

        let (enable_logging, interval) = match config.logging.interval {
            Some(interval) => (true, interval),
            None => (false, Duration::from_secs(1)),
        };

        let expiration_offset = COMPUTE_REPLICA_EXPIRATION_OFFSET.get(&self.dyncfg);

        // Capture dictionary compression once, at replica creation, and hold it fixed for the
        // replica's lifetime (see `InstanceConfig::arrangement_dictionary_compression`). This is
        // why a later flip of the flag only affects replicas created afterwards.
        let arrangement_dictionary_compression =
            ENABLE_ARRANGEMENT_DICTIONARY_COMPRESSION_ALPHA.get(&self.dyncfg);

        let replica_config = ReplicaConfig {
            location,
            logging: LoggingConfig {
                interval,
                enable_logging,
                log_logging: config.logging.log_logging,
                index_logs: Default::default(),
            },
            grpc_client: self.config.grpc_client.clone(),
            expiration_offset: (!expiration_offset.is_zero()).then_some(expiration_offset),
            arrangement_dictionary_compression,
        };

        let instance = self.instance_mut(instance_id).expect("validated");
        instance.replicas.insert(replica_id);

        instance.call(move |i| {
            i.add_replica(replica_id, replica_config, None)
                .expect("validated")
        });

        Ok(())
    }

    /// Removes a replica from an instance, including its service in the orchestrator.
    pub fn drop_replica(