Allow configuring number of node groups and replicas per node directly for "Redis (cluster mode disabled)"

[gdavison]

Typically, when creating a "Redis (cluster mode disabled)" aws_elasticache_replication_group, the number of nodes is specified using number_cache_clusters, and when creating a "Redis (cluster mode enabled)" aws_elasticache_replication_group, the configuration of node groups is specified using cluster_mode.num_node_groups and cluster_mode.replicas_per_node_group. Whether cluster mode is enabled is determined by the parameter group assigned to the replication group.

However, the API returns both parameters regardless of the cluster mode setting in the parameter group used by the replication group.

The value of number_cache_clusters will always be equal to cluster_mode.num_node_groups * (1 + cluster_mode.replicas_per_node_group). With cluster mode disabled, cluster_mode.num_node_groups is 1.

Currently, the resource allows setting

cluster_mode {
  num_node_groups         = 1
  replicas_per_node_group = 1
}

when cluster mode is not enabled, but does not return a value for the cluster_mode block.

This PR adds the returned value for the cluster_mode block and adds a cluster_enabled output parameter.

Release note for CHANGELOG:

* resource/aws_elasticache_replication_group: Allows configuring `replicas_per_node_group` for "Redis (cluster mode disabled)"

Output from acceptance testing:

$ make testacc TESTARGS='-run=TestAccAWSElasticacheReplicationGroup_'

--- PASS: TestAccAWSElasticacheReplicationGroup_clusteringAndCacheNodesCausesError (151.68s)
--- PASS: TestAccAWSElasticacheReplicationGroup_ClusterMode_NonClusteredParameterGroup (868.50s)
--- PASS: TestAccAWSElasticacheReplicationGroup_updateParameterGroup (1128.57s)
--- PASS: TestAccAWSElasticacheReplicationGroup_ClusterMode_Basic (1180.88s)
--- PASS: TestAccAWSElasticacheReplicationGroup_updateMaintenanceWindow (1189.76s)
--- PASS: TestAccAWSElasticacheReplicationGroup_enableSnapshotting (1488.39s)
--- PASS: TestAccAWSElasticacheReplicationGroup_vpc (1498.01s)
--- PASS: TestAccAWSElasticacheReplicationGroup_basic (1498.58s)
--- PASS: TestAccAWSElasticacheReplicationGroup_enableAuthTokenTransitEncryption (1684.19s)
--- PASS: TestAccAWSElasticacheReplicationGroup_multiAzInVpc (1763.90s)
--- PASS: TestAccAWSElasticacheReplicationGroup_useCmkKmsKeyId (1811.39s)
--- PASS: TestAccAWSElasticacheReplicationGroup_enableAtRestEncryption (1822.63s)
--- PASS: TestAccAWSElasticacheReplicationGroup_tags (2021.41s)
--- PASS: TestAccAWSElasticacheReplicationGroup_redisClusterInVpc2 (2076.63s)
--- PASS: TestAccAWSElasticacheReplicationGroup_updateNodeSize (2114.40s)
--- PASS: TestAccAWSElasticacheReplicationGroup_updateDescription (2324.69s)
--- PASS: TestAccAWSElasticacheReplicationGroup_Uppercase (2177.23s)
--- PASS: TestAccAWSElasticacheReplicationGroup_NumberCacheClusters (2993.37s)
--- PASS: TestAccAWSElasticacheReplicationGroup_NumberCacheClusters_Failover_AutoFailoverDisabled (3094.51s)
--- PASS: TestAccAWSElasticacheReplicationGroup_NumberCacheClusters_Failover_AutoFailoverEnabled (3261.51s)
--- PASS: TestAccAWSElasticacheReplicationGroup_ClusterMode_NumNodeGroups (3890.04s)

[YakDriver]

Holy smokes. Nothing like nice, quick, easy acceptance tests. I'll get back to you when they run. I've looked over the code and it looks good.

[YakDriver]

LGTM 🎉

--- PASS: TestAccAWSElasticacheReplicationGroup_clusteringAndCacheNodesCausesError (5.55s)
--- PASS: TestAccAWSElasticacheReplicationGroup_ClusterMode_Basic (1161.24s)
--- PASS: TestAccAWSElasticacheReplicationGroup_ClusterMode_NonClusteredParameterGroup (1456.18s)
--- PASS: TestAccAWSElasticacheReplicationGroup_enableAtRestEncryption (631.29s)
--- PASS: TestAccAWSElasticacheReplicationGroup_enableAuthTokenTransitEncryption (1400.50s)
--- PASS: TestAccAWSElasticacheReplicationGroup_enableSnapshotting (1396.52s)
--- PASS: TestAccAWSElasticacheReplicationGroup_multiAzInVpc (1013.35s)
--- PASS: TestAccAWSElasticacheReplicationGroup_NumberCacheClusters (1398.35s)
--- PASS: TestAccAWSElasticacheReplicationGroup_redisClusterInVpc2 (1460.76s)
--- PASS: TestAccAWSElasticacheReplicationGroup_tags (1396.92s)
--- PASS: TestAccAWSElasticacheReplicationGroup_updateMaintenanceWindow (845.59s)
--- PASS: TestAccAWSElasticacheReplicationGroup_Uppercase (1400.40s)
--- PASS: TestAccAWSElasticacheReplicationGroup_vpc (672.53s)

[ghost]

This has been released in version 3.23.0 of the Terraform AWS provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template for triage. Thanks!

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you feel this issue should be reopened, we encourage creating a new issue linking back to this one for added context. Thanks!