aws_elasticache_replication_group caused a panic
Fixes#9097
The update for `parameter_group_name` was trying to find the incorrect
value to set `cache_parameter_group_name` - this is what was causing the
panic
```
% make testacc TEST=./builtin/providers/aws TESTARGS='-run=TestAccAWSElasticacheReplicationGroup_updateParameterGroup'
==> Checking that code complies with gofmt requirements...
go generate $(go list ./... | grep -v /terraform/vendor/)
2016/09/28 11:17:30 Generated command/internal_plugin_list.go
TF_ACC=1 go test ./builtin/providers/aws -v
-run=TestAccAWSElasticacheReplicationGroup_updateParameterGroup -timeout
120m
=== RUN TestAccAWSElasticacheReplicationGroup_updateParameterGroup
--- PASS: TestAccAWSElasticacheReplicationGroup_updateParameterGroup
(903.90s)
PASS
ok github.com/hashicorp/terraform/builtin/providers/aws903.931s
```
Replication Groups
In order to be able to restore a named snapshot as ElastiCache Cluster
or a Replication Group, the `snapshot_name` parameter was needed to be
passed. Changing the `snapshot_name` will force a new resource to be
created
```
```
`aws_elasticache_replication_group`
Fixes#8377
Now we can output the endpoint of the primary
```
resource "aws_elasticache_replication_group" "bar" {
replication_group_id = "tf-11111"
replication_group_description = "test description"
node_type = "cache.m1.small"
number_cache_clusters = 2
port = 6379
parameter_group_name = "default.redis2.8"
apply_immediately = true
}
output "primary_endpoint_address" {
value = "${aws_elasticache_replication_group.bar.primary_endpoint_address}"
}
```
This gives us:
```
% terraform apply
...................
aws_elasticache_replication_group.bar: Creation complete
Apply complete! Resources: 1 added, 0 changed, 0 destroyed.
Outputs:
primary_endpoint_address = tf-11111.d5jx4z.ng.0001.use1.cache.amazonaws.com
```
This was the addition of a computed field only so the basic test still works as expected:
```
% make testacc TEST=./builtin/providers/aws TESTARGS='-run=TestAccAWSElasticacheReplicationGroup_basic' ✹
==> Checking that code complies with gofmt requirements...
/Users/stacko/Code/go/bin/stringer
go generate $(go list ./... | grep -v /terraform/vendor/)
2016/08/22 17:11:13 Generated command/internal_plugin_list.go
TF_ACC=1 go test ./builtin/providers/aws -v -run=TestAccAWSElasticacheReplicationGroup_basic -timeout 120m
=== RUN TestAccAWSElasticacheReplicationGroup_basic
--- PASS: TestAccAWSElasticacheReplicationGroup_basic (741.71s)
PASS
ok github.com/hashicorp/terraform/builtin/providers/aws 741.735s
```
The AWS documentation tells us the following:
```
--replication-group-id (string)
The replication group identifier. This parameter is stored as a
lowercase string.
Constraints:
A name must contain from *1 to 20* alphanumeric characters or hyphens.
The first character must be a letter.
A name cannot end with a hyphen or contain two consecutive hyphens.
```
This is not correct and is causing users errors:
```
* aws_elasticache_replication_group.bar: Error creating Elasticache
* Replication Group: InvalidParameterValue: Replication group id should
* be no more than 16 characters.
status code: 400, request id:
```
Tuning the Validation from 20 to 16 characters to avoid user issues
stack72