[Issue 1267] Adds foreign data wrapper security group permissions

[coilysiren]

Summary

Helps with #1267

Time to review: 2 mins

Changes proposed

• Adds permissions for the database to query Oracle on port 1521, via means of the foreign data wrapper.
• Renames a variable since it won't be exclusively used for DMS anymore

Relevant terraform plan output

  # module.database.aws_vpc_security_group_egress_rule.egress_to_oracle will be created
  + resource "aws_vpc_security_group_egress_rule" "egress_to_oracle" {
      + arn                    = (known after apply)
      + cidr_ipv4              = "10.220.0.0/16"
      + description            = "Allow Orcale I/O into database"
      + from_port              = 1521
      + id                     = (known after apply)
      + ip_protocol            = "tcp"
      + security_group_id      = "sg-0011e7397e1025c78"
      + security_group_rule_id = (known after apply)
      + tags_all               = {
          + "description"         = "Database resources for the dev environment"
          + "environment"         = "dev"
          + "owner"               = "navapbc"
          + "project"             = "simpler-grants-gov"
          + "repository"          = "https://github.com/HHS/simpler-grants-gov"
          + "terraform"           = "true"
          + "terraform_workspace" = "default"
        }
      + to_port                = 1521
    }

  # module.database.aws_vpc_security_group_ingress_rule.ingress_from_oracle will be created
  + resource "aws_vpc_security_group_ingress_rule" "ingress_from_oracle" {
      + arn                    = (known after apply)
      + cidr_ipv4              = "10.220.0.0/16"
      + description            = "Allow Orcale I/O into database"
      + from_port              = 1521
      + id                     = (known after apply)
      + ip_protocol            = "tcp"
      + security_group_id      = "sg-0011e7397e1025c78"
      + security_group_rule_id = (known after apply)
      + tags_all               = {
          + "description"         = "Database resources for the dev environment"
          + "environment"         = "dev"
          + "owner"               = "navapbc"
          + "project"             = "simpler-grants-gov"
          + "repository"          = "https://github.com/HHS/simpler-grants-gov"
          + "terraform"           = "true"
          + "terraform_workspace" = "default"
        }
      + to_port                = 1521
    }

Testing

[aplybeah]

Non-blocker: I would appreciate some clarity on this comment

[coilysiren]

@aplybeah a VPC CIDR is composed of 4 octets, eg. A.B.C.D. This value is the 2nd octet for our VPC CIDRs. It's the B in A.B.C.D. This specific one is the 0 in 10.0.0.0.

Does that explain the comment? The comment is intentionally succinct because it relies on the reader having previous knowledge of what a "octet VPC CIDR" is.

[aplybeah]

non-blcker: What else is this cidr going to be used for?

[coilysiren]

@aplybeah I/O for the foreign data wrapper, which is what this PR is allowing.