Add separate output for CIDR blocks only; switch output names

README.md

@@ -4,6 +4,8 @@ This module takes one or more input sets of CIDRs and, for each set independentl
 
 The module accepts a map of lists of objects so that multiple CIDR sets can be merged (independently of one another) with a single instance of the module, which prevents a `for_each` or `count` on the module with a value that may not be known at plan time. Each list in the map contains objects that have fields for a CIDR and metadata. The output of the module includes, for each merged CIDR, the set of CIDR/metadata objects that it contains. This allows metadata such as a description (e.g. "route to database subnet") to be merged by the user to create merged metadata (e.g. a description for a merged CIDR that includes the descriptions for all of the CIDRs contained within).
 
+The module produces two outputs: one is just the merged CIDRs in a list (mapped by the same group keys as the input), while the other contains additional metadata that may be useful.
+
 The module works by:
 1. Converting all CIDRs to use their first IP address as the prefix (e.g. `["10.0.1.0/16"]` becomes `["10.0.0.0/16"]`).
 1. Removing any duplicate CIDRs.
@@ -141,6 +143,18 @@ Apply complete! Resources: 0 added, 0 changed, 0 destroyed.
 Outputs:
 
 merged_cidrs = {
+  "set-0" = [
+    "1.0.0.0/14",
+    "1.4.0.0/15",
+    "1.6.0.0/17",
+    "192.168.0.0/21",
+    "192.168.8.0/24",
+  ]
+  "set-1" = [
+    "0.0.0.0/0",
+  ]
+}
+merged_cidrs_with_meta = {
   "set-0" = [
     {
       "cidr" = "1.0.0.0/14"
@@ -164,6 +178,10 @@ merged_cidrs = {
           }
         },
       ]
+      "first_ip" = "1.0.0.0"
+      "first_ip_decimal" = 16777216
+      "last_ip" = "1.3.255.255"
+      "last_ip_decimal" = 17039359
     },
     {
       "cidr" = "1.4.0.0/15"
@@ -181,6 +199,10 @@ merged_cidrs = {
           }
         },
       ]
+      "first_ip" = "1.4.0.0"
+      "first_ip_decimal" = 17039360
+      "last_ip" = "1.5.255.255"
+      "last_ip_decimal" = 17170431
     },
     {
       "cidr" = "1.6.0.0/17"
@@ -198,6 +220,10 @@ merged_cidrs = {
           }
         },
       ]
+      "first_ip" = "1.6.0.0"
+      "first_ip_decimal" = 17170432
+      "last_ip" = "1.6.127.255"
+      "last_ip_decimal" = 17203199
     },
     {
       "cidr" = "192.168.0.0/21"
@@ -245,6 +271,10 @@ merged_cidrs = {
           }
         },
       ]
+      "first_ip" = "192.168.0.0"
+      "first_ip_decimal" = 3232235520
+      "last_ip" = "192.168.7.255"
+      "last_ip_decimal" = 3232237567
     },
     {
       "cidr" = "192.168.8.0/24"
@@ -256,6 +286,10 @@ merged_cidrs = {
           }
         },
       ]
+      "first_ip" = "192.168.8.0"
+      "first_ip_decimal" = 3232237568
+      "last_ip" = "192.168.8.255"
+      "last_ip_decimal" = 3232237823
     },
   ]
   "set-1" = [
@@ -275,6 +309,10 @@ merged_cidrs = {
           }
         },
       ]
+      "first_ip" = "0.0.0.0"
+      "first_ip_decimal" = 0
+      "last_ip" = "255.255.255.255"
+      "last_ip_decimal" = 4294967295
     },
   ]
 }

ipv4.tf

@@ -156,6 +156,7 @@ locals {
             {
               first_ip         = cidr_data.first_ip
               first_ip_decimal = cidr_data.first_ip_decimal
+              last_ip          = contiguous_set[i].last_ip
               last_ip_decimal  = contiguous_set[i].last_ip_decimal
 
               // Calculate the prefix length as 32 minus (the number of IPs in the CIDR, log base 2)
@@ -169,7 +170,6 @@ locals {
 
               // Debugging values
               # cidr_set = slice(contiguous_set, cidr_idx, i + 1)
-              # last_ip          = contiguous_set[i].last_ip
               # ip_count = contiguous_set[i].last_ip_decimal - cidr_data.first_ip_decimal + 1
             }
           ]
@@ -261,14 +261,18 @@ locals {
   }
 
   // Create the final list of CIDRs, which is all of the merges from all of the contiguous sets.
-  final_cidrs_ipv4 = {
+  final_cidrs_ipv4_with_meta = {
     for key, group in local.merged_cidrs :
     key => flatten([
       for contiguous_set in group :
       [
         for merging in contiguous_set :
         {
-          cidr = "${merging.first_ip}/${merging.prefix_length}"
+          cidr             = "${merging.first_ip}/${merging.prefix_length}"
+          first_ip         = merging.first_ip
+          last_ip          = merging.last_ip
+          first_ip_decimal = merging.first_ip_decimal
+          last_ip_decimal  = merging.last_ip_decimal
           contains = [
             for cidr_meta in local.cidrs_with_first_last_decimal[key] :
             {
@@ -281,4 +285,12 @@ locals {
       ]
     ])
   }
+
+  final_cidrs_ipv4 = {
+    for key, group in local.final_cidrs_ipv4_with_meta :
+    key => [
+      for cidr_data in group :
+      cidr_data.cidr
+    ]
+  }
 }

outputs.tf

@@ -13,6 +13,10 @@ output "merged_cidr_sets_ipv4" {
   description = "The merged CIDR sets."
   value       = local.final_cidrs_ipv4
 }
+output "merged_cidr_sets_ipv4_with_meta" {
+  description = "The merged CIDR sets, with additional metadata including the CIDRs that were merged into this one and additional IP data."
+  value       = local.final_cidrs_ipv4_with_meta
+}
 
 //==================================================
 //             Debugging outputs

tests/debug.tf

@@ -116,3 +116,7 @@ module "cidr_merge" {
 output "merged_cidrs" {
   value = module.cidr_merge.merged_cidr_sets_ipv4
 }
+
+output "merged_cidrs_with_meta" {
+  value = module.cidr_merge.merged_cidr_sets_ipv4_with_meta
+}