Add option to limit output id length (#98) @tibbing

Author: tibbing

README.md

@@ -537,6 +537,7 @@ No provider.
 | delimiter | Delimiter to be used between `namespace`, `environment`, `stage`, `name` and `attributes` | `string` | `"-"` | no |
 | enabled | Set to false to prevent the module from creating any resources | `bool` | `true` | no |
 | environment | Environment, e.g. 'prod', 'staging', 'dev', 'pre-prod', 'UAT' | `string` | `""` | no |
+| id\_max\_length | Specify the max length of the `id` output, or 0 for unrestricted length | `number` | `0` | no |
 | label\_order | The naming order of the id output and Name tag | `list(string)` | `[]` | no |
 | name | Solution name, e.g. 'app' or 'jenkins' | `string` | `""` | no |
 | namespace | Namespace, which could be your organization name or abbreviation, e.g. 'eg' or 'cp' | `string` | `""` | no |
@@ -552,7 +553,8 @@ No provider.
 | context | Context of this module to pass to other label modules |
 | delimiter | Delimiter between `namespace`, `environment`, `stage`, `name` and `attributes` |
 | environment | Normalized environment |
-| id | Disambiguated ID |
+| id | Disambiguated ID restricted to id\_max\_length |
+| id\_full | Disambiguated ID not restricted to id\_max\_length |
 | label\_order | The naming order of the id output and Name tag |
 | name | Normalized name |
 | namespace | Normalized namespace |
@@ -706,8 +708,8 @@ Check out [our other projects][github], [follow us on twitter][twitter], [apply
 
 ### Contributors
 
-|  [![Erik Osterman][osterman_avatar]][osterman_homepage]<br/>[Erik Osterman][osterman_homepage] | [![Andriy Knysh][aknysh_avatar]][aknysh_homepage]<br/>[Andriy Knysh][aknysh_homepage] | [![Igor Rodionov][goruha_avatar]][goruha_homepage]<br/>[Igor Rodionov][goruha_homepage] | [![Sergey Vasilyev][s2504s_avatar]][s2504s_homepage]<br/>[Sergey Vasilyev][s2504s_homepage] | [![Michael Pereira][MichaelPereira_avatar]][MichaelPereira_homepage]<br/>[Michael Pereira][MichaelPereira_homepage] | [![Jamie Nelson][Jamie-BitFlight_avatar]][Jamie-BitFlight_homepage]<br/>[Jamie Nelson][Jamie-BitFlight_homepage] | [![Vladimir][SweetOps_avatar]][SweetOps_homepage]<br/>[Vladimir][SweetOps_homepage] | [![Daren Desjardins][darend_avatar]][darend_homepage]<br/>[Daren Desjardins][darend_homepage] | [![Maarten van der Hoef][maartenvanderhoef_avatar]][maartenvanderhoef_homepage]<br/>[Maarten van der Hoef][maartenvanderhoef_homepage] |
-|---|---|---|---|---|---|---|---|---|
+|  [![Erik Osterman][osterman_avatar]][osterman_homepage]<br/>[Erik Osterman][osterman_homepage] | [![Andriy Knysh][aknysh_avatar]][aknysh_homepage]<br/>[Andriy Knysh][aknysh_homepage] | [![Igor Rodionov][goruha_avatar]][goruha_homepage]<br/>[Igor Rodionov][goruha_homepage] | [![Sergey Vasilyev][s2504s_avatar]][s2504s_homepage]<br/>[Sergey Vasilyev][s2504s_homepage] | [![Michael Pereira][MichaelPereira_avatar]][MichaelPereira_homepage]<br/>[Michael Pereira][MichaelPereira_homepage] | [![Jamie Nelson][Jamie-BitFlight_avatar]][Jamie-BitFlight_homepage]<br/>[Jamie Nelson][Jamie-BitFlight_homepage] | [![Vladimir][SweetOps_avatar]][SweetOps_homepage]<br/>[Vladimir][SweetOps_homepage] | [![Daren Desjardins][darend_avatar]][darend_homepage]<br/>[Daren Desjardins][darend_homepage] | [![Maarten van der Hoef][maartenvanderhoef_avatar]][maartenvanderhoef_homepage]<br/>[Maarten van der Hoef][maartenvanderhoef_homepage] | [![Adam Tibbing][tibbing_avatar]][tibbing_homepage]<br/>[Adam Tibbing][tibbing_homepage] |
+|---|---|---|---|---|---|---|---|---|---|
 
   [osterman_homepage]: https://github.com/osterman
   [osterman_avatar]: https://img.cloudposse.com/150x150/https://github.com/osterman.png
@@ -727,6 +729,8 @@ Check out [our other projects][github], [follow us on twitter][twitter], [apply
   [darend_avatar]: https://img.cloudposse.com/150x150/https://github.com/darend.png
   [maartenvanderhoef_homepage]: https://github.com/maartenvanderhoef
   [maartenvanderhoef_avatar]: https://img.cloudposse.com/150x150/https://github.com/maartenvanderhoef.png
+  [tibbing_homepage]: https://github.com/tibbing
+  [tibbing_avatar]: https://img.cloudposse.com/150x150/https://github.com/tibbing.png
 
 [![README Footer][readme_footer_img]][readme_footer_link]
 [![Beacon][beacon]][website]

README.yaml

@@ -481,3 +481,5 @@ contributors:
   github: darend
 - name: Maarten van der Hoef
   github: maartenvanderhoef
+- name: Adam Tibbing
+  github: tibbing

docs/terraform.md

@@ -18,6 +18,7 @@ No provider.
 | delimiter | Delimiter to be used between `namespace`, `environment`, `stage`, `name` and `attributes` | `string` | `"-"` | no |
 | enabled | Set to false to prevent the module from creating any resources | `bool` | `true` | no |
 | environment | Environment, e.g. 'prod', 'staging', 'dev', 'pre-prod', 'UAT' | `string` | `""` | no |
+| id\_max\_length | Specify the max length of the `id` output, or 0 for unrestricted length | `number` | `0` | no |
 | label\_order | The naming order of the id output and Name tag | `list(string)` | `[]` | no |
 | name | Solution name, e.g. 'app' or 'jenkins' | `string` | `""` | no |
 | namespace | Namespace, which could be your organization name or abbreviation, e.g. 'eg' or 'cp' | `string` | `""` | no |
@@ -33,7 +34,8 @@ No provider.
 | context | Context of this module to pass to other label modules |
 | delimiter | Delimiter between `namespace`, `environment`, `stage`, `name` and `attributes` |
 | environment | Normalized environment |
-| id | Disambiguated ID |
+| id | Disambiguated ID restricted to id\_max\_length |
+| id\_full | Disambiguated ID not restricted to id\_max\_length |
 | label\_order | The naming order of the id output and Name tag |
 | name | Normalized name |
 | namespace | Normalized namespace |

examples/autoscalinggroup/main.tf

@@ -64,7 +64,7 @@ resource "aws_autoscaling_group" "default" {
 # Provider                     #
 ################################
 provider "aws" {
-  region  = "eu-west-1"
+  region = "eu-west-1"
 
   # Make it faster by skipping unneeded checks here
   skip_get_ec2_platforms      = true

main.tf

@@ -56,7 +56,14 @@ locals {
 
   labels = [for l in local.label_order : local.id_context[l] if length(local.id_context[l]) > 0]
 
-  id = lower(join(local.delimiter, local.labels))
+  id_full = lower(join(local.delimiter, local.labels))
+  id_md5  = md5(local.id_full)
+  # Truncates ID to given max length, suffixed by 6 character hash of ID for disambiguation 
+  id_short = (var.id_max_length <= 6 ?
+    substr(local.id_md5, 0, var.id_max_length) :
+  "${replace(substr(local.id_full, 0, var.id_max_length - 6), "/-$/", "")}-${substr(local.id_md5, 0, 5)}")
+  id = var.id_max_length != 0 && length(local.id_full) > var.id_max_length ? local.id_short : local.id_full
+
 
   # Context of this label to pass to other label modules
   output_context = {

outputs.tf

@@ -1,6 +1,11 @@
 output "id" {
   value       = local.enabled ? local.id : ""
-  description = "Disambiguated ID"
+  description = "Disambiguated ID restricted to id_max_length"
+}
+
+output "id_full" {
+  value       = local.enabled ? local.id_full : ""
+  description = "Disambiguated ID not restricted to id_max_length"
 }
 
 output "name" {
@@ -52,4 +57,3 @@ output "label_order" {
   value       = local.label_order
   description = "The naming order of the id output and Name tag"
 }
-

variables.tf

@@ -94,3 +94,8 @@ variable "regex_replace_chars" {
   description = "Regex to replace chars with empty string in `namespace`, `environment`, `stage` and `name`. By default only hyphens, letters and digits are allowed, all other chars are removed"
 }
 
+variable "id_max_length" {
+  type        = number
+  default     = 0
+  description = "Specify the max length of the `id` output, or 0 for unrestricted length"
+}