Added WIP files before decided to abandon this project

README.md

@@ -4,7 +4,9 @@
 
 [Terraform](https://www.terraform.io/) is awesome!
 
-As of today, Terraform 0.11 and 0.12 support only static (known, fixed, already computed) values in `tfvars` files. There is no way to use Terraform interpolation functions, or data-sources inside `tfvars` files in Terraform to update values.
+Terraform 0.11 and 0.12 supports only static (known, fixed, already computed) values in `tfvars` files. There is no way to use Terraform functions, or data-sources inside `tfvars` files in Terraform to update values.
+
+Using Terraform modules (eg, terraform-aws-modules) developers are not restricted on specific ways how module arguments can be provided (eg, from modules, remote states, other data-sources, command line arguments, tfvars files, etc). Using tfvars files is often a very good idea, because it separates configurations and values! And this is exactly where `tfvars-annotations` tool helps.
 
 While working on [modules.tf](https://github.com/antonbabenko/modules.tf-lambda) (a tool which converts visual diagrams created with [Cloudcraft.co](https://cloudcraft.co/) into Terraform configurations), I had a need to generate code which would chain invocations of [Terraform AWS modules](https://github.com/terraform-aws-modules) and pass arguments between them without requiring any extra Terraform code as a glue. [Terragrunt](https://github.com/gruntwork-io/terragrunt) is a great fit for this, it allows to reduce amount of Terraform configurations by reusing Terraform modules and providing arguments as values in `tfvars` files.
 
@@ -23,13 +25,56 @@ Some languages I know have concepts like annotations and decorators, so at first
   - [x] terragrunt_output:
      - `@tfvars:terragrunt_output.vpc.vpc_id`
      - `@tfvars:terragrunt_output.security-group.this_security_group_id`
-  - [ ] terraform_output
+  - [x] terraform_output
+     - `@tfvars:terraform_output.vpc.vpc_id`
+     - `@tfvars:terraform_output.security-group.this_security_group_id`
   - [ ] data-sources generic
-1. Type wrapping:
-  - `to_list`: Wrap original value with `[]` to make it it as a list
+     - `@tfvars:terragrunt_data.aws_region.zone_id` ?
+     - `@tfvars:terraform_data.aws_region.zone_id` ?
+
+## General form of the annotations:
+
+`@tfvars:TYPE.DIRECTORY.ATTR[.RETURN_TYPE]`
+
+`TYPE` - Type of the fetcher:
+1. terragrunt_output - Get value from `terragrunt output <ATTR>`
+1. terraform_output - Get value from `terraform output <ATTR>`
+1. terraform_data and terragrunt_data - Get attribute from data-source (eg, `aws_caller_identity.account_id` to ret)
+
+`DIRECTORY` - Working directory where `TYPE` commands should be run. It can be specified in short form if it is a name of directory on the same level as parent directory.
+Long form should be used to specify directories on the same level as well as from parent (no max level).
+
+Examples:
+1. `[./core]` and `[core]` are identical and refer to `core` subfolder, `[../../../core]` - several folders above
+1. `[../core]` and `core` have identical meanings and refer to `core` in the parent directory
+1. `[..]` - parent directory
+1. `[.]` - current directory
+
+`ATTR` - Name of output to return or name of attribute if `TYPE` is data-source (terraform_data and terragrunt_data).
+
+`RETURN_TYPE` - (Optional) Specify desired type to return. `to_list` can be used to wrap original value with `[]` to make it as a list.
+
+## Examples of various annotations
+
+1. `@tfvars:terragrunt_output.vpc.vpc_id`
+1. `@tfvars:terragrunt_output.[../../vpc].vpc_id`
+1. `@tfvars:terraform_output.[./vpc].vpc_id.to_list`
+1. `@tfvars:terraform_output.[../us-east-1/acm].this_acm_arn`
+1. `@tfvars:terragrunt_data.aws_region.zone_id`
+1. `@tfvars:terragrunt_data.aws_caller_identity.account_id.to_list`
 
 ## How to use
 
+```
+Usage: tfvars-annotations [DIR]
+  -debug
+        enable debug logging
+  -version
+        print version information and exit
+
+[DIR] (optional) - If not specified current directory will be used.
+```
+
 Run `tfvars-annotations` before `terraform plan, apply, refresh`.
 
 It will process tfvars file in the current directory and set updated values.
@@ -38,7 +83,9 @@ E.g.:
 
     $ tfvars-annotations examples/project1-terragrunt/eu-west-1/app
     $ terraform plan
-
+
+## Annotations
+
 ## How to disable processing entirely
 
 Put `@tfvars:disable_annotations` anywhere in the `terraform.tfvars` to not process the file.
@@ -50,8 +97,9 @@ See `examples` for some basics.
 ## To-do
 
 1. Get values from other sources:
- - data sources generic
+ - data sources generic (with missing values to use the default value)
  - aws_account_id or aws_region data sources
+ - aws_account_id by alias (reference by alias is friendlier)
 2. terragrunt_outputs from stacks:
  - in any folder
  - in current region
@@ -60,6 +108,8 @@ See `examples` for some basics.
 5. rewrite in go (invoke like this => update_dynamic_values_in_tfvars ${get_parent_tfvars_dir()}/${path_relative_to_include()})
 6. make it much faster, less verbose
 7. add dry-run flag
+9. Add -detailed-exitcode to know if files were changed
+10. Support terraform.tfvars and terragrunt.hcl or custom list of files
 8. Proposed syntax:
 
  - `@tfvars:terragrunt_output.security-group_5.this_security_group_id.to_list`
@@ -71,6 +121,7 @@ See `examples` for some basics.
  - `@tfvars:terragrunt_data.aws_region.zone_id`
 
  - `@tfvars:terragrunt_data.aws_region[{current=true}].zone_id`
+// 9. Describe and compare tfvars-annotations vs using remote_state
 
 ## Bugs
 

examples/project1-terragrunt/eu-west-1/app/terragrunt.hcl

@@ -0,0 +1,50 @@
+terragrunt = {
+  terraform = {
+    source = "."
+  }
+}
+
+dependency "core" {
+  path = "../core"
+}
+
+################
+# Static values
+################
+
+title = "This value is not going to be changed by tfvars-annotations"
+
+#################
+# Dynamic values
+#################
+
+name = "" # @tfvars:terragrunt_output.core.name
+
+score = "" # @tfvars:terragrunt_output.core.score
+
+name_as_list = [""] # @tfvars:terragrunt_output.core.name.to_list
+
+love_sailing = "" # @tfvars:terragrunt_output.core.love_sailing
+
+understand_how_to_use_twitter = "" # @tfvars:terragrunt_output.core.understand_how_to_use_twitter
+
+languages = "" # @tfvars:terragrunt_output.core.languages
+
+###############
+# Compositions
+###############
+
+custom_map = {
+  Score      = "" # @tfvars:terragrunt_output.core.score
+  Name       = "" # @tfvars:terragrunt_output.core.name
+  MixedValue = "" # @ tfvars:terragrunt_output.core.mixed_value <-- same reason as below. Maps are tricky.
+}
+
+######
+# These don't work yet because there are `maps` inside of them.
+######
+list_of_properties = "" # @ tfvars:terragrunt_output.core.list_of_properties
+
+map_of_properties = "" # @ tfvars:terragrunt_output.core.map_of_properties
+
+mixed_value = "" # @ tfvars:terragrunt_output.core.mixed_value

examples/project1-terragrunt/eu-west-1/core/terragrunt.hcl

@@ -0,0 +1,7 @@
+terraform {
+  source = "."
+}
+
+inputs = {
+  name = "test"
+}

examples/project2-terraform/app/terraform.tfvars

@@ -1,11 +1,19 @@
-# @ modulestf:disable_values_updates
+# @ tfvars:disable_annotations
 
-vpc_id = "vpc-443a8116aae25c7e9" # @modulestf:terraform_output.vpc.vpc_id
+name = "Anton Babenko" # @tfvars:terraform_output.core.name
 
-public_subnets = ["subnet-297e8b509d8aeebfe","subnet-3f831847e5802071c","subnet-6c6f959a9063d32b2"] # @modulestf:terraform_output.vpc.public_subnets
+score = "37" # @tfvars:terraform_output.core.score
 
-something = "" # @modulestf:terraform_output.something.id
+name_as_list = [""] # @tfvars:terraform_output.core.name.to_list
 
-vpc4_id = "vpc-443a8116aae25c7e9" # @modulestf:terraform_output.vpc.vpc_id
+love_sailing = "true" # @tfvars:terraform_output.core.love_sailing
 
-the end!
+understand_how_to_use_twitter = "false" # @tfvars:terraform_output.core.understand_how_to_use_twitter
+
+languages = [
+  "ukrainian",
+  "russian",
+  "english",
+  "norwegian",
+  "spanish",
+] # @tfvars:terraform_output.core.languages

examples/project2-terraform/core/main.tf

@@ -0,0 +1,73 @@
+output "name" {
+  value = "Anton Babenko"
+}
+
+output "score" {
+  value = "37"
+}
+
+output "love_sailing" {
+  value = "true"
+}
+
+output "understand_how_to_use_twitter" {
+  value = "false"
+}
+
+output "languages" {
+  value = ["ukrainian", "russian", "english", "norwegian", "spanish"]
+}
+
+output "map_of_properties" {
+  value = {
+    Name        = "Anton Babenko"
+    Age         = 34
+    LoveSailing = true
+  }
+}
+
+output "list_of_properties" {
+  value = [
+    {
+      Name                      = "Anton Babenko"
+      Age                       = 34
+      LoveSailing               = true
+      UnderstandHowToUseTwitter = false
+    },
+    {
+      Name        = "Kapitoshka"
+      Age         = 123
+      LoveSailing = false
+    },
+  ]
+}
+
+output "mixed_value" {
+  value = [
+    "This is just a string",
+    [
+      {
+        Name                      = "Anton Babenko"
+        Age                       = 34
+        LoveSailing               = true
+        UnderstandHowToUseTwitter = false
+      },
+    ],
+    {
+      Github  = "antonbabenko"
+      Twitter = "antonbabenko"
+    },
+  ]
+}
+
+// Failing values ("=" inside values):
+output "failing_values_list" {
+  value = ["ukrainian = 100", "english", "unknown"]
+}
+
+output "failing_values_map" {
+  value = {
+    Name = "Anton Babenko"
+    Age  = 34
+  }
+}

examples/project2-terraform/core/terraform.tfstate

@@ -0,0 +1,108 @@
+{
+    "version": 3,
+    "terraform_version": "0.11.13",
+    "serial": 1,
+    "lineage": "71a91e74-7bee-1d3e-0202-e36cd675d7ac",
+    "modules": [
+        {
+            "path": [
+                "root"
+            ],
+            "outputs": {
+                "failing_values_list": {
+                    "sensitive": false,
+                    "type": "list",
+                    "value": [
+                        "ukrainian = 100",
+                        "english",
+                        "unknown"
+                    ]
+                },
+                "failing_values_map": {
+                    "sensitive": false,
+                    "type": "map",
+                    "value": {
+                        "Age": 34,
+                        "Name": "Anton Babenko"
+                    }
+                },
+                "languages": {
+                    "sensitive": false,
+                    "type": "list",
+                    "value": [
+                        "ukrainian",
+                        "russian",
+                        "english",
+                        "norwegian",
+                        "spanish"
+                    ]
+                },
+                "list_of_properties": {
+                    "sensitive": false,
+                    "type": "list",
+                    "value": [
+                        {
+                            "Age": 34,
+                            "LoveSailing": true,
+                            "Name": "Anton Babenko",
+                            "UnderstandHowToUseTwitter": false
+                        },
+                        {
+                            "Age": 123,
+                            "LoveSailing": false,
+                            "Name": "Kapitoshka"
+                        }
+                    ]
+                },
+                "love_sailing": {
+                    "sensitive": false,
+                    "type": "string",
+                    "value": "true"
+                },
+                "map_of_properties": {
+                    "sensitive": false,
+                    "type": "map",
+                    "value": {
+                        "Age": 34,
+                        "LoveSailing": true,
+                        "Name": "Anton Babenko"
+                    }
+                },
+                "mixed_value": {
+                    "sensitive": false,
+                    "type": "list",
+                    "value": [
+                        "This is just a string",
+                        {
+                            "Age": 34,
+                            "LoveSailing": true,
+                            "Name": "Anton Babenko",
+                            "UnderstandHowToUseTwitter": false
+                        },
+                        {
+                            "Github": "antonbabenko",
+                            "Twitter": "antonbabenko"
+                        }
+                    ]
+                },
+                "name": {
+                    "sensitive": false,
+                    "type": "string",
+                    "value": "Anton Babenko"
+                },
+                "score": {
+                    "sensitive": false,
+                    "type": "string",
+                    "value": "37"
+                },
+                "understand_how_to_use_twitter": {
+                    "sensitive": false,
+                    "type": "string",
+                    "value": "false"
+                }
+            },
+            "resources": {},
+            "depends_on": []
+        }
+    ]
+}