CODEWITHSUNDEEP
amazon-web-servicesterraformterraform-cdk
crazyTech
crazyTech

Reputation: 1477

input variable fails to get applied during the cdktf synth execution

Here is info about our technical development environment :

The AWS Lambda project contains the following:

cdktf debug

language: csharp

cdktf-cli: 0.20.6

node: v18.20.1

cdktf: 0.20.6

constructs: 10.3.0

jsii: 1.96.0

terraform: 1.5.7

arch: x64

os: win32 10.0.22631

dotnet: 8.0.202

providers

HashiCorp.Cdktf.Providers.Aws (PREBUILT)

    terraform provider version: 5.44.0

    prebuilt provider version: 19.13.0

    cdktf version: ^0.20.0 HashiCorp.Cdktf.Providers.Docker (PREBUILT)

    terraform provider version: 3.0.2

    prebuilt provider version: 11.0.0

    cdktf version: ^0.20.0 P

I am trying to use Terraform CDKTF tool to deploy a C#-based AWS Lambda to Amazon AWS Cloud.

In my Visual Studio 2022 Solution, I have the following projects:

I build the AWSSrvlessHelloWorldApp Lambda Project.

I wanted to supply argument parameters when I run cdktf deploy

Therefore, as I researched, I came across the following webpage link that describes how to use Terraform variables as input parameters:

https://developer.hashicorp.com/terraform/cdktf/concepts/variables-and-outputs

Here is an excerpt from the aforementioned webpage that shows sample declaration & instantiation of Terraform variables as input parameters in C#:

I build the AWSSrvlessHelloWorldApp Lambda Project.

I wanted to supply argument parameters when I run cdktf deploy

Therefore, as I researched, I came across the following webpage link that describes how to use Terraform variables as input parameters:

https://developer.hashicorp.com/terraform/cdktf/concepts/variables-and-outputs

Here is an excerpt from the aforementioned webpage that shows sample declaration & instantiation of Terraform variables as input parameters in C#:

TerraformVariable imageId = new TerraformVariable(this, "imageId",
    new TerraformVariableConfig
    {
        Type = "string",
        Default = "ami-abcde123",
        Description = "What AMI to use to create an instance",
    });

new Instance(this, "hello", new InstanceConfig
    {
        Ami = imageId.StringValue,
        InstanceType = "t2.micro",
    });

In the MyTerraformStack ( i.e. the TerraformStack Project) I have the following files:

In Program.cs , I have the following code( Please note that I use Debugger.Launch() so that I can bring up the MyTerraformStack in Visual Studio 2022 whenever I run cdktf from Powershell commandline ) :

class Program
{
    public static void Main(string[] args)
    {
        Debugger.Launch();
        App app = new App();
        MainStack stack = new MainStack(app, "aws_instance");
        app.Synth();
    }
}

In MainStack.cs, the code content’s are:

class MainStack : TerraformStack
{
    public MainStack(Construct scope, string id) : base(scope, id)
    {
        TerraformVariable imageId = new TerraformVariable(this, "imageId", new
        TerraformVariableConfig
        {
        Type = "string",
        Default = "ami-abcde123",
        Description = "What AMI to use to create an instance",
        });

        new Instance(this, "hello", new InstanceConfig
        {
        Ami = imageId.StringValue,
        InstanceType = "t2.micro",
        });

        Console.Error.WriteLine("imageId.ToString()");
        Console.Error.WriteLine(imageId.ToString());

        Console.Error.WriteLine("imageId.StringValue");
        Console.Error.WriteLine(imageId.StringValue);

        ...Blah Blah configuring ITerraformAssetConfig and

        IS3BucketObjectConfig and IIamRoleConfig

        Blah Blah...

        ...Blah Blah instantiating S3BucketObject , IamRole ,

        LambdaFunction Blah Blah Blah

    } 
}

In Windows Powershell, I've run the following:

$Env:TF_VAR_imageId="testing"

cdktf synth

However, when I Console Writeline code gets executes, I gives the following output:

imageId.ToString()

[2024-04-08T14:59:56.904] [ERROR] default - ${TfToken[TOKEN.1]}

imageId.StringValue

[2024-04-08T14:59:56.904] [ERROR] default - ${TfToken[TOKEN.2]}

The imageId's value fails to get applied during the cdktf synth execution. Why, and could someone please tell me how to resolve said problem?

Upvotes: 0

Views: 132

Answers (1)

crazyTech
crazyTech

Reputation: 1477

LOL you stackoverflow folks are all slacking. :)

I got the following solution from someone on reddit

In my C# Terraform CDKTF application, I have the following snippet of code:

TerraformVariable imageId = new TerraformVariable(this, "imageId", new TerraformVariableConfig

{

Type = "string",

Default = "ami-abcde123",

Description = "What AMI to use to create an instance",

});

Console.Error.WriteLine("****************************************");

Console.Error.WriteLine("****************************************");

Console.Error.WriteLine("imageId.StringValue");

Console.Error.WriteLine(imageId.StringValue);

Console.Error.WriteLine("imageId.Value.ToString()");

Console.Error.WriteLine(imageId.Value.ToString());

Console.Error.WriteLine("****************************************");

Console.Error.WriteLine("****************************************");

TerraformOutput outputVar = new TerraformOutput(this, "outputVar", new TerraformOutputConfig

{

Value = imageId.StringValue,

});

Console.Error.WriteLine("****************************************");

Console.Error.WriteLine("****************************************");

Console.Error.WriteLine("outputVar.Value");

Console.Error.WriteLine(outputVar.Value);

I have a file called inputfile.tfvars that will be processed as input, and it contains:

imageId = "testing"

after running the following commands in order, it worked:

cdktf synth

cdktf deploy -var-file="inputfile.tfvars"

Upvotes: 0

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