https://github.com/magodo/terrassist

A small tool to assist Terraform Provider developers to generate flatten/expand function ⚒
https://github.com/magodo/terrassist

codegen terraform terraform-provider

Last synced: 11 days ago
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A small tool to assist Terraform Provider developers to generate flatten/expand function ⚒

• Host: GitHub
• URL: https://github.com/magodo/terrassist
• Owner: magodo
• License: mit
• Created: 2021-03-20T04:59:01.000Z (over 3 years ago)
• Default Branch: main
• Last Pushed: 2021-12-13T06:44:29.000Z (almost 3 years ago)
• Last Synced: 2024-10-13T01:09:41.015Z (26 days ago)
• Topics: codegen, terraform, terraform-provider
• Language: Go
• Homepage:
• Size: 180 KB
• Stars: 5
• Watchers: 3
• Forks: 2
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# Terrassist

A small tool to assist Terraform Provider developers to generate `flatten/expand` functions.

## Install

For Go v1.16+: 

```

go install github.com/magodo/terrassist@latest

```

Otherwise:

```

go get github.com/magodo/terrassist

```

## Usage

This tool is used to generate Go code that defines the Terraform Provider `flatten/expand` function for a particular Go type (e.g. a structure). Normally, the target type is defined in some SDK that your provider mainly depends on (e.g. [terraform-providers/terraform-provider-azurerm](https://github.com/terraform-providers/terraform-provider-azurerm) depends on [Azure/azure-sdk-for-go](https://github.com/azure/azure-sdk-for-go)).

To generate the code, users will need to run this tool under the provider codebase folder, where the codebase is technically a **Go module that has added the dependency towards the target SDK module**. Then follow the usage of this tool as below, to run the tool:

```

terrassist [options]  

Given a type "Foo",  can be one of:

  - Foo

  - *Foo

  - map[string]Foo

  - map[string]*Foo

  - *map[string]Foo

  - *map[string]*Foo

  - []Foo

  - []*Foo

  - *[]Foo

  - *[]*Foo

Options:

  -j    Ignore struct field that has json tag "-" specified

```

## Example

Under the cloned [terraform-providers/terraform-provider-aws](https://github.com/terraform-providers/terraform-provider-aws) repository root folder, run:

```

terrassist github.com/aws/aws-sdk-go/service/elasticache CreateCacheParameterGroupInput

```

It will then output:

```go

package main

import (

        elasticache "github.com/aws/aws-sdk-go/service/elasticache"

        utils "types/utils"

)

func expandCreateCacheParameterGroupInput(input []interface{}) elasticache.CreateCacheParameterGroupInput {

        if len(input) == 0 || input[0] == nil {

                return elasticache.CreateCacheParameterGroupInput{}

        }

        b := input[0].(map[string]interface{})

        output := elasticache.CreateCacheParameterGroupInput{

                CacheParameterGroupFamily: utils.String(b["cache_parameter_group_family"].(string)),

                CacheParameterGroupName:   utils.String(b["cache_parameter_group_name"].(string)),

                Description:               utils.String(b["description"].(string)),

        }

        return output

}

func flattenCreateCacheParameterGroupInput(input elasticache.CreateCacheParameterGroupInput) []interface{} {

        var cacheParameterGroupFamily string

        if input.CacheParameterGroupFamily != nil {

                cacheParameterGroupFamily = *input.CacheParameterGroupFamily

        }

        var cacheParameterGroupName string

        if input.CacheParameterGroupName != nil {

                cacheParameterGroupName = *input.CacheParameterGroupName

        }

        var description string

        if input.Description != nil {

                description = *input.Description

        }

        return []interface{}{map[string]interface{}{

                "cache_parameter_group_family": cacheParameterGroupFamily,

                "cache_parameter_group_name":   cacheParameterGroupName,

                "description":                  description,

        }}

}

```

Note: 

- The `package` name will be set to the package name of the folder you are running this tool.

- The namings used in the Terraform `ResourceData`/schema is the snake cased form of the corresponding field.

- There is a hypothetic `types/utils` package involved. The reason is that most popular providers (e.g. aws, azurerm/azuread, etc.) has their own `utils` package that provides functions that convert a basic type to its pointer. So we are not reinventing this, rather users need only replace the import path to using the one that is available in your provider codebase.