function/direxists: Add function that checks if a directory exists

.changes/unreleased/FEATURES-20240116-180627.yaml

@@ -0,0 +1,6 @@
+kind: FEATURES
+body: 'functions/direxists: Added a new `direxists` function that checks for the existence
+  of a directory, similar to the built-in `fileexists` function.'
+time: 2024-01-16T18:06:27.665639-05:00
+custom:
+  Issue: "285"

.github/workflows/test.yml

@@ -37,6 +37,13 @@ jobs:
         with:
           version: latest
 
+      # TODO: Temporary addition to ensure plugin-docs uses the v1.8.0-beta1 version of Terraform. This should be reverted once Terraform v1.8.0 is released.
+      - name: Setup Terraform (supporting provider functions)
+        uses: hashicorp/setup-terraform@a1502cd9e758c50496cc9ac5308c4843bcd56d36 # v3.0.0
+        with:
+          terraform_version: v1.8.0-beta1
+          terraform_wrapper: false
+
       - name: Generate
         run: make generate
 
@@ -73,7 +80,10 @@ jobs:
       - name: Setup Terraform ${{ matrix.terraform }}
         uses: hashicorp/setup-terraform@a1502cd9e758c50496cc9ac5308c4843bcd56d36 # v3.0.0
         with:
-          terraform_version: ${{ matrix.terraform }}.*
+          # TODO: Temporary change has been made to `vars.TF_VERSIONS_PROTOCOL_V5` to include the `.*` to enable us
+          # to utilize the v1.8.0-beta1 of Terraform. This should be reverted once Terraform v1.8.0 is released.
+          # terraform_version: ${{ matrix.terraform }}.*
+          terraform_version: ${{ matrix.terraform }}
           terraform_wrapper: false
 
       - name: Run acceptance test

docs/functions/direxists.md

@@ -0,0 +1,67 @@
+page_title: "direxists function - terraform-provider-local"
+subcategory: ""
+description: |-
+  Determines whether a directory exists at a given path.
+---
+
+# function: direxists
+
+Given a path string, will return true if the directory exists. This function works only with directories. If used with a file, the function will return an error.
+
+This function behaves similar to the built-in [`fileexists`](https://developer.hashicorp.com/terraform/language/functions/fileexists) function, however, `direxists` will not replace filesystem paths including `~` with the current user's home directory path. This functionality can be achieved by using the built-in [`pathexpand`](https://developer.hashicorp.com/terraform/language/functions/pathexpand) function with `direxists`, see example below.
+
+## Example Usage
+
+### Basic Usage
+
+```terraform
+# Configuration using provider functions must include required_providers configuration.
+terraform {
+  required_providers {
+    local = {
+      source = "hashicorp/local"
+      # Setting the provider version is a strongly recommended practice
+      # version = "..."
+    }
+  }
+  # Provider functions require Terraform 1.8 and later.
+  required_version = ">= 1.8.0"
+}
+
+output "example_output" {
+  value = provider::local::direxists("${path.module}/example-directory")
+}
+```
+
+### Usage with home directory
+
+```terraform
+# Configuration using provider functions must include required_providers configuration.
+terraform {
+  required_providers {
+    local = {
+      source = "hashicorp/local"
+      # Setting the provider version is a strongly recommended practice
+      # version = "..."
+    }
+  }
+  # Provider functions require Terraform 1.8 and later.
+  required_version = ">= 1.8.0"
+}
+
+output "example_output_homedir" {
+  value = provider::local::direxists(pathexpand("~/.ssh"))
+}
+```
+
+## Signature
+
+<!-- signature generated by tfplugindocs -->
+```text
+direxists(path string) bool
+```
+
+## Arguments
+
+<!-- arguments generated by tfplugindocs -->
+1. `path` (String) Relative or absolute path to check for the existence of a directory

examples/functions/direxists/basic.tf

@@ -0,0 +1,16 @@
+# Configuration using provider functions must include required_providers configuration.
+terraform {
+  required_providers {
+    local = {
+      source = "hashicorp/local"
+      # Setting the provider version is a strongly recommended practice
+      # version = "..."
+    }
+  }
+  # Provider functions require Terraform 1.8 and later.
+  required_version = ">= 1.8.0"
+}
+
+output "example_output" {
+  value = provider::local::direxists("${path.module}/example-directory")
+}

examples/functions/direxists/homedir.tf

@@ -0,0 +1,16 @@
+# Configuration using provider functions must include required_providers configuration.
+terraform {
+  required_providers {
+    local = {
+      source = "hashicorp/local"
+      # Setting the provider version is a strongly recommended practice
+      # version = "..."
+    }
+  }
+  # Provider functions require Terraform 1.8 and later.
+  required_version = ">= 1.8.0"
+}
+
+output "example_output_homedir" {
+  value = provider::local::direxists(pathexpand("~/.ssh"))
+}

go.mod

@@ -5,6 +5,7 @@ go 1.21
 toolchain go1.21.6
 
 require (
+	github.com/hashicorp/go-version v1.6.0
 	github.com/hashicorp/terraform-plugin-framework v1.6.1
 	github.com/hashicorp/terraform-plugin-framework-validators v0.12.0
 	github.com/hashicorp/terraform-plugin-go v0.22.0
@@ -27,7 +28,6 @@ require (
 	github.com/hashicorp/go-multierror v1.1.1 // indirect
 	github.com/hashicorp/go-plugin v1.6.0 // indirect
 	github.com/hashicorp/go-uuid v1.0.3 // indirect
-	github.com/hashicorp/go-version v1.6.0 // indirect
 	github.com/hashicorp/hc-install v0.6.3 // indirect
 	github.com/hashicorp/hcl/v2 v2.20.0 // indirect
 	github.com/hashicorp/logutils v1.0.0 // indirect

internal/provider/data_source_local_file_test.go

@@ -7,24 +7,19 @@ import (
 	"encoding/base64"
 	"testing"
 
+	"github.com/hashicorp/terraform-plugin-testing/config"
 	"github.com/hashicorp/terraform-plugin-testing/helper/resource"
 )
 
 func TestLocalFileDataSource(t *testing.T) {
 	content := "This is some content"
 	checkSums := genFileChecksums([]byte(content))
 
-	config := `
-		data "local_file" "file" {
-		  filename = "./testdata/local_file"
-		}
-	`
-
 	resource.UnitTest(t, resource.TestCase{
 		ProtoV5ProviderFactories: protoV5ProviderFactories(),
 		Steps: []resource.TestStep{
 			{
-				Config: config,
+				ConfigDirectory: config.TestNameDirectory(),
 				Check: resource.ComposeAggregateTestCheckFunc(
 					resource.TestCheckResourceAttr("data.local_file.file", "content", content),
 					resource.TestCheckResourceAttr("data.local_file.file", "content_base64", base64.StdEncoding.EncodeToString([]byte(content))),

internal/provider/data_source_local_sensitive_file_test.go

@@ -9,24 +9,19 @@ import (
 	"testing"
 
 	"github.com/hashicorp/terraform-plugin-framework/datasource"
+	"github.com/hashicorp/terraform-plugin-testing/config"
 	"github.com/hashicorp/terraform-plugin-testing/helper/resource"
 )
 
 func TestLocalFileSensitiveDataSource(t *testing.T) {
-	testFileContent := "This is some content"
+	testFileContent := "This is some sensitive content"
 	checkSums := genFileChecksums([]byte(testFileContent))
 
-	config := `
-		data "local_sensitive_file" "file" {
-		  filename = "./testdata/local_file"
-		}
-	`
-
 	resource.UnitTest(t, resource.TestCase{
 		ProtoV5ProviderFactories: protoV5ProviderFactories(),
 		Steps: []resource.TestStep{
 			{
-				Config: config,
+				ConfigDirectory: config.TestNameDirectory(),
 				Check: resource.ComposeAggregateTestCheckFunc(
 					resource.TestCheckResourceAttr("data.local_sensitive_file.file", "content", testFileContent),
 					resource.TestCheckResourceAttr("data.local_sensitive_file.file", "content_base64", base64.StdEncoding.EncodeToString([]byte(testFileContent))),

internal/provider/function_direxists.go

@@ -0,0 +1,83 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: MPL-2.0
+
+package provider
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/hashicorp/terraform-plugin-framework/function"
+	"github.com/hashicorp/terraform-plugin-framework/types"
+)
+
+var _ function.Function = &DirectoryExistsFunction{}
+
+type DirectoryExistsFunction struct{}
+
+func NewDirectoryExistsFunction() function.Function {
+	return &DirectoryExistsFunction{}
+}
+
+func (f *DirectoryExistsFunction) Metadata(ctx context.Context, req function.MetadataRequest, resp *function.MetadataResponse) {
+	resp.Name = "direxists"
+}
+
+func (f *DirectoryExistsFunction) Definition(ctx context.Context, req function.DefinitionRequest, resp *function.DefinitionResponse) {
+	resp.Definition = function.Definition{
+		Summary: "Determines whether a directory exists at a given path.",
+		Description: "Given a path string, will return true if the directory exists. " +
+			"This function works only with directories. If used with a file, the function will return an error.\n\n" +
+			"This function behaves similar to the built-in [`fileexists`](https://developer.hashicorp.com/terraform/language/functions/fileexists) function, " +
+			"however, `direxists` will not replace filesystem paths including `~` with the current user's home directory path. This functionality can be achieved by using the built-in " +
+			"[`pathexpand`](https://developer.hashicorp.com/terraform/language/functions/pathexpand) function with `direxists`, see example below.",
+
+		Parameters: []function.Parameter{
+			function.StringParameter{
+				Name:        "path",
+				Description: "Relative or absolute path to check for the existence of a directory",
+			},
+		},
+		Return: function.BoolReturn{},
+	}
+}
+
+func (f *DirectoryExistsFunction) Run(ctx context.Context, req function.RunRequest, resp *function.RunResponse) {
+	var inputPath string
+
+	resp.Error = req.Arguments.Get(ctx, &inputPath)
+	if resp.Error != nil {
+		return
+	}
+
+	directoryPath := inputPath
+	if !filepath.IsAbs(directoryPath) {
+		var err error
+		directoryPath, err = filepath.Abs(directoryPath)
+		if err != nil {
+			resp.Error = function.NewArgumentFuncError(0, fmt.Sprintf("Error expanding relative path to absolute path: %s", err))
+			return
+		}
+	}
+
+	directoryPath = filepath.Clean(directoryPath)
+
+	fi, err := os.Stat(directoryPath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			resp.Error = resp.Result.Set(ctx, types.BoolValue(false))
+			return
+		} else {
+			resp.Error = function.NewArgumentFuncError(0, fmt.Sprintf("Error checking for directory: %s", err))
+			return
+		}
+	}
+
+	if fi.IsDir() {
+		resp.Error = resp.Result.Set(ctx, types.BoolValue(true))
+		return
+	}
+	resp.Error = function.NewArgumentFuncError(0, fmt.Sprintf("Invalid file mode detected: %q was found, but is not a directory", inputPath))
+}

internal/provider/function_direxists_test.go

@@ -0,0 +1,69 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: MPL-2.0
+
+package provider
+
+import (
+	"regexp"
+	"testing"
+
+	"github.com/hashicorp/go-version"
+	"github.com/hashicorp/terraform-plugin-testing/config"
+	"github.com/hashicorp/terraform-plugin-testing/helper/resource"
+	"github.com/hashicorp/terraform-plugin-testing/knownvalue"
+	"github.com/hashicorp/terraform-plugin-testing/plancheck"
+	"github.com/hashicorp/terraform-plugin-testing/tfversion"
+)
+
+func TestDirectoryExists_basic(t *testing.T) {
+	resource.UnitTest(t, resource.TestCase{
+		TerraformVersionChecks: []tfversion.TerraformVersionCheck{
+			// TODO: Replace with the stable v1.8.0 release when available
+			tfversion.SkipBelow(version.Must(version.NewVersion("v1.8.0-beta1"))),
+		},
+		ProtoV5ProviderFactories: protoV5ProviderFactories(),
+		Steps: []resource.TestStep{
+			{
+				ConfigDirectory: config.TestNameDirectory(),
+				ConfigPlanChecks: resource.ConfigPlanChecks{
+					PreApply: []plancheck.PlanCheck{
+						plancheck.ExpectKnownOutputValue("test_dir_exists", knownvalue.Bool(true)),
+						plancheck.ExpectKnownOutputValue("test_dir_doesnt_exist", knownvalue.Bool(false)),
+					},
+				},
+			},
+		},
+	})
+}
+
+func TestDirectoryExists_invalid_file(t *testing.T) {
+	resource.UnitTest(t, resource.TestCase{
+		TerraformVersionChecks: []tfversion.TerraformVersionCheck{
+			// TODO: Replace with the stable v1.8.0 release when available
+			tfversion.SkipBelow(version.Must(version.NewVersion("v1.8.0-beta1"))),
+		},
+		ProtoV5ProviderFactories: protoV5ProviderFactories(),
+		Steps: []resource.TestStep{
+			{
+				ConfigDirectory: config.TestNameDirectory(),
+				ExpectError:     regexp.MustCompile("\"./testdata/TestDirectoryExists_invalid_file/not_a_dir.txt\" was found, but is\nnot a directory."),
+			},
+		},
+	})
+}
+
+func TestDirectoryExists_invalid_symlink(t *testing.T) {
+	resource.UnitTest(t, resource.TestCase{
+		TerraformVersionChecks: []tfversion.TerraformVersionCheck{
+			// TODO: Replace with the stable v1.8.0 release when available
+			tfversion.SkipBelow(version.Must(version.NewVersion("v1.8.0-beta1"))),
+		},
+		ProtoV5ProviderFactories: protoV5ProviderFactories(),
+		Steps: []resource.TestStep{
+			{
+				ConfigDirectory: config.TestNameDirectory(),
+				ExpectError:     regexp.MustCompile("\"./testdata/TestDirectoryExists_invalid_symlink/not_a_dir_symlink\" was found,\nbut is not a directory."),
+			},
+		},
+	})
+}

internal/provider/provider.go

@@ -13,13 +13,14 @@ import (
 	"encoding/hex"
 
 	"github.com/hashicorp/terraform-plugin-framework/datasource"
+	"github.com/hashicorp/terraform-plugin-framework/function"
 	"github.com/hashicorp/terraform-plugin-framework/provider"
 	"github.com/hashicorp/terraform-plugin-framework/provider/schema"
 	"github.com/hashicorp/terraform-plugin-framework/resource"
 )
 
 var (
-	_ provider.Provider = (*localProvider)(nil)
+	_ provider.ProviderWithFunctions = (*localProvider)(nil)
 )
 
 func New() provider.Provider {
@@ -50,6 +51,12 @@ func (p *localProvider) Resources(ctx context.Context) []func() resource.Resourc
 	}
 }
 
+func (p *localProvider) Functions(ctx context.Context) []func() function.Function {
+	return []func() function.Function{
+		NewDirectoryExistsFunction,
+	}
+}
+
 func (p *localProvider) Schema(ctx context.Context, req provider.SchemaRequest, resp *provider.SchemaResponse) {
 	resp.Schema = schema.Schema{}
 }