Add TFC usage detection

This builds on the existing methods to detect remote backend usage and adds detection of cloud blocks in the terraform block.

backend/cloud.go

@@ -0,0 +1,40 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: MPL-2.0
+
+package backend
+
+type CloudData interface {
+	Copy() CloudData
+	Equals(CloudData) bool
+}
+
+type UnknownCloudData struct{}
+
+func (*UnknownCloudData) Copy() CloudData {
+	return &UnknownCloudData{}
+}
+
+func (*UnknownCloudData) Equals(d CloudData) bool {
+	_, ok := d.(*UnknownCloudData)
+	return ok
+}
+
+type Cloud struct {
+	Organization string
+	Hostname     string
+}
+
+func (r *Cloud) Copy() CloudData {
+	return &Cloud{
+		Organization: r.Organization,
+	}
+}
+
+func (r *Cloud) Equals(d CloudData) bool {
+	data, ok := d.(*Cloud)
+	if !ok {
+		return false
+	}
+
+	return data.Organization == r.Organization
+}

earlydecoder/backend.go

@@ -30,3 +30,26 @@ func decodeBackendsBlock(block *hcl.Block) (backend.BackendData, hcl.Diagnostics
 
 	return &backend.UnknownBackendData{}, diags
 }
+
+func decodeCloudBlock(block *hcl.Block) (backend.CloudData, hcl.Diagnostics) {
+	attrs, diags := block.Body.JustAttributes()
+
+	// https://developer.hashicorp.com/terraform/language/settings/terraform-cloud#usage-example
+	// Required for Terraform Enterprise
+	// Defaults to app.terraform.io for Terraform Cloud
+	if attr, ok := attrs["hostname"]; ok {
+		val, vDiags := attr.Expr.Value(nil)
+		diags = append(diags, vDiags...)
+		if val.IsWhollyKnown() && val.Type() == cty.String {
+			return &backend.Cloud{
+				Hostname: val.AsString(),
+			}, nil
+		}
+	}
+
+	// since it defaults to app.terraform.io, it is safe to return that
+	// if hostname is empty
+	return &backend.Cloud{
+		Hostname: "app.terraform.io",
+	}, nil
+}

earlydecoder/decoder.go

@@ -41,6 +41,13 @@ func LoadModule(path string, files map[string]*hcl.File) (*module.Meta, hcl.Diag
 		coreRequirements = append(coreRequirements, c...)
 	}
 
+	var tfCloud *module.CloudBackend
+	if mod.CloudBackend != nil {
+		tfCloud = &module.CloudBackend{
+			Data: mod.CloudBackend,
+		}
+	}
+
 	var backend *module.Backend
 	if len(mod.Backends) == 1 {
 		for bType, data := range mod.Backends {
@@ -208,6 +215,7 @@ func LoadModule(path string, files map[string]*hcl.File) (*module.Meta, hcl.Diag
 	return &module.Meta{
 		Path:                 path,
 		Backend:              backend,
+		CloudBackend:         tfCloud,
 		ProviderReferences:   refs,
 		ProviderRequirements: providerRequirements,
 		CoreRequirements:     coreRequirements,

earlydecoder/decoder_test.go

@@ -997,6 +997,86 @@ terraform {
 	runTestCases(testCases, t, path)
 }
 
+func TestLoadModule_cloud(t *testing.T) {
+	path := t.TempDir()
+
+	testCases := []testCase{
+		{
+			"cloud backend",
+			`
+terraform {
+	cloud {
+		hostname = "app.terraform.io"
+		organization = "example_corp"
+
+		workspaces {
+			tags = ["app"]
+		}
+	}
+}`,
+			&module.Meta{
+				Path: path,
+				// Backend: &module.Backend{
+				// 	Type: "cloud",
+				// 	Data: &backend.Remote{
+				// 		Hostname: "app.terraform.io",
+				// 	},
+				// },
+				Backend: nil,
+				CloudBackend: &module.CloudBackend{
+					Data: &backend.Cloud{
+						Hostname: "app.terraform.io",
+					},
+				},
+				ProviderReferences:   map[module.ProviderRef]tfaddr.Provider{},
+				ProviderRequirements: map[tfaddr.Provider]version.Constraints{},
+				Variables:            map[string]module.Variable{},
+				Outputs:              map[string]module.Output{},
+				Filenames:            []string{"test.tf"},
+				ModuleCalls:          map[string]module.DeclaredModuleCall{},
+			},
+			nil,
+		},
+		{
+			"cloud backend empy hostname",
+			`
+terraform {
+	cloud {
+		organization = "example_corp"
+
+		workspaces {
+			tags = ["app"]
+		}
+	}
+}`,
+			&module.Meta{
+				Path: path,
+				// Backend: &module.Backend{
+				// 	Type: "cloud",
+				// 	Data: &backend.Remote{
+				// 		Hostname: "app.terraform.io",
+				// 	},
+				// },
+				Backend: nil,
+				CloudBackend: &module.CloudBackend{
+					Data: &backend.Cloud{
+						Hostname: "app.terraform.io",
+					},
+				},
+				ProviderReferences:   map[module.ProviderRef]tfaddr.Provider{},
+				ProviderRequirements: map[tfaddr.Provider]version.Constraints{},
+				Variables:            map[string]module.Variable{},
+				Outputs:              map[string]module.Output{},
+				Filenames:            []string{"test.tf"},
+				ModuleCalls:          map[string]module.DeclaredModuleCall{},
+			},
+			nil,
+		},
+	}
+
+	runTestCases(testCases, t, path)
+}
+
 func TestLoadModule_Modules(t *testing.T) {
 	path := t.TempDir()
 

earlydecoder/load_module.go

@@ -22,6 +22,7 @@ import (
 type decodedModule struct {
 	RequiredCore         []string
 	Backends             map[string]backend.BackendData
+	CloudBackend         backend.CloudData
 	ProviderRequirements map[string]*providerRequirement
 	ProviderConfigs      map[string]*providerConfig
 	Resources            map[string]*resource
@@ -78,6 +79,10 @@ func loadModuleFromFile(file *hcl.File, mod *decodedModule) hcl.Diagnostics {
 
 			for _, innerBlock := range content.Blocks {
 				switch innerBlock.Type {
+				case "cloud":
+					data, bDiags := decodeCloudBlock(innerBlock)
+					diags = append(diags, bDiags...)
+					mod.CloudBackend = data
 				case "backend":
 					bType := innerBlock.Labels[0]
 
@@ -95,7 +100,6 @@ func loadModuleFromFile(file *hcl.File, mod *decodedModule) hcl.Diagnostics {
 					}
 
 					mod.Backends[bType] = data
-
 				case "required_providers":
 					reqs, reqsDiags := decodeRequiredProvidersBlock(innerBlock)
 					diags = append(diags, reqsDiags...)

earlydecoder/schema.go

@@ -49,6 +49,9 @@ var terraformBlockSchema = &hcl.BodySchema{
 		{
 			Type: "required_providers",
 		},
+		{
+			Type: "cloud",
+		},
 		{
 			Type:       "backend",
 			LabelNames: []string{"type"},

module/meta.go

@@ -14,6 +14,7 @@ type Meta struct {
 	Filenames []string
 
 	Backend              *Backend
+	CloudBackend         *CloudBackend
 	ProviderReferences   map[ProviderRef]tfaddr.Provider
 	ProviderRequirements ProviderRequirements
 	CoreRequirements     version.Constraints
@@ -42,6 +43,22 @@ func (pr ProviderRequirements) Equals(reqs ProviderRequirements) bool {
 	return true
 }
 
+type CloudBackend struct {
+	Data backend.CloudData
+}
+
+func (be *CloudBackend) Equals(b *CloudBackend) bool {
+	if be == nil && b == nil {
+		return true
+	}
+
+	if be == nil || b == nil {
+		return false
+	}
+
+	return be.Data.Equals(b.Data)
+}
+
 type Backend struct {
 	Type string
 	Data backend.BackendData