Add more file structure rules for locals and init

main.go

@@ -14,10 +14,11 @@ import (
  *  - Resources should be named `this` where possible.
  *  - No providers in modules (this can be ignored on a module by module basis if needed)
  * For all terraform
- *  - `terraform_remote_state {}` in _init.tf
- *  - `provider {}` in  _init.tf
- *  - `terraform {}` in _init.tf
- *  - Do we want to restrict where locals can be put?
+ *  - The following checks need tests:
+ *    - checkProviders
+ *    - checkTerraformBlock
+ *    - checkLocals
+ *    - checkTerraformRemoteState
  */
 
 //go:embed VERSION

rules/terraform_kb4_file_structure.go

@@ -9,7 +9,7 @@ import (
 	"github.com/terraform-linters/tflint-plugin-sdk/tflint"
 )
 
-var EXPECTED_FILES []string = []string{"_init.tf", "_variables.tf", "_outputs.tf"}
+var EXPECTED_FILES []string = []string{"_init.tf", "_variables.tf", "_outputs.tf", "_locals.tf"}
 
 // TerraformKb4FileStructureRule checks whether modules adhere to Terraform's standard module structure
 type TerraformKb4FileStructureRule struct {
@@ -48,6 +48,10 @@ func (r *TerraformKb4FileStructureRule) Check(runner tflint.Runner) error {
 	r.checkFiles(runner)
 	r.checkVariables(runner)
 	r.checkOutputs(runner)
+	r.checkProviders(runner)
+	r.checkTerraformBlock(runner)
+	r.checkLocals(runner)
+	r.checkTerraformRemoteState(runner)
 
 	return nil
 }
@@ -118,15 +122,127 @@ func (r *TerraformKb4FileStructureRule) checkOutputs(runner tflint.Runner) error
 		return err
 	}
 
-	for _, variable := range content.Blocks {
-		if variable.DefRange.Filename != "_outputs.tf" {
+	for _, output := range content.Blocks {
+		if output.DefRange.Filename != "_outputs.tf" {
 			runner.EmitIssue(
 				r,
-				fmt.Sprintf("variable %q should be moved from %s to %s", variable.Labels[0], variable.DefRange.Filename, "_outputs.tf"),
-				variable.DefRange,
+				fmt.Sprintf("output %q should be moved from %s to %s", output.Labels[0], output.DefRange.Filename, "_outputs.tf"),
+				output.DefRange,
 			)
 		}
 	}
 
 	return nil
 }
+
+func (r *TerraformKb4FileStructureRule) checkProviders(runner tflint.Runner) error {
+
+	content, err := runner.GetModuleContent(&hclext.BodySchema{
+		Blocks: []hclext.BlockSchema{
+			{
+				Type:       "provider",
+				LabelNames: []string{"name"},
+			},
+		},
+	}, nil)
+
+	if err != nil {
+		return err
+	}
+
+	for _, provider := range content.Blocks {
+		if provider.DefRange.Filename != "_init.tf" {
+			runner.EmitIssue(
+				r,
+				fmt.Sprintf("provider %q should be moved from %s to %s", provider.Labels[0], provider.DefRange.Filename, "_init.tf"),
+				provider.DefRange,
+			)
+		}
+	}
+
+	return nil
+}
+
+func (r *TerraformKb4FileStructureRule) checkTerraformBlock(runner tflint.Runner) error {
+
+	content, err := runner.GetModuleContent(&hclext.BodySchema{
+		Blocks: []hclext.BlockSchema{
+			{
+				Type:       "terraform",
+			},
+		},
+	}, nil)
+
+	if err != nil {
+		return err
+	}
+
+	for _, terraformBlock := range content.Blocks {
+		if terraformBlock.DefRange.Filename != "_init.tf" {
+			runner.EmitIssue(
+				r,
+				fmt.Sprintf("terraform block %q should be moved from %s to %s", terraformBlock.Labels[0], terraformBlock.DefRange.Filename, "_init.tf"),
+				terraformBlock.DefRange,
+			)
+		}
+	}
+
+	return nil
+}
+
+func (r *TerraformKb4FileStructureRule) checkLocals(runner tflint.Runner) error {
+
+	content, err := runner.GetModuleContent(&hclext.BodySchema{
+		Blocks: []hclext.BlockSchema{
+			{
+				Type:       "locals",
+			},
+		},
+	}, nil)
+
+	if err != nil {
+		return err
+	}
+
+	for _, locals := range content.Blocks {
+		if locals.DefRange.Filename != "_init.tf" {
+			runner.EmitIssue(
+				r,
+				fmt.Sprintf("locals block %q should be moved from %s to %s", locals.Labels[0], locals.DefRange.Filename, "_init.tf"),
+				locals.DefRange,
+			)
+		}
+	}
+
+	return nil
+}
+
+func (r *TerraformKb4FileStructureRule) checkTerraformRemoteState(runner tflint.Runner) error {
+
+	content, err := runner.GetModuleContent(&hclext.BodySchema{
+		Blocks: []hclext.BlockSchema{
+			{
+				Type:       "data",
+				LabelNames: []string{"name"},
+			},
+		},
+	}, nil)
+
+	if err != nil {
+		return err
+	}
+
+	for _, data := range content.Blocks {
+		if data.DefRange.Filename != "_init.tf" {
+			if data.Type == "terraform_remote_state" {
+				runner.EmitIssue(
+					r,
+					fmt.Sprintf("data terraform_remote_state %q should be moved from %s to %s", data.Name, data.DefRange.Filename, "_init.tf"),
+					data.DefRange,
+				)
+			}
+		}
+	}
+
+	return nil
+}

rules/terraform_kb4_file_structure_test.go

@@ -42,6 +42,14 @@ func Test_TerraformKb4ModuleStructureRule(t *testing.T) {
 						Start:    hcl.InitialPos,
 					},
 				},
+				{
+					Rule:    NewTerraformKb4FileStructureRule(),
+					Message: "Module should include a _locals.tf file.",
+					Range: hcl.Range{
+						Filename: "_locals.tf",
+						Start:    hcl.InitialPos,
+					},
+				},
 			},
 		},
 		{
@@ -50,6 +58,7 @@ func Test_TerraformKb4ModuleStructureRule(t *testing.T) {
 				"_init.tf":      `terraform {}`,
 				"_variables.tf": `variable "v" {}`,
 				// "_outputs.tf": `variable "v" {}`,
+				"_locals.tf": `locals {}`,
 			},
 			Expected: helper.Issues{
 				{
@@ -68,6 +77,7 @@ func Test_TerraformKb4ModuleStructureRule(t *testing.T) {
 				"_init.tf": `terraform {}`,
 				// "_variables.tf": `variable "some_variable" {}`,
 				"_outputs.tf": `output "some_output" {}`,
+				"_locals.tf": `locals {}`,
 			},
 			Expected: helper.Issues{
 				{
@@ -86,6 +96,7 @@ func Test_TerraformKb4ModuleStructureRule(t *testing.T) {
 				// "_init.tf": `terraform {}`,
 				"_variables.tf": `variable "some_variable" {}`,
 				"_outputs.tf":   `output "some_output" {}`,
+				"_locals.tf": `locals {}`,
 			},
 			Expected: helper.Issues{
 				{
@@ -98,12 +109,32 @@ func Test_TerraformKb4ModuleStructureRule(t *testing.T) {
 				},
 			},
 		},
+		{
+			Name: "missing locals file",
+			Content: map[string]string{
+				"_init.tf": `terraform {}`,
+				"_variables.tf": `variable "some_variable" {}`,
+				"_outputs.tf":   `output "some_output" {}`,
+				// "_locals.tf": `locals {}`,
+			},
+			Expected: helper.Issues{
+				{
+					Rule:    NewTerraformKb4FileStructureRule(),
+					Message: "Module should include a _locals.tf file.",
+					Range: hcl.Range{
+						Filename: filepath.Join("_locals.tf"),
+						Start:    hcl.InitialPos,
+					},
+				},
+			},
+		},
 		{
 			Name: "no missing files",
 			Content: map[string]string{
 				"_init.tf":      `terraform {}`,
 				"_variables.tf": `variable "some_variable" {}`,
 				"_outputs.tf":   `output "some_output" {}`,
+				"_locals.tf": `locals {}`,
 			},
 			Expected: helper.Issues{},
 		},
@@ -113,6 +144,7 @@ func Test_TerraformKb4ModuleStructureRule(t *testing.T) {
 				"_init.tf":      `variable "misplace_variable" {}`,
 				"_variables.tf": `variable "some_variable" {}`,
 				"_outputs.tf":   `output "some_output" {}`,
+				"_locals.tf": `locals {}`,
 			},
 			Expected: helper.Issues{
 				{