Config Generation: Configurable Terraform Install

cmd/generate/main.go

@@ -9,6 +9,7 @@ import (
 	"github.com/grafana/terraform-provider-grafana/v3/pkg/generate"
 
 	"github.com/fatih/color"
+	goVersion "github.com/hashicorp/go-version"
 	"github.com/urfave/cli/v2"
 )
 
@@ -74,6 +75,18 @@ This supports a glob format. Examples:
 				EnvVars: []string{"TFGEN_OUTPUT_CREDENTIALS"},
 				Value:   false,
 			},
+			&cli.StringFlag{
+				Name:     "terraform-install-dir",
+				Usage:    `Directory to install Terraform to. If not set, a temporary directory will be created.`,
+				EnvVars:  []string{"TFGEN_TERRAFORM_INSTALL_DIR"},
+				Required: false,
+			},
+			&cli.StringFlag{
+				Name:     "terraform-install-version",
+				Usage:    `Version of Terraform to install. If not set, the latest version _tested in this tool_ will be installed.`,
+				EnvVars:  []string{"TFGEN_TERRAFORM_INSTALL_VERSION"},
+				Required: false,
+			},
 
 			// Grafana OSS flags
 			&cli.StringFlag{
@@ -184,14 +197,24 @@ func parseFlags(ctx *cli.Context) (*generate.Config, error) {
 			StackServiceAccountName:   ctx.String("cloud-stack-service-account-name"),
 		},
 		IncludeResources: ctx.StringSlice("include-resources"),
+		TerraformInstallConfig: generate.TerraformInstallConfig{
+			InstallDir: ctx.String("terraform-install-dir"),
+		},
+	}
+	var err error
+	if tfVersion := ctx.String("terraform-install-version"); tfVersion != "" {
+		config.TerraformInstallConfig.Version, err = goVersion.NewVersion(ctx.String("terraform-install-version"))
+		if err != nil {
+			return nil, fmt.Errorf("terraform-install-version must be a valid version: %w", err)
+		}
 	}
 
 	if config.ProviderVersion == "" {
 		return nil, fmt.Errorf("terraform-provider-version must be set")
 	}
 
 	// Validate flags
-	err := newFlagValidations().
+	err = newFlagValidations().
 		atLeastOne("grafana-url", "cloud-access-policy-token").
 		conflicting(
 			[]string{"grafana-url", "grafana-auth", "synthetic-monitoring-url", "synthetic-monitoring-access-token", "oncall-url", "oncall-access-token"},

pkg/generate/config.go

@@ -1,6 +1,9 @@
 package generate
 
-import "github.com/hashicorp/terraform-exec/tfexec"
+import (
+	"github.com/hashicorp/go-version"
+	"github.com/hashicorp/terraform-exec/tfexec"
+)
 
 type OutputFormat string
 
@@ -29,6 +32,11 @@ type CloudConfig struct {
 	StackServiceAccountName   string
 }
 
+type TerraformInstallConfig struct {
+	InstallDir string
+	Version    *version.Version
+}
+
 type Config struct {
 	// IncludeResources is a list of patterns to filter resources by.
 	// If a resource name matches any of the patterns, it will be included in the output.
@@ -43,5 +51,7 @@ type Config struct {
 	ProviderVersion   string
 	Grafana           *GrafanaConfig
 	Cloud             *CloudConfig
-	Terraform         *tfexec.Terraform
+
+	TerraformInstallConfig TerraformInstallConfig
+	Terraform              *tfexec.Terraform
 }

pkg/generate/generate.go

@@ -63,6 +63,7 @@ func Generate(ctx context.Context, cfg *Config) error {
 	cfg.Terraform = tf
 
 	if cfg.Cloud != nil {
+		log.Printf("Generating cloud resources")
 		stacks, err := generateCloudResources(ctx, cfg)
 		if err != nil {
 			return err
@@ -86,6 +87,7 @@ func Generate(ctx context.Context, cfg *Config) error {
 			onCallToken:   cfg.Grafana.OnCallAccessToken,
 			onCallURL:     cfg.Grafana.OnCallURL,
 		}
+		log.Printf("Generating Grafana resources")
 		if err := generateGrafanaResources(ctx, cfg, stack, true); err != nil {
 			return err
 		}

pkg/generate/generate_test.go

@@ -22,6 +22,9 @@ func TestAccGenerate(t *testing.T) {
 	}
 	testutils.CheckOSSTestsEnabled(t)
 
+	// Install Terraform to a temporary directory to avoid reinstalling it for each test case.
+	installDir := t.TempDir()
+
 	cases := []struct {
 		name           string
 		config         string
@@ -175,6 +178,9 @@ func TestAccGenerate(t *testing.T) {
 									URL:  "http://localhost:3000",
 									Auth: "admin:admin",
 								},
+								TerraformInstallConfig: generate.TerraformInstallConfig{
+									InstallDir: installDir,
+								},
 							}
 							if tc.generateConfig != nil {
 								tc.generateConfig(&config)

pkg/generate/terraform.go

@@ -5,11 +5,13 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"log"
 	"os"
 	"path/filepath"
 	"strings"
 
 	"github.com/hashicorp/go-version"
+	"github.com/hashicorp/hc-install/fs"
 	"github.com/hashicorp/hc-install/product"
 	"github.com/hashicorp/hc-install/releases"
 	"github.com/hashicorp/hcl/v2"
@@ -20,14 +22,42 @@ import (
 )
 
 func setupTerraform(cfg *Config) (*tfexec.Terraform, error) {
-	installer := &releases.ExactVersion{
-		Product: product.Terraform,
-		Version: version.Must(version.NewVersion("1.8.4")),
+	var err error
+
+	tfVersion := cfg.TerraformInstallConfig.Version
+	if tfVersion == nil {
+		// Not using latest to avoid unexpected breaking changes
+		log.Printf("No Terraform version specified, defaulting to version 1.8.5")
+		tfVersion = version.Must(version.NewVersion("1.8.5"))
 	}
 
-	execPath, err := installer.Install(context.Background())
-	if err != nil {
-		return nil, fmt.Errorf("error installing Terraform: %s", err)
+	// Check if Terraform is already installed
+	var execPath string
+	if cfg.TerraformInstallConfig.InstallDir != "" {
+		finder := fs.ExactVersion{
+			Product: product.Terraform,
+			Version: tfVersion,
+			ExtraPaths: []string{
+				cfg.TerraformInstallConfig.InstallDir,
+			},
+		}
+
+		if execPath, err = finder.Find(context.Background()); err == nil {
+			log.Printf("Terraform %s already installed at %s", tfVersion, execPath)
+		}
+	}
+
+	// Install Terraform if not found
+	if execPath == "" {
+		log.Printf("Installing Terraform %s", tfVersion)
+		installer := &releases.ExactVersion{
+			Product:    product.Terraform,
+			Version:    tfVersion,
+			InstallDir: cfg.TerraformInstallConfig.InstallDir,
+		}
+		if execPath, err = installer.Install(context.Background()); err != nil {
+			return nil, fmt.Errorf("error installing Terraform: %s", err)
+		}
 	}
 
 	tf, err := tfexec.NewTerraform(cfg.OutputDir, execPath)