cli: remove/refactor upgrade package (#2266)

* Move IAM migration client to cloudcmd package

* Move Terraform Cluster upgrade client to cloudcmd package

* Use hcl for creating Terraform IAM variables files

* Unify terraform upgrade code

* Rename some cloudcmd files for better clarity

---------

Signed-off-by: Daniel Weiße <dw@edgeless.systems>

cli/internal/cloudcmd/tfupgrade.go

@@ -0,0 +1,82 @@
+/*
+Copyright (c) Edgeless Systems GmbH
+
+SPDX-License-Identifier: AGPL-3.0-only
+*/
+
+package cloudcmd
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"os"
+
+	"github.com/edgelesssys/constellation/v2/cli/internal/terraform"
+	"github.com/edgelesssys/constellation/v2/internal/file"
+)
+
+// planUpgrade prepares a workspace and plans the possible Terraform migrations.
+// In case of possible migrations, the diff is written to outWriter and this function returns true.
+func planUpgrade(
+	ctx context.Context, tfClient tfUpgradePlanner, fileHandler file.Handler,
+	outWriter io.Writer, logLevel terraform.LogLevel, vars terraform.Variables,
+	templateDir, existingWorkspace, backupDir string,
+) (bool, error) {
+	if err := ensureFileNotExist(fileHandler, backupDir); err != nil {
+		return false, fmt.Errorf("workspace is not clean: %w", err)
+	}
+
+	// Prepare the new Terraform workspace and backup the old one
+	err := tfClient.PrepareUpgradeWorkspace(
+		templateDir,
+		existingWorkspace,
+		backupDir,
+		vars,
+	)
+	if err != nil {
+		return false, fmt.Errorf("preparing terraform workspace: %w", err)
+	}
+
+	hasDiff, err := tfClient.Plan(ctx, logLevel)
+	if err != nil {
+		return false, fmt.Errorf("terraform plan: %w", err)
+	}
+
+	if hasDiff {
+		if err := tfClient.ShowPlan(ctx, logLevel, outWriter); err != nil {
+			return false, fmt.Errorf("terraform show plan: %w", err)
+		}
+	}
+
+	return hasDiff, nil
+}
+
+// moveUpgradeToCurrent replaces the an existing Terraform workspace with a workspace holding migrated Terraform resources.
+func moveUpgradeToCurrent(fileHandler file.Handler, existingWorkspace, upgradeWorkingDir string) error {
+	if err := fileHandler.RemoveAll(existingWorkspace); err != nil {
+		return fmt.Errorf("removing old terraform directory: %w", err)
+	}
+	if err := fileHandler.CopyDir(
+		upgradeWorkingDir,
+		existingWorkspace,
+	); err != nil {
+		return fmt.Errorf("replacing old terraform directory with new one: %w", err)
+	}
+
+	if err := fileHandler.RemoveAll(upgradeWorkingDir); err != nil {
+		return fmt.Errorf("removing terraform upgrade directory: %w", err)
+	}
+	return nil
+}
+
+// ensureFileNotExist checks if a single file or directory does not exist, returning an error if it does.
+func ensureFileNotExist(fileHandler file.Handler, fileName string) error {
+	if _, err := fileHandler.Stat(fileName); err != nil {
+		if !os.IsNotExist(err) {
+			return fmt.Errorf("checking %q: %w", fileName, err)
+		}
+		return nil
+	}
+	return fmt.Errorf("%q already exists", fileName)
+}