chore: Refactor to convert package

internal/cli/clu2adv/opts.go

@@ -3,8 +3,8 @@ package clu2adv
 import (
 	"fmt"
 
+	"github.com/mongodb-labs/atlas-cli-plugin-terraform/internal/convert"
 	"github.com/mongodb-labs/atlas-cli-plugin-terraform/internal/file"
-	"github.com/mongodb-labs/atlas-cli-plugin-terraform/internal/hcl"
 	"github.com/spf13/afero"
 )
 
@@ -30,7 +30,7 @@ func (o *opts) Run() error {
 	if err != nil {
 		return fmt.Errorf("failed to read file %s: %w", o.file, err)
 	}
-	outConfig, err := hcl.ClusterToAdvancedCluster(inConfig)
+	outConfig, err := convert.ClusterToAdvancedCluster(inConfig)
 	if err != nil {
 		return err
 	}

internal/convert/const_names.go

@@ -0,0 +1,33 @@
+package convert
+
+const (
+	nRepSpecs                   = "replication_specs"
+	nConfig                     = "region_configs"
+	nConfigSrc                  = "regions_config"
+	nElectableSpecs             = "electable_specs"
+	nAutoScaling                = "auto_scaling"
+	nRegionNameSrc              = "provider_region_name"
+	nRegionName                 = "region_name"
+	nProviderName               = "provider_name"
+	nBackingProviderName        = "backing_provider_name"
+	nInstanceSizeSrc            = "provider_instance_size_name"
+	nInstanceSize               = "instance_size"
+	nClusterType                = "cluster_type"
+	nPriority                   = "priority"
+	nNumShards                  = "num_shards"
+	nBackupEnabled              = "backup_enabled"
+	nCloudBackup                = "cloud_backup"
+	nDiskSizeGB                 = "disk_size_gb"
+	nDiskGBEnabledSrc           = "auto_scaling_disk_gb_enabled"
+	nComputeEnabledSrc          = "auto_scaling_compute_enabled"
+	nComputeScaleDownEnabledSrc = "auto_scaling_compute_scale_down_enabled"
+	nComputeMinInstanceSizeSrc  = "provider_auto_scaling_compute_min_instance_size"
+	nComputeMaxInstanceSizeSrc  = "provider_auto_scaling_compute_max_instance_size"
+	nDiskGBEnabled              = "disk_gb_enabled"
+	nComputeEnabled             = "compute_enabled"
+	nComputeScaleDownEnabled    = "compute_scale_down_enabled"
+	nComputeMinInstanceSize     = "compute_min_instance_size"
+	nComputeMaxInstanceSize     = "compute_max_instance_size"
+	nNodeCount                  = "node_count"
+	nElectableNodes             = "electable_nodes"
+)

internal/convert/convert.go

@@ -0,0 +1,209 @@
+package convert
+
+import (
+	"fmt"
+
+	"github.com/hashicorp/hcl/v2/hclwrite"
+	"github.com/mongodb-labs/atlas-cli-plugin-terraform/internal/hcl"
+	"github.com/zclconf/go-cty/cty"
+)
+
+const (
+	resourceType   = "resource"
+	cluster        = "mongodbatlas_cluster"
+	advCluster     = "mongodbatlas_advanced_cluster"
+	valClusterType = "REPLICASET"
+	valPriority    = 7
+	errFreeCluster = "free cluster (because no " + nRepSpecs + ")"
+	errRepSpecs    = "setting " + nRepSpecs
+)
+
+type attrVals struct {
+	req map[string]hclwrite.Tokens
+	opt map[string]hclwrite.Tokens
+}
+
+// ClusterToAdvancedCluster transforms all mongodbatlas_cluster definitions in a
+// Terraform configuration file into mongodbatlas_advanced_cluster schema v2 definitions.
+// All other resources and data sources are left untouched.
+// Note: hclwrite.Tokens are used instead of cty.Value so expressions like var.region can be preserved.
+// cty.Value only supports resolved values.
+func ClusterToAdvancedCluster(config []byte) ([]byte, error) {
+	parser, err := hcl.GetParser(config)
+	if err != nil {
+		return nil, err
+	}
+	for _, resource := range parser.Body().Blocks() {
+		labels := resource.Labels()
+		resourceName := labels[0]
+		if resource.Type() != resourceType || resourceName != cluster {
+			continue
+		}
+		resourceb := resource.Body()
+		labels[0] = advCluster
+		resource.SetLabels(labels)
+
+		if resourceb.FirstMatchingBlock(nRepSpecs, nil) != nil {
+			err = fillReplicationSpecs(resourceb)
+		} else {
+			err = fillFreeTier(resourceb)
+		}
+		if err != nil {
+			return nil, err
+		}
+
+		resourceb.AppendNewline()
+		hcl.AppendComment(resourceb, "Generated by atlas-cli-plugin-terraform.")
+		hcl.AppendComment(resourceb, "Please confirm that all references to this resource are updated.")
+	}
+	return parser.Bytes(), nil
+}
+
+// fillFreeTier is the entry point to convert clusters in free tier
+func fillFreeTier(resourceb *hclwrite.Body) error {
+	resourceb.SetAttributeValue(nClusterType, cty.StringVal(valClusterType))
+	config := hclwrite.NewEmptyFile()
+	configb := config.Body()
+	hcl.SetAttrInt(configb, "priority", valPriority)
+	if err := hcl.MoveAttr(resourceb, configb, nRegionNameSrc, nRegionName, errFreeCluster); err != nil {
+		return err
+	}
+	if err := hcl.MoveAttr(resourceb, configb, nProviderName, nProviderName, errFreeCluster); err != nil {
+		return err
+	}
+	if err := hcl.MoveAttr(resourceb, configb, nBackingProviderName, nBackingProviderName, errFreeCluster); err != nil {
+		return err
+	}
+	electableSpec := hclwrite.NewEmptyFile()
+	if err := hcl.MoveAttr(resourceb, electableSpec.Body(), nInstanceSizeSrc, nInstanceSize, errFreeCluster); err != nil {
+		return err
+	}
+	configb.SetAttributeRaw(nElectableSpecs, hcl.TokensObject(electableSpec))
+
+	repSpecs := hclwrite.NewEmptyFile()
+	repSpecs.Body().SetAttributeRaw(nConfig, hcl.TokensArrayObject(config))
+	resourceb.SetAttributeRaw(nRepSpecs, hcl.TokensArrayObject(repSpecs))
+	return nil
+}
+
+// fillReplicationSpecs is the entry point to convert clusters with replications_specs (all but free tier)
+func fillReplicationSpecs(resourceb *hclwrite.Body) error {
+	root, errRoot := popRootAttrs(resourceb, errRepSpecs)
+	if errRoot != nil {
+		return errRoot
+	}
+	repSpecsSrc := resourceb.FirstMatchingBlock(nRepSpecs, nil)
+	configSrc := repSpecsSrc.Body().FirstMatchingBlock(nConfigSrc, nil)
+	if configSrc == nil {
+		return fmt.Errorf("%s: %s not found", errRepSpecs, nConfigSrc)
+	}
+
+	resourceb.RemoveAttribute(nNumShards) // num_shards in root is not relevant, only in replication_specs
+	// ok to fail as cloud_backup is optional
+	_ = hcl.MoveAttr(resourceb, resourceb, nCloudBackup, nBackupEnabled, errRepSpecs)
+
+	config, errConfig := getRegionConfigs(configSrc, root)
+	if errConfig != nil {
+		return errConfig
+	}
+	repSpecs := hclwrite.NewEmptyFile()
+	repSpecs.Body().SetAttributeRaw(nConfig, config)
+	resourceb.SetAttributeRaw(nRepSpecs, hcl.TokensArrayObject(repSpecs))
+
+	resourceb.RemoveBlock(repSpecsSrc)
+	return nil
+}
+
+func getRegionConfigs(configSrc *hclwrite.Block, root attrVals) (hclwrite.Tokens, error) {
+	file := hclwrite.NewEmptyFile()
+	fileb := file.Body()
+	fileb.SetAttributeRaw(nProviderName, root.req[nProviderName])
+	if err := hcl.MoveAttr(configSrc.Body(), fileb, nRegionName, nRegionName, errRepSpecs); err != nil {
+		return nil, err
+	}
+	if err := hcl.MoveAttr(configSrc.Body(), fileb, nPriority, nPriority, errRepSpecs); err != nil {
+		return nil, err
+	}
+	autoScaling := getAutoScalingOpt(root.opt)
+	if autoScaling != nil {
+		fileb.SetAttributeRaw(nAutoScaling, autoScaling)
+	}
+	electableSpecs, errElect := getElectableSpecs(configSrc, root)
+	if errElect != nil {
+		return nil, errElect
+	}
+	fileb.SetAttributeRaw(nElectableSpecs, electableSpecs)
+	return hcl.TokensArrayObject(file), nil
+}
+
+func getElectableSpecs(configSrc *hclwrite.Block, root attrVals) (hclwrite.Tokens, error) {
+	file := hclwrite.NewEmptyFile()
+	fileb := file.Body()
+	if err := hcl.MoveAttr(configSrc.Body(), fileb, nElectableNodes, nNodeCount, errRepSpecs); err != nil {
+		return nil, err
+	}
+	fileb.SetAttributeRaw(nInstanceSize, root.req[nInstanceSizeSrc])
+	if root.opt[nDiskSizeGB] != nil {
+		fileb.SetAttributeRaw(nDiskSizeGB, root.opt[nDiskSizeGB])
+	}
+	return hcl.TokensObject(file), nil
+}
+
+func getAutoScalingOpt(opt map[string]hclwrite.Tokens) hclwrite.Tokens {
+	var (
+		names = [][2]string{ // use slice instead of map to preserve order
+			{nDiskGBEnabledSrc, nDiskGBEnabled},
+			{nComputeEnabledSrc, nComputeEnabled},
+			{nComputeMinInstanceSizeSrc, nComputeMinInstanceSize},
+			{nComputeMaxInstanceSizeSrc, nComputeMaxInstanceSize},
+			{nComputeScaleDownEnabledSrc, nComputeScaleDownEnabled},
+		}
+		file  = hclwrite.NewEmptyFile()
+		found = false
+	)
+	for _, tuple := range names {
+		src, dst := tuple[0], tuple[1]
+		if tokens := opt[src]; tokens != nil {
+			file.Body().SetAttributeRaw(dst, tokens)
+			found = true
+		}
+	}
+	if !found {
+		return nil
+	}
+	return hcl.TokensObject(file)
+}
+
+// popRootAttrs deletes the attributes common to all replication_specs/regions_config and returns them.
+func popRootAttrs(body *hclwrite.Body, errPrefix string) (attrVals, error) {
+	var (
+		reqNames = []string{
+			nProviderName,
+			nInstanceSizeSrc,
+		}
+		optNames = []string{
+			nDiskSizeGB,
+			nDiskGBEnabledSrc,
+			nComputeEnabledSrc,
+			nComputeMinInstanceSizeSrc,
+			nComputeMaxInstanceSizeSrc,
+			nComputeScaleDownEnabledSrc,
+		}
+		req = make(map[string]hclwrite.Tokens)
+		opt = make(map[string]hclwrite.Tokens)
+	)
+	for _, name := range reqNames {
+		tokens, err := hcl.PopAttr(body, name, errPrefix)
+		if err != nil {
+			return attrVals{}, err
+		}
+		req[name] = tokens
+	}
+	for _, name := range optNames {
+		tokens, _ := hcl.PopAttr(body, name, errPrefix)
+		if tokens != nil {
+			opt[name] = tokens
+		}
+	}
+	return attrVals{req: req, opt: opt}, nil
+}

internal/hcl/hcl_test.go → internal/convert/convert_test.go

@@ -1,12 +1,12 @@
-package hcl_test
+package convert_test
 
 import (
 	"encoding/json"
 	"path/filepath"
 	"strings"
 	"testing"
 
-	"github.com/mongodb-labs/atlas-cli-plugin-terraform/internal/hcl"
+	"github.com/mongodb-labs/atlas-cli-plugin-terraform/internal/convert"
 	"github.com/sebdah/goldie/v2"
 	"github.com/spf13/afero"
 	"github.com/stretchr/testify/assert"
@@ -38,7 +38,7 @@ func TestClusterToAdvancedCluster(t *testing.T) {
 		t.Run(testName, func(t *testing.T) {
 			inConfig, err := afero.ReadFile(fs, inputFile)
 			require.NoError(t, err)
-			outConfig, err := hcl.ClusterToAdvancedCluster(inConfig)
+			outConfig, err := convert.ClusterToAdvancedCluster(inConfig)
 			if err == nil {
 				g.Assert(t, testName, outConfig)
 			} else {