Ignore unknown attributes error in state

pkg/iac/terraform/state/terraform_state_reader.go

@@ -1,20 +1,19 @@
 package state
 
 import (
-	"github.com/cloudskiff/driftctl/pkg/remote/deserializer"
-	"github.com/hashicorp/terraform/addrs"
-
 	"github.com/cloudskiff/driftctl/pkg/iac"
 	"github.com/cloudskiff/driftctl/pkg/iac/config"
 	"github.com/cloudskiff/driftctl/pkg/iac/terraform/state/backend"
+	"github.com/cloudskiff/driftctl/pkg/remote/deserializer"
 	"github.com/cloudskiff/driftctl/pkg/resource"
 	"github.com/cloudskiff/driftctl/pkg/terraform"
-
-	"github.com/hashicorp/terraform/states/statefile"
-
+	"github.com/hashicorp/terraform/addrs"
 	"github.com/hashicorp/terraform/states"
+	"github.com/hashicorp/terraform/states/statefile"
 	"github.com/sirupsen/logrus"
 	"github.com/zclconf/go-cty/cty"
+	ctyconvert "github.com/zclconf/go-cty/cty/convert"
+	ctyjson "github.com/zclconf/go-cty/cty/json"
 )
 
 const TerraformStateReaderSupplier = "tfstate"
@@ -54,11 +53,13 @@ func (r *TerraformStateReader) retrieve() (map[string][]cty.Value, error) {
 	stateResources := state.RootModule().Resources
 	resMap := make(map[string][]cty.Value)
 	for _, stateRes := range stateResources {
+		resName := stateRes.Addr.Resource.Name
+		resType := stateRes.Addr.Resource.Type
 		if stateRes.Addr.Resource.Mode != addrs.ManagedResourceMode {
 			logrus.WithFields(logrus.Fields{
 				"mode": stateRes.Addr.Resource.Mode,
-				"name": stateRes.Addr.Resource.Name,
-				"type": stateRes.Addr.Resource.Type,
+				"name": resName,
+				"type": resType,
 			}).Debug("Skipping state entry as it is not a managed resource")
 			continue
 		}
@@ -74,8 +75,28 @@ func (r *TerraformStateReader) retrieve() (map[string][]cty.Value, error) {
 		for _, instance := range stateRes.Instances {
 			decodedVal, err := instance.Current.Decode(schema.Block.ImpliedType())
 			if err != nil {
-				logrus.Error(err)
-				continue
+				// Try to do a manual type conversion if we got a path error
+				// It will allow driftctl to read state generated with a superior version of provider
+				// than the actually supported one
+				// by ignoring new fields
+				_, isPathError := err.(cty.PathError)
+				if isPathError {
+					logrus.WithFields(logrus.Fields{
+						"name": resName,
+						"type": resType,
+						"err":  err.Error(),
+					}).Debug("Got a cty path error when deserializing state")
+
+					decodedVal, err = r.convertInstance(instance.Current, schema.Block.ImpliedType())
+				}
+
+				if err != nil {
+					logrus.WithFields(logrus.Fields{
+						"name": resName,
+						"type": resType,
+					}).Error("Unable to decode resource from state")
+					return nil, err
+				}
 			}
 			_, exists := resMap[stateRes.Addr.Resource.Type]
 			if !exists {
@@ -91,6 +112,34 @@ func (r *TerraformStateReader) retrieve() (map[string][]cty.Value, error) {
 	return resMap, nil
 }
 
+func (r *TerraformStateReader) convertInstance(instance *states.ResourceInstanceObjectSrc, ty cty.Type) (*states.ResourceInstanceObject, error) {
+	inputType, err := ctyjson.ImpliedType(instance.AttrsJSON)
+	if err != nil {
+		return nil, err
+	}
+	input, err := ctyjson.Unmarshal(instance.AttrsJSON, inputType)
+	if err != nil {
+		return nil, err
+	}
+
+	convertedVal, err := ctyconvert.Convert(input, ty)
+	if err != nil {
+		return nil, err
+	}
+
+	instanceObj := &states.ResourceInstanceObject{
+		Value:               convertedVal,
+		Status:              instance.Status,
+		Dependencies:        instance.Dependencies,
+		Private:             instance.Private,
+		CreateBeforeDestroy: instance.CreateBeforeDestroy,
+	}
+
+	logrus.Debug("Successfully converted resource")
+
+	return instanceObj, nil
+}
+
 func (r *TerraformStateReader) decode(values map[string][]cty.Value) ([]resource.Resource, error) {
 	results := make([]resource.Resource, 0)
 	for _, deserializer := range r.deserializers {

pkg/iac/terraform/state/terraform_state_reader_test.go

@@ -7,13 +7,12 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/cloudskiff/driftctl/test/goldenfile"
-
 	"github.com/cloudskiff/driftctl/pkg/iac"
 	"github.com/cloudskiff/driftctl/pkg/iac/terraform/state/backend"
 	"github.com/cloudskiff/driftctl/pkg/remote/aws"
 	"github.com/cloudskiff/driftctl/pkg/resource"
 	"github.com/cloudskiff/driftctl/pkg/terraform"
+	"github.com/cloudskiff/driftctl/test/goldenfile"
 	"github.com/cloudskiff/driftctl/test/mocks"
 
 	"github.com/r3labs/diff/v2"
@@ -50,6 +49,7 @@ func TestTerraformStateReader_Resources(t *testing.T) {
 		{name: "RDS DB instance", dirName: "db_instance", wantErr: false},
 		{name: "RDS DB Subnet group", dirName: "db_subnet_group", wantErr: false},
 		{name: "Lambda function", dirName: "lambda_function", wantErr: false},
+		{name: "unsupported attribute", dirName: "unsupported_attribute", wantErr: false},
 		{name: "Unsupported provider", dirName: "unsupported_provider", wantErr: false},
 		{name: "EC2 instance", dirName: "ec2_instance", wantErr: false},
 		{name: "EC2 key pair", dirName: "ec2_key_pair", wantErr: false},

pkg/iac/terraform/state/test/unsupported_attribute/result.golden.json

@@ -0,0 +1,76 @@
+[
+ {
+  "Ami": "ami-0f8e5edde3a79f541",
+  "Arn": "arn:aws:ec2:eu-west-3:929327065333:instance/i-002c7d44410fee60e",
+  "AssociatePublicIpAddress": true,
+  "AvailabilityZone": "eu-west-3a",
+  "CpuCoreCount": 1,
+  "CpuThreadsPerCore": 2,
+  "DisableApiTermination": false,
+  "EbsOptimized": false,
+  "GetPasswordData": false,
+  "Hibernation": false,
+  "HostId": null,
+  "IamInstanceProfile": "",
+  "Id": "i-002c7d44410fee60e",
+  "InstanceInitiatedShutdownBehavior": null,
+  "InstanceState": "running",
+  "InstanceType": "t3.micro",
+  "Ipv6AddressCount": 0,
+  "Ipv6Addresses": [],
+  "KeyName": "",
+  "Monitoring": false,
+  "OutpostArn": "",
+  "PasswordData": "",
+  "PlacementGroup": "",
+  "PrimaryNetworkInterfaceId": "eni-004ddff1c7a130f8b",
+  "PrivateDns": "ip-172-31-11-192.eu-west-3.compute.internal",
+  "PrivateIp": "172.31.11.192",
+  "PublicDns": "ec2-15-188-23-233.eu-west-3.compute.amazonaws.com",
+  "PublicIp": "15.188.23.233",
+  "SecondaryPrivateIps": [],
+  "SecurityGroups": [
+   "default"
+  ],
+  "SourceDestCheck": true,
+  "SubnetId": "subnet-63c5f90a",
+  "Tags": {
+   "Name": "HelloWorld"
+  },
+  "Tenancy": "default",
+  "UserData": null,
+  "UserDataBase64": null,
+  "VolumeTags": {},
+  "VpcSecurityGroupIds": [
+   "sg-a74815c8"
+  ],
+  "CreditSpecification": [
+   {
+    "CpuCredits": "unlimited"
+   }
+  ],
+  "EbsBlockDevice": null,
+  "EphemeralBlockDevice": [],
+  "MetadataOptions": [
+   {
+    "HttpEndpoint": "enabled",
+    "HttpPutResponseHopLimit": 1,
+    "HttpTokens": "optional"
+   }
+  ],
+  "NetworkInterface": [],
+  "RootBlockDevice": [
+   {
+    "DeleteOnTermination": true,
+    "DeviceName": "/dev/sda1",
+    "Encrypted": false,
+    "Iops": 100,
+    "KmsKeyId": "",
+    "VolumeId": "vol-08b1deab4881e2b00",
+    "VolumeSize": 8,
+    "VolumeType": "gp2"
+   }
+  ],
+  "Timeouts": null
+ }
+]