Instance config file checksum handled properly

examples/ssh/aem.tf

@@ -11,18 +11,13 @@ resource "aem_instance" "single" {
     }
   }
   compose {
-    version     = "1.5.7"
+    version     = "1.5.8"
     data_dir    = "/home/ec2-user/aemc"
     lib_dir     = "aem/home/lib"
     config_file = "aem/default/etc/aem.yml"
   }
 }
 
-
 output "aem_instances" {
   value = aem_instance.single.instances
 }
-
-output "aem_config_file_checksum" {
-  value = aem_instance.single.compose.config_file_checksum
-}

examples/ssh/aem/default/etc/aem.yml

@@ -18,11 +18,13 @@ instance:
         - -Duser.country=US
         - -Duser.timezone=UTC
       start_opts: []
+
       secret_vars:
         - ACME_SECRET=value
       env_vars:
         - ACME_VAR=value
       sling_props: []
+
     local_publish:
       active: true
       http_url: http://127.0.0.1:4503

internal/provider/instance/plan_modifiers.go

@@ -0,0 +1,42 @@
+package instance
+
+import (
+	"context"
+	"fmt"
+	"github.com/hashicorp/terraform-plugin-framework/path"
+	"github.com/hashicorp/terraform-plugin-framework/resource/schema/planmodifier"
+	"github.com/hashicorp/terraform-plugin-framework/types"
+	"github.com/wttech/terraform-provider-aem/internal/utils"
+)
+
+func ConfigFileChecksumPlanModifier() planmodifier.String {
+	return &configFileChecksumPlanModifier{}
+}
+
+type configFileChecksumPlanModifier struct{}
+
+func (m *configFileChecksumPlanModifier) Description(ctx context.Context) string {
+	return "Updates AEM configuration file checksum when contents change."
+}
+
+func (m *configFileChecksumPlanModifier) MarkdownDescription(ctx context.Context) string {
+	return m.Description(ctx)
+}
+
+func (m *configFileChecksumPlanModifier) PlanModifyString(ctx context.Context, req planmodifier.StringRequest, resp *planmodifier.StringResponse) {
+	var configFile types.String
+	diags := req.Plan.GetAttribute(ctx, path.Root("compose").AtName("config_file"), &configFile)
+	resp.Diagnostics.Append(diags...)
+	if resp.Diagnostics.HasError() {
+		return
+	}
+	if !configFile.IsNull() {
+		configFilePath := configFile.ValueString()
+		checksum, err := utils.HashFileMD5(configFilePath)
+		if err != nil {
+			resp.Diagnostics.AddError("Unable to calculate checksum of AEM configuration file", fmt.Sprintf("path '%s', error: %s", configFilePath, err))
+			return
+		}
+		resp.PlanValue = types.StringValue(checksum)
+	}
+}

internal/provider/instance_resource.go

@@ -16,6 +16,7 @@ import (
 	"github.com/hashicorp/terraform-plugin-framework/types"
 	"github.com/hashicorp/terraform-plugin-log/tflog"
 	"github.com/wttech/terraform-provider-aem/internal/client"
+	"github.com/wttech/terraform-provider-aem/internal/provider/instance"
 	"time"
 )
 
@@ -106,7 +107,8 @@ func (r *InstanceResource) Schema(ctx context.Context, req resource.SchemaReques
 						Default:             stringdefault.StaticString("aem/default/etc/aem.yml"),
 					},
 					"config_file_checksum": schema.StringAttribute{
-						Computed: true,
+						Computed:      true,
+						PlanModifiers: []planmodifier.String{instance.ConfigFileChecksumPlanModifier()},
 					},
 					"lib_dir": schema.StringAttribute{
 						MarkdownDescription: "Local path to directory from which AEM library files will be copied to the remote AEM machine",
@@ -150,9 +152,10 @@ func (r *InstanceResource) Schema(ctx context.Context, req resource.SchemaReques
 					},
 				},
 				PlanModifiers: []planmodifier.List{
+					listplanmodifier.UseStateForUnknown(),
 					listplanmodifier.RequiresReplaceIf(func(ctx context.Context, request planmodifier.ListRequest, response *listplanmodifier.RequiresReplaceIfFuncResponse) {
 						// TODO check if: [1] list is not empty; [2] the same instances are still created; [3] dirs have not changed
-						response.RequiresReplace = true
+						// response.RequiresReplace = true
 					}, "If the value of this attribute changes, Terraform will destroy and recreate the resource.", "If the value of this attribute changes, Terraform will destroy and recreate the resource."),
 				},
 			},
@@ -200,16 +203,9 @@ func (r *InstanceResource) createOrUpdate(ctx context.Context, plan *tfsdk.Plan,
 		return
 	}
 
-	md5, err := hashFileMD5(model.Compose.ConfigFile.ValueString())
-	if err != nil {
-		diags.AddError("Unable to calculate MD5 checksum for AEM configuration file", fmt.Sprintf("%s", err))
-		return
-	}
-	model.Compose.ConfigFileChecksum = types.StringValue(md5)
-
 	tflog.Info(ctx, "Started setting up AEM instance resource")
 
-	ic, err := r.Client(ctx, model, time.Minute*5)
+	ic, err := r.client(ctx, model, time.Minute*5)
 	if err != nil {
 		diags.AddError("Unable to connect to AEM instance", fmt.Sprintf("%s", err))
 		return
@@ -301,14 +297,7 @@ func (r *InstanceResource) Read(ctx context.Context, req resource.ReadRequest, r
 		return
 	}
 
-	md5, err := hashFileMD5(model.Compose.ConfigFile.ValueString())
-	if err != nil {
-		resp.Diagnostics.AddError("Unable to calculate MD5 checksum for AEM configuration file", fmt.Sprintf("%s", err))
-		return
-	}
-	model.Compose.ConfigFileChecksum = types.StringValue(md5)
-
-	ic, err := r.Client(ctx, model, time.Second*15)
+	ic, err := r.client(ctx, model, time.Second*15)
 	if err != nil {
 		resp.Diagnostics.AddWarning("Unable to connect to AEM instance", fmt.Sprintf("%s", err))
 	} else {
@@ -345,10 +334,11 @@ func (r *InstanceResource) Delete(ctx context.Context, req resource.DeleteReques
 }
 
 func (r *InstanceResource) ImportState(ctx context.Context, req resource.ImportStateRequest, resp *resource.ImportStateResponse) {
+	// TODO implement it properly
 	resource.ImportStatePassthroughID(ctx, path.Root("id"), req, resp)
 }
 
-func (r *InstanceResource) Client(ctx context.Context, model InstanceResourceModel, timeout time.Duration) (*InstanceClient, error) {
+func (r *InstanceResource) client(ctx context.Context, model InstanceResourceModel, timeout time.Duration) (*InstanceClient, error) {
 	tflog.Info(ctx, "Connecting to AEM instance machine")
 
 	typeName := model.Client.Type.ValueString()

internal/provider/provider_utils.go → internal/utils/file.go

@@ -1,4 +1,4 @@
-package provider
+package utils
 
 import (
 	"crypto/md5"
@@ -8,7 +8,7 @@ import (
 )
 
 // TODO hash with ignoring line endings / OS-independent
-func hashFileMD5(file string) (string, error) {
+func HashFileMD5(file string) (string, error) {
 	// Open the file
 	f, err := os.Open(file)
 	if err != nil {