tfschema: Fix rollup/mapping rule interval diff after apply [sc-11120…

…4] (#78)

[sc-111204]

When neither interval or storage_policy is specified, a server-side
default is returned. This causes a diff-after-apply, so mark the field
as computed.

Note: When using a computed field, if the user sets an explicitly value,
say `interval=60s`, and then removes that field, Terraform cannot
differentiate whether the value in the state is a server-side default or
previously set, and will continue to use the existing value as-is.
See hashicorp/terraform-plugin-sdk#282

CHANGELOG.md

@@ -4,6 +4,8 @@
 
 Fixed:
  * Allow creating `chronosphere_slack_notifier` with actions without `action_confirm_text`.
+ * Fix `chronosphere_rollup_rule` and `chronosphere_mapping_rule` diff after applying
+   a rule without an interval or storage policy.
 
 ## v1.5.0
 

chronosphere/resource_mapping_rule.go

@@ -64,6 +64,13 @@ func (mappingRuleConverter) toModel(
 	if err := validateMappingRule(r); err != nil {
 		return nil, fmt.Errorf("invalid mapping rule: %v", err)
 	}
+	// The schema doesn't allow interval and policy to be set together.
+	// However, we receive both because interval is an optional computed field
+	// which will send the last server-returned value even if the user doesn't have it set
+	// in the configuration. Hence we clear it manually to workaround sc-81013.
+	if r.Interval != "" && r.StoragePolicy != nil {
+		r.Interval = ""
+	}
 	filter, err := aggregationfilter.StringToModel(r.Filter, aggregationfilter.MappingRuleDelimiter)
 	if err != nil {
 		return nil, err
@@ -155,23 +162,25 @@ func mappingStoragePolicyFromModel(
 }
 
 func validateMappingRule(rule *intschema.MappingRule) error {
+	hasInterval := rule.Interval != "" || rule.StoragePolicy != nil
+
 	if rule.Drop {
 		if len(rule.Aggregations) > 0 {
 			return fmt.Errorf("cannot set aggregations when drop is true")
 		}
-		if rule.StoragePolicy != nil {
-			return fmt.Errorf("cannot set storage_policy when drop is true")
+		if hasInterval {
+			return fmt.Errorf("cannot set interval or storage_policy when drop is true")
 		}
 		return nil
 	}
 
-	if rule.StoragePolicy == nil && len(rule.Aggregations) == 0 {
-		return fmt.Errorf("must set aggregations and storage_policy when drop is not set")
+	if !hasInterval && len(rule.Aggregations) == 0 {
+		return fmt.Errorf("must set aggregations and interval when drop is not set")
 	}
 
 	// Aggregations and StoragePolicies must be set together.
-	if rule.StoragePolicy != nil && len(rule.Aggregations) == 0 {
-		return fmt.Errorf("must set aggregations")
+	if hasInterval && len(rule.Aggregations) == 0 {
+		return fmt.Errorf("must set aggregations when setting interval")
 	}
 
 	return nil

chronosphere/resource_rollup_rule.go

@@ -73,7 +73,7 @@ func (rollupRuleConverter) toModel(
 	// which will send the last server-returned value even if the user doesn't have it set
 	// in the configuration. Hence we clear it manually to workaround sc-81013.
 	if r.Interval != "" && r.StoragePolicies != nil {
-		r.StoragePolicies = nil
+		r.Interval = ""
 	}
 
 	filter, err := aggregationfilter.StringToModel(r.Filter, aggregationfilter.RollupRuleDelimiter)

chronosphere/tfschema/mapping_rule.go

@@ -78,6 +78,9 @@ var MappingRule = map[string]*schema.Schema{
 	"interval": {
 		Type:     schema.TypeString,
 		Optional: true,
+		// When no interval is specified, a server-side default is used.
+		Computed:      true,
+		ConflictsWith: []string{"storage_policy"},
 	},
 	"mode": Enum{
 		Value:    enum.MappingModeType.ToStrings(),

chronosphere/tfschema/rollup_rule.go

@@ -66,13 +66,13 @@ var RollupRule = map[string]*schema.Schema{
 				}.Schema(),
 			},
 		},
-		// When no policies are specified, the server-side will set the defaults.
-		Computed:   true,
 		Deprecated: "use `interval` instead",
 	},
 	"interval": {
-		Type:          schema.TypeString,
-		Optional:      true,
+		Type:     schema.TypeString,
+		Optional: true,
+		// When no interval is specified, a server-side default is used.
+		Computed:      true,
 		ConflictsWith: []string{"storage_policies"},
 	},
 	"group_by": {