ref 624723: server backup schedules (#416)

Signed-off-by: Adrian Nackov <adrian.nackov@mail.schwarz>

stackit/internal/validate/validate.go

@@ -14,6 +14,7 @@ import (
 	"github.com/hashicorp/terraform-plugin-framework/schema/validator"
 	"github.com/hashicorp/terraform-plugin-framework/types/basetypes"
 	"github.com/stackitcloud/terraform-provider-stackit/stackit/internal/core"
+	"github.com/teambition/rrule-go"
 )
 
 const (
@@ -225,3 +226,30 @@ func CIDR() *Validator {
 		},
 	}
 }
+
+func Rrule() *Validator {
+	description := "value must be in a valid RRULE format"
+
+	return &Validator{
+		description: description,
+		validate: func(ctx context.Context, req validator.StringRequest, resp *validator.StringResponse) {
+			// The go library rrule-go expects \n before RRULE (to be a newline and not a space)
+			// for example: "DTSTART;TZID=America/New_York:19970902T090000\nRRULE:FREQ=DAILY;COUNT=10"
+			// whereas a valid rrule according to the API docs is:
+			// for example: "DTSTART;TZID=America/New_York:19970902T090000 RRULE:FREQ=DAILY;COUNT=10"
+			//
+			// So we will accept a ' ' (which is valid per API docs),
+			// but replace it with a '\n' for the rrule-go validations
+			value := req.ConfigValue.ValueString()
+			value = strings.ReplaceAll(value, " ", "\n")
+
+			if _, err := rrule.StrToRRuleSet(value); err != nil {
+				resp.Diagnostics.Append(validatordiag.InvalidAttributeValueDiagnostic(
+					req.Path,
+					description,
+					req.ConfigValue.ValueString(),
+				))
+			}
+		},
+	}
+}

stackit/internal/validate/validate_test.go

@@ -574,3 +574,57 @@ func TestCIDR(t *testing.T) {
 		})
 	}
 }
+
+func TestRrule(t *testing.T) {
+	tests := []struct {
+		description string
+		input       string
+		isValid     bool
+	}{
+		{
+			"ok",
+			"DTSTART;TZID=Europe/Sofia:20200803T023000 RRULE:FREQ=DAILY;INTERVAL=1",
+			true,
+		},
+		{
+			"ok-2",
+			"DTSTART;TZID=Europe/Sofia:20200803T023000\nRULE:FREQ=DAILY;INTERVAL=1",
+			true,
+		},
+		{
+			"Empty",
+			"",
+			false,
+		},
+		{
+			"not ok",
+			"afssfdfs",
+			false,
+		},
+		{
+			"not ok-missing-space-before-rrule",
+			"DTSTART;TZID=Europe/Sofia:20200803T023000RRULE:FREQ=DAILY;INTERVAL=1",
+			false,
+		},
+		{
+			"not ok-missing-interval",
+			"DTSTART;TZID=Europe/Sofia:20200803T023000 RRULE:FREQ=DAILY;INTERVAL=",
+			false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.description, func(t *testing.T) {
+			r := validator.StringResponse{}
+			Rrule().ValidateString(context.Background(), validator.StringRequest{
+				ConfigValue: types.StringValue(tt.input),
+			}, &r)
+
+			if !tt.isValid && !r.Diagnostics.HasError() {
+				t.Fatalf("Should have failed")
+			}
+			if tt.isValid && r.Diagnostics.HasError() {
+				t.Fatalf("Should not have failed: %v", r.Diagnostics.Errors())
+			}
+		})
+	}
+}