Add validation for start_time to resource_policy (#2940)

Merged PR #2940.

products/compute/api.yaml

@@ -10087,8 +10087,9 @@ objects:
                     name: 'startTime'
                     description: |
                       Time within the window to start the operations.
-                      It must be in format "HH:MM",
-                      where HH : [00-23] and MM : [00-00] GMT.
+                      It must be in an hourly format "HH:MM",
+                      where HH : [00-23] and MM : [00] GMT.
+                      eg: 21:00
                     required: true
               - !ruby/object:Api::Type::NestedObject
                 name: 'dailySchedule'

products/compute/terraform.yaml

@@ -1332,6 +1332,12 @@ overrides: !ruby/object:Overrides::ResourceOverrides
       region: !ruby/object:Overrides::Terraform::PropertyOverride
         required: false
         default_from_api: true
+      snapshotSchedulePolicy.schedule.dailySchedule.startTime: !ruby/object:Overrides::Terraform::PropertyOverride
+        validation: !ruby/object:Provider::Terraform::Validation
+          function: 'validateHourlyOnly'
+      snapshotSchedulePolicy.schedule.hourlySchedule.startTime: !ruby/object:Overrides::Terraform::PropertyOverride
+        validation: !ruby/object:Provider::Terraform::Validation
+          function: 'validateHourlyOnly'
       snapshotSchedulePolicy.schedule.weeklySchedule.dayOfWeeks: !ruby/object:Overrides::Terraform::PropertyOverride
         is_set: true
       snapshotSchedulePolicy.snapshotProperties.storageLocations: !ruby/object:Overrides::Terraform::PropertyOverride

third_party/terraform/utils/validation.go

@@ -261,3 +261,23 @@ func StringNotInSlice(invalid []string, ignoreCase bool) schema.SchemaValidateFu
 		return
 	}
 }
+
+// Ensure that hourly timestamp strings "HH:MM" have the minutes zeroed out for hourly only inputs
+func validateHourlyOnly(val interface{}, key string) (warns []string, errs []error) {
+	v := val.(string)
+	parts := strings.Split(v, ":")
+	if len(parts) != 2 {
+		errs = append(errs, fmt.Errorf("%q must be in the format HH:00, got: %s", key, v))
+		return
+	}
+	if parts[1] != "00" {
+		errs = append(errs, fmt.Errorf("%q does not allow minutes, it must be in the format HH:00, got: %s", key, v))
+	}
+	i, err := strconv.Atoi(parts[0])
+	if err != nil {
+		errs = append(errs, fmt.Errorf("%q cannot be parsed, it must be in the format HH:00, got: %s", key, v))
+	} else if i < 0 || i > 23 {
+		errs = append(errs, fmt.Errorf("%q does not specify a valid hour, it must be in the format HH:00 where HH : [00-23], got: %s", key, v))
+	}
+	return
+}