/
factory.go
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/
factory.go
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// Copyright © 2023 Dell Inc. or its subsidiaries. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package provisioner
import (
"errors"
l "github.com/dell/cosi/pkg/logger"
driver "github.com/dell/cosi/pkg/provisioner/virtualdriver"
"github.com/dell/cosi/pkg/config"
"github.com/dell/cosi/pkg/provisioner/objectscale"
)
// NewVirtualDriver is factory function, that takes configuration, validates if it is correct, and
// returns correct driver.
func NewVirtualDriver(config config.Configuration) (driver.Driver, error) {
// in the future, here can be more than one
if !exactlyOne(config.Objectscale) {
return nil, errors.New("expected exactly one object storage platform in configuration")
}
if config.Objectscale != nil {
l.Log().V(6).Info("ObjectScale config created.")
return objectscale.New(config.Objectscale)
}
panic("programming error")
}
// exactlyOne checks if exactly one of its arguments is not nil.
//
// It takes in a variadic argument list of nillable values (interfaces that can either be nil or non-nil).
// The function then counts the number of non-nil values and returns a boolean indicating whether
// exactly one non-nil value was passed as an argument.
func exactlyOne(nillables ...interface{}) bool {
count := 0
for _, nillable := range nillables {
// we need type switch, because nil not always equals nil, e.g.: `nil != (*config.Objectscale)(nil)`
switch nillable := nillable.(type) {
case *config.Objectscale:
if nillable != (*config.Objectscale)(nil) {
count++
}
default:
if nillable != nil {
count++
}
}
}
return count == 1
}