github.com/lastbackend/toolkit@v0.0.0-20241020043710-cafa37b95aad/pkg/client/grpc/selector/selector.go (about)

     1  /*
     2  Copyright [2014] - [2023] The Last.Backend authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package selector
    18  
    19  import (
    20  	"github.com/pkg/errors"
    21  )
    22  
    23  type Type int
    24  
    25  const (
    26  	Random Type = iota
    27  	RoundRobin
    28  )
    29  
    30  var (
    31  	ErrSelectorNotDetected = errors.New("selector not detected")
    32  	ErrNotAvailable        = errors.New("not available")
    33  )
    34  
    35  type Selector interface {
    36  	Select([]string) (Next, error)
    37  }
    38  
    39  type Next func() string
    40  
    41  func New(t Type) (selector Selector, err error) {
    42  	switch t {
    43  	case Random:
    44  		selector = newRandomSelector()
    45  	case RoundRobin:
    46  		selector = newRRSelector()
    47  	default:
    48  		err = ErrSelectorNotDetected
    49  	}
    50  	return selector, err
    51  }