sigs.k8s.io/external-dns@v0.14.1/source/fake.go (about)

     1  /*
     2  Copyright 2017 The Kubernetes 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  /*
    18  Note: currently only supports IP targets (A records), not hostname targets
    19  */
    20  
    21  package source
    22  
    23  import (
    24  	"context"
    25  	"fmt"
    26  	"math/rand"
    27  	"net"
    28  
    29  	"sigs.k8s.io/external-dns/endpoint"
    30  )
    31  
    32  // fakeSource is an implementation of Source that provides dummy endpoints for
    33  // testing/dry-running of dns providers without needing an attached Kubernetes cluster.
    34  type fakeSource struct {
    35  	dnsName string
    36  }
    37  
    38  const (
    39  	defaultFQDNTemplate = "example.com"
    40  )
    41  
    42  // NewFakeSource creates a new fakeSource with the given config.
    43  func NewFakeSource(fqdnTemplate string) (Source, error) {
    44  	if fqdnTemplate == "" {
    45  		fqdnTemplate = defaultFQDNTemplate
    46  	}
    47  
    48  	return &fakeSource{
    49  		dnsName: fqdnTemplate,
    50  	}, nil
    51  }
    52  
    53  func (sc *fakeSource) AddEventHandler(ctx context.Context, handler func()) {
    54  }
    55  
    56  // Endpoints returns endpoint objects.
    57  func (sc *fakeSource) Endpoints(ctx context.Context) ([]*endpoint.Endpoint, error) {
    58  	endpoints := make([]*endpoint.Endpoint, 10)
    59  
    60  	for i := 0; i < 10; i++ {
    61  		endpoints[i], _ = sc.generateEndpoint()
    62  	}
    63  
    64  	return endpoints, nil
    65  }
    66  
    67  func (sc *fakeSource) generateEndpoint() (*endpoint.Endpoint, error) {
    68  	ep := endpoint.NewEndpoint(
    69  		generateDNSName(4, sc.dnsName),
    70  		endpoint.RecordTypeA,
    71  		generateIPAddress(),
    72  	)
    73  
    74  	return ep, nil
    75  }
    76  
    77  func generateIPAddress() string {
    78  	// 192.0.2.[1-255] is reserved by RFC 5737 for documentation and examples
    79  	return net.IPv4(
    80  		byte(192),
    81  		byte(0),
    82  		byte(2),
    83  		byte(rand.Intn(253)+1),
    84  	).String()
    85  }
    86  
    87  var letterRunes = []rune("abcdefghijklmnopqrstuvwxyz")
    88  
    89  func generateDNSName(prefixLength int, dnsName string) string {
    90  	prefixBytes := make([]rune, prefixLength)
    91  
    92  	for i := range prefixBytes {
    93  		prefixBytes[i] = letterRunes[rand.Intn(len(letterRunes))]
    94  	}
    95  
    96  	prefixStr := string(prefixBytes)
    97  
    98  	return fmt.Sprintf("%s.%s", prefixStr, dnsName)
    99  }