k8s.io/kubernetes@v1.29.3/pkg/kubelet/envvars/envvars.go (about)

     1  /*
     2  Copyright 2014 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  package envvars
    18  
    19  import (
    20  	"fmt"
    21  	"net"
    22  	"strconv"
    23  	"strings"
    24  
    25  	"k8s.io/api/core/v1"
    26  	v1helper "k8s.io/kubernetes/pkg/apis/core/v1/helper"
    27  )
    28  
    29  // FromServices builds environment variables that a container is started with,
    30  // which tell the container where to find the services it may need, which are
    31  // provided as an argument.
    32  func FromServices(services []*v1.Service) []v1.EnvVar {
    33  	var result []v1.EnvVar
    34  	for i := range services {
    35  		service := services[i]
    36  
    37  		// ignore services where ClusterIP is "None" or empty
    38  		// the services passed to this method should be pre-filtered
    39  		// only services that have the cluster IP set should be included here
    40  		if !v1helper.IsServiceIPSet(service) {
    41  			continue
    42  		}
    43  
    44  		// Host
    45  		name := makeEnvVariableName(service.Name) + "_SERVICE_HOST"
    46  		result = append(result, v1.EnvVar{Name: name, Value: service.Spec.ClusterIP})
    47  		// First port - give it the backwards-compatible name
    48  		name = makeEnvVariableName(service.Name) + "_SERVICE_PORT"
    49  		result = append(result, v1.EnvVar{Name: name, Value: strconv.Itoa(int(service.Spec.Ports[0].Port))})
    50  		// All named ports (only the first may be unnamed, checked in validation)
    51  		for i := range service.Spec.Ports {
    52  			sp := &service.Spec.Ports[i]
    53  			if sp.Name != "" {
    54  				pn := name + "_" + makeEnvVariableName(sp.Name)
    55  				result = append(result, v1.EnvVar{Name: pn, Value: strconv.Itoa(int(sp.Port))})
    56  			}
    57  		}
    58  		// Docker-compatible vars.
    59  		result = append(result, makeLinkVariables(service)...)
    60  	}
    61  	return result
    62  }
    63  
    64  func makeEnvVariableName(str string) string {
    65  	// TODO: If we simplify to "all names are DNS1123Subdomains" this
    66  	// will need two tweaks:
    67  	//   1) Handle leading digits
    68  	//   2) Handle dots
    69  	return strings.ToUpper(strings.Replace(str, "-", "_", -1))
    70  }
    71  
    72  func makeLinkVariables(service *v1.Service) []v1.EnvVar {
    73  	prefix := makeEnvVariableName(service.Name)
    74  	all := []v1.EnvVar{}
    75  	for i := range service.Spec.Ports {
    76  		sp := &service.Spec.Ports[i]
    77  
    78  		protocol := string(v1.ProtocolTCP)
    79  		if sp.Protocol != "" {
    80  			protocol = string(sp.Protocol)
    81  		}
    82  
    83  		hostPort := net.JoinHostPort(service.Spec.ClusterIP, strconv.Itoa(int(sp.Port)))
    84  
    85  		if i == 0 {
    86  			// Docker special-cases the first port.
    87  			all = append(all, v1.EnvVar{
    88  				Name:  prefix + "_PORT",
    89  				Value: fmt.Sprintf("%s://%s", strings.ToLower(protocol), hostPort),
    90  			})
    91  		}
    92  		portPrefix := fmt.Sprintf("%s_PORT_%d_%s", prefix, sp.Port, strings.ToUpper(protocol))
    93  		all = append(all, []v1.EnvVar{
    94  			{
    95  				Name:  portPrefix,
    96  				Value: fmt.Sprintf("%s://%s", strings.ToLower(protocol), hostPort),
    97  			},
    98  			{
    99  				Name:  portPrefix + "_PROTO",
   100  				Value: strings.ToLower(protocol),
   101  			},
   102  			{
   103  				Name:  portPrefix + "_PORT",
   104  				Value: strconv.Itoa(int(sp.Port)),
   105  			},
   106  			{
   107  				Name:  portPrefix + "_ADDR",
   108  				Value: service.Spec.ClusterIP,
   109  			},
   110  		}...)
   111  	}
   112  	return all
   113  }