ref.go

Documentation: k8s.io/kubernetes/pkg/kubelet/container

     1  /*
     2  Copyright 2015 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 container
    18  
    19  import (
    20  	"fmt"
    21  
    22  	v1 "k8s.io/api/core/v1"
    23  	ref "k8s.io/client-go/tools/reference"
    24  	"k8s.io/kubernetes/pkg/api/legacyscheme"
    25  )
    26  
    27  // ImplicitContainerPrefix is a container name prefix that will indicate that container was started implicitly (like the pod infra container).
    28  var ImplicitContainerPrefix = "implicitly required container "
    29  
    30  // GenerateContainerRef returns an *v1.ObjectReference which references the given container
    31  // within the given pod. Returns an error if the reference can't be constructed or the
    32  // container doesn't actually belong to the pod.
    33  func GenerateContainerRef(pod *v1.Pod, container *v1.Container) (*v1.ObjectReference, error) {
    34  	fieldPath, err := fieldPath(pod, container)
    35  	if err != nil {
    36  		// TODO: figure out intelligent way to refer to containers that we implicitly
    37  		// start (like the pod infra container). This is not a good way, ugh.
    38  		fieldPath = ImplicitContainerPrefix + container.Name
    39  	}
    40  	ref, err := ref.GetPartialReference(legacyscheme.Scheme, pod, fieldPath)
    41  	if err != nil {
    42  		return nil, err
    43  	}
    44  	return ref, nil
    45  }
    46  
    47  // fieldPath returns a fieldPath locating container within pod.
    48  // Returns an error if the container isn't part of the pod.
    49  func fieldPath(pod *v1.Pod, container *v1.Container) (string, error) {
    50  	for i := range pod.Spec.Containers {
    51  		here := &pod.Spec.Containers[i]
    52  		if here.Name == container.Name {
    53  			if here.Name == "" {
    54  				return fmt.Sprintf("spec.containers[%d]", i), nil
    55  			}
    56  			return fmt.Sprintf("spec.containers{%s}", here.Name), nil
    57  		}
    58  	}
    59  	for i := range pod.Spec.InitContainers {
    60  		here := &pod.Spec.InitContainers[i]
    61  		if here.Name == container.Name {
    62  			if here.Name == "" {
    63  				return fmt.Sprintf("spec.initContainers[%d]", i), nil
    64  			}
    65  			return fmt.Sprintf("spec.initContainers{%s}", here.Name), nil
    66  		}
    67  	}
    68  	for i := range pod.Spec.EphemeralContainers {
    69  		here := &pod.Spec.EphemeralContainers[i]
    70  		if here.Name == container.Name {
    71  			if here.Name == "" {
    72  				return fmt.Sprintf("spec.ephemeralContainers[%d]", i), nil
    73  			}
    74  			return fmt.Sprintf("spec.ephemeralContainers{%s}", here.Name), nil
    75  		}
    76  	}
    77  	return "", fmt.Errorf("container %q not found in pod %s/%s", container.Name, pod.Namespace, pod.Name)
    78  }
    79
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