utils.go

Documentation: k8s.io/kubernetes/cmd/kubeadm/app/preflight

     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  package preflight
    18  
    19  import (
    20  	"regexp"
    21  	"strings"
    22  
    23  	"github.com/pkg/errors"
    24  
    25  	"k8s.io/apimachinery/pkg/util/version"
    26  	utilsexec "k8s.io/utils/exec"
    27  )
    28  
    29  // GetKubeletVersion is helper function that returns version of kubelet available in $PATH
    30  func GetKubeletVersion(execer utilsexec.Interface) (*version.Version, error) {
    31  	kubeletVersionRegex := regexp.MustCompile(`^\s*Kubernetes v((0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)([-\w.+]*)?)\s*$`)
    32  
    33  	command := execer.Command("kubelet", "--version")
    34  	out, err := command.Output()
    35  	if err != nil {
    36  		return nil, errors.Wrap(err, "cannot execute 'kubelet --version'")
    37  	}
    38  
    39  	cleanOutput := strings.TrimSpace(string(out))
    40  	subs := kubeletVersionRegex.FindAllStringSubmatch(cleanOutput, -1)
    41  	if len(subs) != 1 || len(subs[0]) < 2 {
    42  		return nil, errors.Errorf("Unable to parse output from Kubelet: %q", cleanOutput)
    43  	}
    44  	return version.ParseSemantic(subs[0][1])
    45  }
    46
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