github.com/baraj55/containernetworking-cni@v0.7.2-0.20200219164625-56ace59a9e7f/pkg/version/plugin.go (about)

     1  // Copyright 2016 CNI authors
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package version
    16  
    17  import (
    18  	"encoding/json"
    19  	"fmt"
    20  	"io"
    21  	"strconv"
    22  	"strings"
    23  )
    24  
    25  // PluginInfo reports information about CNI versioning
    26  type PluginInfo interface {
    27  	// SupportedVersions returns one or more CNI spec versions that the plugin
    28  	// supports.  If input is provided in one of these versions, then the plugin
    29  	// promises to use the same CNI version in its response
    30  	SupportedVersions() []string
    31  
    32  	// Encode writes this CNI version information as JSON to the given Writer
    33  	Encode(io.Writer) error
    34  }
    35  
    36  type pluginInfo struct {
    37  	CNIVersion_        string   `json:"cniVersion"`
    38  	SupportedVersions_ []string `json:"supportedVersions,omitempty"`
    39  }
    40  
    41  // pluginInfo implements the PluginInfo interface
    42  var _ PluginInfo = &pluginInfo{}
    43  
    44  func (p *pluginInfo) Encode(w io.Writer) error {
    45  	return json.NewEncoder(w).Encode(p)
    46  }
    47  
    48  func (p *pluginInfo) SupportedVersions() []string {
    49  	return p.SupportedVersions_
    50  }
    51  
    52  // PluginSupports returns a new PluginInfo that will report the given versions
    53  // as supported
    54  func PluginSupports(supportedVersions ...string) PluginInfo {
    55  	if len(supportedVersions) < 1 {
    56  		panic("programmer error: you must support at least one version")
    57  	}
    58  	return &pluginInfo{
    59  		CNIVersion_:        Current(),
    60  		SupportedVersions_: supportedVersions,
    61  	}
    62  }
    63  
    64  // PluginDecoder can decode the response returned by a plugin's VERSION command
    65  type PluginDecoder struct{}
    66  
    67  func (*PluginDecoder) Decode(jsonBytes []byte) (PluginInfo, error) {
    68  	var info pluginInfo
    69  	err := json.Unmarshal(jsonBytes, &info)
    70  	if err != nil {
    71  		return nil, fmt.Errorf("decoding version info: %s", err)
    72  	}
    73  	if info.CNIVersion_ == "" {
    74  		return nil, fmt.Errorf("decoding version info: missing field cniVersion")
    75  	}
    76  	if len(info.SupportedVersions_) == 0 {
    77  		if info.CNIVersion_ == "0.2.0" {
    78  			return PluginSupports("0.1.0", "0.2.0"), nil
    79  		}
    80  		return nil, fmt.Errorf("decoding version info: missing field supportedVersions")
    81  	}
    82  	return &info, nil
    83  }
    84  
    85  // ParseVersion parses a version string like "3.0.1" or "0.4.5" into major,
    86  // minor, and micro numbers or returns an error
    87  func ParseVersion(version string) (int, int, int, error) {
    88  	var major, minor, micro int
    89  	if version == "" {
    90  		return -1, -1, -1, fmt.Errorf("invalid version %q: the version is empty", version)
    91  	}
    92  
    93  	parts := strings.Split(version, ".")
    94  	if len(parts) >= 4 {
    95  		return -1, -1, -1, fmt.Errorf("invalid version %q: too many parts", version)
    96  	}
    97  
    98  	major, err := strconv.Atoi(parts[0])
    99  	if err != nil {
   100  		return -1, -1, -1, fmt.Errorf("failed to convert major version part %q: %v", parts[0], err)
   101  	}
   102  
   103  	if len(parts) >= 2 {
   104  		minor, err = strconv.Atoi(parts[1])
   105  		if err != nil {
   106  			return -1, -1, -1, fmt.Errorf("failed to convert minor version part %q: %v", parts[1], err)
   107  		}
   108  	}
   109  
   110  	if len(parts) >= 3 {
   111  		micro, err = strconv.Atoi(parts[2])
   112  		if err != nil {
   113  			return -1, -1, -1, fmt.Errorf("failed to convert micro version part %q: %v", parts[2], err)
   114  		}
   115  	}
   116  
   117  	return major, minor, micro, nil
   118  }
   119  
   120  // GreaterThanOrEqualTo takes two string versions, parses them into major/minor/micro
   121  // numbers, and compares them to determine whether the first version is greater
   122  // than or equal to the second
   123  func GreaterThanOrEqualTo(version, otherVersion string) (bool, error) {
   124  	firstMajor, firstMinor, firstMicro, err := ParseVersion(version)
   125  	if err != nil {
   126  		return false, err
   127  	}
   128  
   129  	secondMajor, secondMinor, secondMicro, err := ParseVersion(otherVersion)
   130  	if err != nil {
   131  		return false, err
   132  	}
   133  
   134  	if firstMajor > secondMajor {
   135  		return true, nil
   136  	} else if firstMajor == secondMajor {
   137  		if firstMinor > secondMinor {
   138  			return true, nil
   139  		} else if firstMinor == secondMinor && firstMicro >= secondMicro {
   140  			return true, nil
   141  		}
   142  	}
   143  	return false, nil
   144  }