util.go

Documentation: github.com/googleapis/enterprise-certificate-proxy/client/util

     1  // Copyright 2022 Google LLC.
     2  // Licensed under the Apache License, Version 2.0 (the "License");
     3  // you may not use this file except in compliance with the License.
     4  // You may obtain a copy of the License at
     5  //
     6  //     https://www.apache.org/licenses/LICENSE-2.0
     7  //
     8  // Unless required by applicable law or agreed to in writing, software
     9  // distributed under the License is distributed on an "AS IS" BASIS,
    10  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    11  // See the License for the specific language governing permissions and
    12  // limitations under the License.
    13  
    14  // Package util provides helper functions for the client.
    15  package util
    16  
    17  import (
    18  	"encoding/json"
    19  	"errors"
    20  	"io"
    21  	"os"
    22  	"os/user"
    23  	"path/filepath"
    24  	"runtime"
    25  	"strings"
    26  )
    27  
    28  const configFileName = "certificate_config.json"
    29  
    30  // EnterpriseCertificateConfig contains parameters for initializing signer.
    31  type EnterpriseCertificateConfig struct {
    32  	Libs Libs `json:"libs"`
    33  }
    34  
    35  // Libs specifies the locations of helper libraries.
    36  type Libs struct {
    37  	ECP string `json:"ecp"`
    38  }
    39  
    40  // ErrConfigUnavailable is a sentinel error that indicates ECP config is unavailable,
    41  // possibly due to entire config missing or missing binary path.
    42  var ErrConfigUnavailable = errors.New("Config is unavailable")
    43  
    44  // LoadSignerBinaryPath retrieves the path of the signer binary from the config file.
    45  func LoadSignerBinaryPath(configFilePath string) (path string, err error) {
    46  	jsonFile, err := os.Open(configFilePath)
    47  	if err != nil {
    48  		if errors.Is(err, os.ErrNotExist) {
    49  			return "", ErrConfigUnavailable
    50  		}
    51  		return "", err
    52  	}
    53  
    54  	byteValue, err := io.ReadAll(jsonFile)
    55  	if err != nil {
    56  		return "", err
    57  	}
    58  	var config EnterpriseCertificateConfig
    59  	err = json.Unmarshal(byteValue, &config)
    60  	if err != nil {
    61  		return "", err
    62  	}
    63  	signerBinaryPath := config.Libs.ECP
    64  	if signerBinaryPath == "" {
    65  		return "", ErrConfigUnavailable
    66  	}
    67  
    68  	signerBinaryPath = strings.ReplaceAll(signerBinaryPath, "~", guessHomeDir())
    69  	signerBinaryPath = strings.ReplaceAll(signerBinaryPath, "$HOME", guessHomeDir())
    70  	return signerBinaryPath, nil
    71  }
    72  
    73  func guessHomeDir() string {
    74  	// Prefer $HOME over user.Current due to glibc bug: golang.org/issue/13470
    75  	if v := os.Getenv("HOME"); v != "" {
    76  		return v
    77  	}
    78  	// Else, fall back to user.Current:
    79  	if u, err := user.Current(); err == nil {
    80  		return u.HomeDir
    81  	}
    82  	return ""
    83  }
    84  
    85  func getDefaultConfigFileDirectory() (directory string) {
    86  	if runtime.GOOS == "windows" {
    87  		return filepath.Join(os.Getenv("APPDATA"), "gcloud")
    88  	}
    89  	return filepath.Join(guessHomeDir(), ".config/gcloud")
    90  }
    91  
    92  // GetDefaultConfigFilePath returns the default path of the enterprise certificate config file created by gCloud.
    93  func GetDefaultConfigFilePath() (path string) {
    94  	return filepath.Join(getDefaultConfigFileDirectory(), configFileName)
    95  }
    96  
    97  // GetConfigFilePathFromEnv returns the path associated with environment variable GOOGLE_API_CERTIFICATE_CONFIG
    98  func GetConfigFilePathFromEnv() (path string) {
    99  	return os.Getenv("GOOGLE_API_CERTIFICATE_CONFIG")
   100  }
   101
View as plain text