config.go

Documentation: github.com/Microsoft/hcsshim/cmd/ncproxy

     1  //go:build windows
     2  
     3  package main
     4  
     5  import (
     6  	"encoding/json"
     7  	"fmt"
     8  	"os"
     9  	"path/filepath"
    10  
    11  	"github.com/pkg/errors"
    12  	"github.com/urfave/cli"
    13  )
    14  
    15  var configCommand = cli.Command{
    16  	Name:  "config",
    17  	Usage: "Information on the ncproxy config",
    18  	Subcommands: []cli.Command{
    19  		{
    20  			Name:  "default",
    21  			Usage: "Print the output of the default config to stdout or to a file",
    22  			Flags: []cli.Flag{
    23  				cli.StringFlag{
    24  					Name:  "file",
    25  					Usage: "Output config to a file",
    26  				},
    27  			},
    28  			Action: func(context *cli.Context) error {
    29  				file := context.String("file")
    30  
    31  				configData, err := json.MarshalIndent(defaultConfig(), "", "  ")
    32  				if err != nil {
    33  					return errors.Wrap(err, "failed to marshal ncproxy config to json")
    34  				}
    35  
    36  				if file != "" {
    37  					// Make the directory if it doesn't exist.
    38  					if _, err := os.Stat(filepath.Dir(file)); err != nil {
    39  						if err := os.MkdirAll(filepath.Dir(file), 0700); err != nil {
    40  							return errors.Wrap(err, "failed to make path to config file")
    41  						}
    42  					}
    43  					if err := os.WriteFile(
    44  						file,
    45  						[]byte(configData),
    46  						0700,
    47  					); err != nil {
    48  						return err
    49  					}
    50  				} else {
    51  					fmt.Fprint(os.Stdout, string(configData))
    52  				}
    53  
    54  				return nil
    55  			},
    56  		},
    57  	},
    58  }
    59  
    60  // defaultConfig generates a default ncproxy configuration file with every config option filled in.
    61  func defaultConfig() *config {
    62  	return &config{
    63  		TTRPCAddr:      "\\\\.\\pipe\\ncproxy-ttrpc",
    64  		GRPCAddr:       "127.0.0.1:6669",
    65  		NodeNetSvcAddr: "127.0.0.1:6668",
    66  		Timeout:        10,
    67  	}
    68  }
    69  
    70  type config struct {
    71  	TTRPCAddr      string `json:"ttrpc,omitempty"`
    72  	GRPCAddr       string `json:"grpc,omitempty"`
    73  	NodeNetSvcAddr string `json:"node_net_svc_addr,omitempty"`
    74  	// Timeout in seconds to wait to connect to a NodeNetworkService.
    75  	// 0 represents no timeout and ncproxy will continuously try and connect in the
    76  	// background.
    77  	Timeout uint32 `json:"timeout,omitempty"`
    78  }
    79  
    80  // Returns config. If path is "" will check the default location of the config
    81  // which is /path/of/executable/ncproxy.json
    82  func loadConfig(path string) (*config, error) {
    83  	// Check if config path was passed in.
    84  	if path != "" {
    85  		return readConfig(path)
    86  	}
    87  	// Otherwise check if config is in default location (same dir as executable)
    88  	if path, exists := configPresent(); exists {
    89  		return readConfig(path)
    90  	}
    91  	return nil, errors.New("no config specified and no config found in current directory. Run `ncproxy config default` to generate a default config")
    92  }
    93  
    94  // Reads config from path and returns config struct if path is valid and marshaling
    95  // succeeds
    96  func readConfig(path string) (*config, error) {
    97  	data, err := os.ReadFile(path)
    98  	if err != nil {
    99  		return nil, errors.Wrap(err, "failed to read config file")
   100  	}
   101  	conf := &config{}
   102  	if err := json.Unmarshal(data, conf); err != nil {
   103  		return nil, errors.New("failed to unmarshal config data")
   104  	}
   105  	return conf, nil
   106  }
   107  
   108  // Checks to see if there is an ncproxy.json in the directory of the executable.
   109  func configPresent() (string, bool) {
   110  	path := filepath.Join(filepath.Dir(os.Args[0]), "ncproxy.json")
   111  	if _, err := os.Stat(path); os.IsNotExist(err) {
   112  		return "", false
   113  	}
   114  	return path, true
   115  }
   116
View as plain text