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package cli
import (
"context"
"fmt"
"os"
"path/filepath"
"runtime"
"strings"
"github.com/spf13/cobra"
"github.com/spf13/viper"
)
const (
HomeFlag = "home"
TraceFlag = "trace"
OutputFlag = "output"
EncodingFlag = "encoding"
)
// Executable is the minimal interface to *corba.Command, so we can
// wrap if desired before the test
type Executable interface {
Execute() error
Context() context.Context
}
// PrepareBaseCmd is meant for tendermint and other servers
func PrepareBaseCmd(cmd *cobra.Command, envPrefix, defaultHome string) Executor {
cobra.OnInitialize(func() { InitEnv(envPrefix) })
cmd.PersistentFlags().StringP(HomeFlag, "", defaultHome, "directory for config and data")
cmd.PersistentFlags().Bool(TraceFlag, false, "print out full stack trace on errors")
cmd.PersistentPreRunE = concatCobraCmdFuncs(BindFlagsLoadViper, cmd.PersistentPreRunE)
return Executor{cmd, os.Exit}
}
// PrepareMainCmd is meant for client side libs that want some more flags
//
// This adds --encoding (hex, btc, base64) and --output (text, json) to
// the command. These only really make sense in interactive commands.
func PrepareMainCmd(cmd *cobra.Command, envPrefix, defaultHome string) Executor {
cmd.PersistentFlags().StringP(EncodingFlag, "e", "hex", "Binary encoding (hex|b64|btc)")
cmd.PersistentFlags().StringP(OutputFlag, "o", "text", "Output format (text|json)")
cmd.PersistentPreRunE = concatCobraCmdFuncs(validateOutput, cmd.PersistentPreRunE)
return PrepareBaseCmd(cmd, envPrefix, defaultHome)
}
// InitEnv sets to use ENV variables if set.
func InitEnv(prefix string) {
copyEnvVars(prefix)
// env variables with TM prefix (eg. TM_ROOT)
viper.SetEnvPrefix(prefix)
viper.SetEnvKeyReplacer(strings.NewReplacer(".", "_", "-", "_"))
viper.AutomaticEnv()
}
// This copies all variables like TMROOT to TM_ROOT,
// so we can support both formats for the user
func copyEnvVars(prefix string) {
prefix = strings.ToUpper(prefix)
ps := prefix + "_"
for _, e := range os.Environ() {
kv := strings.SplitN(e, "=", 2)
if len(kv) == 2 {
k, v := kv[0], kv[1]
if strings.HasPrefix(k, prefix) && !strings.HasPrefix(k, ps) {
k2 := strings.Replace(k, prefix, ps, 1)
os.Setenv(k2, v)
}
}
}
}
// Executor wraps the cobra Command with a nicer Execute method
type Executor struct {
*cobra.Command
Exit func(int) // this is os.Exit by default, override in tests
}
type ExitCoder interface {
ExitCode() int
}
// execute adds all child commands to the root command sets flags appropriately.
// This is called by main.main(). It only needs to happen once to the rootCmd.
func (e Executor) Execute() error {
e.SilenceUsage = true
e.SilenceErrors = true
err := e.Command.Execute()
if err != nil {
if viper.GetBool(TraceFlag) {
const size = 64 << 10
buf := make([]byte, size)
buf = buf[:runtime.Stack(buf, false)]
fmt.Fprintf(os.Stderr, "ERROR: %v\n%s\n", err, buf)
} else {
fmt.Fprintf(os.Stderr, "ERROR: %v\n", err)
}
// return error code 1 by default, can override it with a special error type
exitCode := 1
if ec, ok := err.(ExitCoder); ok {
exitCode = ec.ExitCode()
}
e.Exit(exitCode)
}
return err
}
type cobraCmdFunc func(cmd *cobra.Command, args []string) error
// Returns a single function that calls each argument function in sequence
// RunE, PreRunE, PersistentPreRunE, etc. all have this same signature
func concatCobraCmdFuncs(fs ...cobraCmdFunc) cobraCmdFunc {
return func(cmd *cobra.Command, args []string) error {
for _, f := range fs {
if f != nil {
if err := f(cmd, args); err != nil {
return err
}
}
}
return nil
}
}
// Bind all flags and read the config into viper
func BindFlagsLoadViper(cmd *cobra.Command, args []string) error {
// cmd.Flags() includes flags from this command and all persistent flags from the parent
if err := viper.BindPFlags(cmd.Flags()); err != nil {
return err
}
homeDir := viper.GetString(HomeFlag)
viper.Set(HomeFlag, homeDir)
viper.SetConfigName("config") // name of config file (without extension)
viper.AddConfigPath(homeDir) // search root directory
viper.AddConfigPath(filepath.Join(homeDir, "config")) // search root directory /config
// If a config file is found, read it in.
if err := viper.ReadInConfig(); err == nil {
// stderr, so if we redirect output to json file, this doesn't appear
// fmt.Fprintln(os.Stderr, "Using config file:", viper.ConfigFileUsed())
} else if _, ok := err.(viper.ConfigFileNotFoundError); !ok {
// ignore not found error, return other errors
return err
}
return nil
}
func validateOutput(cmd *cobra.Command, args []string) error {
// validate output format
output := viper.GetString(OutputFlag)
switch output {
case "text", "json":
default:
return fmt.Errorf("unsupported output format: %s", output)
}
return nil
}