package cli import ( "fmt" "os" "strings" "github.com/pkg/errors" "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 } // 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) { fmt.Fprintf(os.Stderr, "ERROR: %+v\n", err) } 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 // 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 { // we ignore not found error, only parse error // stderr, so if we redirect output to json file, this doesn't appear fmt.Fprintf(os.Stderr, "%#v", 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 errors.Errorf("Unsupported output format: %s", output) } return nil }