package xdsconfig import ( "encoding/json" "fmt" "os" "os/user" "path" "path/filepath" "regexp" ) type SyncThingConf struct { BinDir string `json:"binDir"` Home string `json:"home"` GuiAddress string `json:"gui-address"` GuiAPIKey string `json:"gui-apikey"` } type FileConfig struct { HTTPPort string `json:"httpPort"` LogsDir string `json:"logsDir"` SThgConf *SyncThingConf `json:"syncthing"` } // getConfigFromFile reads configuration from a config file. // Order to determine which config file is used: // 1/ from command line option: "--config myConfig.json" // 2/ $HOME/.xds/agent-config.json file // 3/ /agent-config.json file // 4/ /agent-config.json file func updateConfigFromFile(c *Config, confFile string) (*FileConfig, error) { searchIn := make([]string, 0, 3) if confFile != "" { searchIn = append(searchIn, confFile) } if usr, err := user.Current(); err == nil { searchIn = append(searchIn, path.Join(usr.HomeDir, ".xds", "agent-config.json")) } cwd, err := os.Getwd() if err == nil { searchIn = append(searchIn, path.Join(cwd, "agent-config.json")) } exePath, err := filepath.Abs(filepath.Dir(os.Args[0])) if err == nil { searchIn = append(searchIn, path.Join(exePath, "agent-config.json")) } var cFile *string for _, p := range searchIn { if _, err := os.Stat(p); err == nil { cFile = &p break } } fCfg := FileConfig{} if cFile == nil { // No config file found return &fCfg, nil } c.Log.Infof("Use config file: %s", *cFile) // TODO move on viper package to support comments in JSON and also // bind with flags (command line options) // see https://github.com/spf13/viper#working-with-flags fd, _ := os.Open(*cFile) defer fd.Close() if err := json.NewDecoder(fd).Decode(&fCfg); err != nil { return nil, err } // Support environment variables (IOW ${MY_ENV_VAR} syntax) in agent-config.json for _, field := range []*string{ &fCfg.LogsDir, &fCfg.SThgConf.Home, &fCfg.SThgConf.BinDir} { rep, err := resolveEnvVar(*field) if err != nil { return nil, err } *field = path.Clean(rep) } // Config file settings overwrite default config if fCfg.HTTPPort != "" { c.HTTPPort = fCfg.HTTPPort } return &fCfg, nil } // resolveEnvVar Resolved environment variable regarding the syntax ${MYVAR} func resolveEnvVar(s string) (string, error) { re := regexp.MustCompile("\\${(.*)}") vars := re.FindAllStringSubmatch(s, -1) res := s for _, v := range vars { val := os.Getenv(v[1]) if val == "" { return res, fmt.Errorf("ERROR: %s env variable not defined", v[1]) } rer := regexp.MustCompile("\\${" + v[1] + "}") res = rer.ReplaceAllString(res, val) } return res, nil }