file.go

package flagconfig

import (
	"bufio"
	"bytes"
	"io"
	"os"
	"strings"
)

// dumpExampleConfig returns the string representation of a configuration file
// with all parameters filled in with their default values
func (f *FlagConfig) dumpExampleConfig(projname string) string {
	var buffer bytes.Buffer

	buffer.WriteString("\n")
	buffer.WriteString("#####################################\n")
	buffer.WriteString("### " + projname + " configuration\n")
	buffer.WriteString("#####################################\n")
	buffer.WriteString("\n")

	for _, param := range f.fullConfig {
		if _, ok := f.cliOnly[param.Name()]; ok {
			continue
		}
		buffer.WriteString("# " + param.Description() + "\n")
		if defaults, ok := param.DefaultAsStrings(); ok {
			if len(defaults) > 0 {
				for i := range defaults {
					buffer.WriteString(param.Name() + ": " + defaults[i] + "\n")
				}
			} else {
				buffer.WriteString("# " + param.Name() + ": <something>\n")
			}
		} else {
			buffer.WriteString(param.Name() + ": <required>\n")
		}
		buffer.WriteString("\n")
	}
	return buffer.String()
}

func setOrAppend(m map[string][]string, name, val string) {
	if _, ok := m[name]; !ok {
		m[name] = make([]string, 0, 8)
	}
	m[name] = append(m[name], val)
}

// readConfig returns a map of the key/values found in a given configuration file.
// Note: these key/values don't have to actually correspond to expected parameters,
// that parsing is done elsewhere
func readConfig(file string) (map[string][]string, error) {
	fi, err := os.Open(file)
	ret := map[string][]string{}
	if err != nil {
		return ret, err
	}

	r := bufio.NewReader(fi)
	for {
		line, err := r.ReadString('\n')
		if err == io.EOF {
			break
		}
		if err != nil {
			return nil, err
		}

		line = strings.TrimRight(line, "\n")
		if len(line) > 0 && line[0] != '#' {
			spl := strings.SplitN(line, ":", 2)
			name := strings.Trim(spl[0], " \t")
			val := strings.Trim(spl[1], " \t")
			setOrAppend(ret, name, val)
		}
	}

	return ret, nil

}