85 lines
1.9 KiB
Go
85 lines
1.9 KiB
Go
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// Package config implements a simple global configuration system that
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// supports a file with key=value pairs and environment variables. Note
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// that the config system is global.
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package config
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import (
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"bufio"
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"log"
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"os"
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"strings"
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)
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// NB: Rather than define a singleton type, everything is defined at
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// the top-level
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var (
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vars = map[string]string{}
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prefix = ""
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)
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// SetEnvPrefix sets the prefix for all environment variables; it's
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// assumed to not be needed for files.
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func SetEnvPrefix(pfx string) {
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prefix = pfx
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}
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func addLine(line string) {
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if strings.HasPrefix(line, "#") || line == "" {
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return
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}
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lineParts := strings.SplitN(line, "=", 2)
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if len(lineParts) != 2 {
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log.Print("skipping line: ", line)
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return // silently ignore empty keys
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}
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lineParts[0] = strings.TrimSpace(lineParts[0])
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lineParts[1] = strings.TrimSpace(lineParts[1])
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vars[lineParts[0]] = lineParts[1]
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}
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// LoadFile scans the file at path for key=value pairs and adds them
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// to the configuration.
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func LoadFile(path string) error {
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file, err := os.Open(path)
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if err != nil {
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return err
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}
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defer file.Close()
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scanner := bufio.NewScanner(file)
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for scanner.Scan() {
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line := strings.TrimSpace(scanner.Text())
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addLine(line)
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}
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if err = scanner.Err(); err != nil {
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return err
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}
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return nil
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}
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// Get retrieves a value from either a configuration file or the
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// environment. Note that values from a file will override environment
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// variables.
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func Get(key string) string {
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if v, ok := vars[key]; ok {
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return v
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}
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return os.Getenv(prefix + key)
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}
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// GetDefault retrieves a value from either a configuration file or
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// the environment. Note that value from a file will override
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// environment variables. If a value isn't found (e.g. Get returns an
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// empty string), the default value will be used.
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func GetDefault(key, def string) string {
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if v := Get(key); v != "" {
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return v
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}
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return def
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}
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