c4ebd80669
Implements conf.Load to populate tagged structs from a chain of Sources (env, .env, YAML/JSON/TOML, custom). Supports default values, slice separators, nested structs, pointer fields, and a Validator hook. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
103 lines
2.3 KiB
Go
103 lines
2.3 KiB
Go
package conf
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import (
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"bufio"
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"io"
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"os"
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"strings"
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"git.juancwu.dev/juancwu/errx"
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)
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// DotEnvFile loads KEY=VALUE pairs from path. Lines starting with # and blank
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// lines are ignored. Values may be wrapped in single or double quotes; double
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// quotes honor \n, \t, \r, \\, and \" escapes.
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func DotEnvFile(path string) (Source, error) {
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const op = "conf.DotEnvFile"
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f, err := os.Open(path)
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if err != nil {
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return nil, errx.Wrapf(op, err, "open %s", path)
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}
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defer f.Close()
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return DotEnvReader(f)
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}
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// DotEnvReader is DotEnvFile for an arbitrary reader.
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func DotEnvReader(r io.Reader) (Source, error) {
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const op = "conf.DotEnvReader"
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m := map[string]string{}
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sc := bufio.NewScanner(r)
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lineNo := 0
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for sc.Scan() {
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lineNo++
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line := strings.TrimSpace(sc.Text())
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if line == "" || strings.HasPrefix(line, "#") {
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continue
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}
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line = strings.TrimPrefix(line, "export ")
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eq := strings.IndexByte(line, '=')
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if eq < 0 {
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return nil, errx.Newf(op, "line %d: missing '='", lineNo)
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}
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key := strings.TrimSpace(line[:eq])
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val := strings.TrimSpace(line[eq+1:])
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// strip trailing inline comment for unquoted values
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if !isQuoted(val) {
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if i := strings.Index(val, " #"); i >= 0 {
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val = strings.TrimSpace(val[:i])
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}
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}
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v, err := unquote(val)
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if err != nil {
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return nil, errx.Wrapf(op, err, "line %d", lineNo)
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}
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m[key] = v
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}
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if err := sc.Err(); err != nil {
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return nil, errx.Wrap(op, err)
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}
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return MapSource(m), nil
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}
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func isQuoted(s string) bool {
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if len(s) < 2 {
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return false
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}
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return (s[0] == '"' && s[len(s)-1] == '"') || (s[0] == '\'' && s[len(s)-1] == '\'')
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}
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func unquote(s string) (string, error) {
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if len(s) >= 2 && s[0] == '\'' && s[len(s)-1] == '\'' {
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return s[1 : len(s)-1], nil
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}
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if len(s) >= 2 && s[0] == '"' && s[len(s)-1] == '"' {
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inner := s[1 : len(s)-1]
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var b strings.Builder
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for i := 0; i < len(inner); i++ {
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c := inner[i]
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if c != '\\' || i+1 >= len(inner) {
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b.WriteByte(c)
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continue
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}
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i++
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switch inner[i] {
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case 'n':
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b.WriteByte('\n')
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case 't':
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b.WriteByte('\t')
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case 'r':
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b.WriteByte('\r')
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case '\\':
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b.WriteByte('\\')
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case '"':
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b.WriteByte('"')
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default:
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b.WriteByte('\\')
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b.WriteByte(inner[i])
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}
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}
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return b.String(), nil
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}
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return s, nil
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}
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