mirror of
https://github.com/42wim/matterbridge.git
synced 2024-11-22 18:52:02 -08:00
309 lines
6.7 KiB
Go
309 lines
6.7 KiB
Go
// Package gotenv provides functionality to dynamically load the environment variables
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package gotenv
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import (
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"bufio"
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"fmt"
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"io"
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"os"
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"regexp"
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"strings"
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)
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const (
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// Pattern for detecting valid line format
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linePattern = `\A\s*(?:export\s+)?([\w\.]+)(?:\s*=\s*|:\s+?)('(?:\'|[^'])*'|"(?:\"|[^"])*"|[^#\n]+)?\s*(?:\s*\#.*)?\z`
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// Pattern for detecting valid variable within a value
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variablePattern = `(\\)?(\$)(\{?([A-Z0-9_]+)?\}?)`
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// Byte order mark character
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bom = "\xef\xbb\xbf"
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)
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// Env holds key/value pair of valid environment variable
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type Env map[string]string
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/*
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Load is a function to load a file or multiple files and then export the valid variables into environment variables if they do not exist.
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When it's called with no argument, it will load `.env` file on the current path and set the environment variables.
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Otherwise, it will loop over the filenames parameter and set the proper environment variables.
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*/
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func Load(filenames ...string) error {
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return loadenv(false, filenames...)
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}
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/*
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OverLoad is a function to load a file or multiple files and then export and override the valid variables into environment variables.
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*/
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func OverLoad(filenames ...string) error {
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return loadenv(true, filenames...)
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}
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/*
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Must is wrapper function that will panic when supplied function returns an error.
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*/
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func Must(fn func(filenames ...string) error, filenames ...string) {
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if err := fn(filenames...); err != nil {
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panic(err.Error())
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}
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}
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/*
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Apply is a function to load an io Reader then export the valid variables into environment variables if they do not exist.
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*/
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func Apply(r io.Reader) error {
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return parset(r, false)
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}
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/*
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OverApply is a function to load an io Reader then export and override the valid variables into environment variables.
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*/
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func OverApply(r io.Reader) error {
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return parset(r, true)
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}
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func loadenv(override bool, filenames ...string) error {
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if len(filenames) == 0 {
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filenames = []string{".env"}
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}
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for _, filename := range filenames {
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f, err := os.Open(filename)
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if err != nil {
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return err
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}
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err = parset(f, override)
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if err != nil {
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return err
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}
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f.Close()
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}
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return nil
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}
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// parse and set :)
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func parset(r io.Reader, override bool) error {
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env, err := strictParse(r, override)
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if err != nil {
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return err
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}
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for key, val := range env {
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setenv(key, val, override)
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}
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return nil
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}
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func setenv(key, val string, override bool) {
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if override {
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os.Setenv(key, val)
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} else {
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if _, present := os.LookupEnv(key); !present {
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os.Setenv(key, val)
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}
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}
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}
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// Parse is a function to parse line by line any io.Reader supplied and returns the valid Env key/value pair of valid variables.
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// It expands the value of a variable from the environment variable but does not set the value to the environment itself.
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// This function is skipping any invalid lines and only processing the valid one.
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func Parse(r io.Reader) Env {
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env, _ := strictParse(r, false)
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return env
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}
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// StrictParse is a function to parse line by line any io.Reader supplied and returns the valid Env key/value pair of valid variables.
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// It expands the value of a variable from the environment variable but does not set the value to the environment itself.
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// This function is returning an error if there are any invalid lines.
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func StrictParse(r io.Reader) (Env, error) {
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return strictParse(r, false)
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}
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func strictParse(r io.Reader, override bool) (Env, error) {
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env := make(Env)
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scanner := bufio.NewScanner(r)
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firstLine := true
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for scanner.Scan() {
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line := strings.TrimSpace(scanner.Text())
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if firstLine {
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line = strings.TrimPrefix(line, bom)
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firstLine = false
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}
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if line == "" || line[0] == '#' {
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continue
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}
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quote := ""
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idx := strings.Index(line, "=")
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if idx == -1 {
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idx = strings.Index(line, ":")
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}
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if idx > 0 && idx < len(line)-1 {
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val := strings.TrimSpace(line[idx+1:])
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if val[0] == '"' || val[0] == '\'' {
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quote = val[:1]
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idx = strings.LastIndex(strings.TrimSpace(val[1:]), quote)
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if idx >= 0 && val[idx] != '\\' {
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quote = ""
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}
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}
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}
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for quote != "" && scanner.Scan() {
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l := scanner.Text()
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line += "\n" + l
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idx := strings.LastIndex(l, quote)
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if idx > 0 && l[idx-1] == '\\' {
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continue
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}
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if idx >= 0 {
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quote = ""
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}
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}
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if quote != "" {
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return env, fmt.Errorf("missing quotes")
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}
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err := parseLine(line, env, override)
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if err != nil {
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return env, err
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}
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}
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return env, nil
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}
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var (
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lineRgx = regexp.MustCompile(linePattern)
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unescapeRgx = regexp.MustCompile(`\\([^$])`)
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varRgx = regexp.MustCompile(variablePattern)
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)
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func parseLine(s string, env Env, override bool) error {
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rm := lineRgx.FindStringSubmatch(s)
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if len(rm) == 0 {
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return checkFormat(s, env)
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}
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key := rm[1]
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val := rm[2]
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// trim whitespace
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val = strings.TrimSpace(val)
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// determine if string has quote prefix
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hdq := strings.HasPrefix(val, `"`)
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// determine if string has single quote prefix
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hsq := strings.HasPrefix(val, `'`)
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// remove quotes '' or ""
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if l := len(val); (hsq || hdq) && l >= 2 {
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val = val[1 : l-1]
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}
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if hdq {
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val = strings.ReplaceAll(val, `\n`, "\n")
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val = strings.ReplaceAll(val, `\r`, "\r")
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// Unescape all characters except $ so variables can be escaped properly
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val = unescapeRgx.ReplaceAllString(val, "$1")
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}
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fv := func(s string) string {
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return varReplacement(s, hsq, env, override)
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}
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if !hsq {
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val = varRgx.ReplaceAllStringFunc(val, fv)
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val = parseVal(val, env, hdq, override)
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}
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env[key] = val
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return nil
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}
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func parseExport(st string, env Env) error {
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if strings.HasPrefix(st, "export") {
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vs := strings.SplitN(st, " ", 2)
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if len(vs) > 1 {
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if _, ok := env[vs[1]]; !ok {
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return fmt.Errorf("line `%s` has an unset variable", st)
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}
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}
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}
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return nil
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}
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var varNameRgx = regexp.MustCompile(`(\$)(\{?([A-Z0-9_]+)\}?)`)
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func varReplacement(s string, hsq bool, env Env, override bool) string {
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if strings.HasPrefix(s, "\\") {
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return strings.TrimPrefix(s, "\\")
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}
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if hsq {
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return s
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}
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mn := varNameRgx.FindStringSubmatch(s)
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if len(mn) == 0 {
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return s
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}
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v := mn[3]
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if replace, ok := os.LookupEnv(v); ok && !override {
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return replace
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}
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replace, ok := env[v]
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if !ok {
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replace = os.Getenv(v)
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}
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return replace
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}
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func checkFormat(s string, env Env) error {
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st := strings.TrimSpace(s)
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if (st == "") || strings.HasPrefix(st, "#") {
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return nil
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}
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if err := parseExport(st, env); err != nil {
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return err
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}
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return fmt.Errorf("line `%s` doesn't match format", s)
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}
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func parseVal(val string, env Env, ignoreNewlines bool, override bool) string {
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if strings.Contains(val, "=") && !ignoreNewlines {
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kv := strings.Split(val, "\r")
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if len(kv) > 1 {
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val = kv[0]
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for _, l := range kv[1:] {
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_ = parseLine(l, env, override)
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}
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}
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}
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return val
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}
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