/
readenv.go
79 lines (65 loc) · 1.55 KB
/
readenv.go
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package readenv
import (
"bufio"
"io"
"os"
"regexp"
)
// EnvData maps environment keys to values.
type EnvData map[string]string
// Get returns the value of given key from the map,
// returns error if key not found
func (data EnvData) Get(key string) (string, error) {
val, ok := data[key]
if !ok {
return "", errKeyNotInEnvData(key)
}
return val, nil
}
func (data EnvData) add(key, val string) {
data[key] = val
}
// Read takes in an io.Reader, reads env vars from it and returns an EnvData
func Read(reader io.Reader) (EnvData, error) {
envData := make(EnvData)
scanner := bufio.NewScanner(reader)
for scanner.Scan() {
line := scanner.Text()
key, val, err := parse(line)
if err != nil {
continue
}
envData.add(key, val)
}
if err := scanner.Err(); err != nil {
return nil, err
}
return envData, nil
}
// File takes in a filename, reads env vars from it and returns an EnvData
func File(filename string) (EnvData, error) {
file, err := os.OpenFile(filename, os.O_RDONLY, 0444) // open .env file
if err != nil {
return nil, err
}
defer file.Close()
envData, err := Read(file)
if err != nil {
return nil, err
}
return envData, nil
}
// utility function to get key and value from line(string) provided
func parse(line string) (string, string, error) {
re, err := regexp.Compile(`(\w+[^=])(?:=)([a-zA-Z0-9_-]+)`)
if err != nil {
return "", "", err
}
matches := re.FindStringSubmatch(line)
if len(matches) != 3 {
return "", "", errFindingTwoRegexSubmatches(line)
}
key := matches[1]
val := matches[2]
return key, val, nil
}