micro/config/source/env/env.go

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2019-05-31 01:11:13 +03:00
package env
import (
"os"
"strconv"
"strings"
"time"
"github.com/imdario/mergo"
"github.com/micro/go-micro/config/source"
)
var (
DefaultPrefixes = []string{}
)
type env struct {
prefixes []string
strippedPrefixes []string
opts source.Options
}
func (e *env) Read() (*source.ChangeSet, error) {
var changes map[string]interface{}
for _, env := range os.Environ() {
if len(e.prefixes) > 0 || len(e.strippedPrefixes) > 0 {
notFound := true
if _, ok := matchPrefix(e.prefixes, env); ok {
notFound = false
}
if match, ok := matchPrefix(e.strippedPrefixes, env); ok {
env = strings.TrimPrefix(env, match)
notFound = false
}
if notFound {
continue
}
}
pair := strings.SplitN(env, "=", 2)
value := pair[1]
keys := strings.Split(strings.ToLower(pair[0]), "_")
reverse(keys)
tmp := make(map[string]interface{})
for i, k := range keys {
if i == 0 {
if intValue, err := strconv.Atoi(value); err == nil {
tmp[k] = intValue
} else if boolValue, err := strconv.ParseBool(value); err == nil {
tmp[k] = boolValue
} else {
tmp[k] = value
}
continue
}
tmp = map[string]interface{}{k: tmp}
}
if err := mergo.Map(&changes, tmp); err != nil {
return nil, err
}
}
b, err := e.opts.Encoder.Encode(changes)
if err != nil {
return nil, err
}
cs := &source.ChangeSet{
Format: e.opts.Encoder.String(),
Data: b,
Timestamp: time.Now(),
Source: e.String(),
}
cs.Checksum = cs.Sum()
return cs, nil
}
func matchPrefix(pre []string, s string) (string, bool) {
for _, p := range pre {
if strings.HasPrefix(s, p) {
return p, true
}
}
return "", false
}
func reverse(ss []string) {
for i := len(ss)/2 - 1; i >= 0; i-- {
opp := len(ss) - 1 - i
ss[i], ss[opp] = ss[opp], ss[i]
}
}
func (e *env) Watch() (source.Watcher, error) {
return newWatcher()
}
func (e *env) String() string {
return "env"
}
// NewSource returns a config source for parsing ENV variables.
// Underscores are delimiters for nesting, and all keys are lowercased.
//
// Example:
// "DATABASE_SERVER_HOST=localhost" will convert to
//
// {
// "database": {
// "server": {
// "host": "localhost"
// }
// }
// }
func NewSource(opts ...source.Option) source.Source {
options := source.NewOptions(opts...)
var sp []string
var pre []string
if p, ok := options.Context.Value(strippedPrefixKey{}).([]string); ok {
sp = p
}
if p, ok := options.Context.Value(prefixKey{}).([]string); ok {
pre = p
}
if len(sp) > 0 || len(pre) > 0 {
pre = append(pre, DefaultPrefixes...)
}
return &env{prefixes: pre, strippedPrefixes: sp, opts: options}
}