Envh

This library is made up of two parts :

• Env object : it wraps your environments variables in an object and provides convenient helpers.
• Env tree object : it manages environment variables through a tree structure to store a config the same way as in a yaml file or whatever format allows to store a config hierarchically

Install

go get github.com/antham/envh

How it works

Check the godoc, there are many examples provided.

Example with a tree dumped in a config struct

package envh
import (
"encoding/json""fmt""os""strings"
)
typeCONFIG2struct {
DBstruct {
USERNAMEstringPASSWORDstringHOSTstringNAMEstringPORTintURLstringUSAGELIMITfloat32
}
MAILERstruct {
HOSTstringUSERNAMEstringPASSWORDstringENABLEDbool
}
MAPmap[string]string
}
func (c*CONFIG2) Walk(tree*EnvTree, keyChain []string) (bool, error) {
ifsetter, ok:=map[string]func(*EnvTree, []string) error{
"CONFIG2_DB_URL": c.setURL,
"CONFIG2_MAP": c.setMap,
}[strings.Join(keyChain, "_")]; ok {
returntrue, setter(tree, keyChain)
}
returnfalse, nil
}
func (c*CONFIG2) setMap(tree*EnvTree, keyChain []string) error {
datas:=map[string]string{}
keys, err:=tree.FindChildrenKeys(keyChain...)
iferr!=nil {
returnerr
}
for_, key:=rangekeys {
value, err:=tree.FindString(append(keyChain, key)...)
iferr!=nil {
returnerr
}
datas[key] =value
}
c.MAP=datasreturnnil
}
func (c*CONFIG2) setURL(tree*EnvTree, keyChain []string) error {
datas:=map[string]string{}
for_, key:=range []string{"USERNAME", "PASSWORD", "HOST", "NAME"} {
value, err:=tree.FindString("CONFIG2", "DB", key)
iferr!=nil {
returnerr
}
datas[key] =value
}
port, err:=tree.FindInt("CONFIG2", "DB", "PORT")
iferr!=nil {
returnerr
}
c.DB.URL=fmt.Sprintf("jdbc:mysql://%s:%d/%s?user=%s&password=%s", datas["HOST"], port, datas["NAME"], datas["USERNAME"], datas["PASSWORD"])
returnnil
}
funcExampleStructWalker_customFieldSet() {
os.Clearenv()
setEnv("CONFIG2_DB_USERNAME", "foo")
setEnv("CONFIG2_DB_PASSWORD", "bar")
setEnv("CONFIG2_DB_HOST", "localhost")
setEnv("CONFIG2_DB_NAME", "my-db")
setEnv("CONFIG2_DB_PORT", "3306")
setEnv("CONFIG2_DB_USAGELIMIT", "95.6")
setEnv("CONFIG2_MAILER_HOST", "127.0.0.1")
setEnv("CONFIG2_MAILER_USERNAME", "foo")
setEnv("CONFIG2_MAILER_PASSWORD", "bar")
setEnv("CONFIG2_MAILER_ENABLED", "true")
setEnv("CONFIG2_MAP_KEY1", "value1")
setEnv("CONFIG2_MAP_KEY2", "value2")
setEnv("CONFIG2_MAP_KEY3", "value3")
env, err:=NewEnvTree("^CONFIG2", "_")
iferr!=nil {
return
}
s:=CONFIG2{}
err=env.PopulateStruct(&s)
iferr!=nil {
return
}
b, err:=json.Marshal(s)
iferr!=nil {
return
}
fmt.Println(string(b))
// Output:// {"DB":{"USERNAME":"foo","PASSWORD":"bar","HOST":"localhost","NAME":"my-db","PORT":3306,"URL":"jdbc:mysql://localhost:3306/my-db?user=foo\u0026password=bar","USAGELIMIT":95.6},"MAILER":{"HOST":"127.0.0.1","USERNAME":"foo","PASSWORD":"bar","ENABLED":true},"MAP":{"KEY1":"value1","KEY2":"value2","KEY3":"value3"}}
}