Use the package's functionality to simplify the use of flags, environments and config file when starting the application.
Fill custom Golangstructfrom environments, flags or configuration file (JSON) with desired order.
Convenient for setting up an application for acontainer(Docker,Podman)
go get github.com/KusoKaihatsuSha/startupgo get -u
go mod tidy
type CustomConf struct {
VarStr string `json:"t-str" default:"abcd" flag:"t-str" env:"T_STR" help:"description"`
}Order (low -> high) [FILE -> ENV -> FLAG]:
filledCustomConf := startup.Get[CustomConf](
startup.FILE,
startup.ENV,
startup.FLAG,
)// Some struct
type Configuration struct {
TestString string `json:"test-string" default:"abcd" flag:"test-string" env:"TEST_STR" help:"string"`
TestInt int64 `json:"test-int" default:"11" flag:"test-int" env:"TEST_INT" help:"int"`
TestDuration time.Duration `json:"test-duration" default:"1s" flag:"test-duration" env:"TEST_DURATION" help:"duration"`
TestBool bool `json:"test-bool" default:"false" flag:"test-bool" env:"TEST_BOOL" help:"bool"`
TestFloat float64 `json:"test-float" default:"1" flag:"test-float" env:"TEST_FLOAT" help:"float"`
TestUint uint64 `json:"test-uint" default:"111" flag:"test-uint" env:"TEST_UINT" help:"uint"`
}
func main() {
// Emulated settings at startup
os.Setenv("TEST_STR", "dcba")
os.Setenv("TEST_UINT", "999")
os.Setenv("TEST_DURATION", "11h")
os.Args = append(
os.Args,
"-test-bool",
"-test-uint=741",
)
// Get filled configs (ORDER: Environment -> Flags ).
config := startup.GetForce[Configuration](
startup.ENV,
startup.FLAG,
)
// Print result => {dcba 11 11h0m0s true 1 741}
fmt.Printf("%v\n", config)
}package main
import (
"encoding/json"
"fmt"
"net"
"strings"
"time"
"github.com/KusoKaihatsuSha/startup"
)
// Custom struct
type Configuration struct {
TestEmail string `json:"test-email" default:"a@b.c" flag:"test-email" env:"TEST_EMAIL" help:"email"`
TestSlice []string `json:"test-slice" default:"1,2,3,4;5;6" flag:"test-slice" env:"TEST_SLICE" help:"slice" valid:"slice"`
TestInt int64 `json:"test-int" default:"11" flag:"test-int" env:"TEST_INT" help:"int"`
TestDuration time.Duration `json:"test-duration" default:"1s" flag:"test-duration" env:"TEST_DURATION" help:"duration"`
TestBool bool `json:"test-bool" default:"true" flag:"test-bool" env:"TEST_BOOL" help:"bool"`
TestFloat float64 `json:"test-float" default:"1" flag:"test-float" env:"TEST_FLOAT" help:"float"`
TestUint uint64 `json:"test-uint" default:"111" flag:"test-uint" env:"TEST_UINT" help:"uint"`
TestIP net.IP `json:"test-ip" default:"127.0.0.1" flag:"test-ip" env:"TEST_IP" help:"ip"`
TestJSON TestJSON `json:"test-json" default:"{\"param1\":\"default_001\",\"param2\":\"default_002\"}" flag:"test-json" env:"TEST_JSON" help:"json"`
}
// JSON field and unmashalText
type TestJSON struct {
P1 string `json:"param1"`
P2 string `json:"param2"`
}
func (t *TestJSON) UnmarshalText(text []byte) error {
type Tmp TestJSON
tmp := (*Tmp)(t)
if err := json.Unmarshal(text, tmp); err != nil {
return err
}
t = (*TestJSON)(tmp)
return nil
}
// Custom slice validation
type sliceValid string
var sliceValidation sliceValid = "slice"
func (o sliceValid) Valid(def string, value any) (any, bool) {
newValue := strings.ReplaceAll(def, ";", ",")
return strings.Split(newValue, ","), true
}
func main() {
// Add custom validation
startup.AddValidation(sliceValidation)
// Implement all types of configs (ORDER: Json file -> Environment -> Flags ).
get := startup.Get[Configuration](
startup.FILE,
startup.ENV,
startup.FLAG,
)
fmt.Printf(
"string ↣ TYPE [%[1]T] VALUE [%[1]v]\n",
get.TestEmail,
)
fmt.Printf(
"custom slice ↣ TYPE [%[1]T] VALUE [%[1]v]\n",
get.TestSlice,
)
fmt.Printf(
"integer max 10 ↣ TYPE [%[1]T] VALUE [%[1]v]\n",
get.TestInt,
)
fmt.Printf(
"duration ↣ TYPE [%[1]T] VALUE [%[1]v]\n",
get.TestDuration,
)
fmt.Printf(
"boolean ↣ TYPE [%[1]T] VALUE [%[1]v]\n",
get.TestBool,
)
fmt.Printf(
"float ↣ TYPE [%[1]T] VALUE [%[1]v]\n",
get.TestFloat,
)
fmt.Printf(
"uint ↣ TYPE [%[1]T] VALUE [%[1]v]\n",
get.TestUint,
)
fmt.Printf(
"ip ↣ TYPE [%[1]T] VALUE [%[1]v]\n",
get.TestIP,
)
fmt.Printf(
"json unmarshal ↣ TYPE [%[1]T] VALUE [%#[1]v]\n",
get.TestJSON,
)
}tmp_file- Check exist inside Temp folder and create if not exist (string in struct)file- Check exist the filepath and create if not exist (string in struct)url- Check url is correct (string in struct)bool- Parse Bool (bool in struct)int- Parse int (int64 in struct)float- Parse float (float64 in struct)duration- Parse duration (time.Duration in struct)uuid- Check uuid. Return new if not exist (string in struct)
Default config filename:
config.ini
Flags are reserved:
config
Environments are reserved:
CONFIG
Order of priority for settings (low -> high):
Config file (JSON) --> Environment --> Flags
-config
Configuration settings file
Default value: config.ini
Sample JSON config:
{
"startup_configuration_file": "config.ini"
}
Sample environment: CONFIG=config.ini
Sample flag value: testee.exe -config=config.ini
-test-bool
bool
Default value: true
Sample JSON config:
{
"test-bool": true
}
Sample environment: TEST_BOOL=true
Sample(TRUE): testee.exe -test-bool
Sample(default): testee.exe
Sample(TRUE): testee.exe -test-bool=true
Sample(FALSE): testee.exe -test-bool=false
Sample(TRUE): testee.exe -test-bool=1
Sample(FALSE): testee.exe -test-bool=0
Sample(TRUE): testee.exe -test-bool=t
Sample(FALSE): testee.exe -test-bool=f
-test-duration
duration
Default value: 1s
Sample JSON config:
{
"test-duration": 1000000000
}
Sample environment: TEST_DURATION=1s
Sample(Millisecond): testee.exe -test-duration=1ms
Sample(Second): testee.exe -test-duration=1s
Sample(Minute): testee.exe -test-duration=1m
Sample(Hour): testee.exe -test-duration=1h
Sample(Nanosecond): testee.exe -test-duration=1ns
Sample(Microsecond): testee.exe -test-duration=1us
Sample(1 Hour 2 Minutes and 3 Seconds): testee.exe -test-duration=1h2m3s
Sample(111 Seconds): testee.exe -test-duration=111
-test-email
email
Default value: a@b.c
Sample JSON config:
{
"test-email": "a@b.c"
}
Sample environment: TEST_EMAIL=a@b.c
Sample flag value: testee.exe -test-email=a@b.c
-test-float
float
Default value: 1
Sample JSON config:
{
"test-float": 1
}
Sample environment: TEST_FLOAT=1
Sample flag value: testee.exe -test-float=1.000000
-test-int
int
Default value: 11
Sample JSON config:
{
"test-int": 11
}
Sample environment: TEST_INT=11
Sample flag value: testee.exe -test-int=11
-test-ip
ip
Default value: 127.0.0.1
Sample JSON config:
{
"test-ip": "127.0.0.1"
}
Sample environment: TEST_IP=127.0.0.1
-test-json
json
Default value: {default_001 default_002}
Sample JSON config:
{
"test-json": {
"param1": "default_001",
"param2": "default_002"
}
}
Sample environment: TEST_JSON={"param1":"default_001","param2":"default_002"}
-test-slice
slice
Default value: []
Sample JSON config:
{
"test-slice": null
}
Sample environment: TEST_SLICE=1,2,3,4;5;6
-test-uint
uint
Default value: 111
Sample JSON config:
{
"test-uint": 111
}
Sample environment: TEST_UINT=111
Sample flag value: testee.exe -test-uint=111