v0.0.36

confext/confParser.go

@@ -0,0 +1,136 @@
+package confext
+
+import (
+	"errors"
+	"fmt"
+	"gogs.mikescher.com/BlackForestBytes/goext/timeext"
+	"math/bits"
+	"os"
+	"reflect"
+	"strconv"
+	"time"
+)
+
+// ApplyEnvOverrides overrides field values from environment variables
+//
+// fields must be tagged with `env:"env_key"`
+func ApplyEnvOverrides[T any](c *T) error {
+
+	rval := reflect.ValueOf(c).Elem()
+	rtyp := rval.Type()
+
+	for i := 0; i < rtyp.NumField(); i++ {
+
+		rsfield := rtyp.Field(i)
+		rvfield := rval.Field(i)
+
+		envkey := rsfield.Tag.Get("env")
+		if envkey == "" {
+			continue
+		}
+
+		envval, efound := os.LookupEnv(envkey)
+		if !efound {
+			continue
+		}
+
+		if rvfield.Type() == reflect.TypeOf("") {
+
+			rvfield.Set(reflect.ValueOf(envval))
+
+			fmt.Printf("[CONF] Overwrite config '%s' with '%s'\n", envkey, envval)
+
+		} else if rvfield.Type() == reflect.TypeOf(int(0)) {
+
+			envint, err := strconv.ParseInt(envval, 10, bits.UintSize)
+			if err != nil {
+				return errors.New(fmt.Sprintf("Failed to parse env-config variable '%s' to int (value := '%s')", envkey, envval))
+			}
+
+			rvfield.Set(reflect.ValueOf(int(envint)))
+
+			fmt.Printf("[CONF] Overwrite config '%s' with '%s'\n", envkey, envval)
+
+		} else if rvfield.Type() == reflect.TypeOf(int64(0)) {
+
+			envint, err := strconv.ParseInt(envval, 10, 64)
+			if err != nil {
+				return errors.New(fmt.Sprintf("Failed to parse env-config variable '%s' to int64 (value := '%s')", envkey, envval))
+			}
+
+			rvfield.Set(reflect.ValueOf(int64(envint)))
+
+			fmt.Printf("[CONF] Overwrite config '%s' with '%s'\n", envkey, envval)
+
+		} else if rvfield.Type() == reflect.TypeOf(int32(0)) {
+
+			envint, err := strconv.ParseInt(envval, 10, 32)
+			if err != nil {
+				return errors.New(fmt.Sprintf("Failed to parse env-config variable '%s' to int32 (value := '%s')", envkey, envval))
+			}
+
+			rvfield.Set(reflect.ValueOf(int32(envint)))
+
+			fmt.Printf("[CONF] Overwrite config '%s' with '%s'\n", envkey, envval)
+
+		} else if rvfield.Type() == reflect.TypeOf(int8(0)) {
+
+			envint, err := strconv.ParseInt(envval, 10, 8)
+			if err != nil {
+				return errors.New(fmt.Sprintf("Failed to parse env-config variable '%s' to int32 (value := '%s')", envkey, envval))
+			}
+
+			rvfield.Set(reflect.ValueOf(int8(envint)))
+
+			fmt.Printf("[CONF] Overwrite config '%s' with '%s'\n", envkey, envval)
+
+		} else if rvfield.Type() == reflect.TypeOf(time.Duration(0)) {
+
+			dur, err := timeext.ParseDurationShortString(envval)
+			if err != nil {
+				return errors.New(fmt.Sprintf("Failed to parse env-config variable '%s' to duration (value := '%s')", envkey, envval))
+			}
+
+			rvfield.Set(reflect.ValueOf(dur))
+
+			fmt.Printf("[CONF] Overwrite config '%s' with '%s'\n", envkey, dur.String())
+
+		} else if rvfield.Type() == reflect.TypeOf(time.UnixMilli(0)) {
+
+			tim, err := time.Parse(time.RFC3339Nano, envval)
+			if err != nil {
+				return errors.New(fmt.Sprintf("Failed to parse env-config variable '%s' to time.time (value := '%s')", envkey, envval))
+			}
+
+			rvfield.Set(reflect.ValueOf(tim))
+
+			fmt.Printf("[CONF] Overwrite config '%s' with '%s'\n", envkey, tim.String())
+
+		} else if rvfield.Type().ConvertibleTo(reflect.TypeOf(int(0))) {
+
+			envint, err := strconv.ParseInt(envval, 10, 8)
+			if err != nil {
+				return errors.New(fmt.Sprintf("Failed to parse env-config variable '%s' to <%s, ,int> (value := '%s')", rvfield.Type().Name(), envkey, envval))
+			}
+
+			envcvl := reflect.ValueOf(envint).Convert(rvfield.Type())
+
+			rvfield.Set(envcvl)
+
+			fmt.Printf("[CONF] Overwrite config '%s' with '%v'\n", envkey, envcvl.Interface())
+
+		} else if rvfield.Type().ConvertibleTo(reflect.TypeOf("")) {
+
+			envcvl := reflect.ValueOf(envval).Convert(rvfield.Type())
+
+			rvfield.Set(envcvl)
+
+			fmt.Printf("[CONF] Overwrite config '%s' with '%v'\n", envkey, envcvl.Interface())
+
+		} else {
+			return errors.New(fmt.Sprintf("Unknown kind/type in config: [ %s | %s ]", rvfield.Kind().String(), rvfield.Type().String()))
+		}
+	}
+
+	return nil
+}