nats/nats.go at main · core-go/nats · GitHub

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package nats

import (
	"fmt"
	"github.com/nats-io/nats.go"
	"log"
	"reflect"
	"strconv"
	"time"
)

type ConnConfig struct {
	Url    string      `yaml:"url" mapstructure:"url" json:"url,omitempty" gorm:"column:url" bson:"url,omitempty" dynamodbav:"url,omitempty" firestore:"url,omitempty"`
	Option nats.Option `yaml:"option" mapstructure:"option" json:"option,omitempty" gorm:"column:option" bson:"option,omitempty" dynamodbav:"option,omitempty" firestore:"option,omitempty"`
	Retry  RetryConfig `yaml:"retry" mapstructure:"retry" json:"retry,omitempty" gorm:"column:retry" bson:"retry,omitempty" dynamodbav:"retry,omitempty" firestore:"retry,omitempty"`
}
type RetryConfig struct {
	Retry1 int64 `yaml:"1" mapstructure:"1" json:"retry1,omitempty" gorm:"column:retry1" bson:"retry1,omitempty" dynamodbav:"retry1,omitempty" firestore:"retry1,omitempty"`
	Retry2 int64 `yaml:"2" mapstructure:"2" json:"retry2,omitempty" gorm:"column:retry2" bson:"retry2,omitempty" dynamodbav:"retry2,omitempty" firestore:"retry2,omitempty"`
	Retry3 int64 `yaml:"3" mapstructure:"3" json:"retry3,omitempty" gorm:"column:retry3" bson:"retry3,omitempty" dynamodbav:"retry3,omitempty" firestore:"retry3,omitempty"`
	Retry4 int64 `yaml:"4" mapstructure:"4" json:"retry4,omitempty" gorm:"column:retry4" bson:"retry4,omitempty" dynamodbav:"retry4,omitempty" firestore:"retry4,omitempty"`
	Retry5 int64 `yaml:"5" mapstructure:"5" json:"retry5,omitempty" gorm:"column:retry5" bson:"retry5,omitempty" dynamodbav:"retry5,omitempty" firestore:"retry5,omitempty"`
	Retry6 int64 `yaml:"6" mapstructure:"6" json:"retry6,omitempty" gorm:"column:retry6" bson:"retry6,omitempty" dynamodbav:"retry6,omitempty" firestore:"retry6,omitempty"`
	Retry7 int64 `yaml:"7" mapstructure:"7" json:"retry7,omitempty" gorm:"column:retry7" bson:"retry7,omitempty" dynamodbav:"retry7,omitempty" firestore:"retry7,omitempty"`
	Retry8 int64 `yaml:"8" mapstructure:"8" json:"retry8,omitempty" gorm:"column:retry8" bson:"retry8,omitempty" dynamodbav:"retry8,omitempty" firestore:"retry8,omitempty"`
	Retry9 int64 `yaml:"9" mapstructure:"9" json:"retry9,omitempty" gorm:"column:retry9" bson:"retry9,omitempty" dynamodbav:"retry9,omitempty" firestore:"retry9,omitempty"`
}

func NewConn(retries []time.Duration, url string, options ...nats.Option) (*nats.Conn, error) {
	if len(retries) == 0 {
		return nats.Connect(url, options...)
	} else {
		conn, er1 := nats.Connect(url, options...)
		if er1 == nil {
			return conn, er1
		}
		i := 0
		err := Retry(retries, func() (err error) {
			i = i + 1
			conn2, er2 := nats.Connect(url, options...)
			if er2 == nil {
				conn = conn2
			}
			return er2
		})
		if err != nil {
			log.Printf("Cannot conect to nats: %s.", err.Error())
		}
		return conn, err
	}
}
func MakeDurations(vs []int64) []time.Duration {
	durations := make([]time.Duration, 0)
	for _, v := range vs {
		d := time.Duration(v) * time.Second
		durations = append(durations, d)
	}
	return durations
}
func MakeArray(v interface{}, prefix string, max int) []int64 {
	var ar []int64
	v2 := reflect.Indirect(reflect.ValueOf(v))
	for i := 1; i <= max; i++ {
		fn := prefix + strconv.Itoa(i)
		v3 := v2.FieldByName(fn).Interface().(int64)
		if v3 > 0 {
			ar = append(ar, v3)
		} else {
			return ar
		}
	}
	return ar
}
func DurationsFromValue(v interface{}, prefix string, max int) []time.Duration {
	arr := MakeArray(v, prefix, max)
	return MakeDurations(arr)
}
func Retry(sleeps []time.Duration, f func() error) (err error) {
	attempts := len(sleeps)
	for i := 0; ; i++ {
		log.Printf("Retrying %d of %d ", i+1, attempts)
		err = f()
		if err == nil {
			return
		}
		if i >= (attempts - 1) {
			break
		}
		time.Sleep(sleeps[i])
		log.Printf("Retrying %d of %d after error: %s", i+1, attempts, err.Error())
	}
	return fmt.Errorf("after %d attempts, last error: %s", attempts, err)
}