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add error and error easy func

This commit is contained in:
daniel.w 2024-08-20 01:13:31 +08:00
parent 774db25eaa
commit b05ae52d48
6 changed files with 918 additions and 0 deletions
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99
errors/code/define.go Normal file
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package code
const (
OK uint32 = 0
)
// Scope
const (
Unset uint32 = iota
CloudEPPortalGW
CloudEPMember
CloudEPPermission
)
// Category for general operations: 100 - 4900
const (
_ = iota
CatInput uint32 = iota * 100
CatDB
CatResource
CatGRPC
CatAuth
CatSystem
CatPubSub
)
// CatArk Category for specific app/service: 5000 - 9900
const (
CatArk uint32 = (iota + 50) * 100
)
// Detail - Input 1xx
const (
_ = iota + CatInput
InvalidFormat
NotValidImplementation
InvalidRange
)
// Detail - Database 2xx
const (
_ = iota + CatDB
DBError // general error
DBDataConvert
DBDuplicate
)
// Detail - Resource 3xx
const (
_ = iota + CatResource
ResourceNotFound
InvalidResourceFormat
ResourceAlreadyExist
ResourceInsufficient
InsufficientPermission
InvalidMeasurementID
ResourceExpired
ResourceMigrated
InvalidResourceState
InsufficientQuota
ResourceHasMultiOwner
)
/* Detail - GRPC */
// The GRPC detail code uses Go GRPC's built-in codes.
// Refer to "google.golang.org/grpc/codes" for more detail.
// Detail - Auth 5xx
const (
_ = iota + CatAuth
Unauthorized
AuthExpired
InvalidPosixTime
SigAndPayloadNotMatched
Forbidden
)
// Detail - System 6xx
const (
_ = iota + CatSystem
SystemInternalError
SystemMaintainError
SystemTimeoutError
)
// Detail - PubSub 7xx
const (
_ = iota + CatPubSub
Publish
Consume
MsgSizeTooLarge
)
// Detail - Ark 5xxx
const (
_ = iota + CatArk
ArkInternal
ArkHttp400
)

13
errors/code/messsage.go Normal file
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package code
// CatToStr collects general error messages for each Category
// It is used to send back to API caller
var CatToStr = map[uint32]string{
CatInput: "Invalid Input Data",
CatDB: "Database Error",
CatResource: "Resource Error",
CatGRPC: "Internal Service Communication Error",
CatAuth: "Authentication Error",
CatArk: "Internal Service Communication Error",
CatSystem: "System Error",
}

442
errors/easy_func.go Normal file
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package error
import (
"code.30cm.net/digimon/library-go/errors/code"
"errors"
"fmt"
"strings"
"github.com/zeromicro/go-zero/core/logx"
_ "github.com/zeromicro/go-zero/core/logx"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/status"
)
func newErr(scope, detail uint32, msg string) *Err {
cat := detail / 100 * 100
return &Err{
category: cat,
code: detail,
scope: scope,
msg: msg,
}
}
func newBuiltinGRPCErr(scope, detail uint32, msg string) *Err {
return &Err{
category: code.CatGRPC,
code: detail,
scope: scope,
msg: msg,
}
}
// FromError tries to let error as Err
// it supports to unwrap error that has Err
// return nil if failed to transfer
func FromError(err error) *Err {
if err == nil {
return nil
}
var e *Err
if errors.As(err, &e) {
return e
}
return nil
}
// FromCode parses code as following
// Decimal: 120314
// 12 represents Scope
// 03 represents Category
// 14 represents Detail error code
func FromCode(code uint32) *Err {
scope := code / 10000
detail := code % 10000
return &Err{
category: detail / 100 * 100,
code: detail,
scope: scope,
msg: "",
}
}
// FromGRPCError transfer error to Err
// useful for gRPC client
func FromGRPCError(err error) *Err {
s, _ := status.FromError(err)
e := FromCode(uint32(s.Code()))
e.msg = s.Message()
// For GRPC built-in code
if e.Scope() == code.Unset && e.Category() == 0 && e.Code() != code.OK {
e = newBuiltinGRPCErr(Scope, e.Code(), s.Message())
}
return e
}
// Deprecated: check GRPCStatus() in Errs struct
// ToGRPCError returns the status.Status
// Useful to return error in gRPC server
func ToGRPCError(e *Err) error {
return status.New(codes.Code(e.FullCode()), e.Error()).Err()
}
/*** System ***/
// SystemTimeoutError returns Err
func SystemTimeoutError(s ...string) *Err {
return newErr(Scope, code.SystemTimeoutError, fmt.Sprintf("system timeout: %s", strings.Join(s, " ")))
}
// SystemTimeoutErrorL logs error message and returns Err
func SystemTimeoutErrorL(l logx.Logger, s ...string) *Err {
e := SystemTimeoutError(s...)
l.WithCallerSkip(1).Error(e.Error())
return e
}
// SystemInternalError returns Err struct
func SystemInternalError(s ...string) *Err {
return newErr(Scope, code.SystemInternalError, fmt.Sprintf("internal error: %s", strings.Join(s, " ")))
}
// SystemInternalErrorL logs error message and returns Err
func SystemInternalErrorL(l logx.Logger, s ...string) *Err {
e := SystemInternalError(s...)
l.WithCallerSkip(1).Error(e.Error())
return e
}
// SystemMaintainErrorL logs error message and returns Err
func SystemMaintainErrorL(l logx.Logger, s ...string) *Err {
e := SystemMaintainError(s...)
l.WithCallerSkip(1).Error(e.Error())
return e
}
// SystemMaintainError returns Err struct
func SystemMaintainError(s ...string) *Err {
return newErr(Scope, code.SystemMaintainError, fmt.Sprintf("service under maintenance: %s", strings.Join(s, " ")))
}
/*** CatInput ***/
// InvalidFormat returns Err struct
func InvalidFormat(s ...string) *Err {
return newErr(Scope, code.InvalidFormat, fmt.Sprintf("invalid format: %s", strings.Join(s, " ")))
}
// InvalidFormatL logs error message and returns Err
func InvalidFormatL(l logx.Logger, s ...string) *Err {
e := InvalidFormat(s...)
l.WithCallerSkip(1).Error(e.Error())
return e
}
// InvalidRange returns Err struct
func InvalidRange(s ...string) *Err {
return newErr(Scope, code.InvalidRange, fmt.Sprintf("invalid range: %s", strings.Join(s, " ")))
}
// InvalidRangeL logs error message and returns Err
func InvalidRangeL(l logx.Logger, s ...string) *Err {
e := InvalidRange(s...)
l.WithCallerSkip(1).Error(e.Error())
return e
}
// NotValidImplementation returns Err struct
func NotValidImplementation(s ...string) *Err {
return newErr(Scope, code.NotValidImplementation, fmt.Sprintf("not valid implementation: %s", strings.Join(s, " ")))
}
// NotValidImplementationL logs error message and returns Err
func NotValidImplementationL(l logx.Logger, s ...string) *Err {
e := NotValidImplementation(s...)
l.WithCallerSkip(1).Error(e.Error())
return e
}
/*** CatDB ***/
// DBError returns Err
func DBError(s ...string) *Err {
return newErr(Scope, code.DBError, fmt.Sprintf("db error: %s", strings.Join(s, " ")))
}
// DBErrorL logs error message and returns Err
func DBErrorL(l logx.Logger, s ...string) *Err {
e := DBError(s...)
l.WithCallerSkip(1).Error(e.Error())
return e
}
// DBDataConvert returns Err
func DBDataConvert(s ...string) *Err {
return newErr(Scope, code.DBDataConvert, fmt.Sprintf("data from db convert error: %s", strings.Join(s, " ")))
}
// DBDataConvertL logs error message and returns Err
func DBDataConvertL(l logx.Logger, s ...string) *Err {
e := DBDataConvert(s...)
l.WithCallerSkip(1).Error(e.Error())
return e
}
// DBDuplicate returns Err
func DBDuplicate(s ...string) *Err {
return newErr(Scope, code.DBDuplicate, fmt.Sprintf("data Duplicate key error: %s", strings.Join(s, " ")))
}
// DBDuplicateL logs error message and returns Err
func DBDuplicateL(l logx.Logger, s ...string) *Err {
e := DBDuplicate(s...)
l.WithCallerSkip(1).Error(e.Error())
return e
}
/*** CatResource ***/
// ResourceNotFound returns Err and logging
func ResourceNotFound(s ...string) *Err {
return newErr(Scope, code.ResourceNotFound, fmt.Sprintf("resource not found: %s", strings.Join(s, " ")))
}
// ResourceNotFoundL logs error message and returns Err
func ResourceNotFoundL(l logx.Logger, s ...string) *Err {
e := ResourceNotFound(s...)
l.WithCallerSkip(1).Error(e.Error())
return e
}
// InvalidResourceFormat returns Err
func InvalidResourceFormat(s ...string) *Err {
return newErr(Scope, code.InvalidResourceFormat, fmt.Sprintf("invalid resource format: %s", strings.Join(s, " ")))
}
// InvalidResourceFormatL logs error message and returns Err
func InvalidResourceFormatL(l logx.Logger, s ...string) *Err {
e := InvalidResourceFormat(s...)
l.WithCallerSkip(1).Error(e.Error())
return e
}
// InvalidResourceState returns status not correct.
// for example: company should be destroy, agent should be no-sensor/fail-install ...
func InvalidResourceState(s ...string) *Err {
return newErr(Scope, code.InvalidResourceState, fmt.Sprintf("invalid resource state: %s", strings.Join(s, " ")))
}
// InvalidResourceStateL logs error message and returns status not correct.
func InvalidResourceStateL(l logx.Logger, s ...string) *Err {
e := InvalidResourceState(s...)
l.WithCallerSkip(1).Error(e.Error())
return e
}
func ResourceInsufficient(s ...string) *Err {
return newErr(Scope, code.ResourceInsufficient,
fmt.Sprintf("insufficient resource: %s", strings.Join(s, " ")))
}
func ResourceInsufficientL(l logx.Logger, s ...string) *Err {
e := ResourceInsufficient(s...)
l.WithCallerSkip(1).Error(e.Error())
return e
}
// InsufficientPermission returns Err
func InsufficientPermission(s ...string) *Err {
return newErr(Scope, code.InsufficientPermission,
fmt.Sprintf("insufficient permission: %s", strings.Join(s, " ")))
}
// InsufficientPermissionL returns Err and log
func InsufficientPermissionL(l logx.Logger, s ...string) *Err {
e := InsufficientPermission(s...)
l.WithCallerSkip(1).Error(e.Error())
return e
}
// ResourceAlreadyExist returns Err
func ResourceAlreadyExist(s ...string) *Err {
return newErr(Scope, code.ResourceAlreadyExist, fmt.Sprintf("resource already exist: %s", strings.Join(s, " ")))
}
// ResourceAlreadyExistL logs error message and returns Err
func ResourceAlreadyExistL(l logx.Logger, s ...string) *Err {
e := ResourceAlreadyExist(s...)
l.WithCallerSkip(1).Error(e.Error())
return e
}
// InvalidMeasurementID returns Err
func InvalidMeasurementID(s ...string) *Err {
return newErr(Scope, code.InvalidMeasurementID, fmt.Sprintf("missing measurement id: %s", strings.Join(s, " ")))
}
// InvalidMeasurementIDL logs error message and returns Err
func InvalidMeasurementIDL(l logx.Logger, s ...string) *Err {
e := InvalidMeasurementID(s...)
l.WithCallerSkip(1).Error(e.Error())
return e
}
// ResourceExpired returns Err
func ResourceExpired(s ...string) *Err {
return newErr(Scope, code.ResourceExpired, fmt.Sprintf("resource expired: %s", strings.Join(s, " ")))
}
// ResourceExpiredL logs error message and returns Err
func ResourceExpiredL(l logx.Logger, s ...string) *Err {
e := ResourceExpired(s...)
l.WithCallerSkip(1).Error(e.Error())
return e
}
// ResourceMigrated returns Err
func ResourceMigrated(s ...string) *Err {
return newErr(Scope, code.ResourceMigrated, fmt.Sprintf("resource migrated: %s", strings.Join(s, " ")))
}
// ResourceMigratedL logs error message and returns Err
func ResourceMigratedL(l logx.Logger, s ...string) *Err {
e := ResourceMigrated(s...)
l.WithCallerSkip(1).Error(e.Error())
return e
}
// InsufficientQuota returns Err
func InsufficientQuota(s ...string) *Err {
return newErr(Scope, code.InsufficientQuota, fmt.Sprintf("insufficient quota: %s", strings.Join(s, " ")))
}
// InsufficientQuotaL logs error message and returns Err
func InsufficientQuotaL(l logx.Logger, s ...string) *Err {
e := InsufficientQuota(s...)
l.WithCallerSkip(1).Error(e.Error())
return e
}
/*** CatAuth ***/
// Unauthorized returns Err
func Unauthorized(s ...string) *Err {
return newErr(Scope, code.Unauthorized, fmt.Sprintf("unauthorized: %s", strings.Join(s, " ")))
}
// UnauthorizedL logs error message and returns Err
func UnauthorizedL(l logx.Logger, s ...string) *Err {
e := Unauthorized(s...)
l.WithCallerSkip(1).Error(e.Error())
return e
}
// AuthExpired returns Err
func AuthExpired(s ...string) *Err {
return newErr(Scope, code.AuthExpired, fmt.Sprintf("expired: %s", strings.Join(s, " ")))
}
// AuthExpiredL logs error message and returns Err
func AuthExpiredL(l logx.Logger, s ...string) *Err {
e := AuthExpired(s...)
l.WithCallerSkip(1).Error(e.Error())
return e
}
// InvalidPosixTime returns Err
func InvalidPosixTime(s ...string) *Err {
return newErr(Scope, code.InvalidPosixTime, fmt.Sprintf("invalid posix time: %s", strings.Join(s, " ")))
}
// InvalidPosixTimeL logs error message and returns Err
func InvalidPosixTimeL(l logx.Logger, s ...string) *Err {
e := InvalidPosixTime(s...)
l.WithCallerSkip(1).Error(e.Error())
return e
}
// SigAndPayloadNotMatched returns Err
func SigAndPayloadNotMatched(s ...string) *Err {
return newErr(Scope, code.SigAndPayloadNotMatched, fmt.Sprintf("signature and the payload are not match: %s", strings.Join(s, " ")))
}
// SigAndPayloadNotMatchedL logs error message and returns Err
func SigAndPayloadNotMatchedL(l logx.Logger, s ...string) *Err {
e := SigAndPayloadNotMatched(s...)
l.WithCallerSkip(1).Error(e.Error())
return e
}
// Forbidden returns Err
func Forbidden(s ...string) *Err {
return newErr(Scope, code.Forbidden, fmt.Sprintf("forbidden: %s", strings.Join(s, " ")))
}
// ForbiddenL logs error message and returns Err
func ForbiddenL(l logx.Logger, s ...string) *Err {
e := Forbidden(s...)
l.WithCallerSkip(1).Error(e.Error())
return e
}
// IsAuthUnauthorizedError check the err is unauthorized error
func IsAuthUnauthorizedError(err *Err) bool {
switch err.Code() {
case code.Unauthorized, code.AuthExpired, code.InvalidPosixTime,
code.SigAndPayloadNotMatched, code.Forbidden,
code.InvalidFormat, code.ResourceNotFound:
return true
default:
return false
}
}
/*** CatXBC ***/
// ArkInternal returns Err
func ArkInternal(s ...string) *Err {
return newErr(Scope, code.ArkInternal, fmt.Sprintf("ark internal error: %s", strings.Join(s, " ")))
}
// ArkInternalL logs error message and returns Err
func ArkInternalL(l logx.Logger, s ...string) *Err {
e := ArkInternal(s...)
l.WithCallerSkip(1).Error(e.Error())
return e
}
/*** CatPubSub ***/
// Publish returns Err
func Publish(s ...string) *Err {
return newErr(Scope, code.Publish, fmt.Sprintf("publish: %s", strings.Join(s, " ")))
}
// PublishL logs error message and returns Err
func PublishL(l logx.Logger, s ...string) *Err {
e := Publish(s...)
l.WithCallerSkip(1).Error(e.Error())
return e
}
// Consume returns Err
func Consume(s ...string) *Err {
return newErr(Scope, code.Consume, fmt.Sprintf("consume: %s", strings.Join(s, " ")))
}
// MsgSizeTooLarge returns Err
func MsgSizeTooLarge(s ...string) *Err {
return newErr(Scope, code.MsgSizeTooLarge, fmt.Sprintf("kafka error: %s", strings.Join(s, " ")))
}
// MsgSizeTooLargeL logs error message and returns Err
func MsgSizeTooLargeL(l logx.Logger, s ...string) *Err {
e := MsgSizeTooLarge(s...)
l.WithCallerSkip(1).Error(e.Error())
return e
}

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errors/errors.go Normal file
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package error
import (
code2 "code.30cm.net/digimon/library-go/errors/code"
"errors"
"fmt"
"net/http"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/status"
)
// Scope 全域變數應由服務或模組設置
var Scope = code2.Unset
// Err 6 碼，服務 2, 大類 2, 詳細錯誤 2
type Err struct {
category uint32
code uint32
scope uint32
msg string
internalErr error
}
// Error 是錯誤的介面
// 私有屬性 "msg" 的 getter 函數
func (e *Err) Error() string {
if e == nil {
return ""
}
// 如果 internal err 存在，連接錯誤字串
var internalErrStr string
if e.internalErr != nil {
internalErrStr = e.internalErr.Error()
}
if e.msg != "" {
if internalErrStr != "" {
return fmt.Sprintf("%s: %s", e.msg, internalErrStr)
}
return e.msg
}
generalErrStr := e.GeneralError()
if internalErrStr != "" {
return fmt.Sprintf("%s: %s", generalErrStr, internalErrStr)
}
return generalErrStr
}
// Category 私有屬性 "category" 的 getter 函數
func (e *Err) Category() uint32 {
if e == nil {
return 0
}
return e.category
}
// Scope 私有屬性 "scope" 的 getter 函數
func (e *Err) Scope() uint32 {
if e == nil {
return code2.Unset
}
return e.scope
}
// CodeStr 返回帶有零填充的錯誤代碼字串
func (e *Err) CodeStr() string {
if e == nil {
return "00000"
}
if e.Category() == code2.CatGRPC {
return fmt.Sprintf("%d%04d", e.Scope(), e.Category()+e.Code())
}
return fmt.Sprintf("%d%04d", e.Scope(), e.Code())
}
// Code 私有屬性 "code" 的 getter 函數
func (e *Err) Code() uint32 {
if e == nil {
return code2.OK
}
return e.code
}
func (e *Err) FullCode() uint32 {
if e == nil {
return 0
}
if e.Category() == code2.CatGRPC {
return e.Scope()*10000 + e.Category() + e.Code()
}
return e.Scope()*10000 + e.Code()
}
// HTTPStatus 返回對應的 HTTP 狀態碼
func (e *Err) HTTPStatus() int {
if e == nil || e.Code() == code2.OK {
return http.StatusOK
}
// 根據 code 判斷狀態碼
switch e.Code() {
case code2.ResourceInsufficient:
// 400
return http.StatusBadRequest
case code2.Unauthorized, code2.InsufficientPermission:
// 401
return http.StatusUnauthorized
case code2.InsufficientQuota:
// 402
return http.StatusPaymentRequired
case code2.InvalidPosixTime, code2.Forbidden:
// 403
return http.StatusForbidden
case code2.ResourceNotFound:
// 404
return http.StatusNotFound
case code2.ResourceAlreadyExist, code2.InvalidResourceState:
// 409
return http.StatusConflict
case code2.NotValidImplementation:
// 501
return http.StatusNotImplemented
default:
}
// 根據 category 判斷狀態碼
switch e.Category() {
case code2.CatInput:
return http.StatusBadRequest
default:
// 如果沒有符合的條件，返回狀態碼 500
return http.StatusInternalServerError
}
}
// GeneralError 轉換 category 級別錯誤訊息
// 這是給客戶或 API 調用者的一般錯誤訊息
func (e *Err) GeneralError() string {
if e == nil {
return ""
}
errStr, ok := code2.CatToStr[e.Category()]
if !ok {
return ""
}
return errStr
}
// Is 在執行 errors.Is() 時調用。
// 除非你非常確定你在做什麼，否則不要直接使用這個函數。
// 請使用 errors.Is 代替。
// 此函數比較兩個錯誤變量是否都是 *Err，並且具有相同的 code（不檢查包裹的內部錯誤）
func (e *Err) Is(f error) bool {
var err *Err
ok := errors.As(f, &err)
if !ok {
return false
}
return e.Code() == err.Code()
}
// Unwrap 返回底層錯誤
// 解除包裹錯誤的結果本身可能具有 Unwrap 方法;
// 我們稱通過反覆解除包裹產生的錯誤序列為錯誤鏈。
func (e *Err) Unwrap() error {
if e == nil {
return nil
}
return e.internalErr
}
// Wrap 將內部錯誤設置到 Err 結構
func (e *Err) Wrap(internalErr error) *Err {
if e != nil {
e.internalErr = internalErr
}
return e
}
func (e *Err) GRPCStatus() *status.Status {
if e == nil {
return status.New(codes.OK, "")
}
return status.New(codes.Code(e.FullCode()), e.Error())
}
// 工廠函數
// NewErr 創建新的 Err
func NewErr(scope, category, detail uint32, msg string) *Err {
return &Err{
category: category,
code: detail,
scope: scope,
msg: msg,
}
}
// NewGRPCErr 創建新的 gRPC Err
func NewGRPCErr(scope, detail uint32, msg string) *Err {
return &Err{
category: code2.CatGRPC,
code: detail,
scope: scope,
msg: msg,
}
}

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errors/go.mod Normal file
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module code.30cm.net/digimon/library-go/errors
go 1.22
require (
github.com/zeromicro/go-zero v1.7.0
google.golang.org/grpc v1.65.0
)
require (
github.com/fatih/color v1.17.0 // indirect
github.com/mattn/go-colorable v0.1.13 // indirect
github.com/mattn/go-isatty v0.0.20 // indirect
github.com/spaolacci/murmur3 v1.1.0 // indirect
go.opentelemetry.io/otel v1.24.0 // indirect
go.opentelemetry.io/otel/trace v1.24.0 // indirect
go.uber.org/automaxprocs v1.5.3 // indirect
golang.org/x/sys v0.22.0 // indirect
google.golang.org/genproto/googleapis/rpc v0.0.0-20240701130421-f6361c86f094 // indirect
google.golang.org/protobuf v1.34.2 // indirect
)

125
errors/readme.md Normal file
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## Purpose of errs package
1. compatible with `error` interface
2. encapsulate error message with functions in `easy_function.go`
3. easy for gRPC client/server
4. support err's chain by [Working with Errors in Go 1.13](https://blog.golang.org/go1.13-errors)
## Example - Normal function
Using builtin functions `InvalidInput` to generate `Err struct`
**please add your own functions if not exist**
```go
package main
import "adc.github.trendmicro.com/commercial-mgcp/library-go/pkg/errs"
func handleParam(s string) error {
// check user_id format
if ok := userIDFormat(s); !ok {
return errs.InvalidFormat("param user_id")
}
return nil
}
```
## Example - gRPC Server
`GetAgent` is a method of gRPC server, it wraps `Err` struct to `status.Status` struct
```go
func (as *agentService) GetAgent(ctx context.Context, req *cloudep.GetAgentRequest) (*cloudep.GetAgentResponse, error) {
l := log.WithFields(logger.Fields{"tenant_id": req.TenantId, "agent_id": req.AgentId, "method": "GetAgent"})
tenantID, err := primitive.ObjectIDFromHex(req.TenantId)
if err != nil {
// err maybe errs.Err or general error
// it's safe to use Convert() here
return nil, status.Convert(err).Err()
}
...
}
```
## Example - gRPC Client
Calling `GetAgent` and retry when Category is "DB"
```go
client := cloudep.NewAgentServiceClient(conn)
req := cloudep.GetAgentRequest{
TenantId: "not-a-valid-object-id",
AgentId: "5eb4fa99006d53c0cb6f9cfe",
}
// Retry if DB error
for retry := 3; retry > 0 ; retry-- {
resp, err := client.GetAgent(context.Background(), &req)
if err != nil {
e := errs.FromGRPCError(err)
if e.Category() == code.CatGRPC {
if e.Code() == uint32(codes.Unavailable) {
log.warn("GRPC service unavailable. Retrying...")
continue
}
log.errorf("GRPC built-in error: %v", e)
}
if e.Category() == code.CatDB {
log.warn("retry...")
continue
}
}
break
}
```
## Example - REST server
1. handling gRPC client error
2. transfer to HTTP code
3. transfer to Error body
```go
func Handler(c *gin.Context) {
// handle error from gRPC client
resp, err := client.GetAgent(context.Background(), &req)
if err != nil {
// to Err
e := errs.FromGRPCError(err)
// get HTTP code & response struct
// 2nd parameter true means return general error message to user
c.JSON(e.HTTPStatus(), general.NewError(e, true))
}
}
```
## Example - Error Chain
1. set internal error by func `Wrap`
2. check Err has any error in err's chain matches the target by `errors.Is`
3. finds the first error in err's chain that matches target by `errors.As`
```go
// define a specific err type
type testErr struct {
code int
}
func (e *testErr) Error() string {
return strconv.Itoa(e.code)
}
func main() {
layer1Err := &testErr{code: 123}
// error chain: InvalidFormat -> layer 1 err
layer2Err := InvalidFormat("field A", "")
layer2Err.Wrap(layer1Err) //set internal error
// errors.Is should report true
hasLayer1Err := errors.Is(layer2Err, layer1Err)
// errors.As should return internal error
var internalErr *testErr
ok := errors.As(layer2Err, &internalErr)
}
```