我是微服务的新学习者。我试图编写自己的微服务。功能很简单。对localhost:81/balance/{phone_number}
的请求应返回用户余额为数据库。每当我发送此请求时,我都会看到错误:
net/http.(*conn).serve.func1(0xc00021a000)
/usr/local/go/src/net/http/server.go:1767 +0x139
panic(0x8fe8e0, 0xccafc0)
/usr/local/go/src/runtime/panic.go:679 +0x1b2
github.com/jinzhu/gorm.(*DB).clone(0x0, 0x30)
/home/bita/go/src/github.com/jinzhu/gorm/main.go:848 +0x26
github.com/jinzhu/gorm.(*DB).Where(0x0, 0x8d6720, 0xa04b40, 0xc0001fe060, 0x1, 0x1, 0xc00019e5d0)
/home/bita/go/src/github.com/jinzhu/gorm/main.go:235 +0x2f
arvan/wallet/Reository.(*repository).GetBalance(0xc000184c40, 0xa180c0, 0xc0001fa2d0, 0xc00022000d, 0x7, 0xa0f020, 0xc0001fa300, 0x0)
/home/bita/go/src/arvan/wallet/Reository/repo.go:35 +0xeb
arvan/wallet/pkg/service.service.GetBalance(0xa12f80, 0xc000184c40, 0xa0f020, 0xc00019e5d0, 0xa180c0, 0xc0001fa2d0, 0xc00022000d, 0x7, 0xc0001fa270, 0xc0001d0730, ...)
/home/bita/go/src/arvan/wallet/pkg/service/service.go:31 +0x116
arvan/wallet/pkg/http.makeGetBalanceEndpoint.func1(0xa180c0, 0xc0001fa2d0, 0x90d160, 0xc0001fe040, 0xc0001fe040, 0x0, 0x0, 0x0)
/home/bita/go/src/arvan/wallet/pkg/http/endpoint.go:25 +0x72
github.com/go-kit/kit/transport/http.Server.ServeHTTP(0xc000184c80, 0x994260, 0x994270, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x9946a8, ...)
/home/bita/go/src/github.com/go-kit/kit/transport/http/server.go:121 +0x1b2
arvan/wallet/pkg/http.commonMiddleware.func1(0xa17240, 0xc00022e000, 0xc000212300)
/home/bita/go/src/arvan/wallet/pkg/http/server.go:33 +0x100
net/http.HandlerFunc.ServeHTTP(0xc000200020, 0xa17240, 0xc00022e000, 0xc000212300)
/usr/local/go/src/net/http/server.go:2007 +0x44
github.com/gorilla/mux.(*Router).ServeHTTP(0xc0000d8540, 0xa17240, 0xc00022e000, 0xc000212100)
/home/bita/go/src/github.com/gorilla/mux/mux.go:210 +0xe2
net/http.serverHandler.ServeHTTP(0xc0001e6000, 0xa17240, 0xc00022e000, 0xc000212100)
/usr/local/go/src/net/http/server.go:2802 +0xa4
net/http.(*conn).serve(0xc00021a000, 0xa18000, 0xc0001fc100)
/usr/local/go/src/net/http/server.go:1890 +0x875
created by net/http.(*Server).Serve
/usr/local/go/src/net/http/server.go:2928 +0x384
level=error service=account time:=2020-02-29T04:38:08.908274665Z caller=main.go:74 exit=interrupt
我推测是在尝试在数据库中查询时发生的。我将sqlite用作我的基础数据库,并将gorm用于ORM。我想问题出在这一行:
func (repo *repository) GetBalance(ctx context.Context, phoneNumber string) (int, error) {
var user Entity.UserEntity
if phoneNumber == "" {
return -1, RepoErr
}
if err := repo.db.Where("phone_number = ?", phoneNumber).Find(&user).Error; err != nil {
fmt.Println("error: ", err.Error())
return -1, err
}
return user.Balance, nil
}
我不知道为什么会这样。因为当我尝试使用整体架构时,一切都很好。整个代码的链接为here
这与上下文有关吗????现在不知道!附言gokit-tutorial及其在youtube上的教学视频启发了我所有代码。
您省略的实际错误消息就在紧急堆栈跟踪之前:
http: panic serving [::1]:53017: runtime error: invalid memory address or nil pointer dereference
这表明尚未设置某些指针,并且该指针等于nil
。
[深入研究时,我发现当请求到达您的repo.db
方法时,未设置== nil
(C0),这就是为什么对GetBalance
感到恐慌的原因。
您尝试在repo.db.Where
文件中设置此字段,并在该文件中也加载数据库:
main.go
这段代码包含一个细微的错误,与可变阴影有关。基本上,上面声明的var db *gorm.DB
{
dbDriver := "sqlite3"
dbName := "demo.db"
db, err := gorm.Open(dbDriver, dbName)
if err != nil {
_ = level.Error(logger).Log("exit", err)
os.Exit(-1)
}
db.AutoMigrate(&Entity.UserEntity{})
}
变量与db
括号中声明的变量不同,括号中的变量是一个单独的数据库。您可以通过重命名或不重新声明来解决此问题(使用{}
):
:=
现在,它可以正确加载数据库(var db *gorm.DB
{
dbDriver := "sqlite3"
dbName := "demo.db"
dbLoaded, err := gorm.Open(dbDriver, dbName) // Rename the variable
if err != nil {
_ = level.Error(logger).Log("exit", err)
os.Exit(-1)
}
dbLoaded.AutoMigrate(&Entity.UserEntity{})
db = dbLoaded // Set `db` of the outer scope to `dbLoaded` of this scope
} // dbLoaded is lost here, but it can be accessed using `db`
不再是db
),并且您其他模块中的访问现在也可以正常工作。