(GoLang) 报错: panic: sql: Register called twice for driver postgres

huangapple
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英文:

(GoLang) panic: sql: Register called twice for driver postgres

问题

我可能在这上面花了太多时间，所以我决定在这里尝试一下。
我在弄清楚为什么我的 Register 被调用两次时遇到了问题。
我能想到的最好的解释是，在 sql.Register() 和 sqlx.Connect() 处都调用了一次。但是如果我移除 sql.Register()，那么就没有驱动程序了。

老实说，我对 Go 语言还是比较新的，希望能得到任何方向上的帮助。

以下是没有 sql.Register 的代码：

  1. package main
  3. import (
  4. 	"fmt"
  5. 	"database/sql"
  6. 	"github.com/jmoiron/sqlx"
  7. )
  9. const (
  10. 	host     = "localhost"
  11. 	port     = 5432
  12. 	user     = "postgres"
  13. 	password = "password"
  14. 	dbname   = "sampledb"
  15. )
  17. /*-------------------------------------------*/
  18. /*                Functions                  */
  19. /*-------------------------------------------*/
  20. // Error Checking Fn
  21. func CheckError(err error, str string) {
  22. 	if err != nil {
  23. 		fmt.Printf("Error @ : %s\n", str)
  24. 		panic(err)
  25. 	}
  26. }
  28. /*-------------------------------------------*/
  29. /*                 Main()                    */
  30. /*-------------------------------------------*/
  32. func main() {
  33. 	// Open DB Conn
  34. 	psqlconn := fmt.Sprintf("host=%s port=%d user=%s password=%s dbname=%s sslmode=disable", host, port, user, password, dbname)
  35. 	// sql.Register("postgres", &pq.Driver{})
  36. 	fmt.Printf(":: Drivers ::\n%s\n", sql.Drivers())
  37. 	db, err := sqlx.Connect("postgres", psqlconn)
  38. 	CheckError(err, "Main: sqlx.connect")
  39. 	defer db.Close()
  40. }

没有 sql.Register 的错误信息：

  1. $ go run name-generator.go 
  2. :: Drivers ::
  3. []
  4. Error @ : Main: sqlx.connect
  5. panic: sql: unknown driver "postgres" (forgotten import?)
  7. goroutine 1 [running]:
  8. main.CheckError({0xc84320, 0xc000056680}, {0xc6073f, 0x5})
  9.         C:/path/to/program.go:26 +0xa7    <--- Func CheckError(): panic(err)
  10. main.main()
  11.         C:/path/to/program.go:40 +0x125   <--- Func Main(): CheckError()
  12. exit status 2

以下是有 sql.Register 的代码：

  1. package main
  3. import (
  4. 	"fmt"
  5. 	"database/sql"
  6. 	"github.com/jmoiron/sqlx"
  7. 	"github.com/lib/pq"
  8. )
  10. const (
  11. 	host     = "localhost"
  12. 	port     = 5432
  13. 	user     = "postgres"
  14. 	password = "password"
  15. 	dbname   = "sampledb"
  16. )
  18. /*-------------------------------------------*/
  19. /*                Functions                  */
  20. /*-------------------------------------------*/
  21. // Error Checking Fn
  22. func CheckError(err error, str string) {
  23. 	if err != nil {
  24. 		fmt.Printf("Error @ : %s\n", str)
  25. 		panic(err)
  26. 	}
  27. }
  29. /*-------------------------------------------*/
  30. /*                 Main()                    */
  31. /*-------------------------------------------*/
  33. func main() {
  34. 	// Open DB Conn
  35. 	psqlconn := fmt.Sprintf("host=%s port=%d user=%s password=%s dbname=%s sslmode=disable", host, port, user, password, dbname)
  36. 	sql.Register("postgres", &pq.Driver{})
  37. 	fmt.Printf(":: Drivers ::\n%s\n", sql.Drivers())
  38. 	db, err := sqlx.Connect("postgres", psqlconn)
  39. 	CheckError(err, "Main: sqlx.connect")
  40. 	defer db.Close()
  41. }

有 sql.Register 的错误信息：

  1. $ go run name-generator.go 
  2. panic: sql: Register called twice for driver postgres
  4. goroutine 1 [running]:
  5. database/sql.Register({0xa98bc9, 0x8}, {0xae6680, 0xc8a950})
  6.         C:/Program Files/Go/src/database/sql/sql.go:51 +0x13d
  7. main.main()
  8.         C:/path/to/program.go:38 +0x11b
  9. exit status 2

其他资源：

  • 类似的问题，但不能解决我的问题 链接
  • SQLX 文档 链接
  • SQL 文档 链接
英文:

I have probably spent way to much time on this, so I decided to try here.
I'm having trouble figuring out why my Register is being called twice?
Best I can figure, it seems to be calling once at sql.Register() and again at sqlx.Connect(). But if I remove the sql.Register(), then theres no drivers.

Honestly, I am pretty new to GoLang, I'm hoping for any sort of direction here.

Code - w/o sql.Register

  1. package main
  3. import (
  4. 	&quot;fmt&quot;
  6. 	&quot;database/sql&quot;
  8. 	&quot;github.com/jmoiron/sqlx&quot;
  9. )
  11. const (
  12. 	host     = &quot;localhost&quot;
  13. 	port     = 5432
  14. 	user     = &quot;postgres&quot;
  15. 	password = &quot;password&quot;
  16. 	dbname   = &quot;sampledb&quot;
  17. )
  19. /*-------------------------------------------*\
  20. ||                Functions                  ||
  21. \*-------------------------------------------*/
  22. // Error Checking Fn
  23. func CheckError(err error, str string) {
  24. 	if err != nil {
  25. 		fmt.Printf(&quot;Error @ : %s\n&quot;, str)
  26. 		panic(err)
  27. 	}
  28. }
  30. /*-------------------------------------------*\
  31. ||                 Main()                    ||
  32. \*-------------------------------------------*/
  34. func main() {
  35. 	// Open DB Conn
  36. 	psqlconn := fmt.Sprintf(&quot;host=%s port=%d user=%s password=%s dbname=%s sslmode=disable&quot;, host, port, user, password, dbname)
  37. 	// sql.Register(&quot;postgres&quot;, &amp;pq.Driver{})
  38. 	fmt.Printf(&quot;:: Drivers ::\n%s\n&quot;, sql.Drivers())
  39. 	db, err := sqlx.Connect(&quot;postgres&quot;, psqlconn)
  40. 	CheckError(err, &quot;Main: sqlx.connect&quot;)
  41. 	defer db.Close()
  42. }

Error - w/o sql.Register

  1. $ go run name-generator.go 
  2. :: Drivers ::
  3. []
  4. Error @ : Main: sqlx.connect
  5. panic: sql: unknown driver &quot;postgres&quot; (forgotten import?)
  7. goroutine 1 [running]:
  8. main.CheckError({0xc84320, 0xc000056680}, {0xc6073f, 0x5})
  9.         C:/path/to/program.go:26 +0xa7    &lt;--- Func CheckError(): panic(err)
  10. main.main()
  11.         C:/path/to/program.go:40 +0x125   &lt;--- Func Main(): CheckError()
  12. exit status 2

Code - w/ sql.Register

  1. package main
  3. import (
  4. 	&quot;fmt&quot;
  6. 	&quot;database/sql&quot;
  8. 	&quot;github.com/jmoiron/sqlx&quot;
  9. 	&quot;github.com/lib/pq&quot;
  10. )
  12. const (
  13. 	host     = &quot;localhost&quot;
  14. 	port     = 5432
  15. 	user     = &quot;postgres&quot;
  16. 	password = &quot;password&quot;
  17. 	dbname   = &quot;sampledb&quot;
  18. )
  20. /*-------------------------------------------*\
  21. ||                Functions                  ||
  22. \*-------------------------------------------*/
  23. // Error Checking Fn
  24. func CheckError(err error, str string) {
  25. 	if err != nil {
  26. 		fmt.Printf(&quot;Error @ : %s\n&quot;, str)
  27. 		panic(err)
  28. 	}
  29. }
  31. /*-------------------------------------------*\
  32. ||                 Main()                    ||
  33. \*-------------------------------------------*/
  35. func main() {
  36. 	// Open DB Conn
  37. 	psqlconn := fmt.Sprintf(&quot;host=%s port=%d user=%s password=%s dbname=%s sslmode=disable&quot;, host, port, user, password, dbname)
  38. 	sql.Register(&quot;postgres&quot;, &amp;pq.Driver{})
  39. 	fmt.Printf(&quot;:: Drivers ::\n%s\n&quot;, sql.Drivers())
  40. 	db, err := sqlx.Connect(&quot;postgres&quot;, psqlconn)
  41. 	CheckError(err, &quot;Main: sqlx.connect&quot;)
  42. 	defer db.Close()
  43. }

Error - w/ sql.Register

  1. $ go run name-generator.go 
  2. panic: sql: Register called twice for driver postgres
  4. goroutine 1 [running]:
  5. database/sql.Register({0xa98bc9, 0x8}, {0xae6680, 0xc8a950})
  6.         C:/Program Files/Go/src/database/sql/sql.go:51 +0x13d
  7. main.main()
  8.         C:/path/to/program.go:38 +0x11b
  9. exit status 2

Additional Resources

  • Similar issue, but doesn't solve my problem Link
  • SQLX Documentation Link
  • SQL Documentation Link

答案1

得分: 2

包github.com/lib/pq在一个init函数中注册了它的驱动。

从应用程序中删除直接调用注册驱动的代码行：

  1.  sql.Register("postgres", &pq.Driver{})  // <-- 删除这行

导入github.com/lib/pq以执行init()函数的副作用：

  1. package main
  2. import (
  3. "fmt"
  4. "database/sql"
  5. "github.com/jmoiron/sqlx"
  6. _ "github.com/lib/pq"  // <-- 添加这行
  7. )
英文:

The package github.com/lib/pq registers it's driver in an init function.

Remove the direct call to register the driver from the application:

  1.  sql.Register(&quot;postgres&quot;, &amp;pq.Driver{}) &lt;-- delete this line

Import github.com/lib/pq for the side effect of executing the init() function:

  1. package main
  2. import (
  3. &quot;fmt&quot;
  4. &quot;database/sql&quot;
  5. &quot;github.com/jmoiron/sqlx&quot;
  6. _ &quot;github.com/lib/pq&quot;  // &lt;-- add this line
  7. )

huangapple
  • 本文由 发表于 2022年1月22日 12:57:10
  • 转载请务必保留本文链接：https://go.coder-hub.com/70810126.html
  • go
  • postgresql
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