Hi,
I am trying to load dynamically implementation of particular interface.
I've created the example in following
repo: https://github.com/mateuszdyminski/go-plugin
I have interface - let's call it Printer:
package printer
type Printer interface {
Print(text string)
}
And implementation of this interface:
package main
import (
"fmt"
"github.com/mateuszdyminski/go-plugin/printer"
)
func main() {
Impl.Print("test")
}
type PrinterImpl struct{}
func (p PrinterImpl) Print(text string) {
fmt.Printf("[PrinterImpl] %s\n", text)
}
var Impl printer.Printer = PrinterImpl{}
Then I can build that implementation of Printer as following:
go build -buildmode=plugin printer.go
The last step is to load dynamically created library 'printer.so':
package main
import (
"fmt"
"plugin"
"reflect"
"github.com/mateuszdyminski/go-plugin/printer"
)
func main() {
lib, err := plugin.Open("printer.so")
if err != nil {
panic(err)
}
p, err := lib.Lookup("Impl")
if err != nil {
panic(err)
}
printerImpl, ok := p.(printer.Printer)
if !ok {
fmt.Printf("wrong type: %+v \n", reflect.TypeOf(p))
panic("wrong type")
}
printerImpl.Print("test")
}
But when I run it with 'go run main.go' I got following error:
wrong type: *printer.Printer
panic: wrong type
goroutine 1 [running]:
panic(0x50fda0, 0xc42000c2d0)
/home/md/.gvm/gos/master/src/runtime/panic.go:531 +0x1cf
main.main()
/home/md/workspace/go/src/github.com/mateuszdyminski/go-plugin/main.go:25
+0x231
exit status 2
The type of the 'Impl' taken from 'reflect' package is '*printer.Printer'.
Is it possible to cast it to the printer.Printer and not to the pointer to
the interface?
Thanks for any help!
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