OpenCensus embedded wrapper generator.
- Detect traceable functions/methods.
- Generate wrapper functions/methods. Wrapper set a span for tracing and just call original functions/methods.
Write go generate to the file which you want to generate wrapper.
//go:generate otwgen generate -d ./wrapper github.com/xxx/foo
package foo
import (
"context"
"net/http"
)
func NewService() *Service {
return &Service{}
}
type Service struct {
client http.Client
}
func (s *Service) GetContent(ctx context.Context) (header http.Header, err error) {
req, err := http.NewRequest(http.MethodHead, "http://example.com", nil)
if err != nil {
return nil, err
}
req = req.WithContext(ctx)
resp, err := s.client.Do(req)
if err != nil {
return nil, err
}
defer resp.Body.Close()
return resp.Header, nil
}Then, the wrapper is generated.
package foo
import (
"context"
"github.com/xxx/foo"
"go.opencensus.io/trace"
"net/http"
)
type Service struct {
*foo.Service
}
func NewService(orig *foo.Service) *Service {
return &Service{orig}
}
func (r *Service) GetContent(ctx context.Context) (header http.Header, err error) {
ctx, span := trace.StartSpan(ctx, "auto generated span")
defer span.End()
return r.Service.GetContent(ctx)
}