Merge #472

472: feat(http): Distinct app and internal error codes in the handleError function r=48d90782 a=48d90782

This PR introduces distinct error codes for the app and internal RR errors.
Errors: 
```go
roadrunner.ErrNoAssociatedPool
roadrunner.ErrAllocateWorker
roadrunner.ErrWorkerNotReady
roadrunner.ErrEmptyPayload
roadrunner.ErrPoolStopped
roadrunner.ErrWorkerAllocateTimeout
roadrunner.ErrAllWorkersAreDead
```
now associated with the internal error codes. All other errors are application errors.
Some types of errors are impossible to distinguish in the RR1, for example `json.Unmarshall` internal error or similar.
The `.rr.yaml` now contain two more options for the errors.
```yaml
http:
    internalErrorCode: 502,
    appErrorCode: 502
```
Default behavior unchanged (500 error code as before), but now might be overridden.
closes #471 

Co-authored-by: Valery Piashchynski <[email protected]>

1 files changed, 4 insertions, 3 deletions

diff --git a/service/http/response.go b/service/http/response.go
index f34754be..a2540edf 100644
--- a/service/http/response.go
+++ b/service/http/response.go
@@ -5,11 +5,12 @@ import (
 	"net/http"
 	"strings"
 
-	json "github.com/json-iterator/go"
+	j "github.com/json-iterator/go"
 
 	"github.com/spiral/roadrunner"
 )
 
+var json = j.ConfigCompatibleWithStandardLibrary
 
 // Response handles PSR7 response logic.
 type Response struct {
@@ -26,8 +27,8 @@ type Response struct {
 // NewResponse creates new response based on given rr payload.
 func NewResponse(p *roadrunner.Payload) (*Response, error) {
 	r := &Response{body: p.Body}
-	j := json.ConfigCompatibleWithStandardLibrary
-	if err := j.Unmarshal(p.Context, r); err != nil {
+
+	if err := json.Unmarshal(p.Context, r); err != nil {
 		return nil, err
 	}