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, 16 insertions, 3 deletions

diff --git a/service/http/config.go b/service/http/config.go
index 00f61652..34733e44 100644
--- a/service/http/config.go
+++ b/service/http/config.go
@@ -3,15 +3,21 @@ package http
 import (
 	"errors"
 	"fmt"
-	"github.com/spiral/roadrunner"
-	"github.com/spiral/roadrunner/service"
 	"net"
+	"net/http"
 	"os"
 	"strings"
+
+	"github.com/spiral/roadrunner"
+	"github.com/spiral/roadrunner/service"
 )
 
 // Config configures RoadRunner HTTP server.
 type Config struct {
+	// AppErrorCode is error code for the application errors (default 500)
+	AppErrorCode uint64
+	// Error code for the RR pool or worker errors
+	InternalErrorCode uint64
 	// Port and port to handle as http server.
 	Address string
 
@@ -60,7 +66,6 @@ type HTTP2Config struct {
 func (cfg *HTTP2Config) InitDefaults() error {
 	cfg.Enabled = true
 	cfg.MaxConcurrentStreams = 128
-
 	return nil
 }
 
@@ -109,6 +114,14 @@ func (c *Config) EnableFCGI() bool {
 
 // Hydrate must populate Config values using given Config source. Must return error if Config is not valid.
 func (c *Config) Hydrate(cfg service.Config) error {
+	if c.AppErrorCode == 0 {
+		// set default behaviour - 500 error code
+		c.AppErrorCode = http.StatusInternalServerError
+	}
+	if c.InternalErrorCode == 0 {
+		// set default behaviour - 500 error code
+		c.InternalErrorCode = http.StatusInternalServerError
+	}
 	if c.Workers == nil {
 		c.Workers = &roadrunner.ServerConfig{}
 	}