admin: fix warnings and status code in /load API

admin.go

@@ -40,6 +40,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/caddyserver/caddy/v2/caddyconfig/warning"
 	"github.com/caddyserver/certmagic"
 	"github.com/cespare/xxhash/v2"
 	"github.com/prometheus/client_golang/prometheus"
@@ -1314,9 +1315,10 @@ func (f AdminHandlerFunc) ServeHTTP(w http.ResponseWriter, r *http.Request) erro
 // and client responses. If Message is unset, then
 // Err.Error() will be serialized in its place.
 type APIError struct {
-	HTTPStatus int    `json:"-"`
-	Err        error  `json:"-"`
-	Message    string `json:"error"`
+	HTTPStatus int               `json:"-"`
+	Err        error             `json:"-"`
+	Message    string            `json:"error"`
+	Warnings   []warning.Warning `json:"warnings,omitempty"`
 }
 
 func (e APIError) Error() string {

caddyconfig/configadapters.go

@@ -19,6 +19,7 @@ import (
 	"fmt"
 
 	"github.com/caddyserver/caddy/v2"
+	"github.com/caddyserver/caddy/v2/caddyconfig/warning"
 )
 
 // Adapter is a type which can adapt a configuration to Caddy JSON.
@@ -28,20 +29,7 @@ type Adapter interface {
 }
 
 // Warning represents a warning or notice related to conversion.
-type Warning struct {
-	File      string `json:"file,omitempty"`
-	Line      int    `json:"line,omitempty"`
-	Directive string `json:"directive,omitempty"`
-	Message   string `json:"message,omitempty"`
-}
-
-func (w Warning) String() string {
-	var directive string
-	if w.Directive != "" {
-		directive = fmt.Sprintf(" (%s)", w.Directive)
-	}
-	return fmt.Sprintf("%s:%d%s: %s", w.File, w.Line, directive, w.Message)
-}
+type Warning = warning.Warning
 
 // JSON encodes val as JSON, returning it as a json.RawMessage. Any
 // marshaling errors (which are highly unlikely with correct code)

caddyconfig/load.go

@@ -91,23 +91,19 @@ func (adminLoad) handleLoad(w http.ResponseWriter, r *http.Request) error {
 	}
 	body := buf.Bytes()
 
+	var warnings []Warning
 	// if the config is formatted other than Caddy's native
 	// JSON, we need to adapt it before loading it
 	if ctHeader := r.Header.Get("Content-Type"); ctHeader != "" {
-		result, warnings, err := adaptByContentType(ctHeader, body)
+		result, wns, err := adaptByContentType(ctHeader, body)
 		if err != nil {
 			return caddy.APIError{
 				HTTPStatus: http.StatusBadRequest,
 				Err:        err,
+				Warnings:   wns,
 			}
 		}
-		if len(warnings) > 0 {
-			respBody, err := json.Marshal(warnings)
-			if err != nil {
-				caddy.Log().Named("admin.api.load").Error(err.Error())
-			}
-			_, _ = w.Write(respBody)
-		}
+		warnings = wns
 		body = result
 	}
 
@@ -118,6 +114,7 @@ func (adminLoad) handleLoad(w http.ResponseWriter, r *http.Request) error {
 		return caddy.APIError{
 			HTTPStatus: http.StatusBadRequest,
 			Err:        fmt.Errorf("loading config: %v", err),
+			Warnings:   warnings,
 		}
 	}
 
@@ -130,6 +127,16 @@ func (adminLoad) handleLoad(w http.ResponseWriter, r *http.Request) error {
 
 	caddy.Log().Named("admin.api").Info("load complete")
 
+	// Send any warnings back even if there were no errors
+	if len(warnings) > 0 {
+		out := struct {
+			Warnings []Warning `json:"warnings"`
+		}{
+			Warnings: warnings,
+		}
+		return json.NewEncoder(w).Encode(out)
+	}
+
 	return nil
 }
 

caddyconfig/warning/warning.go

@@ -0,0 +1,19 @@
+package warning
+
+import "fmt"
+
+// Warning represents a warning or notice related to conversion.
+type Warning struct {
+	File      string `json:"file,omitempty"`
+	Line      int    `json:"line,omitempty"`
+	Directive string `json:"directive,omitempty"`
+	Message   string `json:"message,omitempty"`
+}
+
+func (w Warning) String() string {
+	var directive string
+	if w.Directive != "" {
+		directive = fmt.Sprintf(" (%s)", w.Directive)
+	}
+	return fmt.Sprintf("%s:%d%s: %s", w.File, w.Line, directive, w.Message)
+}