[api] placement delete: return 404 if not found (#1701)

src/query/api/v1/handler/placement/delete_all.go

@@ -26,6 +26,7 @@ import (
 	"path"
 	"time"
 
+	"github.com/m3db/m3/src/cluster/kv"
 	"github.com/m3db/m3/src/query/api/v1/handler"
 	"github.com/m3db/m3/src/query/util/logging"
 	xhttp "github.com/m3db/m3/src/x/net/http"
@@ -79,6 +80,11 @@ func (h *DeleteAllHandler) ServeHTTP(serviceName string, w http.ResponseWriter,
 	}
 
 	if err := service.Delete(); err != nil {
+		if err == kv.ErrNotFound {
+			logger.Info("cannot delete absent placement", zap.String("service", serviceName))
+			xhttp.Error(w, err, http.StatusNotFound)
+			return
+		}
 		logger.Error("unable to delete placement", zap.Error(err))
 		xhttp.Error(w, err, http.StatusInternalServerError)
 		return

src/query/api/v1/handler/placement/delete_all_test.go

@@ -27,6 +27,7 @@ import (
 	"testing"
 
 	"github.com/m3db/m3/src/cmd/services/m3query/config"
+	"github.com/m3db/m3/src/cluster/kv"
 
 	"github.com/golang/mock/gomock"
 	"github.com/stretchr/testify/assert"
@@ -64,5 +65,15 @@ func TestPlacementDeleteAllHandler(t *testing.T) {
 
 		resp = w.Result()
 		assert.Equal(t, http.StatusInternalServerError, resp.StatusCode)
+
+		// Test delete not found error
+		w = httptest.NewRecorder()
+		req = httptest.NewRequest(DeleteAllHTTPMethod, M3DBDeleteAllURL, nil)
+		require.NotNil(t, req)
+		mockPlacementService.EXPECT().Delete().Return(kv.ErrNotFound)
+		handler.ServeHTTP(serviceName, w, req)
+
+		resp = w.Result()
+		assert.Equal(t, http.StatusNotFound, resp.StatusCode)
 	})
 }