Add more oauth logging and note about GitLab ToS for login (#8949)

app/oauth.go

@@ -8,6 +8,7 @@ import (
 	b64 "encoding/base64"
 	"fmt"
 	"io"
+	"io/ioutil"
 	"net/http"
 	"net/url"
 	"strings"
@@ -690,10 +691,13 @@ func (a *App) AuthorizeOAuthUser(w http.ResponseWriter, r *http.Request, service
 	if resp, err := a.HTTPClient(true).Do(req); err != nil {
 		return nil, "", stateProps, model.NewAppError("AuthorizeOAuthUser", "api.user.authorize_oauth_user.token_failed.app_error", nil, err.Error(), http.StatusInternalServerError)
 	} else {
+		bodyBytes, _ = ioutil.ReadAll(resp.Body)
+		resp.Body = ioutil.NopCloser(bytes.NewBuffer(bodyBytes))
+
 		ar = model.AccessResponseFromJson(resp.Body)
 		consumeAndClose(resp)
 
-		if ar == nil {
+		if ar == nil || resp.StatusCode != http.StatusOK {
 			return nil, "", stateProps, model.NewAppError("AuthorizeOAuthUser", "api.user.authorize_oauth_user.bad_response.app_error", nil, "response_body="+string(bodyBytes), http.StatusInternalServerError)
 		}
 	}
@@ -717,6 +721,15 @@ func (a *App) AuthorizeOAuthUser(w http.ResponseWriter, r *http.Request, service
 	if resp, err := a.HTTPClient(true).Do(req); err != nil {
 		return nil, "", stateProps, model.NewAppError("AuthorizeOAuthUser", "api.user.authorize_oauth_user.service.app_error", map[string]interface{}{"Service": service}, err.Error(), http.StatusInternalServerError)
 	} else {
+		bodyBytes, _ = ioutil.ReadAll(resp.Body)
+		if resp.StatusCode != http.StatusOK {
+			bodyString := string(bodyBytes)
+			mlog.Error("Error getting OAuth user: " + bodyString)
+			if service == model.SERVICE_GITLAB && resp.StatusCode == http.StatusForbidden && strings.Contains(bodyString, "Terms of Service") {
+				return nil, "", stateProps, model.NewAppError("AuthorizeOAuthUser", "oauth.gitlab.tos.error", nil, "", http.StatusBadRequest)
+			}
+		}
+		resp.Body = ioutil.NopCloser(bytes.NewBuffer(bodyBytes))
 		return resp.Body, teamId, stateProps, nil
 	}
 

i18n/en.json

@@ -2842,6 +2842,10 @@
     "id": "api.user.complete_switch_with_oauth.blank_email.app_error",
     "translation": "Blank email"
   },
+  {
+    "id": "oauth.gitlab.tos.error",
+    "translation": "GitLab's Terms of Service have updated. Please go to gitlab.com to accept them and then try logging into Mattermost again."
+  },
   {
     "id": "api.user.complete_switch_with_oauth.parse.app_error",
     "translation": "Could not parse auth data out of {{.Service}} user object"