Delay printf until logging is required.

Using % will cause the string to be generated even if debugging
is off.

1 files changed, 6 insertions, 6 deletions

diff --git a/synapse/rest/media/v1/preview_url_resource.py b/synapse/rest/media/v1/preview_url_resource.py
index 0c68c3aad5..13782d3120 100644
--- a/synapse/rest/media/v1/preview_url_resource.py
+++ b/synapse/rest/media/v1/preview_url_resource.py
@@ -117,8 +117,8 @@ class PreviewUrlResource(DirectServeResource):
                 pattern = entry[attrib]
                 value = getattr(url_tuple, attrib)
                 logger.debug(
-                    ("Matching attrib '%s' with value '%s' against" " pattern '%s'")
-                    % (attrib, value, pattern)
+                    "Matching attrib '%s' with value '%s' against" " pattern '%s'",
+                    attrib, value, pattern
                 )
 
                 if value is None:
@@ -186,7 +186,7 @@ class PreviewUrlResource(DirectServeResource):
 
         media_info = yield self._download_url(url, user)
 
-        logger.debug("got media_info of '%s'" % media_info)
+        logger.debug("got media_info of '%s'", media_info)
 
         if _is_media(media_info["media_type"]):
             file_id = media_info["filesystem_id"]
@@ -254,7 +254,7 @@ class PreviewUrlResource(DirectServeResource):
                         og["og:image:width"] = dims["width"]
                         og["og:image:height"] = dims["height"]
                     else:
-                        logger.warn("Couldn't get dims for %s" % og["og:image"])
+                        logger.warn("Couldn't get dims for %s", og["og:image"])
 
                     og["og:image"] = "mxc://%s/%s" % (
                         self.server_name,
@@ -268,7 +268,7 @@ class PreviewUrlResource(DirectServeResource):
             logger.warn("Failed to find any OG data in %s", url)
             og = {}
 
-        logger.debug("Calculated OG for %s as %s" % (url, og))
+        logger.debug("Calculated OG for %s as %s", url, og)
 
         jsonog = json.dumps(og)
 
@@ -297,7 +297,7 @@ class PreviewUrlResource(DirectServeResource):
 
         with self.media_storage.store_into_file(file_info) as (f, fname, finish):
             try:
-                logger.debug("Trying to get url '%s'" % url)
+                logger.debug("Trying to get url '%s'", url)
                 length, headers, uri, code = yield self.client.get_file(
                     url, output_stream=f, max_size=self.max_spider_size
                 )