From b5b96ea65731f3eb86d5c06b7defd1ab3c23d004 Mon Sep 17 00:00:00 2001
From: Patrick Cloke <patrickc@matrix.org>
Date: Wed, 9 Sep 2020 07:42:18 -0400
Subject: [PATCH] Add original error to log lines.

---
 synapse/rest/media/v1/media_repository.py | 15 +++++++++------
 synapse/rest/media/v1/thumbnailer.py      |  4 ++--
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/synapse/rest/media/v1/media_repository.py b/synapse/rest/media/v1/media_repository.py
index 20a14a9eea40..69f353d46f9e 100644
--- a/synapse/rest/media/v1/media_repository.py
+++ b/synapse/rest/media/v1/media_repository.py
@@ -474,12 +474,13 @@ async def generate_local_exact_thumbnail(
 
         try:
             thumbnailer = Thumbnailer(input_path)
-        except ThumbnailError:
+        except ThumbnailError as e:
             logger.warning(
-                "Unable to generate a thumbnail for local media %s using a method of %s and type of %s",
+                "Unable to generate a thumbnail for local media %s using a method of %s and type of %s: %s",
                 media_id,
                 t_method,
                 t_type,
+                e,
             )
             return None
 
@@ -541,13 +542,14 @@ async def generate_remote_exact_thumbnail(
 
         try:
             thumbnailer = Thumbnailer(input_path)
-        except ThumbnailError:
+        except ThumbnailError as e:
             logger.warning(
-                "Unable to generate a thumbnail for remote media %s from %s using a method of %s and type of %s",
+                "Unable to generate a thumbnail for remote media %s from %s using a method of %s and type of %s: %s",
                 media_id,
                 server_name,
                 t_method,
                 t_type,
+                e,
             )
             return None
 
@@ -632,12 +634,13 @@ async def _generate_thumbnails(
 
         try:
             thumbnailer = Thumbnailer(input_path)
-        except ThumbnailError:
+        except ThumbnailError as e:
             logger.warning(
-                "Unable to generate thumbnails for remote media %s from %s using a method of %s and type of %s",
+                "Unable to generate thumbnails for remote media %s from %s using a method of %s and type of %s: %s",
                 media_id,
                 server_name,
                 media_type,
+                e,
             )
             return None
 
diff --git a/synapse/rest/media/v1/thumbnailer.py b/synapse/rest/media/v1/thumbnailer.py
index 93dd77e474ea..457ad6031ce2 100644
--- a/synapse/rest/media/v1/thumbnailer.py
+++ b/synapse/rest/media/v1/thumbnailer.py
@@ -42,10 +42,10 @@ class Thumbnailer:
     def __init__(self, input_path):
         try:
             self.image = Image.open(input_path)
-        except OSError:
+        except OSError as e:
             # If an error occurs opening the image, a thumbnail won't be able to
             # be generated.
-            raise ThumbnailError()
+            raise ThumbnailError from e
 
         self.width, self.height = self.image.size
         self.transpose_method = None