return LaTeX logs when pandoc fails

server.py

@@ -7,7 +7,7 @@ import os
 
 PORT = 8000
 URL_FORMAT = re.compile(
-    r"^(?:(?:https://)?platform\.physik\.kit\.edu/codimd/)?(?P<id>[\w_-]+)([\?#].*)?$"
+    r"^(?:(?:https://)?platform\.physik\.kit\.edu/codimd/)?(?P<id>[\w_-]+)([\?#].*)?$",
 )
 
 TMP_MD = "tmp.md"
@@ -78,7 +78,7 @@ class CodiToPdfHandler(http.server.SimpleHTTPRequestHandler):
             return
 
         try:
-            subprocess.check_call(
+            subprocess.check_output(
                 [
                     "pandoc",
                     # disable yaml in markdown
@@ -89,13 +89,17 @@ class CodiToPdfHandler(http.server.SimpleHTTPRequestHandler):
                     "-s", "-V", "papersize:a4",
                     "-V", "geometry:margin=1in",
                     "-o", TMP_PDF,
-                    TMP_MD
-                ]
+                    TMP_MD,
+                ],
+                stderr=subprocess.STDOUT,
             )
             assert os.path.isfile(TMP_PDF)
         except Exception as e:
             if isinstance(e, subprocess.CalledProcessError):
-                self.errored("Error while converting markdown to pdf:\n" + str(e))
+                self.errored(
+                    "Error occured while converting markdown to pdf:\n\n" +
+                    e.output.decode("utf-8"),
+                )
             else:
                 self.errored("Unknown error")
             clean_up()