We see periodic errors caching assets due to a combination of transient
networking and server problems. With the previous patch to skip running
a test when it has missing assets, we can now treat most cache download
errors as non-fatal.

Only HTTP 404 is retained as fatal, since it is a strong indicator of
a fully broken test rather than a transient error.

Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
 tests/functional/qemu_test/asset.py | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/tests/functional/qemu_test/asset.py b/tests/functional/qemu_test/asset.py
index 39832b2587..f0730695f0 100644
--- a/tests/functional/qemu_test/asset.py
+++ b/tests/functional/qemu_test/asset.py
@@ -15,6 +15,7 @@
 from time import sleep
 from pathlib import Path
 from shutil import copyfileobj
+from urllib.error import HTTPError
 
 
 # Instances of this class must be declared as class level variables
@@ -170,7 +171,18 @@ def precache_test(test):
         for name, asset in vars(test.__class__).items():
             if name.startswith("ASSET_") and type(asset) == Asset:
                 log.info("Attempting to cache '%s'" % asset)
-                asset.fetch()
+                try:
+                    asset.fetch()
+                except HTTPError as e:
+                    # Treat 404 as fatal, since it is highly likely to
+                    # indicate a broken test rather than a transient
+                    # server or networking problem
+                    if e.code == 404:
+                        raise
+
+                    log.debug(f"HTTP error {e.code} from {asset.url} " +
+                              "skipping asset precache")
+
         log.removeHandler(handler)
 
     def precache_suite(suite):
-- 
2.46.0