Implement exponential backoff for throttling repeated AU downloads.
Today we retry the same payload over and over again every hour. Ideally,
we shouldn't require ever to re-download the same payload again. But
from experience we find that post-install or firmware updates may succeed
on a second attempt. So until we have code that can do such selective
retries of those steps, we currently re-download and re-apply the whole
payload. So instead of retrying over and over again, we backoff the
successive payload download attempts at 1 day, 2 days, 4 days, etc. with
an upper limit of 16 days.
Another subtle reason for which we depend on the payload retry mechanism
today is if we've failed downloading the payload via all the URLs that are
specified in the rule, we don't want to keep re-attempting the download.
This case is different from the case discussed above, because in this case
we haven't even downloaded a payload once completely. In this case also,
there's a need for throttling the amount of bytes we end up downloading
repeatedly for a particular operation that may fail. This is done by
treating the exhaustion of all URLs as equivalent to having downloaded
a full payload and subjecting it to the same backoff behavior.
We waive backoffs for dev/test images so as not to cause any delay in
our testing or development.
BUG=chromium-os:36806
TEST=Added new unit tests. Tested all scenarios on my ZGB.
Change-Id: I6bd0d3f296a3c0da0a8026fb71b24785d825e39c
Reviewed-on: https://gerrit.chromium.org/gerrit/40220
Commit-Queue: Jay Srinivasan <jaysri@chromium.org>
Reviewed-by: Jay Srinivasan <jaysri@chromium.org>
Tested-by: Jay Srinivasan <jaysri@chromium.org>
diff --git a/payload_state_interface.h b/payload_state_interface.h
index 031fbec..35bab04 100644
--- a/payload_state_interface.h
+++ b/payload_state_interface.h
@@ -8,13 +8,10 @@
#include <string>
#include "update_engine/action_processor.h"
+#include "update_engine/omaha_response.h"
namespace chromeos_update_engine {
-// Forward declaration here because we get a circular dependency if
-// we include omaha_request_action.h directly.
-struct OmahaResponse;
-
// Describes the methods that need to be implemented by the PayloadState class.
// This interface has been carved out to support mocking of the PayloadState
// object.
@@ -47,8 +44,13 @@
// depending on the type of the error that happened.
virtual void UpdateFailed(ActionExitCode error) = 0;
- // Returns the currently stored response.
- virtual std::string GetResponse() = 0;
+ // Returns true if we should backoff the current download attempt.
+ // False otherwise.
+ virtual bool ShouldBackoffDownload() = 0;
+
+ // Returns the currently stored response "signature". The signature is a
+ // subset of fields that are of interest to the PayloadState behavior.
+ virtual std::string GetResponseSignature() = 0;
// Returns the payload attempt number.
virtual uint32_t GetPayloadAttemptNumber() = 0;
@@ -58,6 +60,9 @@
// Returns the current URL's failure count.
virtual uint32_t GetUrlFailureCount() = 0;
+
+ // Returns the expiry time for the current backoff period.
+ virtual base::Time GetBackoffExpiryTime() = 0;
};
} // namespace chromeos_update_engine