UM: Policy for deciding download URL.
This adds a new private policy (UpdateDownloadUrl) for determining which
download URL should be used for obtaining the update payload. We further
extend an existing public policy (UpdateCanStart) to return the download
URL details, based on the current URL index and the number of failures
associated with it. This renders the explicit notion of "HTTP download
allowed" in the return value unnecessary: If HTTP is not allowed, then
HTTP URLs will not be considered.
We also implement logic for logging the start/end of a policy
evaluation, so that intermediate log messages emitted during evaluation
have a clear context.
BUG=chromium:358329
TEST=Unit tests.
Change-Id: Ib5343417480d8825082f83bed2630a6611360b61
Reviewed-on: https://chromium-review.googlesource.com/203373
Tested-by: Gilad Arnold <garnold@chromium.org>
Reviewed-by: Alex Deymo <deymo@chromium.org>
Commit-Queue: Gilad Arnold <garnold@chromium.org>
diff --git a/update_manager/chromeos_policy.h b/update_manager/chromeos_policy.h
index 3c47c60..68cda65 100644
--- a/update_manager/chromeos_policy.h
+++ b/update_manager/chromeos_policy.h
@@ -13,6 +13,12 @@
namespace chromeos_update_manager {
+// Parameters for update download URL, as determined by UpdateDownloadUrl.
+struct UpdateDownloadUrlResult {
+ int url_idx;
+ int url_num_failures;
+};
+
// Parameters for update scattering, as determined by UpdateNotScattering.
struct UpdateScatteringResult {
bool is_scattering;
@@ -45,6 +51,12 @@
std::string* error,
bool* result) const override;
+ protected:
+ // Policy override.
+ virtual std::string PolicyName() const override {
+ return "ChromeOSPolicy";
+ }
+
private:
friend class UmChromeOSPolicyTest;
FRIEND_TEST(UmChromeOSPolicyTest,
@@ -86,18 +98,34 @@
// TimeDelta.
static base::TimeDelta FuzzedInterval(PRNG* prng, int interval, int fuzz);
+ // A private policy for determining which download URL to use. Within
+ // |update_state|, |download_urls| should contain the download URLs as listed
+ // in the Omaha response; |download_failures_max| the maximum number of
+ // failures per URL allowed per the response; |download_url_idx| the index of
+ // the previously used URL; |download_url_num_failures| the previously known
+ // number of failures associated with that URL; and |download_url_error_codes|
+ // the list of failures occurring since the latest evaluation.
+ //
+ // Upon successly deciding a URL to use, returns |EvalStatus::kSucceeded| and
+ // writes the current URL index and the number of failures associated with it
+ // in |result|. Otherwise, returns |EvalStatus::kFailed|.
+ EvalStatus UpdateDownloadUrl(EvaluationContext* ec, State* state,
+ std::string* error,
+ UpdateDownloadUrlResult* result,
+ const UpdateState& update_state) const;
+
// A private policy for checking whether scattering is due. Writes in |result|
// the decision as to whether or not to scatter; a wallclock-based scatter
// wait period, which ranges from zero (do not wait) and no greater than the
// current scatter factor provided by the device policy (if available) or the
// maximum wait period determined by Omaha; and an update check-based
// threshold between zero (no threshold) and the maximum number determined by
- // the update engine. Within |update_state|, |wait_period| should contain the
- // last scattering period returned by this function, or zero if no wait period
- // is known; |check_threshold| is the last update check threshold, or zero if
- // no such threshold is known. If not scattering, or if any of the scattering
- // values has changed, returns |EvalStatus::kSucceeded|; otherwise,
- // |EvalStatus::kAskMeAgainLater|.
+ // the update engine. Within |update_state|, |scatter_wait_period| should
+ // contain the last scattering period returned by this function, or zero if no
+ // wait period is known; |scatter_check_threshold| is the last update check
+ // threshold, or zero if no such threshold is known. If not scattering, or if
+ // any of the scattering values has changed, returns |EvalStatus::kSucceeded|;
+ // otherwise, |EvalStatus::kAskMeAgainLater|.
EvalStatus UpdateScattering(EvaluationContext* ec, State* state,
std::string* error,
UpdateScatteringResult* result,