Proposal: Provide the ability to monitor the usage of origins

Proposal: Provide the ability to monitor the usage of origins

BUG=347801

[tmdiep, 2014-03-17 00:52:13]

tzik: We would like to monitor the disk usage of extensions and apps that are
granted unlimited storage and display notifications to the user when we detect
possible abuse. Please see the linked bug for more background.

This patch does not contain any implementation, just a proposed interface for
achieving this. Some class in extension system will implement UsageObserver and
register as an observer for all extensions and apps that we are interested in
monitoring. QuotaManager will fire events when thresholds are exceeded.

WDYT? If you can think of a better way to monitor usage, please let me know.
Thanks.

[tzik, 2014-03-17 04:16:58]

On 2014/03/17 00:52:13, tmdiep wrote:
> tzik: We would like to monitor the disk usage of extensions and apps that are
> granted unlimited storage and display notifications to the user when we detect
> possible abuse. Please see the linked bug for more background.
> 
> This patch does not contain any implementation, just a proposed interface for
> achieving this. Some class in extension system will implement UsageObserver
and
> register as an observer for all extensions and apps that we are interested in
> monitoring. QuotaManager will fire events when thresholds are exceeded.
> 
> WDYT? If you can think of a better way to monitor usage, please let me know.
> Thanks.

Looks good.
We need this kind of observer to follow the latest Quota Management API spec.

Hiroki-san: You may be interested in this, since you've been looking new Quota
APIs.
Could you also take a look?
Don't we need to be able to change the threshold or to get finer grained usage
observation?

[tzik, 2014-03-17 05:31:56]

https://codereview.chromium.org/196573024/diff/1/webkit/browser/quota/usage_o...
File webkit/browser/quota/usage_observer.h (right):

https://codereview.chromium.org/196573024/diff/1/webkit/browser/quota/usage_o...
webkit/browser/quota/usage_observer.h:40: int64 threshold;
IMO, it's also desirable to get a notification on the usage goes below
|threashold|.

https://codereview.chromium.org/196573024/diff/1/webkit/browser/quota/usage_o...
webkit/browser/quota/usage_observer.h:46: int64 increments;
Can we start without |increments| for simpler implementation?
I think updatable |threashold| or multiple |threashold| are enough.

[tmdiep, 2014-03-17 06:27:07]

Thanks for the review.  I wasn't aware of the new Quota Management API spec and
looking at it, the StorageWatcher interface is sufficient for our usage in
extensions.

I've modified the patch to support the more generic StorageWatcher. Extension
system will manage thresholds instead and will likely only need to receive
events at a low rate.

https://codereview.chromium.org/196573024/diff/20001/webkit/browser/quota/quo...
File webkit/browser/quota/quota_manager.h (right):

https://codereview.chromium.org/196573024/diff/20001/webkit/browser/quota/quo...
webkit/browser/quota/quota_manager.h:230: void AddStorageObserver(const
StorageObserver::MonitorParams& params,
If we need the ability to update the params for an observer, we can rename this
function and have it perform both add and update.

[nhiroki, 2014-03-17 06:41:51]

Thank you for working on this!
The new version (PatchSet 2) looks good to me.

https://codereview.chromium.org/196573024/diff/20001/webkit/browser/quota/sto...
File webkit/browser/quota/storage_observer.h (right):

https://codereview.chromium.org/196573024/diff/20001/webkit/browser/quota/sto...
webkit/browser/quota/storage_observer.h:25: // threshold will apply to the
accumulated total usage.
"In this case, ..." seems to be deprecated by PatchSet 2.

https://codereview.chromium.org/196573024/diff/20001/webkit/browser/quota/sto...
webkit/browser/quota/storage_observer.h:54: int64 quota;
What does |quota| contains when the aggregated usage is notified (that is,
|client_id| is kAllClientsMask)?

[nhiroki, 2014-03-17 06:51:40]

https://codereview.chromium.org/196573024/diff/20001/webkit/browser/quota/quo...
File webkit/browser/quota/quota_manager.h (right):

https://codereview.chromium.org/196573024/diff/20001/webkit/browser/quota/quo...
webkit/browser/quota/quota_manager.h:230: void AddStorageObserver(const
StorageObserver::MonitorParams& params,
On 2014/03/17 06:27:08, tmdiep wrote:
> If we need the ability to update the params for an observer, we can rename
this
> function and have it perform both add and update.

From the viewpoint of the Quota spec, I think we don't need the ability because
StorageWatcher is immutable.

[nhiroki, 2014-03-17 07:23:22]

https://codereview.chromium.org/196573024/diff/20001/webkit/browser/quota/sto...
File webkit/browser/quota/storage_observer.h (right):

https://codereview.chromium.org/196573024/diff/20001/webkit/browser/quota/sto...
webkit/browser/quota/storage_observer.h:54: int64 quota;
On 2014/03/17 06:41:51, nhiroki wrote:
> What does |quota| contains when the aggregated usage is notified (that is,
> |client_id| is kAllClientsMask)?

Oops... sorry I misunderstood. I thought "aggregated usage" means a sum of all
origins. Please ignore this comment.

[tmdiep, 2014-03-17 09:12:20]

On 2014/03/17 06:41:51, nhiroki wrote:
> Thank you for working on this!
> The new version (PatchSet 2) looks good to me.

I will try to implement this, but I may need to ask a lot of questions :)

[tmdiep, 2014-03-17 10:31:51]

This website
(http://updates.html5rocks.com/2011/11/Quota-Management-API-Fast-Facts) states
that:

"unlimitedStorage on manifest.json of Chrome Web App has been brought as a
temporary solution for apps to work without Quota API. So, there’s no guarantee
that Chrome will support this feature forever."

This page is outdated, but are we planning to deprecate "unlimitedStorage"
anytime soon?

[nhiroki, 2014-03-17 11:08:35]

On 2014/03/17 10:31:51, tmdiep wrote:
> This website
> (http://updates.html5rocks.com/2011/11/Quota-Management-API-Fast-Facts) states
> that:
> 
> "unlimitedStorage on manifest.json of Chrome Web App has been brought as a
> temporary solution for apps to work without Quota API. So, there’s no
guarantee
> that Chrome will support this feature forever."
> 
> This page is outdated, but are we planning to deprecate "unlimitedStorage"
> anytime soon?

I'm not sure there are any plans to remove it, but I don't think it will be
deprecated soon because that option can be generally used.