|Status note||Product Management needs to flesh out the feature page so that development can be unblocked.|
|Product manager||Jennifer Arguello|
|Directly Responsible Individual||Jennifer Arguello|
|Lead engineer||Gregory Szorc|
|Security lead||Yvan Boily|
|Localization lead||Axel Hecht|
|QA lead||Tracy Walker|
|UX lead||Alex Faaborg|
|Product marketing lead||Jaclyn Fu|
|Additional members||Ibai Garcia (SUMO)|
Stage 1: Definition
1. Feature overview
Add-ons are synchronized between sync clients.
2. Users & use cases
User installs an add-on on one browser. When a sync occurs, the add-on is automagically installed on other sync clients.
Stage 2: Design
5. Functional specification
The Addon Manager maintainers would like to see Sync support all add-on providers so as to not introduce 1st and 2nd class providers. This will require some APIs.
The solution to this problem will consist of the following:
- Optional properties on add-on objects that describe the add-on for purposes of use in Sync
- Functions on AddonManager that take above properties and perform actions
For add-on objects, providers wishing to opt in to Sync will expose the following read-only, optional properties:
- a string that describes data necessary to synchronize the add-on between clients. The format of the string is opaque to Sync code. From the perspective of add-on providers, it should be a JSON object with a *type* field that is used to route it to the proper provider.
- a GUID used to identify this add-on across Sync client instances. The GUID should be generated using Utils.makeGUID() from the Sync code. It is basically a Base64-encoded representation of 9 random bytes.
(These properties will need to be documented at https://developer.mozilla.org/en/Addons/Add-on_Manager/Addon)
The AddonManager will support the following APIs:
- getAddonBySyncGUID(syncGUID, callback)
- Obtain an add-on from its Sync GUID. Calls the supplied function when that add-on is retrieved. The callback receives null on unknown add-on or the add-on object (generated from the underlying provider) on success.
- applySyncDataRecords(records, callbackObj)
- This applies an array of records that contain add-on metadata and makes the current state of the world agree with that data as much as possible.
The callbackObj is an object containing the following optional keys:
- onSuccess - Invoked when an individual record is processed successfully. Arguments are the record itself.
- onFailure - Invoked when an individual record could not be processed successfully. Arguments are the record itself.
- onFinished - Invoked when all records have finished processing.
Each record is an object containing the following keys:
- syncGUID (required) - The Sync GUID for this record
- syncData (optional) - The .syncData field from an add-on
- isDeleted (optional) - If evaluates to true, indicates that the record was deleted. Application of this record should involve trying to delete this add-on if present or no-op if not present.
The implementation of applySyncDataRecords() will resemble the following pseudocode:
foreach record in records: if record.isDeleted: found = this.getAddonBySyncGUID(record.syncGUID) if found: this.deleteAddon(found) callbackObj.onSuccess(record) continue
existing = this.getExistingAddonBySyncData(record.syncData) if existing: existing.merge(record.syncData) else: this.installAddonFromSyncData(syncGUID, syncData)
// call onSuccess on onFailure depending on result of above
The add-ons Sync engine will discover the set of add-ons that can be synced via the following procedure:
- Query AddonManager.getAllAddons()
- Filter the returned list by items that have the *syncData* and *syncGUID* properties and are installed in the profile add-on scope (addon.scope == AddonManager.SCOPE_PROFILE)
The engine will process incoming records via the following procedure:
- Obtain the set of locally-installed add-ons (using above)
- For each incoming record: TODO
The Sync add-on tracker will install add-on listeners in the AddonManager and will listen for the following events:
When these are observed, the tracker will:
- Verify the changed add-on is in the set of Sync-able add-ons (using same heuristics as add-on discovery documented above)
- Mark the GUID as changed
- This will result in a new record for that GUID being created automagically. The createRecord() procedure will create the necessary record which will be queued for upload to the Sync server.
On start-up, the add-on engine will query AddonManager.getStartupChanges() for changes applied on application start-up. These are not observed by Sync because they occur before Sync is registered and running. Even if Sync does catch them in its tracker, it should be safe to mark records as changed. The only side-effect will be a slightly different modified time.
AddonManager.getStartupChanges() will be queried for the following change types:
TODO: Sync should catch all startup change types (the constants above) and react to them. We may need an API or some kind of verification/test to ensure newly-introduced startup changes/constants aren't missed by Sync. (This is all because getStartupChanges() takes a type as a parameter.)
- What's the best way to reconcile installed add-ons with different Sync GUIDs? This will happen when two clients have installed the same add-on on different clients and then sets up Sync. The first Sync client will upload the records. Then, the 2nd will download that set and apply them. Should the Sync engine query AddonManager to see which add-ons (from the opaque *syncData* field) are not present or just call out into AddonManager and have it automagically recognize the dupe and update the Sync GUID? Either way, the Sync engine will need to know which Sync GUID disappeared so it can create a record saying the add-on was deleted/updated.
6. User experience design
Stage 3: Planning
7. Implementation plan
Quality Assurance review
Stage 4: Development
Stage 5: Release
10. Landing criteria
|Theme / Goal||Experience|
Team status notes
Discussion notes from 2011-08-16:
- add 'guid' column to 'addon' table in extensions.sqlite
- add GUID support to AddonsManager (have it automatically generated, 12 chars base64url)
- findings addons shouldn't count as daily update pings, or if they do, is it a problem?
- generate one record per app per addon, silently drop records from other apps and unknown addons (unknown to AMO)
- add option to locally disable enabled state sync (the "web developer case") in about:config