CPS-1812 - Getting issue details... STATUS
Requirements
Functional
| # | Interface | Requirement | Additional Information | Sign Off |
|---|---|---|---|---|
| 1 | CPS-E-08.e | NCMP is to merge CM Notification Subscriptions Create request for the same CM Handle & XPath(s) |
| |
| 2 | CPS-E-08.e | Last lights out: upon subscription Delete request only when there is no more subscription for a cm-handle & xpath combination a subscription-delete request wil be send to the relevant DMI(s) | ||
| 3 | CPS-E-08.e | Amalgamation per DMI: all subscription updates originating from a single client request should be send to a single DMI in one request (message). Of course there can be several message if more than 1 DMI is involved. | ||
| 4 | CPS-NCMP-I-01 | CM Handle deletion should update subscription details | do NOT delete dmi-subscription entry until owning subscription is deleted, see issue #4 below |
Error Handling
| # | Error Scenario | Expected behavior | Sign-off |
|---|---|---|---|
| 1 | |||
| 2 |
Characteristics
| # | Parameter | Expectation | Notes |
|---|---|---|---|
| 1 | |||
| 2 | |||
| 3 | |||
| 4 | |||
| 5 |
Out-of-scope
- CM Notification Forwarding Check: When forwarding CM Notification NCMP will not check the content to see if the is a valid active subscription. It is assumed that the DMI Plugin as acted on the 'delete subscription' request (that request is NCMPs responsibility). And of course there wil be timing issues it also possible a CM Notification was send just after the subscription-delete was send (from client) but before the whole change had acted upon that.
- Retry: NCMP wil only report when actions are pending or rejected. NCMP will not implement a retry mechanism
- Wildcards: Wildcards or similar functionality where one string represent 0 or more xpaths is not covered as part of this requirement but it should be kept in mind as a future possibility
- Dynamic Topic: Topic for CM Data Notifications back to client will be hardcode for now
Assumptions
| # | Assumption | Notes |
|---|---|---|
| 1 | Targets is a collection of xpaths | can be implemented as a json array of strings |
| 2 | for the DMI plugin cm-handle-id and xpath are the key to a unique subscription | the client-id and subscription name are not relevant for the DMI (should not be included in the request) as this would break the concept of merging! |
Issues & Decisions
| # | Issue | Notes | Decision |
|---|---|---|---|
| 1 | Is it intended that CM Notification subscription request cover (all) descendants of the given xpath too?! | e.g.. if a child is removed and there is a subscription for the parent node, will a notification be send (grandchild, child leaf updates etc.) I hope NOT! | |
| 2 | Could xpath point to an element that does not exist (yet) | if not how, how can I client be informed about a create event? | |
| 3 | Should NCMP support re-homing, moving of a CM Handle from one DMI to another? | assume only trough delete & create | |
| 4 | CM Handle Delete: Should DMI or Clients be sent a subscription update (assume no) | do NOT delete dmi-subscription entry until owning subscription is deleted (just ignore upon future delete if cm handle is gone altogether) |
Solution Proposals
Merge → Split
- NCMP treat a Client Subscription as one or more (small) DMI Subscriptions, each of which wil have there own state.
Each DMI Subscription is related to 1 or more client subscription.
If there is no more related client subscription the DMI Subscription can be deleted (once accepted by DMI Plugin)!
Data Model (not a great diagram...)
Create Combinations
| Existing Subscription A | Client Create Subscription B Request | DMI Create Request | Data Model | |
|---|---|---|---|---|
| 1 | CH-1, [ /p/c1, p/c2 ] | CH-1, [ /p/c1 ] | None | |
| 2 | CH-1, [ /p/c1, p/c2 ] | CH-1, [ /p/c2, /p/c3 ] | CH-1, [ /p/c3 ] | |
| 3 | CH-1, [ /p/c1] CH-2, [ /p/c1] | CH-2, [ /p/c1] CH-3, [ /p/c1] | CH-3, [ /p/c1] | |
| 4 | CH-1, [ /p/c1] | CH-1, [ /p/c1/gc1 ] | CH-1, [ /p/c1/gc1 ] (see issue #1) |
Delete Combinations
| NCMP Existing A | NCMP Existing B | Client Delete A Request | DMI Delete Request | |
|---|---|---|---|---|
| 1 | CH-1, [ /p/c1, p/c2 ] | CH-1, [ /p/c1 ] | CH-1, [ /p/c1, p/c2 ] | CH-1, [ p/c2 ] |
| 2 | CH-1, [ /p/c1] CH-2, [ /p/c1] | CH-2, [ /p/c1] CH-3, [ /p/c1] | CH-1, [ /p/c1] CH-2, [ /p/c1] | CH-1, [ /p/c1] |
| 3 | CH-1, [ /p/c1] | CH-1, [ /p/c1] CH-2, [ /p/c1] | CH-1, [ /p/c1] | None |
Proposed JIRAs
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