Access delta link from delta cmdlets

[maisarissi]

Customers can use the delta commands to list all changes on a resource from start to finish and the nextLink will be followed to the end as stated at Use delta query to track changes in Microsoft Graph data - Microsoft Graph | Microsoft Learn.

However, today there is no way to access the deltaLink, that's returned on the last page to track changes from "last delta call".

I want to be able to access the deltaLink as well as passing it to the delta command, so I can track the changes from the last call.

[maisarissi]

@peombwa @timayabi2020 can you validate whether AutoREST supports it?

[peombwa]

The CSDL will also need to be annotated to signal to SDKs that delta functions support deltaToken query parameter - microsoftgraph/msgraph-metadata#354.

[peombwa]

Per the discussion at microsoftgraph/msgraph-metadata#354 (comment), the SDK should instead add support -DeltaLink parameter, which takes the @odata.deltalink value from the previous call:

Get-Mg*Delta -DeltaLink $link # value from the odata.deltalink property of the previous call

The implementation should ensure:

• @odata.deltalink property from the previous request is available to the caller. This can be a global variable, etc.
• Get-Mg*Delta -DeltaLink parameter set should only support -DeltaLink parameter to avoid sending malformed request URIs. Query parameters are specified once in the initial request. Microsoft Graph automatically encodes the specified parameter into the @odata.deltaLink returned in the response.

[pgarm]

Hey folks, just adding my 2c - been talking over this with @SteveMutungi254 since May and then it got kinda forgotten for a while, as I mistakenly popped the bug in ADO and not here :)
Got a bit of flak from customers on this as they were building automation around the delta functionality. Given them this sample as a workaround, but certainly seems an overlooked capability ;)

@CarolKigoonya

[pgarm]

Copying from ADO

Solution options

1. Implement session/module variable to cache deltaLink, and implicitly use it on subsequent Get-MgXxxxDelta executions.
   Downside - only persistent within session, so not suitable for scheduled jobs (based on customer conversations, this is mostly used in non-interactive automation).
2. Add explicit -DeltaLinkVariable parameter to push the link into current scope so user can handle the saving/retrieval themselves, and explicit -DeltaLink parameter to use the link in subsequent calls.

(ideally - both options to give users flexibility)
Instead of full deltaLink, can save just the deltaToken (marginally reduces memory/storage use, but makes it harder to reuse the link elsewhere.

[jreinhardtproarch]

I just want to share that this is also impacting me, and is another case of the Graph SDK's lack of "fit and finish." I will attempt to use the workaround provided here, thank you, or just use Invoke-MgGraphRequest. Thanks