topic Re: Rest API Get Snapshot Collection: Cannot index into a null array. in Array Performance and Data Protection

Rest API Get Snapshot Collection: Cannot index into a null array.

adamscabana128 — Fri, 08 Apr 2016 15:18:47 GMT

Hi All.

I have a powershell script using the REST API to refresh dev/qa environments.

The refresh has been working great for some time. All of the sudden today I had 2 machines fail with Cannot index into a null array.

Here is the snippet of code:

$prod_array = @();

$ProdVolume_array = @();

$topsnapshot_array = @();

$uri = "https://" + $ArrayIP + "snapshot_collections/detail"

$snaplist = Invoke-RestMethod -Uri $uri -Method get -Header $header

$prod_array += $snaplist.data

$ProdVolume_array = $prod_array | select snapshots_list, name, creation_time |where-object name -like $ProdVolumeCollection* | sort-object -Property creation_time -descending

$topsnapshot_array = $ProdVolume_array[0].snapshots_list

$snaplist does have information in it. when I look at $prod_array and $ProdVolume_array I see nothing. I don't understand why.

Thanks,

Jeff

Re: Rest API Get Snapshot Collection: Cannot index into a null array.

jcates98 — Tue, 12 Apr 2016 19:07:08 GMT

Hey Jeff,

Are you certain that $snaplist contains valid data? Depending on what value $ArrayIP has, I see a potential error. If it's simply the IP/hostname of the array as I expect it might be, then I suggest that you change this line:

$uri = "https://" + $ArrayIP + "snapshot_collections/detail"

to instead be

$uri = "https://" + $ArrayIP + ":5392/v1/snapshot_collections/detail"

Otherwise, when you invoke the API in the following line, you are likely to get an error. The only other thing that jumps out is that I don't know what $ProdVolumeCollection looks like here. If it's invalid, then $ProdVolume_array would wind up being empty.

Cheers,

Julian

Re: Rest API Get Snapshot Collection: Cannot index into a null array.

rshekar42 — Wed, 13 Apr 2016 17:13:26 GMT

Not sure about the snapshot_collections failure, but the snapshots object failed with this error:

Invoke-RestMethod : The remote server returned an error: (400) Bad Request.

snapshots objectset does not support listing all objects. The complete response for this error would be some thing like this:

{

"messages":[

{

"code":"SM_http_bad_request",

"text":"The request could not be understood by the server."

{

"code":"SM_missing_arg",

"arguments":{

"arg":"vol_id"

"text":"Missing the argument 'vol_id' in the request."

}

]

}

You will have to provide the id of a particular volume to list the snapshots. For e.g. you can use a query URL like this:

https://<array-ip>:5392/v1/snapshots/detail?vol_id=0611f49156c08fdc81000000000000000000000007

Re: Rest API Get Snapshot Collection: Cannot index into a null array.

adamscabana128 — Wed, 13 Apr 2016 21:27:44 GMT

I may have found the problem:

changing

$ProdVolume_array = $prod_array | select snapshots_list, name, creation_time |where-object name -like $ProdVolumeCollection* | sort-object -Property creation_time -descending

to:

$ProdVolume_array = $prod_array | select * |where-object volcoll_name -eq $ProdVolumeCollection | sort-object -Property creation_time -descending

In some local testing this appears to take care of the issue, but I need to validate.

I'm still not sure why it all of the sudden failed.

Re: Rest API Get Snapshot Collection: Cannot index into a null array.

adamscabana128 — Thu, 14 Apr 2016 15:12:59 GMT

This has corrected the problem.