Cannot create event subscriptions | Redfish Specification Forum

amteixeira
Minnow

Posts: 2

Cannot create event subscriptions Aug 22, 2023 0:22:05 GMT

Quote

Post by amteixeira on Aug 22, 2023 0:22:05 GMT

When I post to http://{{ _.serverAddress}}/redfish/v1/EventService/Subscriptions a 200 OK is returned with the list of current subscriptions, but no subscription is created. and if I post using https, then 405 status is returned.

This is my payload:

{

    "Context": "Apenas para fins de teste",

    "Destination": "https://10.20.4.221:44389/api/Events",

    "Protocol": "Redfish",

    "SubscriptionType": "RedfishEvent",

    "EventFormatType": "Event",

    "SendHeartbeat": true,

    "HeartbeatIntervalMinutes": 5,

    "MessageIds": [],

    "EventTypes": [],

    "OriginResources": [],

    "RegistryPrefixes": [],

    "ResourceTypes": [],

    "VerifyCertificate": false

}

I am sending an X-Auth-Token in the header with the session token.

Am I missing something?

mraineri
Administrator

Posts: 1,054

Cannot create event subscriptions Aug 22, 2023 0:45:07 GMT

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Post by mraineri on Aug 22, 2023 0:45:07 GMT

I'm wondering if when you're using the POST to "http://{{ _.serverAddress}}/redfish/v1/EventService/Subscriptions", it's doing a redirection to HTTPS and in turn just performing a GET... Are you using curl to perform this operation? Would you be able to provide HTTP traces so we might see what's going on? The fact that you're getting a 405 if you perform a POST with HTTPS is a bit troublesome since I would expect that to be more reliable. If you have curl available to debug, can you try the following and send back the output?

curl -k -u USER:PASSWORD -H "Content-Type: application/json" -X POST 'http://{{ _.serverAddress}}/redfish/v1/EventService/Subscriptions' -d '{"Destination": "https://10.20.4.221:44389/api/Events", "Protocol": "Redfish"}' -vvvvv
curl -k -u USER:PASSWORD -H "Content-Type: application/json" -X POST 'https://{{ _.serverAddress}}/redfish/v1/EventService/Subscriptions' -d '{"Destination": "https://10.20.4.221:44389/api/Events", "Protocol": "Redfish"}' -vvvvv

Also, when you're performing the POST request to make the subscription, only two properties in the schema are listed as "required on create": Destination and Protocol. So, as a starting point, it might be worth reducing your POST request to simply contain this as your payload to ensure you have the basics working properly:

{
    "Destination": "https://10.20.4.221:44389/api/Events",
    "Protocol": "Redfish"
}

Once that's working properly, you can start adding in additional subscription parameters if you'd like to control what sort of events you want to listen for.

Lastly, we do have some sample code that creates event subscriptions that might be worth checking out too. In the Tacklebox project (https://github.com/DMTF/Redfish-Tacklebox), there's a script called "rf_event_service.py" that lets you inspect the event service, create subscriptions, and delete subscriptions.

In the end, it might be time we make a white paper to help step through the flows here...

amteixeira
Minnow

Posts: 2

Cannot create event subscriptions Aug 22, 2023 18:33:56 GMT

Quote

Post by amteixeira on Aug 22, 2023 18:33:56 GMT

I am using the Insomnia client to perform the requests.

Here is the output of the first command:

Note: Unnecessary use of -X or --request, POST is already inferred.
* Trying 10.55.130.53:80...
* Connected to 10.55.130.53 (10.55.130.53) port 80 (#0)
> POST /redfish/v1/EventService/Subscriptions HTTP/1.1
> Host: 10.55.130.53
> User-Agent: curl/8.1.2
> Accept: */*
> Content-Type: application/json
> Content-Length: 78
>
< HTTP/1.1 301 Moved Permanently
< Location: 10.55.130.53:443/redfish/v1/EventService/Subscriptions/
< Content-Length: 0
< Connection: close
< Date: Tue, 22 Aug 2023 18:32:11 GMT
<
* Closing connection 0

And this is the output of the second command:

Note: Unnecessary use of -X or --request, POST is already inferred.
* Trying 10.55.130.53:443...
* Connected to 10.55.130.53 (10.55.130.53) port 443 (#0)
* schannel: disabled automatic use of client certificate
* schannel: using IP address, SNI is not supported by OS.
* using HTTP/1.x
> POST /redfish/v1/EventService/Subscriptions HTTP/1.1
> Host: 10.55.130.53
> User-Agent: curl/8.1.2
> Accept: */*
> Content-Type: application/json
> Content-Length: 78
>
* schannel: remote party requests renegotiation
* schannel: renegotiating SSL/TLS connection
* schannel: SSL/TLS connection renegotiated
* schannel: remote party requests renegotiation
* schannel: renegotiating SSL/TLS connection
* schannel: SSL/TLS connection renegotiated
< HTTP/1.1 405 Method Not Allowed
< Content-Length: 0
< Strict-Transport-Security: max-age=31536000; includeSubdomains
< X-XSS-Protection: 1; mode=block
< Content-Security-Policy: default-src 'self';connect-src 'self' ws: wss:;frame-src 'self';img-src 'self' data:;object-src 'self';font-src 'self' data:;script-src 'self' 'unsafe-inline' 'unsafe-eval';style-src 'self' 'unsafe-inline';worker-src 'self' blob:;
< Cache-Control: private
< X-Frame-Options: SAMEORIGIN
< X-Content-Type-Options: nosniff
< OData-Version: 4.0
< Date: Tue, 22 Aug 2023 18:33:33 GMT
<
* Connection #0 to host 10.55.130.53 left intact

mraineri
Administrator

Posts: 1,054

Cannot create event subscriptions Aug 23, 2023 1:46:46 GMT

Quote

Post by mraineri on Aug 23, 2023 1:46:46 GMT

Thanks for the output.

So, for the HTTP portion, your output confirmed my suspicion. The service is using 301 to redirect, which is problematic for non-GET operations. So, an off the shelf tool will handle this by performing a GET on the URI in the Location header of the 301 response, which essentially drops the original POST request entirely. HTTP 308 would make more sense in this case since we want to preserve the original POST semantics.

However, that redirection issue can be avoided by using HTTPS, but shows the more troubling issue in that POST is not supported. Unfortunately the output also shows the service doesn't even show the "Allow" HTTP response header, which makes this even more difficult to trace. The other thing I notice is the trace doesn't show either the X-Auth-Token or the Authorization headers; are you removing these from the post? If so, that's understandable, but would be good to confirm to ensure we're not heading off in the wrong direction. If you are removing the tokens/credentials from the trace, then that would indicate to me the service you're using really doesn't have much capabilities in terms of eventing. It seems very odd to have an event service while not allowing a user to subscribe to event notifications.