PATCH method required for /api/admin/context/{contextField}

[preetiakrohilla]

Describe the feature request

Hi Team,

We have a use case where we are trying to update the Unleash UserId context field in parallel. Here are the steps we follow:

We are using REST APIs to update the context field.

1. To get the current list of legal values for a given userId context field, use the following GET request:

curl --header "Authorization: xxxxxxxxxxxxxxxxxx" --header "Content-Type: application/json" http://localhost:4242/api/admin/context/userId
Sample response:
{
"name": "userId",
"description": "Allows you to constrain on userId",
"stickiness": false,
"sortOrder": 1,
"legalValues": [
{
"value": "aeb27c26-8952-434c-a724-e86fbd124e15",
"description": "test1"
}
],
"createdAt": "2023-10-29T13:25:26.078Z"
}

2. Add the new userId value to the list of legalValues received in the response from step Agree on a license #1

For example, you may want to add a new user ID like this:
{
"value": "6880e05c-df57-4a06-af65-418e57754d19",
"description": "test2"
}

3. Use a PUT request to update the userId context field with the modified legalValues list:

curl --request PUT 'http://localhost:4242/api/admin/context/userId'
--header 'Authorization: xxxxxxxxxxxxxx'
--header 'Content-Type: application/json'
--data-raw '{
"name": "userId",
"description": "Allows you to constrain on userId",
"legalValues": [
{
"value": "aeb27c26-8952-434c-a724-e86fbd124e15",
"description": "test1"
},
{
"value": "6880e05c-df57-4a06-af65-418e57754d19",
"description": "test2"
}
],
"stickiness": false
}'

Potential Issue:
Two concurrent requests might lead to data overwriting on the server, as both requests may fetch the same state in step #1 and update the context field simultaneously. This can result in the loss of changes made by one request when the other request is processed later.

Background

No response

Solution suggestions

Introduce Patch Method for Unleash Rest API /api/admin/context/{contextField}

[FredrikOseberg]

@preetiakrohilla

Hi.

I can see the use-case for this functionality, however we have other priorities that are more pressing right now. If you would like to contribute this functionality we'd be happy to take a look at it, otherwise we'll have to revisit this in the future.

[kwasniew]

You can add/update and delete single legal values now: #9056 and #9058

[preetiakrohilla]

Hello @kwasniew

Thanks for your support!

Could you please confirm when this change is planned for release?

Additionally, we are facing a similar issue when adding whitelisted values for constraints under feature flag strategy.
This operation also requires the complete set of whitelisted values in the PUT request. Two parallel threads are overwriting our values.

Is it possible to support single-value updates and deletions in this case, or is there another workaround available?

[kwasniew]

Hi @preetiakrohilla
If you're Unleash hosted client then you should already have it available. If you're self-hosted Enterprise or using OSS version then you'll get it in the next minor release at the end of this month.

For the strategy updates are you using UI or API? In the UI code there's a staleness check that verifies if you're looking at the most recent version. But since you mentioned threads I'm assuming you're updating them with our API.

[preetiakrohilla]

We are using API to update the strategy.
Initially, we considered using the ETag header, but later we realized that Unleash uses a weak ETag.