Latest version of Unleash SDKs are incompatible with Gitlab Feature Flags

Synopsis

Unleash SDKs are removing the instanceId attribute from the configuration, and instead are auto-generating it. This makes them incompatible with Gitlab Feature Flags.

Details

For instance, NodeSDK 6.0.0 does not allow providing instanceId, as therefore calls fail with

Unleash Repository error: https://gitlab.com/api/v4/feature_flags/unleash/{PROJECT_ID}/client/features responded 401 which means your API key is not allowed to connect. Stopping refresh of toggles

References

• Node client dropping the support for instanceId in the 6.0.0 version.
  • https://github.com/Unleash/unleash-client-node/releases/tag/v6.0.0
• Ruby client
  • https://github.com/Unleash/unleash-client-ruby/pull/179
• Dotnet client
  • https://github.com/Unleash/unleash-client-dotnet/pull/226

Other SDKs are going to follow the same trend.

Possible Workarounds

It seems like it's possible to pass the instance id as a custom header.

For instance, the following works for me with unleash-node version 6.0.0

import {UnleashConfig} from "unleash-client"

const config: UnleashConfig = 
{
  url: "https://gitlab.com/api/v4/feature_flags/unleash/MY_PROJECT", // nonprod
  appName: "YOUR_ENV)NAME",
  customHeaders: {
    "UNLEASH-INSTANCEID": "MY_INSTANCE_ID"
  },
}

So if the Unleash team can verify that this is a reliable approach for the long-term, this will be a matter of updating the Gitlab Feature Flags docs to mention this pre-6.0.0 vs post-6.0.0 caveat (and likewise for other language SDKS, e.g. Java, Ruby)