[BUG] Remote endpoint connector cannot parse array param

[ps48]

What is the bug?
Different Language models have different types of parameters that need to be passed in to the model endpoints. The connectors should support different data-types including array for such model.s

How can one reproduce the bug?
Steps to reproduce the behavior:

1. Use dev tools to create a model connector
2. API Sample with payload

POST /_plugins/_ml/connectors/_create
{
  "name": "Test connector",
  "description": "Test Connector",
  "version": 1,
  "protocol": "aws/v1",
  "access_mode": "public",
  "parameters": {
  "sample_param": [ "\n\nHuman:" ]
  },
  "credential": {
      "access_key": "<new access key>",
      "secret_key": "<new secret key>",
      "session_token": "<new session>"
  },
  "actions": [
    {
      "predict": {
        "method": "POST",
        "url": "URL",
        "headers": { 
          "content-type": "application/json",
          "x-amz-content-sha256": "required"
        },
        "request_body": "PARAMS"
      }
    },
    {
      "metadata": {
        "method": "GET",
        "url": "URL",
        "headers": {
          "content-type": "application/json"
        }
      }
    }
  ]
}

NOTE: The issue is with sample_param in the above payload

What is the expected behavior?
All parameters with different data-type should work out of the box with all APIs

What is your host/environment?

• OS: MacOS
• Version 2.8
• Plugins
  • ML Commons 2.8 from branch: feature/remote-inference-rebase-2.x

Do you have any screenshots?
If applicable, add screenshots to help explain your problem.

Do you have any additional context?

1. The issue may trickle down to model register and deploy APIs. Need to test more without connector and directly register/deploy models.

[Zhangxunmt]

This bug is fix in 2.9 in #1075.

[ps48]

@Zhangxunmt @ylwu-amzn Was this solved in 2.9? I still see the same error as earlier in the 2.9 version:

{
  "error": {
    "root_cause": [
      {
        "type": "illegal_argument_exception",
        "reason": "Invalid JSON in payload"
      }
    ],
    "type": "illegal_argument_exception",
    "reason": "Invalid JSON in payload"
  },
  "status": 400
}

[ylwu-amzn]

you should change action part

"actions": [
    {
        "action_type": "predict",
        "method": "POST",
        "url": "URL",
        "headers": { 
          "content-type": "application/json",
          "x-amz-content-sha256": "required"
        },
        "request_body": "PARAMS"
    }
  ]