Support s3 using repackage

[xinyual]

Description

This PR is to support t2ppl in spark PPL like s3/cloudwatch. We cannot use mapping API to get schema and samples. So frontend need to pass schema and samples. We need to re-parse the schema since the schema is the string. The request body is like

{
  "parameters": {
    "question": "what is the error rate yesterday",
    "index": "flight",
    "samples": [
        {
            "httpRequest": {
				"args": "",
				"country": "US",
				"headers": [
					{
						"name": "accept",
						"value": "*/*"
					},
					{
						"name": "accept-language",
						"value": "*"
					},
					{
						"name": "sec-fetch-mode",
						"value": "cors"
					},
					{
						"name": "user-agent",
						"value": "node"
					},
					{
						"name": "accept-encoding",
						"value": "br, gzip, deflate"
					}
				],
				"httpVersion": "HTTP/1.1",
				"requestId": "ALAqbFTqvHcEWEQ=",
				"clientIp": "34.210.155.133",
				"httpMethod": "POST",
				"uri": "/dev"
			}
        }
    ],
    "schema": {
        "httpRequest": {
            "col_name": "httpRequest",
            "data_type": "struct<clientIp:string,country:string,headers:array<struct<name:string,value:string>>,uri:string,args:string,httpVersion:string,httpMethod:string,requestId:string>",
            "comment": null
        }
    },
    "type": "s3"
  }
}

Related Issues

Resolves #[Issue number to be closed when this PR is merged]

Check List

• New functionality includes testing.
• New functionality has been documented.
• API changes companion pull request created.
• Commits are signed per the DCO using --signoff.
• Public documentation issue/PR created.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
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[codecov]

Codecov Report

Attention: Patch coverage is 91.36691% with 12 lines in your changes missing coverage. Please review.

Project coverage is 82.31%. Comparing base (2b76e3c) to head (50cc2eb).
Report is 44 commits behind head on main.

Files with missing lines	Patch %	Lines
.../main/java/org/opensearch/agent/tools/PPLTool.java	91.36%	5 Missing and 7 partials ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main     #482      +/-   ##
============================================
+ Coverage     81.78%   82.31%   +0.52%     
- Complexity      193      355     +162     
============================================
  Files            11       17       +6     
  Lines           961     1685     +724     
  Branches        137      240     +103     
============================================
+ Hits            786     1387     +601     
- Misses          121      204      +83     
- Partials         54       94      +40     

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[yuye-aws]

@xinyual Can you update the PR description?

[yuye-aws]

wildcard import is not prefered

[zhichao-aws]

neat: remove the commented out line

[zhichao-aws]

neat: remove the new added blank lines

[zhichao-aws]

where is this permission used?

[xinyual]

Use it in AccessController.doPrivileged((PrivilegedExceptionAction) () -> DataType.fromDDL(schema)) The dataType needs class loader.

[zhichao-aws]

Do we need to handle the corner case? e.g. type != "array" and type != "struct"; or "fields" key not in structMap etc

[xinyual]

The input schema is generated by calling "describe <index_name>" in front end. So we expect the type only equals to "array", "struct" or leaf type (what we want). And the schema is from "describe <index_name>", it muse contain "fields"

[zhichao-aws]

@xinyual The PR looks good to me overall. As the codecov action fails (80.31% of diff hit (target 81.78%)), I'll approve it once have enough tests

[xinyual]

@zhichao-aws Hi Zhichao, I already add enough UT, please approve this PR.

[opensearch-trigger-bot]

The backport to 2.x failed:

The process '/usr/bin/git' failed with exit code 128

To backport manually, run these commands in your terminal:

# Navigate to the root of your repository
cd $(git rev-parse --show-toplevel)
# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add ../.worktrees/skills/backport-2.x 2.x
# Navigate to the new working tree
pushd ../.worktrees/skills/backport-2.x
# Create a new branch
git switch --create backport/backport-482-to-2.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 785404ddefaa835113d8a525bf7e50f4897b4ba5
# Push it to GitHub
git push --set-upstream origin backport/backport-482-to-2.x
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/skills/backport-2.x

Then, create a pull request where the base branch is 2.x and the compare/head branch is backport/backport-482-to-2.x.