Prometheus Query Exemplars

[vmmusings]

Description

This PR introduces new capability of querying exemplars in prometheus connectors.

Documentation Link with sample request and response: https://github.com/vamsi-amazon/sql/blob/query_exemplars/docs/user/ppl/admin/prometheus_connector.rst#prometheus-connector-table-functions
Sample Request:

####
POST http://localhost:9200/_plugins/_ppl
content-type: application/json

{
    "query" : "source=my_prometheus.query_exemplars(query='prometheus_http_requests_total', starttime=1686694425, endtime=1686700130)"  
}

Sample Response

{
  "schema": [
    {
      "name": "seriesLabels",
      "type": "struct"
    },
    {
      "name": "exemplars",
      "type": "array"
    }
  ],
  "datarows": [
    [
      {
        "telemetry_sdk_language": "java",
        "instance": "otelcol:9464",
        "telemetry_sdk_version": "1.24.0",
        "service_name": "adservice",
        "os_description": "Linux 5.15.49-linuxkit-pr",
        "process_command_line": "/opt/java/openjdk/bin/java -javaagent:/usr/src/app/opentelemetry-javaagent.jar",
        "service_namespace": "opentelemetry-demo",
        "process_pid": "1",
        "app_ads_ad_request_type": "NOT_TARGETED",
        "process_runtime_version": "17.0.6+10",
        "telemetry_auto_version": "1.24.0",
        "process_runtime_description": "Eclipse Adoptium OpenJDK 64-Bit Server VM 17.0.6+10",
        "telemetry_sdk_name": "opentelemetry",
        "app_ads_ad_response_type": "RANDOM",
        "__name__": "app_ads_ad_requests_total",
        "os_type": "linux",
        "process_executable_path": "/opt/java/openjdk/bin/java",
        "process_runtime_name": "OpenJDK Runtime Environment",
        "host_arch": "aarch64",
        "job": "opentelemetry-demo/adservice",
        "container_id": "95cd785d0ce6c3867bf134b5f6d09b2a93f639c397a5f3dafaa6a10821345416",
        "host_name": "95cd785d0ce6"
      },
      [
        {
          "labels": {
            "trace_id": "ff1c56eeeb2cb52b8ef41f35238f3e8c",
            "span_id": "a6f169d1b34ae518"
          },
          "timestamp": "2023-07-13 06:14:34.929",
          "value": 1.0
        },
        {
          "labels": {
            "trace_id": "6dbff827314088960dec20a2a4426131",
            "span_id": "d1f86d293d5a0dd0"
          },
          "timestamp": "2023-07-13 06:15:04.977",
          "value": 1.0
        },
        {
          "labels": {
            "trace_id": "701f7039860aedc2658feb27090169d5",
            "span_id": "9281016f3f6abeb6"
          },
          "timestamp": "2023-07-13 06:16:14.241",
          "value": 1.0
        } ]
    ]
}

Issues Resolved

#1750
BWC failures are unrelated. WIll get fixed with the below PRs
#1876
#1868

Check List

• New functionality includes testing.
  • All tests pass, including unit test, integration test and doctest
• New functionality has been documented.
  • New functionality has javadoc added
  • New functionality has user manual doc added
• Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[codecov]

Codecov Report

Merging #1782 (d73c3cc) into main (1a7134b) will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##               main    #1782      +/-   ##
============================================
+ Coverage     97.39%   97.42%   +0.02%     
- Complexity     4603     4647      +44     
============================================
  Files           401      408       +7     
  Lines         11397    11526     +129     
  Branches        835      839       +4     
============================================
+ Hits          11100    11229     +129     
  Misses          290      290              
  Partials          7        7              

Flag	Coverage Δ
sql-engine	97.42% <100.00%> (+0.02%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
...theus/data/constants/PrometheusFieldConstants.java	0.00% <ø> (ø)
...ch/sql/prometheus/client/PrometheusClientImpl.java	100.00% <100.00%> (ø)
...mentation/QueryExemplarFunctionImplementation.java	100.00% <100.00%> (ø)
.../resolver/QueryExemplarsTableFunctionResolver.java	100.00% <100.00%> (ø)
...ions/resolver/QueryRangeTableFunctionResolver.java	100.00% <100.00%> (ø)
...response/QueryExemplarsFunctionResponseHandle.java	100.00% <100.00%> (ø)
...ons/response/QueryRangeFunctionResponseHandle.java	100.00% <100.00%> (ø)
...s/scan/QueryExemplarsFunctionTableScanBuilder.java	100.00% <100.00%> (ø)
.../scan/QueryExemplarsFunctionTableScanOperator.java	100.00% <100.00%> (ø)
...ions/scan/QueryRangeFunctionTableScanOperator.java	100.00% <100.00%> (ø)
... and 4 more

[vmmusings]

BWC failures are unrelated. WIll get fixed with the below PRs
#1876
#1868

[opensearch-trigger-bot]

The backport to 2.x failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-2.x 2.x
# Navigate to the new working tree
cd .worktrees/backport-2.x
# Create a new branch
git switch --create backport/backport-1782-to-2.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 430d7a9e60a7cace25784d569ff48f30ec47b150
# Push it to GitHub
git push --set-upstream origin backport/backport-1782-to-2.x
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-2.x

Then, create a pull request where the base branch is 2.x and the compare/head branch is backport/backport-1782-to-2.x.