SOLR-16396: Migrate GET /config/requestHandler to JAX-RS by jaykay12 · Pull Request #5168 · apache/solr

jaykay12 · 2026-10-16T06:55:34Z

https://issues.apache.org/jira/browse/SOLR-16396

Description

Migrate GET /config/requestHandler to JAX-RS

Already landed / related:

Full GET /config: SOLR-16396 | Migration of Get Config V2 API to JAX-RS construct #4951
Overlay / znodeVersion: SOLR-16396 | Migrate GET /config/overlay and GET /config/znodeVersion to JAX-RS. #5022
4 previous sections: SOLR-16396 | Migrate GET config sections updateHandler, directoryFactory, indexConfig, and codecFactory to JAX-RS. #5023
3 more sections: SOLR-16396 | Migrate GET config sections query, searchComponent & queryResponseWriter to JAX-RS #5125

Solution

AI Disclaimer: Used Cursor for Approach formulation, code is fully vetted & reviewed by me.

Tests

GetConfigTest covers the scenarios.

Checklist

Please review the following and check all that apply:

I have reviewed the guidelines for How to Contribute and my code conforms to the standards described there to the best of my ability.
I have created a Jira issue and added the issue ID to my pull request title.
I have given Solr maintainers access to contribute to my PR branch. (optional but recommended, not available for branches on forks living under an organisation)
I have developed this patch against the main branch.
I have run ./gradlew check.
I have added tests for my changes.
I have added documentation for the Reference Guide
I have added a changelog entry for my change

jaykay12

self-review ✅
@epugh Can you have a look into this PR & trigger the workflows once?

once codewise lgtm is there, i will do the local testing.

jaykay12 · 2026-10-16T06:57:37Z

+        @QueryParam("componentName")
+            @Parameter(description = "Name of the specific request handler")
+            String component,


this is the most restful we can get here.
we can't use PathParams here like we have used for /searchComponents & /queryResponseWriters.

jaykay12 · 2026-10-16T07:03:51Z

Testing for requestHandler

Type	Url
V1 API	http://localhost:8983/solr/techproducts/config/requestHandler
Current V2 API	~~http://localhost:8983/api/collections/techproducts/config/requestHandler~~
Proposed V2 API	http://localhost:8983/api/collections/techproducts/config/requestHandlers
-	-
V1 API with expandParams=true(false by default)	http://localhost:8983/solr/techproducts/config/requestHandler?expandParams=true
Current V2 API with expandParams=true	~~http://localhost:8983/api/collections/techproducts/config/requestHandler?expandParams=true~~
Proposed V2 API with expandParams=true	http://localhost:8983/api/collections/techproducts/config/requestHandlers?expandParams=true
-	-
V1 API with filter	http://localhost:8983/solr/techproducts/config/requestHandler?componentName=/update/json/docs
Current V2 API with filter	~~http://localhost:8983/api/collections/techproducts/config/requestHandler?componentName=/update/json/docs~~
Proposed V2 API with filter	http://localhost:8983/api/collections/techproducts/config/requestHandlers?componentName=/update/json/docs
-	-
V1 API with filter & expandParams	http://localhost:8983/solr/techproducts/config/requestHandler?componentName=/update/json/docs&expandParams=true
Current V2 API with filter & expandParams	~~http://localhost:8983/api/collections/techproducts/config/requestHandler?componentName=/update/json/docs&expandParams=true~~
Proposed V2 API with filter & expandParams	http://localhost:8983/api/collections/techproducts/config/requestHandlers?componentName=/update/json/docs&expandParams=true

type	main branch	feature branch
v1 api - all
-	-	-
v2 api - all
-	-	-
v1 api - filtered
-	-	-
v2 api - filtered
-	-	-
v1 api - filtered & expandParams
-	-	-
v2 api - filtered & expandParams

epugh

double check some of the chnages I made in our last PR together, I think they are patterns we need on this one too!

so excited!

epugh · 2026-10-16T11:49:53Z

            int expectedParamsVersion);

+    @GET
+    @Path("/requestHandler")


doiuble check sheet, but I think this is now plural? "requestHandlers"????

done.

V2 is @path("/requestHandlers") (plural), matching the sheet.
V1 stays singular requestHandler.

epugh · 2026-10-16T11:50:17Z


+    @GET
+    @Path("/requestHandler")
+    @StoreApiParameters


what does @StoreApiParameters mean?

i got introduced to this annotation when doing TaskAPI JAX-RS migrations, this annotations automatically wires the cores/collection & indexName stuffs in the v2 APIs endpoints.

Got this understanding confirmed via Cursor as well now.

epugh · 2026-10-16T11:50:36Z

+        summary = "Fetch request handlers (including implicit handler)",
+        tags = {"config"})
+    ConfigInfoResponse getRequestHandler(
+        @QueryParam("componentName")


i think this is now a path param as well....

Stated the reasoning here in my self-review: #5168 (comment)

We can’t put the handler name in the path the way we do for searchComponents/{name} / queryResponseWriters/{name}.

Request-handler names are paths themselves (/select, /update/json/docs, /admin/ping, …). A @PathParam would be a single segment, so names with / break routing (and encoding gets ugly).

So for request handlers we keep filtering via query param:
GET .../config/requestHandlers?componentName=/update/json/docs

jaykay12 · 2026-10-16T17:51:35Z

Thanks @epugh for the quick review! I have addressed the comments.
Local testing is done ✅

PackageToolTest is failing right now, mostly looks like it is due to "requestHandler" -> "requestHandlers" in the v2 endpoint, but I am not yet able to debug & fix it. Trying more.

Solr forwards a v2 request to the node that actually hosts the target collection using the short "/c/{collection}/..." path alias (see HttpSolrCall#sendRemoteProxy), but Constants.INDEX_PATH_PREFIX's JAX-RS @path regex only recognized "cores" or "collections", not "c". Any JAX-RS resource built on that prefix therefore 404'd with "Cannot find API for the path" whenever a request needed to be proxied cross-node. Reproduced with a new 2-node test in GetConfigSolrCloudTest that deliberately sends a GET /config/overlay request to the node that does NOT host the collection's only replica, then fixed by accepting "c" as an alias for "collections" in the path regex. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01RzzUgiebQ8ZhhgE2E7ZZU5

CI builds with -Werror, and errorprone flags comparing JettySolrRunner instances with != instead of .equals(). Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01RzzUgiebQ8ZhhgE2E7ZZU5

…equestHandler

jaykay12 · 2026-10-17T20:32:50Z

@epugh maybe we are having more issues than just this one, I can see that PackageToolTest still fails even after i merged your fix PR on top of this.

one suggestion - can i take this PR scope as migration to JAX-RS with requestHandler to requestHandler, pluralising of this end point, I can take up in a follow-up PR? that will actually help us divide & conquer the issue.

which means that - #5168 (comment) gets addressed in the follow-up PR.

jaykay12 added 7 commits October 16, 2026 00:36

rebased with main

a05946a

queryparam

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minor

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corrections

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minor fix

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added cl

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added tests

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github-actions Bot added tests cat:api labels Oct 16, 2026

cl minor

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jaykay12 commented Oct 16, 2026

View reviewed changes

epugh requested changes Oct 16, 2026

View reviewed changes

changes

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github-actions Bot added the cat:cli label Oct 16, 2026

jaykay12 added 3 commits October 16, 2026 18:30

fix

061c966

fix for v1 consistency

13dd067

test fixes

1291fff

github-actions Bot added the documentation Improvements or additions to documentation label Oct 16, 2026

jaykay12 added 4 commits October 16, 2026 22:06

minor cleanup

3372ab7

todo

ba2c8a9

more tests coverage & strictness

e84d371

minor

6fede4c

jaykay12 requested a review from epugh October 16, 2026 17:51

jaykay12 mentioned this pull request Oct 16, 2026

SOLR-16396: Migrate remaining GET /config/{component} sections to JAX-RS #5174

Draft

7 of 8 tasks

jaykay12 and others added 3 commits October 17, 2026 19:11

Merge branch 'main' into SOLR-16396-config-requestHandler

d444b97

tidying

c045334

epugh mentioned this pull request Oct 17, 2026

Fix v2 API 404 when a /config request is proxied to another node #5178

Open

5 tasks done

epugh and others added 2 commits October 17, 2026 11:13

Merge branch 'fix-v2-proxy-collection-alias' into SOLR-16396-config-r…

1270dbf

…equestHandler

Merge branch 'main' into SOLR-16396-config-requestHandler

6f5d540

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jaykay12 commented Oct 16, 2026

Description

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Solution

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