feat(clickhouseexporter): Per pipeline JSON support by Garbett1 · Pull Request #46553 · open-telemetry/opentelemetry-collector-contrib

Garbett1 · 2026-03-02T15:24:32Z

Description

Currently, JSON support for ClickHouse is added via a feature flag, so it's turned off or on for all ClickHouse pipelines.

This may not be desirable.

At this moment, there are a few features where Map might still win out, compared to JSON (at least in the medium term)

This shifts the config down to the pipeline level, but also still keeps the feature flag around for now. The behaviour is:

feature flag enabled == always JSON (parity with current)
feature flag disabled && config.use_json == JSON
feature flag disabled && config.!use_json (default) == Map

Testing

Added many tests in the PR!

Documentation

linux-foundation-easycla · 2026-03-02T15:24:40Z

The committers listed above are authorized under a signed CLA.

✅ login: Garbett1 / name: Xander Garbett (3ec66e4, b2c2f31, 2146bc1, 4d1990b, 711478c)

github-actions · 2026-03-02T15:24:53Z

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Garbett1 · 2026-03-02T15:33:41Z

Well, I'm definitely not a first time contributor 😅 Looks like my CLA has dropped off though.

Garbett1 · 2026-03-02T15:37:13Z

+// testLogsCombinedExporter verifies that Map-based and JSON-based logs exporters
+// can operate side-by-side against the same ClickHouse instance.
+func testLogsCombinedExporter(t *testing.T, endpoint string, mapBody bool) {
+	overrideJSONStringSetting := func(config *Config) {


This is aping the other tests, debated extracting into helpers, but decided against it.

paulojmdias · 2026-03-02T16:20:58Z

If you're proposing control the JSON support using config instead of feature gate, I don't think the feature gate is needed at all. Otherwise, the user will need to really do two actions to ensure the JSON is supported.

You may also need to add enable_json_type=1 to your endpoint query string parameters.

Looking into the README.md also shouldn't be enough, adding enable_json_type=0 to the ones you want to disable?

Just sharing my thoughts, but let's see what codeowners say about it.

Garbett1 · 2026-03-02T16:24:41Z

If you're proposing control the JSON support using config instead of feature gate, I don't think the feature gate is needed at all. Otherwise, the user will need to really do two actions to ensure the JSON is supported.

You may also need to add enable_json_type=1 to your endpoint query string parameters.

Looking into the README.md also shouldn't be enough, adding enable_json_type=0 to the ones you want to disable?

Just sharing my thoughts, but let's see what codeowners say about it.

On enable_json_type=1
This is ClickHouse side config on the query param, and doesn't really interfere with the map or not. TBH, it's a bit outdated, as I think all LTS supported versions of CH have this enabled these days.

I don't think the feature gate is needed at all

I agree, but dropping it is not backwards compatible. If we shifted to the config and ignored the feature flag, this would break prod workloads as soon as you updated.

IMO, the config approach I suggest above gives a more graceful way to update. My proposed end state would be that it's controlled only by config.

paulojmdias · 2026-03-02T16:29:08Z

I agree, but dropping it is not backwards compatible. If we shifted to the config and ignored the feature flag, this would break prod workloads as soon as you updated.

Feature gate is in Alpha stage and not enabled by default at all. You could mark it as deprecated in favor of a config option and open an issue to remove the feature gate code related to it later.

Garbett1 · 2026-03-02T17:41:17Z

You could mark it as deprecated in favor of a config option and open an issue to remove the feature gate code related to it later.

That's a good shout for the issue, will make a follow up.

In terms of the feature flag being in alpha, I know of a few places that are currently relying on the feature gate, so felt it would be better to do it in two phases (maybe warn at startup)

SpencerTorres

Excellent PR! It's indeed hard to share pipelines with/without JSON, so this is a reasonable feature. I agree with the other review comments, we should deprecate the feature flag. Originally this was added under a feature flag because Map was supposed to be deprecated with JSON becoming the primary pipeline, we didn't want to maintain both implementations. Considering we have both implementations now I suppose there's not much harm in adding this config option. Everything looks good, my only nit is I would prefer json over use_json, but that's not a blocker.

Thanks for the PR!

Garbett1 · 2026-03-05T10:55:02Z

~~Just reading the code on the StageDeprecated.~~

~~It will throw an error if anyone sets it, not sure if we want a grace period of 1 release before marking that (so if your binary version and config aren't synced up, you don't immediately error)~~

~~Happy to defer to how you want to handle it as maintainers.~~

I mis-read the code! Ran a test, and it worked as we'd hope.

Garbett1 · 2026-03-05T11:01:39Z

@SpencerTorres , do you want to approve it with workflow perms so it can run the tests?

paulojmdias · 2026-03-05T11:33:12Z

/workflow-approve

paulojmdias · 2026-03-05T11:53:22Z

/workflow-approve

paulojmdias · 2026-03-05T14:04:44Z

/workflow-approve

…6553) #### Description Currently, JSON support for ClickHouse is added via a feature flag, so it's turned off or on for _all_ ClickHouse pipelines. This may not be desirable. At this moment, there are a few features where Map might still win out, compared to JSON (at least in the medium term) This shifts the config down to the pipeline level, but also still keeps the feature flag around for now. The behaviour is: * feature flag enabled == always JSON (parity with current) * feature flag disabled && config.use_json == JSON * feature flag disabled && config.!use_json (default) == Map  #### Testing Added many tests in the PR!  #### Documentation

feat(clickhouseexporter): Per pipeline JSON support

e1fb463

Garbett1 requested a review from a team as a code owner March 2, 2026 15:24

Garbett1 requested a review from crobert-1 March 2, 2026 15:24

github-actions Bot added the first-time contributor PRs made by new contributors label Mar 2, 2026

Garbett1 commented Mar 2, 2026

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github-actions Bot added the exporter/clickhouse label Mar 2, 2026

github-actions Bot requested review from Frapschen, SpencerTorres and hanjm March 2, 2026 15:45

github-actions Bot assigned jmacd Mar 2, 2026

paulojmdias added the waiting-for-code-owners label Mar 2, 2026

jmacd approved these changes Mar 4, 2026

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SpencerTorres approved these changes Mar 5, 2026

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Garbett1 and others added 2 commits March 5, 2026 11:00

Address PR comments, rename config, add deprecation to gate

4d1990b

Merge branch 'main' into per-pipeline-json-support

3ec66e4

Garbett1 requested a review from SpencerTorres March 5, 2026 11:01

JSON not experimental in CH

b2c2f31

APPEASE THE LINTER

711478c

Add change yaml, and update schema

2146bc1

SpencerTorres approved these changes Mar 5, 2026

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crobert-1 removed the waiting-for-code-owners label Mar 5, 2026

crobert-1 approved these changes Mar 5, 2026

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crobert-1 added the ready to merge Code review completed; ready to merge by maintainers label Mar 5, 2026

songy23 merged commit a4bd57e into open-telemetry:main Mar 5, 2026
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dloucasfx mentioned this pull request Mar 24, 2026

[chore] Changelog for v0.148.0 signalfx/splunk-otel-collector#7357

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Garbett1 commented Mar 2, 2026

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