feat: support chash on multiple headers #7198

shreealt · 2025-10-11T10:02:40Z

What type of PR is this?

Enhancement.

What this PR does / why we need it:

Chash on multiple headers is a legit use case. Example: when user identity is split across multiple headers, X-Tenant-ID + X-User-ID in multi-tenant apps.

Which issue(s) this PR fixes:

Fixes #7186

Release Notes: Yes/No

jukie · 2025-10-13T03:16:25Z

api/v1alpha1/loadbalancer_types.go

 	HeaderConsistentHashType ConsistentHashType = "Header"
+	// HeadersConsistentHashType hashes based on multiple request headers.
+	HeadersConsistentHashType ConsistentHashType = "Headers"


The API and implementation between HeadersConsistentHashType and HeaderConsistentHashType looks nearly identical. Should we instead deprecate HeaderConsistentHashType?

oh, that was actually the ask by Arko in the issue description, I was unaware how we would deprecate the HeaderConsistentHashType.

Do we replace HeaderConsistentHashType with the new HeadersConsistentHashType directly in the code?

You'd mark the API field as deprecated similar to

gateway/api/v1alpha1/policy_helpers.go

Line 34 in 481a2ca

// Deprecated: use targetRefs/targetSelectors instead

with a mention that HeadersConsistentHashType should be used instead as well as including it in the release notes file.

It would stick around in deprecated fashion for the upcoming release and actually removed in a future one (most likely the following release).

done, thanks a lot for the help <3

codecov · 2025-10-13T03:22:22Z

Codecov Report

❌ Patch coverage is 66.66667% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 71.01%. Comparing base (c68db79) to head (c1173f1).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
internal/gatewayapi/clustersettings.go	38.46%	8 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7198      +/-   ##
==========================================
- Coverage   71.04%   71.01%   -0.03%     
==========================================
  Files         229      229              
  Lines       41099    41113      +14     
==========================================
  Hits        29198    29198              
- Misses      10181    10194      +13     
- Partials     1720     1721       +1

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api/v1alpha1/loadbalancer_types.go

arkodg · 2025-10-15T00:59:56Z

internal/ir/xds.go

 	// Hash based on the Source IP Address
 	SourceIP  *bool          `json:"sourceIP,omitempty" yaml:"sourceIP,omitempty"`
 	Header    *Header        `json:"header,omitempty" yaml:"header,omitempty"`
+	Headers   []*Header      `json:"headers,omitempty" yaml:"headers,omitempty"`


in this layer can you delete Header and copy over the Header API field into Headers ?

doing so would introduce a breaking change, won't it?

This is an internal layer, not user facing, and our libs are /internal too

done, please review again

still see Header, suggestion was to delete it to improve maintenance

sorry for the confusion. I removed it finally.

arkodg · 2025-10-16T02:48:15Z

api/v1alpha1/loadbalancer_types.go

 	// Header configures the header hash policy when the consistent hash type is set to Header.
 	//
-	// +optional
+	// Deprecated: use Headers instead


can you add the optional tag back

arkodg · 2025-10-20T20:47:24Z

internal/xds/translator/testdata/out/xds-ir/load-balancer.routes.yaml

      name: seventh-route
      route:
        cluster: seventh-route-dest
-        hashPolicy:


can the input file be fixed with headers to fix this output

arkodg

LGTM thanks

test/e2e/tests/load_balancing.go

Signed-off-by: Shreemaan Abhishek <[email protected]>

This reverts commit 5c1e2f0. Signed-off-by: Shreemaan Abhishek <[email protected]>

Signed-off-by: Shreemaan Abhishek <[email protected]>

* feat: support chash based on multiple headers Signed-off-by: Shreemaan Abhishek <[email protected]> Signed-off-by: Lin Moskovitch <[email protected]>

shreealt requested a review from a team as a code owner October 11, 2025 10:02

shreealt changed the title ~~feat: support chash based on multiple headers~~ feat: support chash on multiple headers Oct 11, 2025

shreealt marked this pull request as draft October 11, 2025 16:14

shreealt marked this pull request as ready for review October 12, 2025 09:25

jukie reviewed Oct 13, 2025

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arkodg reviewed Oct 15, 2025

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api/v1alpha1/loadbalancer_types.go Show resolved Hide resolved

arkodg reviewed Oct 15, 2025

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arkodg reviewed Oct 16, 2025

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shreealt force-pushed the feat/implement-multi-header-hash-in-chash branch from 8e3632d to c82805c Compare October 16, 2025 18:34

arkodg reviewed Oct 20, 2025

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arkodg approved these changes Oct 21, 2025

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arkodg requested review from a team and jukie October 21, 2025 17:43

zirain reviewed Oct 22, 2025

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test/e2e/tests/load_balancing.go Outdated Show resolved Hide resolved

shreealt added 14 commits October 22, 2025 14:05

feat: support chash based on multiple headers

24eb4a7

Signed-off-by: Shreemaan Abhishek <[email protected]>

generate

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Signed-off-by: Shreemaan Abhishek <[email protected]>

generate

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Signed-off-by: Shreemaan Abhishek <[email protected]>

manifests

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Signed-off-by: Shreemaan Abhishek <[email protected]>

generate

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Signed-off-by: Shreemaan Abhishek <[email protected]>

cluster settings

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Signed-off-by: Shreemaan Abhishek <[email protected]>

e2e tests

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Signed-off-by: Shreemaan Abhishek <[email protected]>

deprecation

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Signed-off-by: Shreemaan Abhishek <[email protected]>

rm header

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Signed-off-by: Shreemaan Abhishek <[email protected]>

optional

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fix

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doc

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unify header struct

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Signed-off-by: Shreemaan Abhishek <[email protected]>

Revert "rm header"

81a54da

This reverts commit 5c1e2f0. Signed-off-by: Shreemaan Abhishek <[email protected]>

shreealt added 10 commits October 22, 2025 14:05

bring back header

9b75ce3

Signed-off-by: Shreemaan Abhishek <[email protected]>

fix

71962d9

Signed-off-by: Shreemaan Abhishek <[email protected]>

gen

4a36d1c

Signed-off-by: Shreemaan Abhishek <[email protected]>

gen again

ef302f7

Signed-off-by: Shreemaan Abhishek <[email protected]>

the gen returns

08e6bbe

Signed-off-by: Shreemaan Abhishek <[email protected]>

lint

34c2cbf

Signed-off-by: Shreemaan Abhishek <[email protected]>

reuse headers in ir level

af4efbf

Signed-off-by: Shreemaan Abhishek <[email protected]>

fix

c6abd0f

Signed-off-by: Shreemaan Abhishek <[email protected]>

fix: xds translate tests multi and single header yaml files

b608f95

Signed-off-by: Shreemaan Abhishek <[email protected]>

lint

c1173f1

Signed-off-by: Shreemaan Abhishek <[email protected]>

zirain force-pushed the feat/implement-multi-header-hash-in-chash branch from 1ff0f42 to c1173f1 Compare October 22, 2025 06:06

zirain approved these changes Oct 22, 2025

View reviewed changes

arkodg merged commit 06f961e into envoyproxy:main Oct 22, 2025
33 of 35 checks passed

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feat: support chash on multiple headers #7198

feat: support chash on multiple headers #7198

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shreealt commented Oct 11, 2025 •

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