Adds expressions to headers propagation #453

kamilkisiela · 2025-09-26T08:49:50Z

No description provided.

gemini-code-assist · 2025-09-26T08:50:16Z

Summary of Changes

Hello @kamilkisiela, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly enhances the router's header manipulation capabilities by introducing support for dynamic header values derived from VRL (Vector Remap Language) expressions. This allows for highly flexible and powerful header generation, where values can be computed based on various contextual information such as client request details, GraphQL operation specifics, and subgraph response headers. The change involves integrating the vrl library, updating the header compilation and application logic to process these expressions, and extending the configuration schema to enable users to define expression-based header insertion rules.

Highlights

Expression-based Header Insertion: Introduced the ability to define header values using VRL (Vector Remap Language) expressions for both request and response headers, allowing for dynamic and contextual header generation.
VRL Integration: Integrated the vrl crate into the project, enabling the compilation and execution of VRL expressions to determine header values. This includes adding vrl as a dependency and handling its compilation errors.
Rich Context for Expressions: New data structures (ClientRequestDetails, OperationDetails, RequestExpressionContext, ResponseExpressionContext) were added to provide comprehensive contextual information (client request method, URL, headers, operation details, subgraph name, subgraph response headers) to the VRL expressions.
Configuration and Documentation Updates: The configuration schema (lib/router-config/src/headers.rs) and documentation (docs/README.md) have been updated to reflect the new expression option for header insertion rules, providing clear guidance on its usage.
Header Logic Refactoring: Significant refactoring of the header processing logic across multiple files (lib/executor/src/headers/compile.rs, lib/executor/src/headers/request.rs, lib/executor/src/headers/response.rs) was performed to seamlessly incorporate the new expression-based insertion mechanism and pass the enriched context objects.

Using Gemini Code Assist

The full guide for Gemini Code Assist can be found on our documentation page, here are some quick tips.

Invoking Gemini

You can request assistance from Gemini at any point by creating a comment using either /gemini <command> or @gemini-code-assist <command>. Below is a summary of the supported commands on the current page.

Feature	Command	Description
Code Review	`/gemini review`	Performs a code review for the current pull request in its current state.
Pull Request Summary	`/gemini summary`	Provides a summary of the current pull request in its current state.
Comment	@gemini-code-assist	Responds in comments when explicitly tagged, both in pull request comments and review comments.
Help	`/gemini help`	Displays a list of available commands.

Customization

To customize Gemini Code Assist for GitHub experience, repository maintainers can create a configuration file and/or provide a custom code review style guide (such as PEP-8 for Python) by creating and adding files to a .gemini/ folder in the base of the repository. Detailed instructions can be found here.

Limitations & Feedback

Gemini Code Assist may make mistakes. Please leave feedback on any instances where its feedback is incorrect or counter productive. You can react with 👍 and 👎 on @gemini-code-assist comments. If you're interested in giving your feedback about your experience with Gemini Code Assist for Github and other Google products, sign up here.

You can also get AI-powered code generation, chat, as well as code reviews directly in the IDE at no cost with the Gemini Code Assist IDE Extension.

Review the Privacy Notices, Generative AI Prohibited Use Policy, Terms of Service, and learn how to configure Gemini Code Assist in GitHub here. Gemini can make mistakes, so double check it and use code with caution. ↩

gemini-code-assist

Code Review

This pull request introduces a powerful new feature for header manipulation using VRL expressions. The implementation is well-structured, but there are a few critical issues that could lead to panics due to unhandled errors when resolving VRL expressions. Additionally, there are some incomplete sections marked with TODO that need to be addressed to fully realize the feature, a bug in default port detection for URLs, and some opportunities for performance and documentation improvements. My review provides specific feedback on these points.

lib/executor/src/headers/request.rs

lib/executor/src/headers/response.rs

bin/router/src/pipeline/execution.rs

lib/executor/src/headers/expression.rs

lib/executor/src/headers/compile.rs

gemini-code-assist · 2025-09-26T08:52:19Z

lib/executor/src/headers/expression.rs

+            ("name".into(), details.operation.name.clone().into()),
+            ("type".into(), details.operation.kind.into()),


The operation object in the VRL context is missing the query field, even though OperationDetails contains it. To provide complete information to VRL expressions, you should also include the query string.

Suggested change

("name".into(), details.operation.name.clone().into()),

("type".into(), details.operation.kind.into()),

("name".into(), details.operation.name.clone().into()),

("type".into(), details.operation.kind.into()),

("query".into(), details.operation.query.into()),

lib/router-config/src/headers.rs

github-actions · 2025-09-26T08:58:54Z

✅ `k6-benchmark` results

     ✓ response code was 200
     ✓ no graphql errors
     ✓ valid response structure

     █ setup

     checks.........................: 100.00% ✓ 236454      ✗ 0    
     data_received..................: 6.9 GB  230 MB/s
     data_sent......................: 93 MB   3.1 MB/s
     http_req_blocked...............: avg=3.33µs   min=761ns   med=1.79µs  max=5.68ms   p(90)=2.54µs  p(95)=2.92µs  
     http_req_connecting............: avg=760ns    min=0s      med=0s      max=2.13ms   p(90)=0s      p(95)=0s      
     http_req_duration..............: avg=18.6ms   min=1.82ms  med=17.64ms max=230.36ms p(90)=25.69ms p(95)=28.82ms 
       { expected_response:true }...: avg=18.6ms   min=1.82ms  med=17.64ms max=230.36ms p(90)=25.69ms p(95)=28.82ms 
     http_req_failed................: 0.00%   ✓ 0           ✗ 78838
     http_req_receiving.............: avg=176.58µs min=23.14µs med=38.8µs  max=202.64ms p(90)=84.96µs p(95)=353.73µs
     http_req_sending...............: avg=24.32µs  min=5.54µs  med=10.42µs max=27.49ms  p(90)=16.23µs p(95)=28.46µs 
     http_req_tls_handshaking.......: avg=0s       min=0s      med=0s      max=0s       p(90)=0s      p(95)=0s      
     http_req_waiting...............: avg=18.4ms   min=1.77ms  med=17.52ms max=53.42ms  p(90)=25.45ms p(95)=28.52ms 
     http_reqs......................: 78838   2623.249367/s
     iteration_duration.............: avg=19.02ms  min=4.47ms  med=18.01ms max=289.6ms  p(90)=26.14ms p(95)=29.35ms 
     iterations.....................: 78818   2622.583888/s
     vus............................: 50      min=50        max=50 
     vus_max........................: 50      min=50        max=50

github-actions · 2025-09-26T09:02:07Z

🐋 This PR was built and pushed to the following Docker images:

Image Names: ghcr.io/graphql-hive/router

Platforms: linux/amd64,linux/arm64

Image Tags: ghcr.io/graphql-hive/router:pr-453 ghcr.io/graphql-hive/router:sha-c4f5781

Docker metadata

{
"buildx.build.ref": "builder-0c067d5b-9522-4ce7-86e0-d544eda133f6/builder-0c067d5b-9522-4ce7-86e0-d544eda133f60/hyfuq2izgtns03hdq9r125f8f",
"containerimage.descriptor": {
  "mediaType": "application/vnd.oci.image.index.v1+json",
  "digest": "sha256:31f171af6f5692ac0e1c767eb0a9c8e2501a0185f8793875b219e237ccbae86c",
  "size": 1609
},
"containerimage.digest": "sha256:31f171af6f5692ac0e1c767eb0a9c8e2501a0185f8793875b219e237ccbae86c",
"image.name": "ghcr.io/graphql-hive/router:pr-453,ghcr.io/graphql-hive/router:sha-c4f5781"
}

To hold the VRL functions. This should improve performance.

kamilkisiela · 2025-09-26T10:07:54Z

/gemini review

gemini-code-assist

Code Review

This pull request introduces a significant new feature allowing the use of VRL expressions for dynamic header generation. The implementation is extensive, touching on configuration, compilation, and execution logic. A major part of the change is also a commendable refactoring of error handling to use Result propagation throughout the execution plan, which greatly improves robustness. My review focuses on a few areas for improvement: completing a TODO to pass the full query context to expressions, enhancing the VRL value conversion to handle complex types, and adding the necessary documentation for this powerful new feature.

bin/router/src/pipeline/execution.rs

lib/executor/src/headers/expression.rs

lib/router-config/src/headers.rs

kamilkisiela added 2 commits September 25, 2025 15:51

init

829dbd1

Refactor

9019cbe

gemini-code-assist bot reviewed Sep 26, 2025

View reviewed changes

kamilkisiela added 2 commits September 26, 2025 11:43

Introduce a compiler context

d2eec62

To hold the VRL functions. This should improve performance.

refactor

aef0ea0

gemini-code-assist bot reviewed Sep 26, 2025

View reviewed changes

bin/router/src/pipeline/execution.rs Outdated Show resolved Hide resolved

lib/executor/src/headers/expression.rs Show resolved Hide resolved

lib/router-config/src/headers.rs Outdated Show resolved Hide resolved

kamilkisiela added 4 commits September 26, 2025 12:24

Warn about unsupported conversions

14d299d

pass query

f664c06

use query in vrl value

c2b550a

descr

5ea8c3f

kamilkisiela merged commit ff48667 into kamil-header-prop Sep 26, 2025
16 checks passed

kamilkisiela deleted the kamil-header-prop-expr branch September 26, 2025 10:51

kamilkisiela added a commit that referenced this pull request Sep 26, 2025

Adds expressions to headers propagation (#453)

dd08cbb

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

Adds expressions to headers propagation #453

Adds expressions to headers propagation #453

Uh oh!

kamilkisiela commented Sep 26, 2025

Uh oh!

gemini-code-assist bot commented Sep 26, 2025

Uh oh!

gemini-code-assist bot left a comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

gemini-code-assist bot Sep 26, 2025

Uh oh!

Uh oh!

github-actions bot commented Sep 26, 2025 •

edited

Loading

Uh oh!

github-actions bot commented Sep 26, 2025 •

edited

Loading

Uh oh!

kamilkisiela commented Sep 26, 2025

Uh oh!

gemini-code-assist bot left a comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

		("name".into(), details.operation.name.clone().into()),
		("type".into(), details.operation.kind.into()),

Adds expressions to headers propagation #453

Adds expressions to headers propagation #453

Uh oh!

Conversation

kamilkisiela commented Sep 26, 2025

Uh oh!

gemini-code-assist bot commented Sep 26, 2025

Summary of Changes

Highlights

Footnotes

Uh oh!

gemini-code-assist bot left a comment

Choose a reason for hiding this comment

Code Review

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

gemini-code-assist bot Sep 26, 2025

Choose a reason for hiding this comment

Uh oh!

Uh oh!

github-actions bot commented Sep 26, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

✅ k6-benchmark results

Uh oh!

github-actions bot commented Sep 26, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

kamilkisiela commented Sep 26, 2025

Uh oh!

gemini-code-assist bot left a comment

Choose a reason for hiding this comment

Code Review

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

github-actions bot commented Sep 26, 2025 •

edited

Loading

✅ `k6-benchmark` results

github-actions bot commented Sep 26, 2025 •

edited

Loading