[TT-11997] Backend logic for request_headers_rewrite

[buraksezer]

User description

See https://tyktech.atlassian.net/browse/TT-11997 for details of the request headers rewrite rules.

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PR Type

Enhancement, Tests

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Description

• Added tests for request headers rewrite rules in GraphQL middleware.
• Integrated request headers rewrite logic into the reverse proxy handler.
• Added RequestHeadersRewrite to ReverseProxyParams struct.
• Passed RequestHeadersRewrite to the GraphQL engine transport for both v1 and v2.
• Implemented logic to apply request headers rewrite rules in the GraphQL engine transport, covering three different rewrite scenarios.

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Changes walkthrough 📝

	Relevant files
Tests	mw_graphql_test.go Add tests for request headers rewrite rules in GraphQL middleware. gateway/mw_graphql_test.go Added tests for request headers rewrite rules. Implemented three test cases for different rewrite scenarios. +137/-0
Enhancement	reverse_proxy.go Integrate request headers rewrite logic in reverse proxy handler. gateway/reverse_proxy.go Integrated request headers rewrite logic into the reverse proxy handler. +8/-7      engine.go Add RequestHeadersRewrite to ReverseProxyParams struct.    internal/graphengine/engine.go Added RequestHeadersRewrite to ReverseProxyParams struct. +8/-7      graphql_go_tools_v1.go Pass RequestHeadersRewrite to GraphQL engine transport (v1). internal/graphengine/graphql_go_tools_v1.go Passed RequestHeadersRewrite to the GraphQL engine transport. +1/-0      graphql_go_tools_v2.go Pass RequestHeadersRewrite to GraphQL engine transport (v2). internal/graphengine/graphql_go_tools_v2.go Passed RequestHeadersRewrite to the GraphQL engine transport. +1/-0      transport.go Implement request headers rewrite logic in GraphQL engine transport. internal/graphengine/transport.go Added logic to apply request headers rewrite rules in the GraphQL engine transport. Implemented three rewrite rules for request headers. +96/-1

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[github-actions]

API Changes

no api changes detected

[github-actions]

PR Description updated to latest commit (46b54fa)

[github-actions]

PR Review 🔍

⏱️ Estimated effort to review [1-5]	3, because the PR involves multiple files and integrates new functionality across different components of the system. The complexity of the changes, especially around header rewriting logic, requires careful review to ensure correctness and efficiency.
🧪 Relevant tests	Yes
⚡ Possible issues	Possible Bug: The header rewrite logic in GraphQLEngineTransport might not correctly handle cases where headers are supposed to be removed or added based on complex conditions. The current implementation could lead to unintended header manipulations.
🔒 Security concerns	No

Code feedback:

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relevant file	gateway/mw_graphql_test.go
suggestion	Consider adding more comprehensive test cases to cover scenarios where multiple headers are manipulated simultaneously, ensuring that the rewrite rules do not interfere with each other. [important]
relevant line	_, _ = g.Run(t, []test.TestCase{

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relevant file	internal/graphengine/transport.go
suggestion	Refactor the applyRequestHeadersRewriteRules function to separate the concerns of checking and applying rewrite rules into distinct methods. This will improve readability and maintainability of the code. [important]
relevant line	func (g *GraphQLEngineTransport) applyRequestHeadersRewriteRules(r *http.Request) {

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relevant file	internal/graphengine/transport.go
suggestion	Implement unit tests specifically for the applyRequestHeadersRewriteRules function to ensure each rewrite rule behaves as expected under various scenarios. [important]
relevant line	func (g *GraphQLEngineTransport) applyRequestHeadersRewriteRules(r *http.Request) {

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relevant file	internal/graphengine/transport.go
suggestion	Optimize the header rewrite logic to avoid unnecessary deletions and re-sets of headers which could lead to performance issues in high-load environments. Consider checking if the header actually needs changing before modifying it. [medium]
relevant line	r.Header.Del(key)

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[github-actions]

PR Code Suggestions ✨

Category	Suggestion	Score
Enhancement	Add a test case to verify header addition when the header is not present but defined in the rewrite rules with Remove set to false Consider adding a test case to verify the behavior when the header key is not present in the request but is defined in the RequestHeadersRewrite with Remove set to false. This will ensure that the header is added as expected. gateway/mw_graphql_test.go [646-663] _, _ = g.Run(t, []test.TestCase{ { Data: request, Method: http.MethodPost, Headers: map[string]string{ "X-Tyk-Key": "tyk-value", "X-Other-Key": "other-value", - "X-Tyk-Test": "value-from-consumer", }, Code: http.StatusOK, BodyMatch: `{"data":{"hello":"World","httpMethod":"POST"}}`, HeadersMatch: map[string]string{ "X-Tyk-Key": "tyk-value", "X-Other-Key": "other-value", "X-Tyk-Test": "value-from-rewrite-config", }, }, }...) Suggestion importance[1-10]: 8 Why: The suggestion is valid and enhances the test coverage by ensuring that the header is added when it is defined in the rewrite rules with Remove set to false. This is a crucial test case to verify the correct behavior of the header rewrite functionality.	8

[sonarcloud]

Quality Gate failed

Failed conditions
16.4% Coverage on New Code (required ≥ 80%)
C Reliability Rating on New Code (required ≥ A)

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