feat(auth): add support for internal service-to-service request handling in throttler

[Artuomka]

Summary by CodeRabbit

• Performance
  • Internal service-to-service requests are no longer subject to global rate limiting, improving communication reliability between backend services.
• Security
  • Requests authenticated through internal service credentials are identified and handled appropriately while external traffic remains protected by throttling.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: c0f6d8ab-2807-4156-8979-f76ed05292c1

📥 Commits

Reviewing files that changed from the base of the PR and between c24e6e7 and 7b08392.

📒 Files selected for processing (3)

• backend/src/app.module.ts
• backend/src/authorization/cognito-decoded.interface.ts
• backend/src/authorization/saas-auth.middleware.ts

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📝 Walkthrough

Walkthrough

The request interface and authentication middleware now mark authenticated microservice calls, while the global throttler skips requests carrying that marker.

Changes

Microservice throttling exemption

Layer / File(s)	Summary
Internal request flag and middleware marking backend/src/authorization/cognito-decoded.interface.ts, backend/src/authorization/saas-auth.middleware.ts	Adds the optional isMicroserviceRequest request property and sets it during microservice-JWT authentication.
Global throttler exemption backend/src/app.module.ts	Adds a typed skipIf callback that bypasses throttling for marked microservice requests.

Estimated code review effort: 2 (Simple) | ~10 minutes

Sequence Diagram(s)

sequenceDiagram
  participant Client
  participant SaaSAuthMiddleware
  participant ThrottlerModule
  Client->>SaaSAuthMiddleware: Send authenticated microservice request
  SaaSAuthMiddleware->>SaaSAuthMiddleware: Set isMicroserviceRequest = true
  SaaSAuthMiddleware->>ThrottlerModule: Pass request
  ThrottlerModule->>ThrottlerModule: Skip rate limiting

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Suggested reviewers: copilot

Poem

A rabbit hops through service lanes,
With flags instead of throttling chains.
The middleware marks the way,
The limiter skips without delay.
Internal calls go on their run—
A carrot cheers: the flow is done! 🐇

🚥 Pre-merge checks | ✅ 6

✅ Passed checks (6 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: exempting internal service-to-service requests from throttling.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Security Check	✅ Passed	PASS: the throttle bypass is only set after successful microservice JWT verification, and no user-controlled path writes the flag.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch backend_improvements

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[Copilot]

Pull request overview

Adds a mechanism to identify internal service-to-service HTTP requests (authenticated via the microservice JWT) and exempts them from global rate limiting to avoid unintended collective throttling when traffic originates from shared satellite IPs.

Changes:

• Flags microservice-JWT-authenticated requests in SaaSAuthMiddleware via req.isMicroserviceRequest.
• Extends the request typing (IRequestWithCognitoInfo) to include the new flag with documentation.
• Configures the global Nest throttler to skipIf the request is marked as an internal microservice call.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
backend/src/authorization/saas-auth.middleware.ts	Marks microservice-authenticated requests as internal so throttling logic can treat them differently.
backend/src/authorization/cognito-decoded.interface.ts	Extends the request interface with isMicroserviceRequest and documents its purpose.
backend/src/app.module.ts	Adds a global throttler skipIf based on the new request flag.

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