fix: add back NewServer

[SkArchon]

This PR adds back the NewServer function as it is needed by our AWS Lambda provider, additionally it could be used by external consumers.

Summary by CodeRabbit

• Tests

  • Added integration tests validating server lifecycle: startup without a listener, health/ready checks, proper shutdown behavior and request failure after shutdown.

• New Features

  • Added a new server initialization flow with improved bootstrap, observability (tracing/metrics) and config handling to support static and dynamic startup scenarios.

Checklist

• I have discussed my proposed changes in an issue and have received approval to proceed.
• I have followed the coding standards of the project.
• Tests or benchmarks have been added or updated.
• Documentation has been updated on https://github.com/wundergraph/cosmo-docs.
• I have read the Contributors Guide.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 47fccb5 and 745fe1c.

📒 Files selected for processing (1)

• router-tests/lifecycle/new_server_test.go

🚧 Files skipped from review as they are similar to previous changes (1)

• router-tests/lifecycle/new_server_test.go

---

Walkthrough

Adds Router.NewServer(ctx) to bootstrap and return a runnable server, enhances test utilities to allow client-aware GraphQL requests, and introduces integration tests that exercise server lifecycle, health endpoint, and shutdown behavior using a mocked subgraph.

Changes

Cohort / File(s)	Summary
New Server Lifecycle Tests router-tests/lifecycle/new_server_test.go	New integration test file that starts an in-memory router, queries a mocked Employees subgraph, verifies /health/ready returns 200, and asserts requests fail after shutdown.
Test environment helpers router-tests/testenv/testenv.go	Exposed GqlURL, added MakeGraphQLRequestRawFromClient(request *http.Request, routerClient *http.Client) and refactored MakeGraphQLRequestRaw to call the new helper to allow explicit HTTP client usage.
Router initialization & bootstrap router/core/router.go	Added exported Router.NewServer(ctx) (Server, error) to initialize bootstrap, health/config state, observability (tracing/metrics), control-plane registration logic, and to start the HTTP server with static or polled initial config flows. Also added a bootstrap guard to prevent double-bootstrap.

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~45 minutes

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 12.50% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main change: reintroducing the NewServer method to the Router class.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

• 📝 Generate docstrings (stacked PR)
• 📝 Generate docstrings (commit on current branch)

---

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[github-actions]

Router image scan passed

✅ No security vulnerabilities found in image:

ghcr.io/wundergraph/cosmo/router:sha-b5ab7920b05a61e9c6c3b2b4b77d2817c5114cf2

[codecov]

Codecov Report

❌ Patch coverage is 60.60606% with 13 lines in your changes missing coverage. Please review.
✅ Project coverage is 62.32%. Comparing base (c8a6a5d) to head (745fe1c).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
router/core/router.go	60.60%	11 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2546      +/-   ##
==========================================
+ Coverage   61.69%   62.32%   +0.62%     
==========================================
  Files         239      239              
  Lines       25423    25456      +33     
==========================================
+ Hits        15685    15865     +180     
+ Misses       8418     8241     -177     
- Partials     1320     1350      +30     

Files with missing lines	Coverage Δ
router/core/router.go	68.48% <60.60%> (-0.90%)	⬇️

... and 27 files with indirect coverage changes

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[coderabbitai]

Actionable comments posted: 1

🧹 Nitpick comments (1)

router/core/router.go (1)

731-787: Consider mirroring usage-tracking calls from Start().

NewServer configures usage tracking but doesn’t call trackRouterConfigUsage / trackExecutionConfigUsage, so usage telemetry is skipped when this path is used. If that’s unintentional, consider invoking those once the config (static or polled) is available.

💡 Possible alignment (illustrative)

 if r.staticExecutionConfig != nil {
+    r.trackRouterConfigUsage()
+    r.trackExecutionConfigUsage(r.staticExecutionConfig, true)
     r.logger.Info("Static execution config provided. Polling is disabled. Updating execution config is only possible by providing a config.")
     return r.httpServer, r.newServer(ctx, r.staticExecutionConfig)
 }
 ...
 cfg, err := r.configPoller.GetRouterConfig(ctx)
 if err != nil {
     return nil, fmt.Errorf("failed to get initial execution config: %w", err)
 }
+ r.trackRouterConfigUsage()
+ r.trackExecutionConfigUsage(cfg.Config, false)

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@router/core/router.go` around lines 731 - 787, NewServer configures usage
tracking but never emits telemetry because it doesn't call
trackRouterConfigUsage and trackExecutionConfigUsage; update NewServer to invoke
r.trackRouterConfigUsage(...) and r.trackExecutionConfigUsage(...) once a config
is available: for the static path call them before returning after
r.newServer(ctx, r.staticExecutionConfig), and for the polled path call them
after retrieving cfg (and/or after successfully applying it via r.newServer(ctx,
cfg.Config)). Place these calls near the existing
r.reloadPersistentState.UpdateReloadPersistentState(&r.Config) / right after
successful r.newServer(...) so telemetry is recorded on both code paths.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@router-tests/lifecycle/new_server_test.go`:
- Around line 24-110: The subtest for shutdown only closes the httptest.Server
and never invokes the router/server shutdown, so update the "new server shutdown
prevents further requests" subtest to call rr.Shutdown (or the server shutdown
method) before asserting requests fail: after verifying the server works, call
rr.Shutdown(ctx) (or svr.Shutdown(ctx) if present) with a short timeout context,
then attempt the POST to ts.URL+"/graphql" and assert it errors; ensure you
still close ts (httptest.Server) and cancel the context to clean up.

---

Nitpick comments:
In `@router/core/router.go`:
- Around line 731-787: NewServer configures usage tracking but never emits
telemetry because it doesn't call trackRouterConfigUsage and
trackExecutionConfigUsage; update NewServer to invoke
r.trackRouterConfigUsage(...) and r.trackExecutionConfigUsage(...) once a config
is available: for the static path call them before returning after
r.newServer(ctx, r.staticExecutionConfig), and for the polled path call them
after retrieving cfg (and/or after successfully applying it via r.newServer(ctx,
cfg.Config)). Place these calls near the existing
r.reloadPersistentState.UpdateReloadPersistentState(&r.Config) / right after
successful r.newServer(...) so telemetry is recorded on both code paths.

---

ℹ️ Review info

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between d69be79 and 47fccb5.

📒 Files selected for processing (3)

• router-tests/lifecycle/new_server_test.go
• router-tests/testenv/testenv.go
• router/core/router.go

[StarpTech]

LGTM