feat: router Prometheus /metrics endpoint (JEP-0013 Phase 2) - #933
Open
RoddieKieley wants to merge 3 commits into
Open
feat: router Prometheus /metrics endpoint (JEP-0013 Phase 2)#933RoddieKieley wants to merge 3 commits into
RoddieKieley wants to merge 3 commits into
Conversation
- Add HTTP `GET /metrics` on the Jumpstarter router (Prometheus/OpenMetrics text) via `--metrics-bind-address` (or equivalent). - Operator wires Router Deployment metrics bind address and container port. - Tests assert `/metrics` returns 200 and parseable exposition; no undocumented `jumpstarter_*` router series invented in this PR.
Contributor
📝 WalkthroughWalkthroughThe router now supports an optional Prometheus metrics endpoint. The deployment binds it to port ChangesRouter metrics
Estimated code review effort: 3 (Moderate) | ~20 minutes Sequence Diagram(s)sequenceDiagram
participant RouterDeployment
participant RouterMain
participant MetricsServer
participant PrometheusClient
RouterDeployment->>RouterMain: pass -metrics-bind-address=:8080
RouterMain->>MetricsServer: start metrics server
MetricsServer-->>RouterMain: bound :8080
PrometheusClient->>MetricsServer: GET /metrics
MetricsServer-->>PrometheusClient: Prometheus exposition text
RouterMain->>MetricsServer: graceful shutdown on termination
Possibly related PRs
Suggested reviewers: Poem
🚥 Pre-merge checks | ✅ 5✅ Passed checks (5 passed)
✨ Finishing Touches🧪 Generate unit tests (beta)
Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out. Comment |
![coderabbitai[bot]](https://avatars.githubusercontent.com/in/347564?s=60&v=4){kind=small}
Contributor
There was a problem hiding this comment.
Actionable comments posted: 3
🧹 Nitpick comments (1)
controller/Makefile (1)
116-125: 📐 Maintainability & Code Quality | 🔵 TrivialRun the repository-required validation.
Run:
make pkg-test-router make pkg-test-operator make pkg-ty-router make pkg-ty-operator make test make lint-fixAs per coding guidelines: package tests/type checks, the complete suite, and
make lint-fixare required for repository changes.🤖 Prompt for AI Agents
Verify each finding against current code. Fix only still-valid issues, skip the rest with a brief reason, keep changes minimal, and validate. In `@controller/Makefile` around lines 116 - 125, Run the repository-required validation targets: pkg-test-router, pkg-test-operator, pkg-ty-router, pkg-ty-operator, test, and lint-fix. Address any failures and leave the changes passing all listed checks.Source: Coding guidelines
🤖 Prompt for all review comments with AI agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
Inline comments:
In `@controller/cmd/router/metrics_test.go`:
- Around line 58-65: The metrics test should validate the response as Prometheus
exposition rather than checking for metric-name substrings. Update the test
around the body read and existing strings.Contains assertion to parse text with
the project’s Prometheus exposition parser and fail the test when parsing
returns an error.
In `@controller/cmd/router/metrics.go`:
- Around line 40-45: Configure explicit ReadHeaderTimeout, ReadTimeout,
WriteTimeout, and IdleTimeout values on the http.Server created in the metrics
server setup before calling srv.Serve(ln), ensuring slow requests and idle
connections are bounded.
In
`@controller/deploy/operator/internal/controller/jumpstarter/router_metrics_bind_test.go`:
- Around line 27-44: The TestRouterDeploymentMetricsBind test should use the
operator’s existing envtest-based suite instead of directly invoking
JumpstarterReconciler.createRouterDeployment. Move the assertion there, or
create the Jumpstarter resource through the fake Kubernetes API and validate the
resulting Deployment through the client.
---
Nitpick comments:
In `@controller/Makefile`:
- Around line 116-125: Run the repository-required validation targets:
pkg-test-router, pkg-test-operator, pkg-ty-router, pkg-ty-operator, test, and
lint-fix. Address any failures and leave the changes passing all listed checks.
🪄 Autofix (Beta)
Fix all unresolved CodeRabbit comments on this PR:
- Push a commit to this branch (recommended)
- Create a new PR with the fixes
ℹ️ Review info
⚙️ Run configuration
Configuration used: Organization UI
Review profile: CHILL
Plan: Pro Plus
Run ID: 45597983-e224-4fdc-8003-fe0dac4c48d8
📒 Files selected for processing (7)
controller/Containerfilecontroller/Makefilecontroller/cmd/router/main.gocontroller/cmd/router/metrics.gocontroller/cmd/router/metrics_test.gocontroller/deploy/operator/internal/controller/jumpstarter/jumpstarter_controller.gocontroller/deploy/operator/internal/controller/jumpstarter/router_metrics_bind_test.go
Comment on lines
+27
to
+44
| // Stdlib unit test (no envtest): asserts Router Deployment metrics bind for JEP-0013 Phase 2. | ||
| func TestRouterDeploymentMetricsBind(t *testing.T) { | ||
| r := &JumpstarterReconciler{} | ||
| js := &operatorv1alpha1.Jumpstarter{ | ||
| ObjectMeta: metav1.ObjectMeta{ | ||
| Name: "jumpstarter", | ||
| Namespace: "jumpstarter-lab", | ||
| }, | ||
| Spec: operatorv1alpha1.JumpstarterSpec{ | ||
| Routers: operatorv1alpha1.RoutersConfig{ | ||
| Image: "example.com/router:test", | ||
| ImagePullPolicy: corev1.PullIfNotPresent, | ||
| Replicas: 1, | ||
| }, | ||
| }, | ||
| } | ||
|
|
||
| dep := r.createRouterDeployment(js, 0) |
Contributor
There was a problem hiding this comment.
📐 Maintainability & Code Quality | 🟠 Major | ⚡ Quick win
🧩 Analysis chain
🏁 Script executed:
#!/bin/bash
set -euo pipefail
echo "== candidate files =="
fd -a '_test\.go$' controller/deploy/operator/internal/controller 2>/dev/null | sed 's#^\./##' | head -200 || true
echo "== target file excerpt =="
target='controller/deploy/operator/internal/controller/jumpstarter/router_metrics_bind_test.go'
if [ -f "$target" ]; then
wc -l "$target"
sed -n '1,140p' "$target"
else
echo "target missing"
fi
echo "== package declarations in target dir tests =="
rg -n "^(package|func Test|var Environment|NewTestEnvironment|Setup|Suite)" controller/deploy/operator/internal/controller -g '*_test.go' | head -200
echo "== helper/envtest related references =="
rg -n "envtest|NewTestEnvironment|Setup|fake|Fake|clientset|NewClient|JumpstarterReconciler|Reconcile\\(" controller/deploy/operator -g '*_test.go' | head -300Repository: jumpstarter-dev/jumpstarter
Length of output: 14214
Use envtest for this operator test.
This file is under controller/deploy/operator/internal/controller/jumpstarter, and the test directly constructs JumpstarterReconciler objects and calls createRouterDeployment. Move the assertion into the existing envtest-based suite or exercise creation through the fake Kubernetes API instead.
🤖 Prompt for AI Agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
In
`@controller/deploy/operator/internal/controller/jumpstarter/router_metrics_bind_test.go`
around lines 27 - 44, The TestRouterDeploymentMetricsBind test should use the
operator’s existing envtest-based suite instead of directly invoking
JumpstarterReconciler.createRouterDeployment. Move the assertion there, or
create the Jumpstarter resource through the fake Kubernetes API and validate the
resulting Deployment through the client.
Source: Coding guidelines
raballew
requested changes
Jul 31, 2026
Comment on lines
+30
to
+49
| func startMetricsServer(addr string) (string, error) { | ||
| if addr == "" || addr == "0" { | ||
| return "", nil | ||
| } | ||
|
|
||
| ln, err := net.Listen("tcp", addr) | ||
| if err != nil { | ||
| return "", err | ||
| } | ||
|
|
||
| mux := http.NewServeMux() | ||
| mux.Handle("/metrics", promhttp.Handler()) | ||
|
|
||
| srv := &http.Server{Handler: mux} | ||
| go func() { | ||
| _ = srv.Serve(ln) | ||
| }() | ||
|
|
||
| return ln.Addr().String(), nil | ||
| } |
Member
There was a problem hiding this comment.
startMetricsServer returns only (string, error) but creates an http.Server and launches srv.Serve(ln) in a detached goroutine. The caller has no way to call srv.Shutdown(ctx) on SIGINT/SIGTERM, so the server never gets a graceful shutdown.
Comment on lines
+44
to
+46
| go func() { | ||
| _ = srv.Serve(ln) | ||
| }() |
Member
There was a problem hiding this comment.
go func() {
if err := srv.Serve(ln); err != nil && err != http.ErrServerClosed {
ctrl.Log.WithName("metrics").Error(err, "metrics server stopped unexpectedly")
}
}()| mux := http.NewServeMux() | ||
| mux.Handle("/metrics", promhttp.Handler()) | ||
|
|
||
| srv := &http.Server{Handler: mux} |
Member
There was a problem hiding this comment.
Set at least ReadHeaderTimeout and IdleTimeout:
srv := &http.Server{
Handler: mux,
ReadHeaderTimeout: 10 * time.Second,
IdleTimeout: 60 * time.Second,
}
Member
There was a problem hiding this comment.
The idle timeout may need to be higher, i.e. it really depends on prometheus doing keepalive & the periodicity of checks, I'd give it 5 minutes perhaps.
| } | ||
| text := string(body) | ||
| // Default Go process metrics should appear; do not require undocumented jumpstarter_* series. | ||
| if !strings.Contains(text, "go_") && !strings.Contains(text, "process_") && !strings.Contains(text, "promhttp_") { |
Member
There was a problem hiding this comment.
If go_* metrics were removed but promhttp_* remained, the test would still pass. Assert each required family independently.
Bound router metrics HTTP server timeouts, parse /metrics with a Prometheus exposition parser in tests, and fold the router metrics-bind assertion into a Ginkgo Describe consistent with sibling operator unit tests. Co-authored-by: Cursor <cursoragent@cursor.com>
Contributor
There was a problem hiding this comment.
Actionable comments posted: 1
🤖 Prompt for all review comments with AI agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
Inline comments:
In `@controller/cmd/router/metrics_test.go`:
- Around line 76-91: Update the metrics test around the families iteration and
assertions to explicitly reject any jumpstarter_* metric family, while
preserving the existing required go_* and process_* checks. Add a negative
assertion that fails with the discovered family names if a jumpstarter_* prefix
is present.
🪄 Autofix
Fix all unresolved CodeRabbit comments on this PR:
- Push a commit to this branch (recommended)
- Create a new PR with the fixes
ℹ️ Review info
⚙️ Run configuration
Configuration used: Organization UI
Review profile: CHILL
Plan: Pro Plus
Run ID: 004a2560-f5a9-4b70-af53-5e08741a9d8a
📒 Files selected for processing (3)
controller/cmd/router/metrics.gocontroller/cmd/router/metrics_test.gocontroller/deploy/operator/internal/controller/jumpstarter/router_metrics_bind_test.go
🚧 Files skipped from review as they are similar to previous changes (1)
- controller/cmd/router/metrics.go
Comment on lines
+76
to
+91
| // Default Go process metrics should appear; do not require undocumented jumpstarter_* series. | ||
| hasGo, hasProcess := false, false | ||
| for name := range families { | ||
| switch { | ||
| case strings.HasPrefix(name, "go_"): | ||
| hasGo = true | ||
| case strings.HasPrefix(name, "process_"): | ||
| hasProcess = true | ||
| } | ||
| } | ||
| if !hasGo { | ||
| t.Fatalf("expected go_* metric family, got families: %v", familyNames(families)) | ||
| } | ||
| if !hasProcess { | ||
| t.Fatalf("expected process_* metric family, got families: %v", familyNames(families)) | ||
| } |
Contributor
There was a problem hiding this comment.
🎯 Functional Correctness | 🟡 Minor | ⚡ Quick win
Enforce the no-jumpstarter_* metric contract.
The test requires go_* and process_* families, but it allows any jumpstarter_* family. The PR objective requires no undocumented jumpstarter_* router metrics. Add a negative assertion or an explicit allowlist.
Proposed assertion
for name := range families {
+ if strings.HasPrefix(name, "jumpstarter_") {
+ t.Fatalf("unexpected undocumented metric family %q", name)
+ }
switch {📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
Suggested change
| // Default Go process metrics should appear; do not require undocumented jumpstarter_* series. | |
| hasGo, hasProcess := false, false | |
| for name := range families { | |
| switch { | |
| case strings.HasPrefix(name, "go_"): | |
| hasGo = true | |
| case strings.HasPrefix(name, "process_"): | |
| hasProcess = true | |
| } | |
| } | |
| if !hasGo { | |
| t.Fatalf("expected go_* metric family, got families: %v", familyNames(families)) | |
| } | |
| if !hasProcess { | |
| t.Fatalf("expected process_* metric family, got families: %v", familyNames(families)) | |
| } | |
| // Default Go process metrics should appear; do not require undocumented jumpstarter_* series. | |
| hasGo, hasProcess := false, false | |
| for name := range families { | |
| if strings.HasPrefix(name, "jumpstarter_") { | |
| t.Fatalf("unexpected undocumented metric family %q", name) | |
| } | |
| switch { | |
| case strings.HasPrefix(name, "go_"): | |
| hasGo = true | |
| case strings.HasPrefix(name, "process_"): | |
| hasProcess = true | |
| } | |
| } | |
| if !hasGo { | |
| t.Fatalf("expected go_* metric family, got families: %v", familyNames(families)) | |
| } | |
| if !hasProcess { | |
| t.Fatalf("expected process_* metric family, got families: %v", familyNames(families)) | |
| } |
🤖 Prompt for AI Agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
In `@controller/cmd/router/metrics_test.go` around lines 76 - 91, Update the
metrics test around the families iteration and assertions to explicitly reject
any jumpstarter_* metric family, while preserving the existing required go_* and
process_* checks. Add a negative assertion that fails with the discovered family
names if a jumpstarter_* prefix is present.
Return a shutdown callback from the router metrics server and invoke it on SIGINT/SIGTERM, and log unexpected Serve errors. Timeouts and independent metric-family assertions were already covered by the CodeRabbit follow-up. Co-authored-by: Cursor <cursoragent@cursor.com>
Contributor
There was a problem hiding this comment.
🧹 Nitpick comments (1)
controller/cmd/router/metrics_test.go (1)
111-122: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick winTest the empty disabled address.
Line 112 tests
"0"only.startMetricsServeralso disables metrics when the address is"". Convert this to a table-driven test for both""and"0".🤖 Prompt for AI Agents
Verify each finding against current code. Fix only still-valid issues, skip the rest with a brief reason, keep changes minimal, and validate. In `@controller/cmd/router/metrics_test.go` around lines 111 - 122, Update TestMetricsServerDisabledWhenAddrZero to a table-driven test covering both "" and "0" as disabled addresses. Run startMetricsServer for each case and preserve the existing assertions that the returned address is empty and shutdown is nil.
🤖 Prompt for all review comments with AI agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
Nitpick comments:
In `@controller/cmd/router/metrics_test.go`:
- Around line 111-122: Update TestMetricsServerDisabledWhenAddrZero to a
table-driven test covering both "" and "0" as disabled addresses. Run
startMetricsServer for each case and preserve the existing assertions that the
returned address is empty and shutdown is nil.
ℹ️ Review info
⚙️ Run configuration
Configuration used: Organization UI
Review profile: CHILL
Plan: Pro Plus
Run ID: 030615c6-249e-48c2-9e4a-28f874360256
📒 Files selected for processing (3)
controller/cmd/router/main.gocontroller/cmd/router/metrics.gocontroller/cmd/router/metrics_test.go
🚧 Files skipped from review as they are similar to previous changes (1)
- controller/cmd/router/metrics.go
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
GET /metricson the Jumpstarter router (Prometheus/OpenMetrics text) via--metrics-bind-address(or equivalent)./metricsreturns 200 and parseable exposition; no undocumentedjumpstarter_*router series invented in this PR.