Files
mc-proxy/internal/metrics/metrics_test.go
Kyle Isom ffc31f7d55 Add Prometheus metrics for connections, firewall, L7, and bytes transferred
Instrument mc-proxy with prometheus/client_golang. New internal/metrics/
package defines counters, gauges, and histograms for connection totals,
active connections, firewall blocks by reason, backend dial latency,
bytes transferred, L7 HTTP status codes, and L7 policy blocks. Optional
[metrics] config section starts a scrape endpoint. Firewall gains
BlockedWithReason() to report block cause. L7 handler wraps
ResponseWriter to record status codes per hostname.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-03-25 18:05:25 -07:00

122 lines
3.2 KiB
Go

package metrics
import (
"context"
"io"
"net"
"net/http"
"strings"
"testing"
"time"
)
func TestListenAndServeShutdown(t *testing.T) {
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
errCh := make(chan error, 1)
go func() {
errCh <- ListenAndServe(ctx, "127.0.0.1:0", "/metrics")
}()
time.Sleep(50 * time.Millisecond)
cancel()
select {
case err := <-errCh:
if err != nil {
t.Fatalf("ListenAndServe returned error: %v", err)
}
case <-time.After(2 * time.Second):
t.Fatal("ListenAndServe did not return after context cancel")
}
}
func TestMetricsEndpoint(t *testing.T) {
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
ln, err := net.Listen("tcp", "127.0.0.1:0")
if err != nil {
t.Fatal(err)
}
addr := ln.Addr().String()
_ = ln.Close()
// Increment counters so they appear in output.
ConnectionsTotal.WithLabelValues("127.0.0.1:4430", "l4").Inc()
FirewallBlockedTotal.WithLabelValues("ip").Inc()
ConnectionsActive.WithLabelValues("127.0.0.1:4430").Set(1)
go func() { _ = ListenAndServe(ctx, addr, "/metrics") }()
time.Sleep(100 * time.Millisecond)
resp, err := http.Get("http://" + addr + "/metrics")
if err != nil {
t.Fatalf("GET /metrics: %v", err)
}
defer func() { _ = resp.Body.Close() }()
if resp.StatusCode != 200 {
t.Fatalf("status = %d, want 200", resp.StatusCode)
}
body, err := io.ReadAll(resp.Body)
if err != nil {
t.Fatalf("reading body: %v", err)
}
text := string(body)
for _, want := range []string{
"mcproxy_connections_total",
"mcproxy_firewall_blocked_total",
"mcproxy_connections_active",
} {
if !strings.Contains(text, want) {
t.Errorf("response missing %s", want)
}
}
}
func TestMetricsDefaultPath(t *testing.T) {
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
ln, err := net.Listen("tcp", "127.0.0.1:0")
if err != nil {
t.Fatal(err)
}
addr := ln.Addr().String()
_ = ln.Close()
go func() { _ = ListenAndServe(ctx, addr, "") }()
time.Sleep(100 * time.Millisecond)
resp, err := http.Get("http://" + addr + "/metrics")
if err != nil {
t.Fatalf("GET /metrics: %v", err)
}
defer func() { _ = resp.Body.Close() }()
if resp.StatusCode != 200 {
t.Fatalf("status = %d, want 200", resp.StatusCode)
}
}
func TestMetricsSanity(t *testing.T) {
// Verify all metric vars can be used without panicking.
ConnectionsTotal.WithLabelValues("test:443", "l4").Inc()
ConnectionsActive.WithLabelValues("test:443").Set(5)
FirewallBlockedTotal.WithLabelValues("ip").Inc()
FirewallBlockedTotal.WithLabelValues("cidr").Inc()
FirewallBlockedTotal.WithLabelValues("country").Inc()
FirewallBlockedTotal.WithLabelValues("rate_limit").Inc()
BackendDialDuration.WithLabelValues("127.0.0.1:8080").Observe(0.005)
TransferredBytesTotal.WithLabelValues("client_to_backend", "example.com").Add(1024)
TransferredBytesTotal.WithLabelValues("backend_to_client", "example.com").Add(2048)
L7ResponsesTotal.WithLabelValues("example.com", "200").Inc()
L7ResponsesTotal.WithLabelValues("example.com", "502").Inc()
L7PolicyBlocksTotal.WithLabelValues("example.com", "block_user_agent").Inc()
L7PolicyBlocksTotal.WithLabelValues("example.com", "require_header").Inc()
}