feat: implement additional checks functionality

cf #61

Signed-off-by: Clément Nussbaumer <[email protected]>

internal/kubenurse/server.go

@@ -176,6 +176,19 @@ func New(c client.Client) (*Server, error) { //nolint:funlen // TODO: use a flag
 
 	chk.UseTLS = server.useTLS
 
+	// Extra checks parsing
+	if extraChecks := os.Getenv("KUBENURSE_EXTRA_CHECKS"); extraChecks != "" {
+		for _, extraCheck := range strings.Split(extraChecks, "|") {
+			requestType, url, fnd := strings.Cut(extraCheck, ":")
+			if !fnd {
+				slog.Error("couldn't parse one of extraChecks", "extraCheck", extraCheck)
+				return nil, fmt.Errorf("extra checks parsing - missing colon ':' between metric name and url")
+			}
+
+			chk.ExtraChecks[requestType] = url
+		}
+	}
+
 	server.checker = chk
 
 	// setup http routes

internal/kubenurse/server_test.go

@@ -2,6 +2,7 @@ package kubenurse
 
 import (
 	"context"
+	"os"
 	"testing"
 	"time"
 
@@ -12,16 +13,22 @@ import (
 func TestCombined(t *testing.T) {
 	r := require.New(t)
 
+	os.Setenv("KUBENURSE_EXTRA_CHECKS", "cloudy_endpoint:http://cloudy.enpdoint:1234/test|ep_number_two:http://interesting.endpoint:8080/abcd")
 	fakeClient := fake.NewFakeClient()
 	kubenurse, err := New(fakeClient)
 	r.NoError(err)
 	r.NotNil(kubenurse)
 
+	r.Equal(map[string]string{
+		"ep_number_two":   "http://interesting.endpoint:8080/abcd",
+		"cloudy_endpoint": "http://cloudy.enpdoint:1234/test",
+	}, kubenurse.checker.ExtraChecks)
+
 	t.Run("start/stop", func(t *testing.T) {
 		r := require.New(t)
 		errc := make(chan error, 1)
 
-		ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+		ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
 		go func() {
 			// blocks until shutdown is called
 			err := kubenurse.Run(ctx)

internal/servicecheck/servicecheck.go

@@ -63,6 +63,7 @@ func New(cl client.Client, promRegistry *prometheus.Registry,
 		client:             cl,
 		httpClient:         httpClient,
 		cacheTTL:           cacheTTL,
+		ExtraChecks:        make(map[string]string),
 	}, nil
 }
 
@@ -95,6 +96,14 @@ func (c *Checker) Run(ctx context.Context) {
 	go c.measure(ctx, &wg, &result, c.MeIngress, meIngress)
 	go c.measure(ctx, &wg, &result, c.MeService, meService)
 
+	wg.Add(len(c.ExtraChecks))
+
+	for metricName, url := range c.ExtraChecks {
+		go c.measure(ctx, &wg, &result,
+			func(ctx context.Context) string { return c.doRequest(ctx, url, false) },
+			metricName)
+	}
+
 	if c.SkipCheckNeighbourhood {
 		result.Store(NeighbourhoodState, skippedStr)
 		return

internal/servicecheck/servicecheck_test.go

@@ -37,6 +37,10 @@ func TestCombined(t *testing.T) {
 	fakeClient := fake.NewFakeClient(&fakeNeighbourPod)
 
 	checker, err := New(fakeClient, prometheus.NewRegistry(), false, 3*time.Second, prometheus.DefBuckets)
+	checker.ExtraChecks = map[string]string{
+		"check_number_two": "http://interesting.endpoint:8080/abcd",
+		"cloudy_check":     "http://cloudy.enpdoint:1234/test",
+	}
 	r.NoError(err)
 	r.NotNil(checker)
 
@@ -45,5 +49,6 @@ func TestCombined(t *testing.T) {
 		checker.Run(context.Background())
 
 		r.Equal(okStr, checker.LastCheckResult[NeighbourhoodState])
+		r.Equal(errStr, checker.LastCheckResult["cloudy_check"]) // test extra endpoint functionality
 	})
 }

internal/servicecheck/types.go

@@ -41,6 +41,9 @@ type Checker struct {
 	allowUnschedulable     bool
 	SkipCheckNeighbourhood bool
 
+	// Additional endpoints
+	ExtraChecks map[string]string
+
 	// TLS
 	UseTLS bool