Various improvements

cmd/deployment-tracker/main.go

@@ -3,6 +3,7 @@ package main
 import (
 	"context"
 	"flag"
+	"fmt"
 	"log"
 	"log/slog"
 	"net/http"
@@ -44,6 +45,13 @@ func main() {
 	flag.StringVar(&metricsPort, "metrics-port", "9090", "port to listen to for metrics")
 	flag.Parse()
 
+	// Validate worker count
+	if workers < 1 || workers > 100 {
+		slog.Error("Invalid worker count, must be between 1 and 100",
+			"workers", workers)
+		os.Exit(1)
+	}
+
 	// init logging
 	log.SetFlags(log.LstdFlags | log.Lshortfile | log.LUTC)
 	opts := slog.HandlerOptions{Level: slog.LevelInfo}
@@ -59,6 +67,13 @@ func main() {
 		Organization:        os.Getenv("GITHUB_ORG"),
 	}
 
+	if !controller.ValidTemplate(cntrlCfg.Template) {
+		slog.Error("Template must contain at least one placeholder",
+			"template", cntrlCfg.Template,
+			"valid_placeholders", []string{controller.TmplNS, controller.TmplDN, controller.TmplCN})
+		os.Exit(1)
+	}
+
 	if cntrlCfg.LogicalEnvironment == "" {
 		slog.Error("Logical environment is required")
 		os.Exit(1)
@@ -87,20 +102,20 @@ func main() {
 	}
 
 	// Start the metrics server
+	var promSrv = &http.Server{
+		Addr:              ":" + metricsPort,
+		ReadTimeout:       10 * time.Second,
+		WriteTimeout:      10 * time.Second,
+		ReadHeaderTimeout: 10 * time.Second,
+		IdleTimeout:       120 * time.Second,
+		Handler:           http.NewServeMux(),
+	}
+	promSrv.Handler.(*http.ServeMux).Handle("/metrics", promhttp.Handler())
+
 	go func() {
-		var mm = http.NewServeMux()
-		mm.Handle("/metrics", promhttp.Handler())
-
-		var promSrv = &http.Server{
-			Addr:              ":" + metricsPort,
-			ReadTimeout:       10 * time.Second,
-			WriteTimeout:      10 * time.Second,
-			ReadHeaderTimeout: 10 * time.Second,
-			Handler:           mm,
-		}
 		slog.Info("starting Prometheus metrics server",
 			"url", promSrv.Addr)
-		if err := promSrv.ListenAndServe(); err != nil {
+		if err := promSrv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
 			slog.Error("failed to start metrics server",
 				"error", err)
 		}
@@ -113,10 +128,24 @@ func main() {
 	go func() {
 		<-sigCh
 		slog.Info("Shutting down...")
+
+		// Gracefully shutdown the metrics server
+		shutdownCtx, shutdownCancel := context.WithTimeout(context.Background(), 5*time.Second)
+		defer shutdownCancel()
+		if err := promSrv.Shutdown(shutdownCtx); err != nil {
+			slog.Error("failed to shutdown metrics server gracefully",
+				"error", err)
+		}
+
 		cancel()
 	}()
 
-	cntrl := controller.New(clientset, namespace, &cntrlCfg)
+	cntrl, err := controller.New(clientset, namespace, &cntrlCfg)
+	if err != nil {
+		slog.Error("Failed to create controller",
+			"error", err)
+		os.Exit(1)
+	}
 
 	slog.Info("Starting deployment-tracker controller")
 	if err := cntrl.Run(ctx, workers); err != nil {
@@ -144,6 +173,9 @@ func createK8sConfig(kubeconfig string) (*rest.Config, error) {
 	}
 
 	// Fall back to default kubeconfig location
-	homeDir, _ := os.UserHomeDir()
+	homeDir, err := os.UserHomeDir()
+	if err != nil {
+		return nil, fmt.Errorf("failed to get user home directory: %w", err)
+	}
 	return clientcmd.BuildConfigFromFlags("", homeDir+"/.kube/config")
 }

go.mod

@@ -41,7 +41,7 @@ require (
 	golang.org/x/sys v0.38.0 // indirect
 	golang.org/x/term v0.37.0 // indirect
 	golang.org/x/text v0.31.0 // indirect
-	golang.org/x/time v0.9.0 // indirect
+	golang.org/x/time v0.14.0 // indirect
 	google.golang.org/protobuf v1.36.8 // indirect
 	gopkg.in/evanphx/json-patch.v4 v4.13.0 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect

go.sum

@@ -111,6 +111,8 @@ golang.org/x/text v0.31.0 h1:aC8ghyu4JhP8VojJ2lEHBnochRno1sgL6nEi9WGFGMM=
 golang.org/x/text v0.31.0/go.mod h1:tKRAlv61yKIjGGHX/4tP1LTbc13YSec1pxVEWXzfoeM=
 golang.org/x/time v0.9.0 h1:EsRrnYcQiGH+5FfbgvV4AP7qEZstoyrHB0DzarOQ4ZY=
 golang.org/x/time v0.9.0/go.mod h1:3BpzKBy/shNhVucY/MWOyx10tF3SFh9QdLuxbVysPQM=
+golang.org/x/time v0.14.0 h1:MRx4UaLrDotUKUdCIqzPC48t1Y9hANFKIRpNx+Te8PI=
+golang.org/x/time v0.14.0/go.mod h1:eL/Oa2bBBK0TkX57Fyni+NgnyQQN4LitPmob2Hjnqw4=
 golang.org/x/tools v0.38.0 h1:Hx2Xv8hISq8Lm16jvBZ2VQf+RLmbd7wVUsALibYI/IQ=
 golang.org/x/tools v0.38.0/go.mod h1:yEsQ/d/YK8cjh0L6rZlY8tgtlKiBNTL14pGDJPJpYQs=
 google.golang.org/protobuf v1.36.8 h1:xHScyCOEuuwZEc6UtSOvPbAT4zRh0xcNRYekJwfqyMc=

internal/controller/config.go

@@ -1,5 +1,9 @@
 package controller
 
+import (
+	"strings"
+)
+
 const (
 	// TmplNS is the meta variable for the k8s namespace.
 	TmplNS = "{{namespace}}"
@@ -19,3 +23,13 @@ type Config struct {
 	BaseURL             string
 	Organization        string
 }
+
+// ValidTemplate verifies that at least one placeholder is present
+// in the provided template t.
+func ValidTemplate(t string) bool {
+	hasPlaceholder := strings.Contains(t, TmplNS) ||
+		strings.Contains(t, TmplDN) ||
+		strings.Contains(t, TmplCN)
+
+	return hasPlaceholder
+}

internal/controller/config_test.go

@@ -0,0 +1,113 @@
+package controller
+
+import (
+	"testing"
+)
+
+func TestValidTemplate(t *testing.T) {
+	tests := []struct {
+		name     string
+		template string
+		expected bool
+	}{
+		{
+			name:     "empty string",
+			template: "",
+			expected: false,
+		},
+		{
+			name:     "static string without placeholders",
+			template: "static-deployment-name",
+			expected: false,
+		},
+		{
+			name:     "namespace placeholder only",
+			template: "{{namespace}}",
+			expected: true,
+		},
+		{
+			name:     "deployment name placeholder only",
+			template: "{{deploymentName}}",
+			expected: true,
+		},
+		{
+			name:     "container name placeholder only",
+			template: "{{containerName}}",
+			expected: true,
+		},
+		{
+			name:     "all three placeholders",
+			template: "{{namespace}}/{{deploymentName}}/{{containerName}}",
+			expected: true,
+		},
+		{
+			name:     "namespace and deployment name",
+			template: "{{namespace}}-{{deploymentName}}",
+			expected: true,
+		},
+		{
+			name:     "mixed static and placeholders",
+			template: "prefix-{{namespace}}-suffix",
+			expected: true,
+		},
+		{
+			name:     "placeholder with surrounding text",
+			template: "app/{{containerName}}/prod",
+			expected: true,
+		},
+		{
+			name:     "similar but invalid placeholder",
+			template: "{{namespaces}}",
+			expected: false,
+		},
+		{
+			name:     "partial placeholder - missing closing braces",
+			template: "{{namespace",
+			expected: false,
+		},
+		{
+			name:     "partial placeholder - missing opening braces",
+			template: "namespace}}",
+			expected: false,
+		},
+		{
+			name:     "wrong case placeholder",
+			template: "{{Namespace}}",
+			expected: false,
+		},
+		{
+			name:     "placeholder with extra space",
+			template: "{{ namespace }}",
+			expected: false,
+		},
+		{
+			name:     "default template format",
+			template: TmplNS + "/" + TmplDN + "/" + TmplCN,
+			expected: true,
+		},
+		{
+			name:     "complex valid template",
+			template: "org/{{namespace}}/env/{{deploymentName}}/container/{{containerName}}",
+			expected: true,
+		},
+		{
+			name:     "whitespace only",
+			template: "   ",
+			expected: false,
+		},
+		{
+			name:     "special characters without placeholders",
+			template: "app-name_v1.2.3",
+			expected: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := ValidTemplate(tt.template)
+			if result != tt.expected {
+				t.Errorf("ValidTemplate(%q) = %v, expected %v", tt.template, result, tt.expected)
+			}
+		})
+	}
+}

internal/controller/controller.go

@@ -3,6 +3,7 @@ package controller
 import (
 	"context"
 	"errors"
+	"fmt"
 	"log/slog"
 	"strings"
 	"time"
@@ -36,7 +37,7 @@ type Controller struct {
 }
 
 // New creates a new deployment tracker controller.
-func New(clientset kubernetes.Interface, namespace string, cfg *Config) *Controller {
+func New(clientset kubernetes.Interface, namespace string, cfg *Config) (*Controller, error) {
 	// Create informer factory
 	var factory informers.SharedInformerFactory
 	if namespace == "" {
@@ -63,11 +64,14 @@ func New(clientset kubernetes.Interface, namespace string, cfg *Config) *Control
 	if cfg.APIToken != "" {
 		clientOpts = append(clientOpts, deploymentrecord.WithAPIToken(cfg.APIToken))
 	}
-	apiClient := deploymentrecord.NewClient(
+	apiClient, err := deploymentrecord.NewClient(
 		cfg.BaseURL,
 		cfg.Organization,
 		clientOpts...,
 	)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create API client: %w", err)
+	}
 
 	cntrl := &Controller{
 		clientset:   clientset,
@@ -78,7 +82,7 @@ func New(clientset kubernetes.Interface, namespace string, cfg *Config) *Control
 	}
 
 	// Add event handlers to the informer
-	_, err := podInformer.AddEventHandler(cache.ResourceEventHandlerFuncs{
+	_, err = podInformer.AddEventHandler(cache.ResourceEventHandlerFuncs{
 		AddFunc: func(obj any) {
 			pod, ok := obj.(*corev1.Pod)
 			if !ok {
@@ -172,11 +176,10 @@ func New(clientset kubernetes.Interface, namespace string, cfg *Config) *Control
 	})
 
 	if err != nil {
-		slog.Error("Failed to add event handlers",
-			"error", err)
+		return nil, fmt.Errorf("failed to add event handlers: %w", err)
 	}
 
-	return cntrl
+	return cntrl, nil
 }
 
 // Run starts the controller.
@@ -304,6 +307,13 @@ func (c *Controller) recordContainer(ctx context.Context, pod *corev1.Pod, conta
 	digest := getContainerDigest(pod, container.Name)
 
 	if dn == "" || digest == "" {
+		slog.Debug("Skipping container: missing deployment name or digest",
+			"namespace", pod.Namespace,
+			"pod", pod.Name,
+			"container", container.Name,
+			"deployment_name", dn,
+			"has_digest", digest != "",
+		)
 		return nil
 	}