fix: use safe prometheus.Register instead of MustRegister in main (#522)

Author: tekenstam

.github/workflows/golangci-lint.yml

@@ -9,7 +9,7 @@ on:
     branches: [ "master" ]
 
 env:
-  GO_VERSION: stable
+  GO_VERSION: "1.24"
   GOLANGCI_LINT_VERSION: v2.1.1
 
 jobs:

.golangci.yml

@@ -7,6 +7,12 @@ linters:
       - common-false-positives
       - legacy
       - std-error-handling
+    rules:
+      # Suppress SA1019 deprecation warnings for aws-sdk-go v1 until migration to v2
+      # is complete. Tracked in https://github.com/keikoproj/instance-manager/issues/523
+      - linters:
+          - staticcheck
+        text: "SA1019.*\"github.com/aws/aws-sdk-go/"
     paths:
       - third_party$
       - builtin$

main.go

@@ -137,7 +137,18 @@ func main() {
 		Ec2Metadata: metadata,
 	}
 
-	prometheus.MustRegister(cacheCollector, controllerCollector)
+	if err := prometheus.Register(cacheCollector); err != nil {
+		if _, ok := err.(prometheus.AlreadyRegisteredError); !ok {
+			setupLog.Error(err, "failed to register cache metrics collector")
+			os.Exit(1)
+		}
+	}
+	if err := prometheus.Register(controllerCollector); err != nil {
+		if _, ok := err.(prometheus.AlreadyRegisteredError); !ok {
+			setupLog.Error(err, "failed to register controller metrics collector")
+			os.Exit(1)
+		}
+	}
 	kube := kubeprovider.KubernetesClientSet{
 		Kubernetes:  client,
 		KubeDynamic: dynClient,