[BUG] operator crashes if tls config is invalid

[thesn10]

If tls config is invalid,
the operator just crashes instead of giving a proper validation error.

2022-09-09T16:22:38.660Z	DEBUG	controllers/replica_set_controller.go:140	Validating MongoDB.Spec	{"ReplicaSet": "..."}
2022-09-09T16:22:38.661Z	DEBUG	controllers/replica_set_controller.go:149	Ensuring the service exists	{"ReplicaSet": "..."}
2022-09-09T16:22:38.864Z	DEBUG	agent/replica_set_port_manager.go:122	No port change required	{"ReplicaSet": "..."}
2022-09-09T16:22:38.874Z	INFO	controllers/replica_set_controller.go:464	Create/Update operation succeeded	{"ReplicaSet": "...", "operation": "updated"}
2022-09-09T16:22:38.874Z	INFO	controllers/mongodb_tls.go:39	Ensuring TLS is correctly configured	{"ReplicaSet": "..."}
panic: runtime error: invalid memory address or nil pointer dereference [recovered]
	panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x13d202e]

goroutine 354 [running]:
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Reconcile.func1()
	/go/pkg/mod/sigs.k8s.io/controller-runtime@v0.12.3/pkg/internal/controller/controller.go:118 +0x1f4
panic({0x15247e0, 0x24553c0})
	/usr/local/go/src/runtime/panic.go:838 +0x207
github.com/mongodb/mongodb-kubernetes-operator/api/v1.MongoDBCommunity.TLSConfigMapNamespacedName(...)
	/workspace/api/v1/mongodbcommunity_types.go:797
github.com/mongodb/mongodb-kubernetes-operator/controllers.getCaCrt({_, _}, {_, _}, {{{0x14080c8, 0x10}, {0xc0004b61e0, 0x1f}}, {{0xc0003f9d20, 0x10}, ...}, ...})
	/workspace/controllers/mongodb_tls.go:166 +0x12e
github.com/mongodb/mongodb-kubernetes-operator/controllers.(*ReplicaSetReconciler).validateTLSConfig(_, {{{0x14080c8, 0x10}, {0xc0004b61e0, 0x1f}}, {{0xc0003f9d20, 0x10}, {0x0, 0x0}, {0xc0003f9d18, ...}, ...}, ...})
	/workspace/controllers/mongodb_tls.go:42 +0x125
github.com/mongodb/mongodb-kubernetes-operator/controllers.ReplicaSetReconciler.Reconcile({{0x19c5b60, 0xc0005248a0}, 0xc000158540, 0xc0003fe158, 0xc0003fe370, 0xc0003fe378}, {0x19bd600?, 0xc000130d20?}, {{{0xc0003f9d18, 0x8}, ...}})
	/workspace/controllers/replica_set_controller.go:158 +0x7d9
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Reconcile(0x19bd558?, {0x19bd600?, 0xc000130d20?}, {{{0xc0003f9d18?, 0x1627a00?}, {0xc0003f9d20?, 0x4041f4?}}})
	/go/pkg/mod/sigs.k8s.io/controller-runtime@v0.12.3/pkg/internal/controller/controller.go:121 +0xc8
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).reconcileHandler(0xc0004a28c0, {0x19bd558, 0xc000526f00}, {0x1574ca0?, 0xc000348060?})
	/go/pkg/mod/sigs.k8s.io/controller-runtime@v0.12.3/pkg/internal/controller/controller.go:320 +0x33c
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).processNextWorkItem(0xc0004a28c0, {0x19bd558, 0xc000526f00})
	/go/pkg/mod/sigs.k8s.io/controller-runtime@v0.12.3/pkg/internal/controller/controller.go:273 +0x1d9
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Start.func2.2()
	/go/pkg/mod/sigs.k8s.io/controller-runtime@v0.12.3/pkg/internal/controller/controller.go:234 +0x85
created by sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Start.func2
	/go/pkg/mod/sigs.k8s.io/controller-runtime@v0.12.3/pkg/internal/controller/controller.go:230 +0x325

apiVersion: mongodbcommunity.mongodb.com/v1
kind: MongoDBCommunity
metadata:
  name: ...
spec:
  members: 1
  type: ReplicaSet
  version: "5.0.6"
  security:
    tls:
      enabled: true
      certificateKeySecretRef:
        name: mongodb-cert-secret
      #missing caConfigMapRef

[dan-mckean]

Hi, I'm Dan and I'm the Product Manager for MongoDB's support of Kubernetes.

I'm doing some work right now to try and identify how the Community Operator is being used. The Community Operator is something I inherited when I started at MongoDB, but it doesn't get as much attention from us as we'd like and we're trying to understand how it's used in order to establish its future. It will help us prioritize future issues and PRs raised by the community 🙂

Here's a super short survey (it's much easier for us to review all the feedback that way!): https://docs.google.com/forms/d/e/1FAIpQLSfwrwyxBSlUyJ6AmC-eYlgW_3JEdfA48SB2i5--_WpiynMW2w/viewform?usp=sf_link

If you'd rather email me instead: dan.mckean@mongodb.com

Thank you in advance!
Dan