Retry fetching Kubernetes Secret token

Since Kubernetes is creating the Secret and token asynchronously it is
necessary that we implement some delay or retrying logic to avoid a race
condition where we fetch a Secret before the token is even set. There
does not appear to be any way for us to force it to be set with any
synchronous API call so retrying seems to be the only option.

1 files changed, 16 insertions, 3 deletions

diff --git a/app/services/clusters/gcp/kubernetes/fetch_kubernetes_token_service.rb b/app/services/clusters/gcp/kubernetes/fetch_kubernetes_token_service.rb
index 4ad04ab801e..5d9bdc52d37 100644
--- a/app/services/clusters/gcp/kubernetes/fetch_kubernetes_token_service.rb
+++ b/app/services/clusters/gcp/kubernetes/fetch_kubernetes_token_service.rb
@@ -4,17 +4,30 @@ module Clusters
   module Gcp
     module Kubernetes
       class FetchKubernetesTokenService
+        DEFAULT_TOKEN_RETRY_DELAY = 5.seconds
+        TOKEN_RETRY_LIMIT = 5
+
         attr_reader :kubeclient, :service_account_token_name, :namespace
 
-        def initialize(kubeclient, service_account_token_name, namespace)
+        def initialize(kubeclient, service_account_token_name, namespace, token_retry_delay: DEFAULT_TOKEN_RETRY_DELAY)
           @kubeclient = kubeclient
           @service_account_token_name = service_account_token_name
           @namespace = namespace
+          @token_retry_delay = token_retry_delay
         end
 
         def execute
-          token_base64 = get_secret&.dig('data', 'token')
-          Base64.decode64(token_base64) if token_base64
+          # Kubernetes will create the Secret and set the token asynchronously
+          # so it is necessary to retry
+          # https://kubernetes.io/docs/reference/access-authn-authz/service-accounts-admin/#token-controller
+          TOKEN_RETRY_LIMIT.times do
+            token_base64 = get_secret&.dig('data', 'token')
+            return Base64.decode64(token_base64) if token_base64
+
+            sleep @token_retry_delay
+          end
+
+          nil
         end
 
         private