fix cleanup when context/namespace changes

Author: kvaps

kubectl-node_shell

@@ -4,6 +4,8 @@ set -e
 kubectl=kubectl
 generator=""
 node=""
+nodefaultctx=0
+nodefaultns=0
 cmd='[ "nsenter", "--target", "1", "--mount", "--uts", "--ipc", "--net", "--pid", "--", '
 custom=false
 if ! [ -p /dev/stdin ] && ! [ -p /dev/stdout ]; then
@@ -16,11 +18,13 @@ while [ $# -gt 0 ]; do
 
   case $key in
   --context)
+    nodefaultctx=1
     kubectl="$kubectl --context $2"
     shift
     shift
     ;;
   --kubecontext=*)
+    nodefaultctx=1
     kubectl="$kubectl --context=${key##*=}"
     shift
     ;;
@@ -34,11 +38,13 @@ while [ $# -gt 0 ]; do
     shift
     ;;
   -n | --namespace)
+    nodefaultns=1
     kubectl="$kubectl --namespace $2"
     shift
     shift
     ;;
   --namespace=*)
+    nodefaultns=1
     kubectl="$kubectl --namespace=${key##*=}"
     shift
     ;;
@@ -58,6 +64,10 @@ while [ $# -gt 0 ]; do
   esac
 done
 
+# Set the default context and namespace to avoid situations where the user switch them during the build process
+[ "$nodefaultctx" = 1 ] || kubectl="$kubectl --context=$(kubectl config current-context)"
+[ "$nodefaultns" = 1 ] || kubectl="$kubectl --namespace=$(kubectl config view --minify --output 'jsonpath={.contexts..namespace}')"
+
 while [ $# -gt 0 ]; do
   cmd="$cmd\"$1\", "
   custom=true
@@ -75,7 +85,7 @@ if [ -z "$node" ]; then
 fi
 
 image="docker.io/library/alpine"
-pod="nsenter-$(env LC_ALL=C tr -dc a-z0-9 < /dev/urandom | head -c 6)"
+pod="nsenter-$(env LC_ALL=C tr -dc a-z0-9 </dev/urandom | head -c 6)"
 
 # Check the node
 kubectl get node "$node" $context $kubeconfig >/dev/null || exit 1
@@ -116,7 +126,7 @@ EOT
 )"
 
 # Support Kubectl <1.18
-m=$(kubectl version --client -o yaml | awk -F'[ :"]+' '$2 == "minor" {print $3+0}' )
+m=$(kubectl version --client -o yaml | awk -F'[ :"]+' '$2 == "minor" {print $3+0}')
 if [ "$m" -lt 18 ]; then
   generator="--generator=run-pod/v1"
 fi