Copy a K8S secret to another namespace. If the secret exists, it is updated.

copy_secret.sh

#!/usr/bin/env bash
# Depedency: requires yq>=4.x and kubectl

if [ "$#" -ne 4 ]; then
    echo "Usage: copy_secret <src_namespace> <src_secret_name> <dest_namespace> <dest_secret_name>"
    exit 1
fi

function copy_secret {
    local src_ns=$1
    local src_name=$2
    local dest_ns=$3
    local dest_name=$4
    kubectl get secret -n=$dest_ns $dest_name 1> /dev/null 2> /dev/null
    exit_status=$?
    if [ $exit_status -eq 0 ]; then
      echo "Secret $dest_name in $dest_ns does already exist. Updating it with data from secret $src_name in $src_ns namespace."
      export data=$(kubectl get secret -n=$src_ns $src_name -oyaml | yq '.data')
      kubectl get secret -n=$dest_ns $dest_name -oyaml | yq '.data=env(data)' | kubectl apply -f -
    else
      echo "Secret $dest_name in $dest_ns doesn't exist yet. Creating it with data from secret $src_name in $src_ns namespace."
      kubectl get secret -n=$src_ns $src_name -oyaml | yq 'del( .metadata[] )' | yq ".metadata += {\"name\": \"$dest_name\"}" | kubectl apply -n=$dest_ns -f -     
    fi
}

copy_secret $1 $2 $3 $4