added kubernetes_foreach_namespace.sh

kubernetes_foreach_namespace.sh

@@ -0,0 +1,80 @@
+#!/usr/bin/env bash
+#  vim:ts=4:sts=4:sw=4:et
+#  args: echo namespace is now {namespace}
+#
+#  Author: Hari Sekhon
+#  Date: 2020-09-08 19:20:40 +0100 (Tue, 08 Sep 2020)
+#
+#  https://github.com/HariSekhon/bash-tools
+#
+#  License: see accompanying Hari Sekhon LICENSE file
+#
+#  If you're using my code you're welcome to connect with me on LinkedIn and optionally send me feedback to help steer this or other code I publish
+#
+#  https://www.linkedin.com/in/HariSekhon
+#
+
+set -euo pipefail
+[ -n "${DEBUG:-}" ] && set -x
+srcdir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+
+# shellcheck disable=SC1090
+. "$srcdir/lib/utils.sh"
+
+# shellcheck disable=SC2034,SC2154
+usage_description="
+Run a command against each Kubernetes kubectl namespace in the current context
+
+Can chain with kubernetes_foreach_context.sh
+
+This is powerful so use carefully!
+
+Requires 'kubectl' to be configured and available in \$PATH
+
+All arguments become the command template
+
+Sets the kubectl namespace on the current context in each iteration and then returns the context to the original namespace on any exit except kill -9
+
+Replaces {namespace} if present in the command template with the namespace in each iteration, but often this isn't necessary to specify explicitly given the kubectl context's namespace is changed in each iteration for convenience running short commands local to the namespace
+
+eg.
+    ${0##*/} gcp_secrets_to_kubernetes.sh
+"
+
+# used by usage() in lib/utils.sh
+# shellcheck disable=SC2034
+usage_args="<command> <args>"
+
+help_usage "$@"
+
+min_args 1 "$@"
+
+cmd_template="$*"
+
+current_context="$(kubectl config current-context)"
+
+# there is no -o jsonpath/namespace so must just get column
+original_namespace="$(kubectl config get-contexts "$current_context" --no-headers | awk '{print $5}')"
+
+set_namespace(){
+    local namespace="$1"
+    kubectl config set-context "$current_context" --namespace "$namespace"
+}
+
+while read -r namespace; do
+    #if [[ "$context" =~ kube-system ]]; then
+    #    echo "Skipping context '$context'..."
+    #    echo
+    #    continue
+    #fi
+    echo "# ============================================================================ #" >&2
+    echo "# Kubernetest namespace = $namespace, content = $current_context" >&2
+    echo "# ============================================================================ #" >&2
+    # shellcheck disable=SC2064  # want interpolation now
+    trap "echo; echo 'Reverting context to original namespace:' ; set_namespace '$original_namespace'" EXIT
+    set_namespace "$namespace"
+    cmd="${cmd_template//\{namespace\}/$namespace}"
+    eval "$cmd"
+    echo
+#done < <(kubectl get namespaces -o name | sed 's,namespace/,,')
+done < <(kubectl get namespaces -o 'jsonpath={range .items[*]}{.metadata.name}{"\n"}')