Add script for updating source image of ATST deploy

deploy/kubernetes/atst-update-deploy.sh

@@ -0,0 +1,40 @@
+#!/usr/bin/env bash
+#
+# deploy/kubernetes/atst-update-deploy.sh: Updates the existing ATST deployment 
+#                                          with a new source image
+
+set -o pipefail
+set -o errexit
+set -o nounset
+# set -o xtrace
+
+# Decode and save the K8S CA cert
+echo "${K8S_CA_CRT}" | base64 --decode -i > "${HOME}/k8s_ca.crt"
+
+# Setup the local kubectl client
+kubectl config set-cluster atat-cluster \
+    --embed-certs=true \
+    --server="${K8S_CLUSTER_ENDPOINT}"  \
+    --certificate-authority="${HOME}/k8s_ca.crt"
+
+kubectl config set-credentials atat-deployer --token="${K8S_USER_TOKEN}"
+
+kubectl config set-context travis \
+    --cluster=atat-cluster \
+    --user=atat-deployer \
+    --namespace=atat
+
+kubectl config use-context travis
+kubectl config current-context
+
+# Update the ATST deployment
+kubectl set image deployment.apps/atst atst="${PROD_IMAGE_NAME}"
+
+# Remove the K8S CA file when the script exits
+function cleanup {
+    printf "Cleaning up...\n"
+    rm -vf "${HOME}/k8s_ca.crt"
+    printf "Cleaning done."
+}
+
+trap cleanup EXIT