Initial pass on a warm standby start/update tool

This is meant to allow us to start the warm standby and try to keep it up to date with changes published to the image.

Signed-off-by: mward matt@eclipse.org

runme.sh

+#!/bin/bash
+#*******************************************************************************
+#* Copyright (c) 2022 onward Eclipse Foundation and others.
+#* All rights reserved. This program and the accompanying materials
+#* are made available under the terms of the Eclipse Public License v2.0
+#* which accompanies this distribution, and is available at
+#* http://www.eclipse.org/legal/epl-v20.html
+#*
+#* Contributors:
+#*   Matt Ward (Eclipse Foundation)
+#*******************************************************************************/
+
+umask 0022
+
+#setup basic definitions
+IMAGE="docker.io/eclipsefdn/www-eclipse-org:latest"
+#podman should be a drop in replacement for docker
+PODMAN="/usr/bin/podman"
+CONTAINER_NAME="www-httpd"
+IMAGE_TRACKER="/var/run/eclipse.org-image"
+LATEST_IMAGE=""
+
+function pull_image {
+#  echo "Fetching $IMAGE"
+  # -q doesn't seem to supress all output, so let's trap it in a local var
+  local RETURN=$($PODMAN pull -q $IMAGE)
+}
+
+function get_image_id {
+  local IMAGE_ID=$($PODMAN history --format "{{.ID}}" $IMAGE | head -1)
+  echo $IMAGE_ID
+}
+
+function run_image {
+  echo "Running Image $LATEST_IMAGE"
+  $PODMAN run --name=$CONTAINER_NAME -d -p 18181:8080 $LATEST_IMAGE
+}
+
+#main loop starts here.
+if [ -f ${IMAGE_TRACKER} ] && [ -s ${IMAGE_TRACKER} ] ; then
+  RUNNING_IMAGE=$(cat $IMAGE_TRACKER)
+else
+  RUNNING_IMAGE=""
+fi
+
+#pull and get the image id
+pull_image
+
+LATEST_IMAGE=$(get_image_id)
+if [[ $RUNNING_IMAGE == "" ]]; then
+  echo "Init setting RUNNING_IMAGE=LATEST_IMAGE"
+  run_image
+  echo -n $LATEST_IMAGE > $IMAGE_TRACKER
+elif [[ $RUNNING_IMAGE != $LATEST_IMAGE ]]; then
+  echo "Latest image id is not the running image, restarting"
+  $PODMAN stop $CONTAINER_NAME
+  $PODMAN rm $CONTAINER_NAME
+  run_image
+  #update the image 'version' tracker file
+  echo -n $LATEST_IMAGE > $IMAGE_TRACKER
+fi