update-plugins.sh

#!/bin/bash
# This script updates all the installed plugins of a Jenkins docker container,
# restart the instance and outputs the resulting list of updated plugins (aka. "plugins.txt")
#

set -eu -o pipefail

JENKINS_URL=https://"${JENKINS_HOST}"
JENKINS_TEST_CREDZ="admin:${ADMIN_TOKEN}"
JENKINS_CONTAINER_NAME="${PROJECT_ID:-default}_jenkins_1"
CURL_OPTS=("--insecure" "--fail" "--location" "--silent" "--show-error" "--user" "${JENKINS_TEST_CREDZ}")
PLUGINS_TXT_FILE="${PLUGINS_TXT_FILE:-"plugins.txt"}"

## Check for CLI requirements
for CLI in perl sed curl sort uniq docker
do
    command -v "${CLI}" >/dev/null 2>&1  || {
        echo "ERROR: Command Line ${CLI} not found but is required. Exiting."
        exit 1
    }
done

###### get_jenkins_plugins_list()
# Prints on the stdout the alphabetically order list of plugins installed on the provided Jenkins instance.
# The format of the stdout is one line per plugin, with the name and version on each line, separated by a colon (':')
#
# Arguments: none
function get_jenkins_plugins_list() {
    curl "${CURL_OPTS[@]}" "${1}/pluginManager/api/xml?depth=1&xpath=/*/*/shortName|/*/*/version&wrapper=plugins" \
    | perl -pe 's/.*?<shortName>([\w-]+).*?<version>([^<]+)()(<\/\w+>)+/\1 \2\n/g' \
    | sed 's/ /:/' | sort | uniq
}

function retry() {
    counter=0
    max_retries="$1"
    shift
    waiting_time="$1"
    shift
    until [ "${counter}" -ge "${max_retries}" ]
    do
        if "$@"
        then
            break
        fi
        sleep "${waiting_time}"
        counter=$((counter+1))
    done
    if [ "${counter}" -ge "${max_retries}" ]
    then
        return 1
    fi
    return 0
}

echo "== Checking if Jenkins container is up and healty..."
retry 30 10 bash -c "docker inspect -f '{{json .State.Health.Status}}' ${JENKINS_CONTAINER_NAME} | grep -q '\"healthy\"'" || {
    echo "== ERROR: the Jenkins container ${JENKINS_CONTAINER_NAME} is not healthy after 1 minute. Exiting."
    exit 1
}
echo "== Jenkins container ${JENKINS_CONTAINER_NAME} is up and healthy."

echo "== Retrieving list of plugins from Jenkins instance at ${JENKINS_URL}..."

curl "${CURL_OPTS[@]}" -o /dev/null "${JENKINS_URL}/manage" 2>/dev/null
echo "== The Jenkins instance management page at ${JENKINS_URL}/manage can be accessed."

### Get the list of CURRENTLY installed packages
CURRENT_PLUGINS_LIST="$(get_jenkins_plugins_list "${JENKINS_URL}")"
echo "== List of plugins retrieved successfully."


echo "== Upgrading the list of plugins in a new Docker image..."

DOCKER_IMAGE_NAME=jenkins-plugins-upgrade
DOCKER_CONTAINER_NAME=jenkins-plugins-upgrade

cat <<EOF | docker build --pull --no-cache --tag="${DOCKER_IMAGE_NAME}" -
 # Always use the latest LTS
FROM jenkins/jenkins:lts

# Install Plugins (latest version)
RUN /usr/local/bin/install-plugins.sh $(echo "${CURRENT_PLUGINS_LIST}" | cut -d: -f1 | tr "\n" " ")
ENV JAVA_OPTS="-Djenkins.install.runSetupWizard=false"
EOF
echo "== Docker image built successfully."

echo "== Starting a temp Jenkins instance in a Docker container from this new image..."
docker kill "${DOCKER_CONTAINER_NAME}" || true
docker rm -f -v "${DOCKER_CONTAINER_NAME}" || true
docker run --rm -d -P --name="${DOCKER_CONTAINER_NAME}" "${DOCKER_IMAGE_NAME}"

TEMP_JENKINS_ADDRESS="$(docker port "${DOCKER_CONTAINER_NAME}" 8080/tcp)"

retry 30 2 curl "${CURL_OPTS[@]}" "${TEMP_JENKINS_ADDRESS}" || {
    echo "== ERROR: could not access the temp Jenkins instance in the docker container ${DOCKER_CONTAINER_NAME}. Check its logs. Exiting."
    exit 1
}
echo "== The temp Jenkins instance is available."

echo "== Exporting the new plugins list..."
get_jenkins_plugins_list "${TEMP_JENKINS_ADDRESS}" | tee "${PLUGINS_TXT_FILE}"
echo "== Updated plugin list is available at ${PLUGINS_TXT_FILE}. End of Script"
exit 0