launch_java_agent.sh

#!/bin/env bash

set -e

# ==============================================================================
# Script Name: launch_java_agent.sh
#
# Description:
#        This script automates the process of launching a Jenkins agent
#        on a specified machine. It ensures that the necessary
#        prerequisites are met, such as the availability of JAVA_HOME,
#        the Jenkins agent launch directory, and proper authentication
#        with GitHub.
#
#       It then proceeds to check if the Jenkins node is online and
#       decides whether to launch the Jenkins agent based on the node's
#       status. The agent is launched in the background,
#       and its PID is logged for reference.
#
# Prerequisites:
#         JAVA_HOME must be set to a valid JDK installation.
#         Jenkins agent launch directory must exist and be specified.
#         GitHub CLI (gh) must be installed and authenticated for messeging
#           from the Jenkins controller to GitHub PR via shell commands.
#           Jenkins agent launch directory must exist and be specified.
#           TODO: Must use GitHub CLI v2.25.1 (newer versoins have issues)
#           /~https://github.com/cli/cli/releases/download/v2.25.1/gh_2.25.1_linux_amd64.tar.gz
#         Jenkins controller URL and authentication token must be provided.
#         jenkins-secret-file:
#           Must be present in the Jenkins agent launch directory.
#           This file contains the secret key for the Jenkins agent
#           established by the Jenkins administrator for each Node.
#         jenkins_token:
#           Must be present in the Jenkins agent launch directory.
#           This file contains the user authentication token for the Jenkins controller
#           to use the Remote API. This token can be generated by the user
#           on the Jenkins controller.
#         controller_user:
#           Must be set to the Jenkins controller username corresponing to the jenkins_token.
#
# Usage: ./launch_java_agent.sh [now] [-f]
#        The optional 'now' argument forces the script to launch the Jenkins
#        agent without waiting before trying again.
#        The optional 'force' argument forces the script to launch the Jenkins regarless of the node status.
#
# ==============================================================================

force_launch="False"
skip_wait="False"
while getopts ":fnh" flag; do
  case "${flag}" in
    f) force_launch="True";;
    n) skip_wait="True";;
    h) echo "Usage: ./launch_java_agent.sh [now] [force]
Two mutually exclusive optional arguments:
    -n (now) causes the script to launch the Jenkins agent without waiting before trying again.
    -f (force) forces the script to launch the Jenkins regarless of its connection status."
       exit 0 ;;
    *) echo "Unknown flag: ${flag}"
       exit 1;;
  esac
done

controller_url="https://jenkins.epic.oarcloud.noaa.gov"
controller_user=${controller_user:-"terry.mcguinness"}
controller_user_auth_token="jenkins_token"

HOMEgfs="$(cd "$(dirname  "${BASH_SOURCE[0]}")/../../.." >/dev/null 2>&1 && pwd )"
host=$(hostname)

#########################################################################
#  Set up runtime environment varibles for accounts on supproted machines
#########################################################################

source "${HOMEgfs}/ush/detect_machine.sh"
case ${MACHINE_ID} in
  hera | orion | hercules | wcoss2 | gaea)
    echo "Launch Jenkins Java Controler on ${MACHINE_ID}";;
  *)
    echo "Unsupported platform. Exiting with error."
    exit 1;;
esac

LOG=lanuched_agent-$(date +%Y%m%d%M).log
rm -f "${LOG}"

source "${HOMEgfs}/ush/module-setup.sh"
module use "${HOMEgfs}/modulefiles"
module load "module_gwsetup.${MACHINE_ID}"
source "${HOMEgfs}/ci/platforms/config.${MACHINE_ID}"

JAVA_HOME="${JENKINS_AGENT_LANUCH_DIR}/JAVA/jdk-17.0.10"
if [[ ! -d "${JAVA_HOME}" ]]; then
  JAVA_HOME=/usr/lib/jvm/jre-17
  if [[ ! -d "${JAVA_HOME}" ]]; then
    echo "ERROR: JAVA_HOME not found. Exiting with error."
    exit 1
  fi
fi

JAVA="${JAVA_HOME}/bin/java"
echo "JAVA VERSION: "
${JAVA} -version

export GH="${HOME}/bin/gh"
[[ -f "${GH}" ]] || echo "gh is not installed in ${HOME}/bin"
${GH} --version

check_mark=$(gh auth status -t 2>&1 | grep "Token:" | awk '{print $1}') || true
if [[ "${check_mark}" != "✓" ]]; then
  echo "gh not authenticating with emcbot token"
  exit 1
fi
echo "gh authenticating with emcbot TOKEN ok"

if [[ -d "${JENKINS_AGENT_LANUCH_DIR}" ]]; then
  echo "Jenkins Agent Lanuch Directory: ${JENKINS_AGENT_LANUCH_DIR}"
else
  echo "ERROR: Jenkins Agent Lanuch Directory not found. Exiting with error."
  exit 1
fi
cd "${JENKINS_AGENT_LANUCH_DIR}"

if ! [[ -f agent.jar ]]; then
  curl -sO "${controller_url}/jnlpJars/agent.jar"
  echo "Updated agent.jar downloaded"
fi

if [[ ! -f "${controller_user_auth_token}" ]]; then
   echo "User Jenkins authetication TOKEN to the controller for using the Remote API does not exist"
   exit 1
fi
JENKINS_TOKEN=$(cat "${controller_user_auth_token}")

cat << EOF > parse.py
#!/usr/bin/env python3
import json,sys
with open(sys.argv[1], 'r') as file:
    data = json.load(file)
print(data.get('offline','True'))
EOF
chmod u+x parse.py

check_node_online() {
    rm -f curl_response
    curl_response=$(curl --silent -u "${controller_user}:${JENKINS_TOKEN}" "${controller_url}/computer/${MACHINE_ID^}-EMC/api/json?pretty=true") || true
    if [[ "${curl_response}" == "" ]]; then
       echo "ERROR: Jenkins controller not reachable. Exiting with error."
       exit 1
    fi
    echo -n "${curl_response}" > curl_response
    ./parse.py curl_response
}

lauch_agent () {
    echo "Launching Jenkins Agent on ${host}"
    command="nohup ${JAVA} -jar agent.jar -jnlpUrl ${controller_url}/computer/${MACHINE_ID^}-EMC/jenkins-agent.jnlp  -secret @jenkins-secret-file -workDir ${JENKINS_WORK_DIR}"
    echo -e "Launching Jenkins Agent on ${host} with the command:\n${command}" >& "${LOG}"
    ${command} >> "${LOG}" 2>&1 &
    nohup_PID=$!
    echo "Java agent running on PID: ${nohup_PID}" >> "${LOG}" 2>&1
}

if [[ "${force_launch}" == "True" ]]; then
  lauch_agent
  exit
fi

offline=$(set -e; check_node_online)

if [[ "${offline}" != "False" ]]; then
   if [[ "${skip_wait}" != "True" ]]; then
      echo "Jenkins Agent is offline. Waiting 5 more minutes to check again in the event it is a temp network issue"
      sleep 300
      offline=$(set -e; check_node_online)
   fi
   if [[ "${offline}" != "False" ]]; then
     lauch_agent
    else
      echo "Jenkins Agent is online (nothing done)"
    fi
else
  echo "Jenkins Agent is online (nothing done)"
fi