entrypoint.sh

#!/usr/bin/env bash

# The MIT License
#
#  Copyright (c) 2015, CloudBees, Inc.
#
#  Permission is hereby granted, free of charge, to any person obtaining a copy
#  of this software and associated documentation files (the "Software"), to deal
#  in the Software without restriction, including without limitation the rights
#  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
#  copies of the Software, and to permit persons to whom the Software is
#  furnished to do so, subject to the following conditions:
#
#  The above copyright notice and this permission notice shall be included in
#  all copies or substantial portions of the Software.
#
#  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
#  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
#  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
#  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
#  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
#  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
#  THE SOFTWARE.

# Usage jenkins-slave.sh [options] -url http://jenkins SECRET SLAVE_NAME
# Optional environment variables :
# * JENKINS_TUNNEL : HOST:PORT for a tunnel to route TCP traffic to jenkins host, when jenkins can't be directly accessed over network
# * JENKINS_URL : alternate jenkins URL

if [ $# -eq 1 ]; then

  # if `docker run` only has one arguments, we assume user is running alternate command like `bash` to inspect the image
  exec "$@"

else

  # if -tunnel is not provided try env vars
  if [[ "$@" != *"-tunnel "* ]]; then
    if [ ! -z "$JENKINS_TUNNEL" ]; then
      TUNNEL="-tunnel $JENKINS_TUNNEL"
    fi
  fi

  if [ ! -z "$JENKINS_URL" ]; then
    URL="-url $JENKINS_URL"
  fi

  if [ -z "$JNLP_PROTOCOL_OPTS" ]; then
    echo "Warning: JnlpProtocol3 is disabled by default, use JNLP_PROTOCOL_OPTS to alter the behavior"
    JNLP_PROTOCOL_OPTS="-Dorg.jenkinsci.remoting.engine.JnlpProtocol3.disabled=true"
  fi

  exec java $JAVA_OPTS $JNLP_PROTOCOL_OPTS -cp /usr/share/jenkins/slave.jar hudson.remoting.jnlp.Main -headless $TUNNEL $URL "$@"
fi