Helper functions for using Docker in shell scripts

The script docker-shell-helpers.sh provides a list of helper functions for making even simpler the creation, usage, and destruction of Docker containers inside a shell script.

List of Helper Functions

The docker-shell-helpers library currently provides the following public functions:

• container_id()
  • desc: return the Docker Id of a container
  • args: container name
• container_exists()
  • desc: return true if the container exists, and false otherwise
  • args: container name
• container_is_running()
  • desc: return true if the container is running, and false otherwise
  • args: container name
• container_stop()
  • desc: stop a container, if it's running
  • args: container name
• container_remove()
  • desc: stop and remove a container from the host node
  • args: container name
• container_exec_command()
  • desc: run a command (or a sequence of commands) inside a container
  • args: container name
• container_property()
  • desc: get a container property
  • args: container name and one of the options: --id, --ipaddr, --os
• container_create()
  • desc: create a container and return its name
  • args: --name (or --random-name), --os and a host folder (--disk) to map
  • example: container_create --random-name --os "centos:latest" --disk ~/docker-datadisk:/shared:rw
• container_start()
  • desc: start a container if not running
  • args: container name
• container_status_table()
  • desc: return the status of a container
  • args: container name of no args to list all the containers
• container_list()
  • desc: return the available container name
  • args: none

Example

Here's is a simple example of how the library functions can be used.

. docker-shell-helpers.sh

cname="$(container_create --random-name --os "centos:latest")"
container_list | while read elem; do echo " - $elem"; done
  #--> - centos.latest_kw05yg2Y

container_start $cname
echo "The running OS is: $(container_property --os $cname)"
  #--> The running OS is: centos-7.2.1511

container_exec_command $cname "\
   yum install -y autoconf automake gcc git make
   cd /root
   git clone https://github.com/madrisan/nagios-plugins-linux
   cd nagios-plugins-linux
   autoreconf
   ./configure && make && ./plugins/check_uptime --clock-monotonic
"
  #--> ...
  #    uptime OK: 19 hours 18 min | uptime=1158

container_remove $cname