Custom prompt showing the current Docker context configured using environment variables. ZSH theme is "agnoster". This gist is not the whole zshrc file, only the relevant parts.

zsh-docker-context-prompt-agnoster.sh

ZSH_THEME="agnoster"

plugins=(git docker docker-compose)

prompt_docker_host() {
  docker_icon="\xF0\x9F\x90\xB3"
  if [[ -n "$DOCKER_HOST" ]]; then
    if [[ -n "$DOCKER_CONTEXT_HOST" ]] && [[ "$DOCKER_CONTEXT_HOST" == "$DOCKER_HOST" ]]; then
      prompt_segment red default "$docker_icon $DOCKER_CONTEXT"
    else
      prompt_segment red default "$docker_icon $DOCKER_HOST"
    fi
  elif [[ -n "$DOCKER_CONTEXT" ]]; then
    prompt_segment red default "$docker_icon $DOCKER_CONTEXT"
  fi
}

build_prompt() {
 RETVAL=$?
 prompt_status
 prompt_virtualenv
 prompt_context
 prompt_dir
 prompt_git
 prompt_docker_host
 prompt_end
 echo
 echo " » "
}