dot_bash_prompt

#!/usr/bin/env bash
#
# DESCRIPTION:
#
#   Set the bash prompt according to:
#    * the active virtualenv
#    * the branch of the current git/mercurial repository
#    * the return value of the previous command
#
# USAGE:
#
#   1. Save this file as ~/.bash_prompt
#   2. Add the following line to the end of your ~/.bashrc or ~/.bash_profile:
#        . ~/.bash_prompt
#
# LINEAGE:
#
#   Based on work by woods
#
#   https://gist.github.com/31967

# shellcheck disable=SC2034
# The various escape codes that we can use to color our prompt.
       BLACK="\[\033[0;30m\]"
 LIGHT_BLACK="\[\033[1;30m\]"
         RED="\[\033[0;31m\]"
   LIGHT_RED="\[\033[1;31m\]"
       GREEN="\[\033[0;32m\]"
 LIGHT_GREEN="\[\033[1;32m\]"
      YELLOW="\[\033[0;33m\]"
LIGHT_YELLOW="\[\033[1;33m\]"
        BLUE="\[\033[0;34m\]"
  LIGHT_BLUE="\[\033[1;34m\]"
      PURPLE="\[\033[0;35m\]"
LIGHT_PURPLE="\[\033[1;35m\]"
        CYAN="\[\033[0;36m\]"
  LIGHT_CYAN="\[\033[1;36m\]"
       WHITE="\[\033[0;37m\]"
 LIGHT_WHITE="\[\033[1;37m\]"
  COLOR_NONE="\[\e[0m\]"

function swatch() {
  echo "black${BLACK}black${COLOR_NONE}"
  echo "light black${LIGHT_BLACK}light black${COLOR_NONE}"
  echo "red${RED}red${COLOR_NONE}"
  echo "light red${LIGHT_RED}light red${COLOR_NONE}"
  echo "green${GREEN}green${COLOR_NONE}"
  echo "light green${LIGHT_GREEN}light green${COLOR_NONE}"
  echo "yellow${YELLOW}yellow${COLOR_NONE}"
  echo "light yellow${LIGHT_YELLOW}light yellow${COLOR_NONE}"
  echo "blue${BLUE}blue${COLOR_NONE}"
  echo "light blue${LIGHT_BLUE}light blue${COLOR_NONE}"
  echo "purple${PURPLE}purple${COLOR_NONE}"
  echo "light purple${LIGHT_PURPLE}light purple${COLOR_NONE}"
  echo "cyan${CYAN}cyan${COLOR_NONE}"
  echo "light cyan${LIGHT_CYAN}light cyan${COLOR_NONE}"
  echo "white${WHITE}white${COLOR_NONE}"
  echo "light white${LIGHT_WHITE}light white${COLOR_NONE}"
}

# determine git branch name
function parse_git_branch() {
  command git branch 2> /dev/null | sed -e '/^[^*]/d' -e 's/* \(.*\)/(\1)/'
}

function parse_git_dirty() {
  if test -n "$(git status --porcelain)" ; then
    echo -n " *"
  fi
}

# Determine the branch/state information for this git repository.
function set_git_branch() {
  if (command -v git && command git rev-parse --git-dir) > /dev/null 2>&1 ; then
    # Get the name of the branch.
    branch=$(parse_git_branch)
    dirty=$(parse_git_dirty)

    # Set the final branch string.
    BRANCH="${RED}${branch}${LIGHT_RED}${dirty}${COLOR_NONE} "
  else
    BRANCH=""
  fi
}

function set_k8s_namespace() {
  command kubectl config view --minify -o jsonpath="{.contexts[0].context.namespace}" 2>/dev/null
}

function set_k8s_context() {
  command kubectl config current-context 2>/dev/null
}

function set_k8s_prompt () {
  if command -v kubectl > /dev/null 2>&1 ; then
    CONTEXT=$(set_k8s_context)
    NAMESPACE=$(set_k8s_namespace)
    if [ -n "${NAMESPACE}" ] ; then
      K8S="${LIGHT_GREEN}${CONTEXT}${WHITE}|${GREEN}${NAMESPACE}${COLOR_NONE} "
    else
      K8S="${LIGHT_GREEN}${CONTEXT}${COLOR_NONE} "
    fi
  else
    K8S=""
  fi
}

function set_shlvl_prompt() {
  if [ -n "${SSH_TTY}" ] ; then
    SSH_SESSION="${YELLOW}-ssh-${COLOR_NONE} "
  else
    SSH_SESSION=""
  fi
  SHLVL_PROMPT="${SSH_SESSION} ${LIGHT_CYAN}(${SHLVL})${COLOR_NONE}"
}

# Return the prompt symbol to use, colorized based on the return value of the
# previous command.
function set_prompt_symbol () {
  if test "$(id -u)" -eq 0; then
    SYM="#"
  else
    SYM="\$"
  fi
  if test "$1" -eq 0 ; then
    PROMPT_SYMBOL="${SYM}"
  else
    PROMPT_SYMBOL="${LIGHT_RED}$1 ${SYM}${COLOR_NONE}"
  fi
}

# Determine active Python virtualenv details.
function set_virtualenv () {
  if test -z "$VIRTUAL_ENV" ; then
    PYTHON_VIRTUALENV=""
  else
    # shellcheck disable=SC2006
    PYTHON_VIRTUALENV="${LIGHT_WHITE}[`basename \"$VIRTUAL_ENV\"`]${COLOR_NONE} "
  fi
}

function set_date_prompt () {
  DATE_PROMPT="${WHITE}$(date +'%H:%M:%S')${COLOR_NONE} "
}

# Set the full bash prompt.
function set_bash_prompt () {
  # Set the PROMPT_SYMBOL variable. We do this first so we don't lose the
  # return value of the last command.
  set_prompt_symbol $?

  # Set the PYTHON_VIRTUALENV variable.
  set_virtualenv

  # Set the BRANCH variable.
  set_git_branch

  # set k8s prompt
  set_k8s_prompt

  # set date string
  set_date_prompt

  USERLINE="${CYAN}\u@${LIGHT_CYAN}\h${COLOR_NONE}:${LIGHT_YELLOW}\w${COLOR_NONE} "

  # Set the bash prompt variable.
  PS1="
${PYTHON_VIRTUALENV}${USERLINE}${BRANCH}${K8S}
${DATE_PROMPT}${PROMPT_SYMBOL} "
}

# Tell bash to execute this function just before displaying its prompt.
PROMPT_COMMAND=set_bash_prompt