bash_prompt

#!/usr/bin/env bash
#
# DESCRIPTION:
#
#   Set the bash prompt according to:
#    * the active virtualenv / conda env
#    * 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

# 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="\[\e[0m\]"

# determine time
function parse_datetime() {
  # inconsistent across terminals or shells
  # date | tr -s ' ' | cut -d ' ' -f5
  printf '%(%H:%M:%S)T' -1
}

function set_time() {
  time_str=$(parse_datetime)
  TIME="${WHITE}(${time_str})${COLOR_NONE} "
}

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

# determine mercurial branch name
function parse_hg_branch() {
  hg branch 2>/dev/null | awk '{print " (" $1 ")"}'
}

# Determine the branch/state information for this git repository.
function set_git_branch() {
  # Get the name of the branch.
  branch=$(parse_git_branch)
  # if not git then maybe mercurial
  if [ "$branch" == "" ]; then
    branch=$(parse_hg_branch)
  fi

  # Set the final branch string.
  BRANCH="${CYAN}${branch}${COLOR_NONE} "
}

function set_k8s_namespace() {
  kubectl config view --minify -o jsonpath="{.contexts[0].context.namespace}"
}

function set_k8s_context() {
  kubectl config current-context
}

function set_k8s_prompt() {
  CONTEXT=$(set_k8s_context)
  NAMESPACE=$(set_k8s_namespace)
  K8S="${LIGHT_WHITE}[${PURPLE}${CONTEXT}|${NAMESPACE}${LIGHT_WHITE}]${COLOR_NONE}"
}

function set_aws_profile() {
  CURRENT_AWS_PROFILE=" ${WHITE}(${AWS_PROFILE})${COLOR_NONE} "
}

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

# Determine active Python virtualenv details.
# NOTE: obsolete as we're using conda envs
function set_virtualenv() {
  if test -z "$VIRTUAL_ENV"; then
    PYTHON_VIRTUALENV=""
  else
    PYTHON_VIRTUALENV="${BLUE}[$(basename \"$VIRTUAL_ENV\")]${COLOR_NONE} "
  fi
}

function set_conda_env() {
  CONDA_ENV_PROMPT="${BLUE}${CONDA_PROMPT_MODIFIER}${COLOR_NONE}"
}

# Set the full bash prompt.
function set_bash_prompt() {
  set_time

  # 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_conda_env

  # Set the BRANCH variable.
  set_git_branch

  # set k8s prompt
  set_k8s_prompt

  # set AWS profile
  set_aws_profile

  # Set the bash prompt variable.
  PS1="
${TIME}${PYTHON_VIRTUALENV} ${YELLOW}\w${COLOR_NONE}${BRANCH}${K8S}${CURRENT_AWS_PROFILE}
${PROMPT_SYMBOL} "
}

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