#!/usr/bin/env python2
#
# OpenStack allows a client to have multiple "projects". To access the
# OpenStack API, the client side libraries need some environment
# variables set (OS_AUTH_URL, OS_PROJECT_NAME, etc), to tell the
# libraries which OpenStack user and project, etc, are used. (As an
# aside, one of the environment variblaes is OS_PASSWORD, which is a
# bad idea, but we can't help that.) 
#
# OpenStack allows you to download shell "rc" scripts that you source
# (". foorc.sh") to set up the environment variables. However, it gets
# a bit tedious to manage several such rc scripts. Also, each script
# wants you to enter the API password manually, which is just nasty.
#
# This is os-rchelper, which improves the situation a bit:
#
#    * it reads the environment variables from a YAML file, indexed
#      by a project name given on the command line (you'll need to
#      download the rc script and copy the values to the config file)
#
#    * it reads the password with pass(1) so nothing needs to be typed
#      manually (i.e., don't put OS_PASSWORD in the config file)
#
# Additionally, this script unsets any pre-existing OS_* environment
# variables.
#
# To use this helper:
#
# 1. Save API password with pass:
#
#       pass insert openstack-foo
#
#    You need to have pass and gpg set up for this to work.
#
# 2. Create ~/.config/qvarnlabs/openstack.conf (see example below). Add
#    the key openstack-pass-name in addition to the OS_* environment
#    variables. Set openstack-pass-name to the key name you gave
#    pass (openstack-foo above).
#
# 3. To set up a shell session:
#
#       eval `os-rchelper foo`
#
# You may want to define a shell function to make this easier (put it
# in .bashrc or similar file):
#
#    osrc() { eval `./os-rchelper "$1"`; }
#
# Example conf file (~/.config/qvarnlabs/openstack.conf):
#
# dev:
#   openstack-pass-name: qvarnlabs-nebula-cloud
#   OS_AUTH_URL: "https://identity.fi-1.nebulacloud.fi:5000/v3"
#   OS_PROJECT_ID: "2603e0bfcf624053945a35afa1730dc8"
#   OS_PROJECT_NAME: "QvarnLabs development"
#   OS_USER_DOMAIN_NAME: "Default"
#   OS_USERNAME: "liw@qvarnlabs.com"
#   OS_REGION_NAME: "fi-1"
#   OS_INTERFACE: "public"
#   OS_IDENTITY_API_VERSION: 3
# infra:
#   openstack-pass-name: qvarnlabs-nebula-cloud
#   OS_AUTH_URL: "https://identity.fi-1.nebulacloud.fi:5000/v3"
#   OS_PROJECT_ID: "5b0e1abf166442f2967edc5233f2e6a6"
#   OS_PROJECT_NAME: "QvarnLabs Infra"
#   OS_USER_DOMAIN_NAME: "Default"
#   OS_USERNAME: "liw@qvarnlabs.com"
#   OS_REGION_NAME: "fi-1"
#   OS_INTERFACE: "public"
#   OS_IDENTITY_API_VERSION: 3
#
# See:
# - https://control.nebulacloud.fi/project/access_and_security/
#   for downloading rc files (one per project in OpenStack) from the
#   Nebula clou


import os
import pipes
import subprocess
import sys

import yaml


def env(name, value):
    sys.stdout.write('export {}={};\n'.format(name, pipes.quote(value)))


project_name = sys.argv[1]

filename = os.path.expanduser('~/.config/qvarnlabs/openstack.conf')
with open(filename) as f:
    conf = yaml.safe_load(f)


keyname = conf[project_name]['openstack-pass-name']
p = subprocess.Popen(['pass', 'show', keyname], stdout=subprocess.PIPE)
password, stderr = p.communicate('')
password = password.rstrip()

keys_to_remove = [x for x in os.environ if x.startswith('OS_')]
for key in keys_to_remove:
    sys.stdout.write('unset {};\n'.format(key))

keys = conf[project_name].keys()
keys.remove('openstack-pass-name')
for key in sorted(keys):
    env(key, conf[project_name][key])
env('OS_PASSWORD', password)