Here is one way to test which YAML implementation the user has selected on the virtualenv (or the system) and then define load_yaml_file appropriately:
load_yaml_file = None
if not load_yaml_file:
try:
import yaml
load_yaml_file = lambda fn: yaml.load(open(fn))
except:
pass
if not load_yaml_file:
import commands, json
if commands.getstatusoutput('ruby --version')[0] == 0:
def load_yaml_file(fn):
ruby = "puts YAML.load_file('%s').to_json" % fn
j = commands.getstatusoutput('ruby -ryaml -rjson -e "%s"' % ruby)
return json.loads(j[1])
if not load_yaml_file:
import os, sys
print """
ERROR: %s requires ruby or python-yaml to be installed.
apt-get install ruby
OR
apt-get install python-yaml
OR
Demonstrate your mastery of Python by using pip.
Please research the latest pip-based install steps for python-yaml.
Usually something like this works:
apt-get install epel-release
apt-get install python-pip
apt-get install libyaml-cpp-dev
python2.7 /usr/bin/pip install pyyaml
Notes:
Non-base library (yaml) should never be installed outside a virtualenv.
"pip install" is permanent:
https://stackoverflow.com/questions/1550226/python-setup-py-uninstall
Beware when using pip within an aptitude or RPM script.
Pip might not play by all the rules.
Your installation may be permanent.
Ruby is 7X faster at loading large YAML files.
pip could ruin your life.
https://stackoverflow.com/questions/46326059/
https://stackoverflow.com/questions/36410756/
https://stackoverflow.com/questions/8022240/
Never use PyYaml in numerical applications.
https://stackoverflow.com/questions/30458977/
If you are working for a Fortune 500 company, your choices are
1. Ask for either the "ruby" package or the "python-yaml"
package. Asking for Ruby is more likely to get a fast answer.
2. Work in a VM. I highly recommend Vagrant for setting it up.
""" % sys.argv[0]
os._exit(4)
# test
import sys
print load_yaml_file(sys.argv[1])