How to check if python package is latest version programmatically?

Question

How do you check if a package is at its latest version programmatically in a script and return a true or false?

I can check with a script like this:

Answer 1

Edit: Remove pip search

Thanks for the several suggestions. Here is a new version that doesn't use pip search but instead pulls the latest version directly from pypi as proposed by Daniel Hill. This also resolves the issue with the substring false matches.

def check(name):
    import subprocess
    import sys
    import json
    import urllib.request

    # create dictionary of package versions
    pkgs = subprocess.check_output([sys.executable, '-m', 'pip', 'freeze'])
    keys = [p.decode().split('==')[0] for p in pkgs.split()]
    values = [p.decode().split('==')[1] for p in pkgs.split()]
    d = dict(zip(keys, values)) # dictionary of all package versions

    # retrieve info on latest version
    contents = urllib.request.urlopen('https://pypi.org/pypi/'+name+'/json').read()
    data = json.loads(contents)
    latest_version = data['info']['version']

    if d[name]==latest_version:
        print('Latest version (' + d[name] + ') of '+str(name)+' is installed')
        return True
    else:
        print('Version ' + d[name] + ' of '+str(name)+' not the latest '+latest_version)
        return False

print(check('gekko'))

Original Response

Here is a fast solution that retrieves latest version information on only the gekko package of interest.

def check(name):
    import subprocess
    import sys
    # create dictionary of package versions
    pkgs = subprocess.check_output([sys.executable, '-m', 'pip', 'freeze'])
    keys = [p.decode().split('==')[0] for p in pkgs.split()]
    values = [p.decode().split('==')[1] for p in pkgs.split()]
    d = dict(zip(keys, values)) # dictionary of all package versions

    # retrieve info on latest version
    s = subprocess.check_output([sys.executable, '-m', 'pip', 'search', name])

    if d[name] in s.decode():  # weakness
        print('Latest version (' + d[name] + ') of '+str(name)+' is installed')
        return True
    else:
        print(s.decode())
        return False

print(check('gekko'))

This produces the message Latest version (0.2.3) of gekko is installed and returns True to indicate latest version (or False if not the latest version). This may not be the best solution because it only checks for a version substring with if d[name] in s.decode(): but it is faster than pip list --outdated that checks all the packages. This isn't the most reliable method because it will return an incorrect True if current installed version is 0.2.3 but latest version is 0.2.30 or 0.2.3a. An improvement would be to programmatically get the latest version and do a direct comparison.