[tune] tune.run_experiments local_dir starting with tilde (~) is interpreted as relative path on macOS

[hartikainen]

System information

• OS Platform and Distribution (e.g., Linux Ubuntu 16.04): macOS High Sierra 10.13.1
• Ray installed from (source or binary): pip binary
• Ray version: 0.4.0
• Python version: Python 3.6.5 :: Anaconda, Inc.

Describe the problem

The following example considers local_dir to be relative to the directory where I run the script, whereas I believe it should consider it to be in the home directory. As an example, if I run the script in /Users/username/ray_local_dir_test, my results get written into /Users/username/ray_local_dir_test/~/ray_results/my_experiment instead of /Users/username/ray_results as I would expect.

This also confuses the ray.tune.log_sync.get_syncer to not correctly modify the remote_dir and thus all the files are written directly to the upload_dir instead of e.g. upload_dir/upload_dir_test/my_experiment/my_func_0_alpha=0.2,beta=2_2018-05-06_15-13-31lkpz7e9q.

import ray
from ray import tune


def my_func(config, reporter):  # add the reporter parameter
    import time, numpy as np
    i = 0
    while True:
        reporter(timesteps_total=i, mean_accuracy=i ** config['alpha'])
        i += config['beta']
        time.sleep(.01)


tune.register_trainable('my_func', my_func)
ray.init(resources={'cpu': 1})


tune.run_experiments({
    'my_experiment': {
        'run': 'my_func',
        'trial_resources': {'cpu':1},
        'stop': { 'mean_accuracy': 100 },
        'config': {
            'alpha': tune.grid_search([0.2, 0.4]),
            'beta': tune.grid_search([2]),
        },
        'local_dir': '~/ray_results',
    }
})

Happy to submit a PR to fix this. I guess the upload_dir should be run through os.path.expanduser at some point, maybe in Trial.__init__. Does that sound correct?

[richardliaw]

@hartikainen expanduser in Trial.init` in line 113 seems to be a right fix for this - would you be willing to submit a PR?

[hartikainen]

Thanks @richardliaw. Will do once I get my dev environment running.

[richardliaw]

Merged via #2013 - thanks!