Correctly handle the case where the destination folder does not exist in local mode

[derekhh]

Issue #, if available:

Description of changes:

Right now local mode would break if the output_path is a file:// but doesn't exist yet. This PR uses distutils.dir_util.copy_tree to handle this.

I've verified via a local job that the change fixes the issue.

Previous stack trace:

tmp8gc4u4zv_algo-1-RQ5K9_1_ce427f3ec602 exited with code 0
Aborting on container exit...
Traceback (most recent call last):
  File "sagemaker_train.py", line 107, in <module>
    submit_sagemaker_job(args.image_name, args.role_name, args.config_path)
  File "sagemaker_train.py", line 96, in submit_sagemaker_job
    estimator.fit(inputs=inputs, wait=False, job_name=job_name)
  File "/home/ubuntu/.virtualenvs/sagemaker-sdk_py3/lib/python3.5/site-packages/sagemaker/estimator.py", line 209, in fit
    self.latest_training_job = _TrainingJob.start_new(self, inputs)
  File "/home/ubuntu/.virtualenvs/sagemaker-sdk_py3/lib/python3.5/site-packages/sagemaker/estimator.py", line 444, in start_new
    tags=estimator.tags)
  File "/home/ubuntu/.virtualenvs/sagemaker-sdk_py3/lib/python3.5/site-packages/sagemaker/session.py", line 277, in train
    self.sagemaker_client.create_training_job(**train_request)
  File "/home/ubuntu/.virtualenvs/sagemaker-sdk_py3/lib/python3.5/site-packages/sagemaker/local/local_session.py", line 74, in create_training_job
    training_job.start(InputDataConfig, OutputDataConfig, hyperparameters, TrainingJobName)
  File "/home/ubuntu/.virtualenvs/sagemaker-sdk_py3/lib/python3.5/site-packages/sagemaker/local/entities.py", line 70, in start
    self.model_artifacts = self.container.train(input_data_config, output_data_config, hyperparameters, job_name)
  File "/home/ubuntu/.virtualenvs/sagemaker-sdk_py3/lib/python3.5/site-packages/sagemaker/local/image.py", line 132, in train
    artifacts = self.retrieve_artifacts(compose_data, output_data_config, job_name)
  File "/home/ubuntu/.virtualenvs/sagemaker-sdk_py3/lib/python3.5/site-packages/sagemaker/local/image.py", line 238, in retrieve_artifacts
    self.sagemaker_session)
  File "/home/ubuntu/.virtualenvs/sagemaker-sdk_py3/lib/python3.5/site-packages/sagemaker/local/utils.py", line 55, in move_to_destination
    recursive_copy(source, parsed_uri.path)
  File "/home/ubuntu/.virtualenvs/sagemaker-sdk_py3/lib/python3.5/site-packages/sagemaker/local/utils.py", line 81, in recursive_copy
    shutil.copy(os.path.join(current_path, file), os.path.join(target_path, file))
  File "/home/ubuntu/.virtualenvs/sagemaker-sdk_py3/lib/python3.5/shutil.py", line 235, in copy
    copyfile(src, dst, follow_symlinks=follow_symlinks)
  File "/home/ubuntu/.virtualenvs/sagemaker-sdk_py3/lib/python3.5/shutil.py", line 115, in copyfile
    with open(dst, 'wb') as fdst:
FileNotFoundError: [Errno 2] No such file or directory: '/tmp/model-output/./output.tar.gz'

With this change:

tmp28hhnmra_algo-1-JYEW7_1_759be53ea024 exited with code 0
Aborting on container exit...
WARNING:sagemaker.local.image:Failed to delete: /tmp/tmp28hhnmra/algo-1-JYEW7 Please remove it manually.
===== Job Complete =====

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• I have read the CONTRIBUTING doc
• I have added tests that prove my fix is effective or that my feature works (if appropriate)
• I have updated the changelog with a description of my changes (if appropriate)
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By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov-io]

Codecov Report

Merging #458 into master will decrease coverage by 0.15%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #458      +/-   ##
==========================================
- Coverage   94.02%   93.87%   -0.16%     
==========================================
  Files          57       57              
  Lines        4269     4262       -7     
==========================================
- Hits         4014     4001      -13     
- Misses        255      261       +6

Impacted Files	Coverage Δ
src/sagemaker/local/utils.py	96.15% <100%> (-0.82%)	⬇️
src/sagemaker/local/image.py	88.08% <0%> (-1.89%)	⬇️

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[derekhh]

Kindly ping @iquintero ? Thanks!

[iquintero]

Can you add a changelog entry? And a unit test for this would be nice as well. Otherwise looks good.

[derekhh]

@iquintero - Thanks for the review.

Actually, I've made some updates and used distutils.dir_util.copy_tree instead of the original implementation in recursive_copy. I've also updated the CHANGELOG and the unit test. Can you help take another look? Thanks!

[derekhh]

@iquintero - Thanks for the approval! Can you also help merge this PR? I don't think I can merge it. :p