SNOW-1296805 Remove option tmpdir from SnowflakeEncryptionUtil.decrypt_file

[sfc-gh-stan]

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1. What GitHub issue is this PR addressing? Make sure that there is an accompanying issue to your PR.

   Fixes SNOW-1296805

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3. Please describe how your code solves the related issue.

snowflake-connector-python/src/snowflake/connector/storage_client.py

Line 382 in 972accd

shutil.move(tmp_dst_file_name, self.full_dst_file_name)

is problematic where self.tmp_dir are on a different device than target directory (self.full_dst_file_name) in a network filesystem (e.g. persistent storage mounted to a docker container). Cross device file operations could cause the program to hang (especially on windows machines). We can eliminate this by making the decrypted intermediate file is written to the same directory as target directory (self.full_dst_file_name), where we know is writable.

[sfc-gh-mkeller]

Great job. Same thing should be done to encrypt_file and forever put temp directory in the rear-view mirror.
Also, be aware that we started down on the .part naming, maybe we should follow that.

[sfc-gh-mkeller]

Ohh and unfortunately this is a breaking change that needs to be announced ahead of time!

[sfc-gh-stan]

Great job. Same thing should be done to encrypt_file and forever put temp directory in the rear-view mirror. Also, be aware that we started down on the .part naming, maybe we should follow that.

encrypt_file should be immune from the cross-device file operation issue because it just writes the encrypted file to a temp dir and later deletes that file. It's also more likely that the we don't have write access to the incoming directory. I prefer keeping tmpdir in encrypt_file for that reason.

For .part naming, what decrypt_file returns should look like <filename>.part<random_suffix>. Immediately after decrypt_file returns, this file gets renamed to just the final filename and the part file is unlinked:

snowflake-connector-python/src/snowflake/connector/storage_client.py

Line 389 in 706bc2f

shutil.move(tmp_dst_file_name, self.full_dst_file_name)

. I don't think we have to worry about the filenames here too much?

[sfc-gh-mkeller]

For .part naming, what decrypt_file returns should look like .part<random_suffix>

This was done by design, I wanted to overwrite half-done download with new attempts, so a ctrl+c left file would be cleaned up on a second try