pycloudlib.util module

Helpers for shell string and processing.

pycloudlib.util.chmod(path, mode)

Run chmod on a file or directory.

Parameters:

• path – string of path to run on
• mode – int of mode to apply

pycloudlib.util.get_timestamped_tag(tag)

Create tag with current timestamp.

Parameters:tag – string, Base tag to be used

Returns

An updated tag with current timestamp

pycloudlib.util.is_writable_dir(path)

Make sure dir is writable.

Parameters:path – path to determine if writable Returns:boolean with result

pycloudlib.util.mkdtemp(prefix='pycloudlib')

Make a temporary directory.

Parameters:prefix – optional, temproary dir name prefix (default: pycloudlib) Returns:tempfile object that was created

pycloudlib.util.rmfile(path)

Delete a file.

Parameters:path – run unlink on specific path

pycloudlib.util.shell_pack(cmd)

Return a string that can shuffled through ‘sh’ and execute cmd.

In Python subprocess terms:

check_output(cmd) == check_output(shell_pack(cmd), shell=True)

Parameters:cmd – list or string of command to pack up Returns:base64 encoded string

pycloudlib.util.shell_quote(cmd)

Quote a shell string.

Parameters:cmd – command to quote Returns:quoted string

pycloudlib.util.shell_safe(cmd)

Produce string safe shell string.

Create a string that can be passed to $(set – <string>) to produce the same array that cmd represents.

Internally we utilize ‘getopt’s ability/knowledge on how to quote strings to be safe for shell. This implementation could be changed to be pure python. It is just a matter of correctly escaping or quoting characters like: ‘ ” ^ & $ ; ( ) …

Parameters:cmd – command as a list Returns:shell safe string

pycloudlib.util.subp(args, data=None, env=None, shell=False, rcs=(0, ), shortcircuit_stdin=True)

Subprocess wrapper.

Parameters:

• args – command to run
• data – data to pass
• env – optional env to use
• shell – optional shell to use
• rcs – tuple of successful exit codes, default: (0)
• shortcircuit_stdin – bind stdin to /dev/null if no data is given

Returns:

Tuple of out, err, return_code

pycloudlib.util.touch(path, mode=None)

Ensure a directory exists with a specific mode, it not create it.

Parameters:

• path – path to directory to create
• mode – optional, mode to set directory to

pycloudlib.util.update_nested(mapping, update)

Update mapping with update value at given update key.

Example

original_dict = {‘a’: {‘b’: {‘c’: ‘d’}}} update = {‘a’: {‘b’: {‘c’: ‘e’}}} update_nested(original_dict, update) original_dict == {‘a’: {‘b’: {‘c’: ‘e’}}}

pycloudlib.util.validate_tag(tag)

Ensure tag will work as name for clouds that use it.