SIF Python Client

SIF Python provides a command line executable to easily give you access to a Python shell with your container loaded. After you install SIF Python, you can see the client with the command line executable “sif”:

$ sif


SIF Python v0.0.11
usage: sif [-h] [--debug] [--quiet] [--version] {shell} ...

SIF Python

optional arguments:
  -h, --help  show this help message and exit
  --debug     use verbose logging to debug.
  --quiet     show SIF Python verison and exit
  --version   suppress additional output.

actions:
  actions for SIF Python

  {shell}     sif python actions
    shell     shell into a session a client.

Version

To see the version:

$ sif --version
0.0.11

Shell

The purpose of SIF Python is to give an interactive Python shell, and so the client is currently optimized to do this. You can provide the SIF container as the first argument to get an interactive shell.

$ sif shell boxes.simg

boxes.simg is a SIF file.
SIF Header version 01
SIF Header arch 02
SIF Header uuid 0eae46df-1975-e44c-888b-8b9915f87f52
...
Python 3.6.4 |Anaconda custom (64-bit)| (default, Jan 16 2018, 18:10:19) 
Type 'copyright', 'credits' or 'license' for more information
IPython 6.2.1 -- An enhanced Interactive Python. Type '?' for help.

You get loaded for you the header, and are provided with your original image name under the variable image along with the SIFHeader class:

In [1]: header
Out[1]: <SIF:boxes.simg>

In [2]: image
Out[2]: 'boxes.simg'

In [3]: SIFHeader
Out[3]: sif.main.header.SIFHeader

Let’s look at our header! The chunk of content you are interested in are within the descriptor blocks. You’ll again see sections for the header, definition file, partition, and signature (if present). You can inspect each of these in more detail by looking at the defs dictionary:

header.desc.keys()
dict_keys(['deffile', 'partition', 'signature'])

Here is the signature block, for example:

header.desc['signature']
{'Ctime': 1546726508,
 'Datatype': 16389,
 'Filelen': 955,
 'Fileoff': 196984832,
 'Gid': 0,
 'Groupid': 4026531841,
 'ID': 3,
 'Link': 2,
 'Mtime': 1546726508,
 'Storelen': 955,
 'UID': 0,
 'Used': True,
 'hastype': 2,
 'name': 'part-signature',
 'publicKey': '-----BEGIN PGP SIGNED MESSAGE-----\nHash: SHA256\n\nSIFHASH...
...}

The header metadata is under the meta attribute:

> header.meta
{'arch': '02',
 'ctime': 1544537033,
 'datalen': 196953019,
 'dataoff': 32768,
 'descrlen': 28080,
 'descroff': 4096,
 'dfree': 45,
 'dtotal': 48,
 'mtime': 1546726508,
 'uuid': '0eae46df-1975-e44c-888b-8b9915f87f52',
 'version': '01'}

There is also a function to easily get the definition file (also a part of header.desc[‘deffile’])

> header.print_deffile()
bootstrap: docker
from: vanessa/boxes

If you have any questions or issues, please open an issue! SIF Python is a new library and its development will be driven by the needs of its users.

Getting Started