Doing stuff apt-get does

Author:Julian Andres Klode <jak@debian.org> Release:1.4.0~beta3 Date:January 15, 2019

The following article will show how you can use python-apt to do actions done by the apt-get command.

Printing the URIs of all index files

We all now that we can print the URIs of all our index files by running a simple apt-get --print-uris update. We can do the same. Responsible for the source entries is the class apt_pkg.SourceList, which can be combined with an apt_pkg.Acquire object using get_indexes().

First of all, we have to create the objects:

acquire = apt_pkg.Acquire()
slist = apt_pkg.SourceList()

Now we have to parse /etc/apt/sources.list and its friends, by using apt_pkg.SourceList.read_main_list():

slist.read_main_list()

The slist object now knows about the location of the indexes. We now have to load those indexes into the acquire object by calling apt_pkg.SourceList.get_indexes():

slist.get_indexes(acquire, True)

The first argument is the acquire object into which we will load these indexes, and the second argument means that we want to fetch all indexes. Now the only thing left to do is iterating over the list of items and printing out their URIs. Luckily, there is apt_pkg.Acquire.items which allows us to iterate over the items:

for item in acquire.items:
    print(item.desc_uri)

In the end a program could look like this:

#!/usr/bin/python
"""Print out the URIs of all indexes files.

This behaves somewhat like apt-get --print-uris update."""
import apt_pkg


def main():
    apt_pkg.init_config()
    apt_pkg.init_system()
    acquire = apt_pkg.Acquire()
    slist = apt_pkg.SourceList()
    # Read the list
    slist.read_main_list()
    # Add all indexes to the fetcher.
    slist.get_indexes(acquire, True)

    # Now print the URI of every item.
    for item in acquire.items:
        print(item.desc_uri)

if __name__ == '__main__':
    main()