Utility Classes

The loglab.utils module provides utility classes that may be helpful when developing log processing applications.

class loglab.utils.LineDisplay(iterable)

Display a count of the number of lines processed.

A single line display can sum lines through more than one pipeline.

instrument(iter)

Return an generator that iterators through the values of iter. However as a side-effect, the LineDisplay will add the number of lines received through this iterator to its total, printing the total at regular intervals.

class loglab.utils.RandomLineFilter(iterable)

Select a random subset of lines from a log.

Useful for shortening a 1e6-line logfile for testing.

class loglab.utils.AssertLogNotEmpty(iterable)

Raises an error when iterated if no lines are received.

This class provides a useful sanity check, especially when working with logs merged from multiple sources, when it can be hard to spot that some filter or source is not yielding any log lines.