Sort Lines in Text File by Timestamp with Ruby

Question

I'm trying to sort a series of logs according to the timestamp. I am only able to sort by month given the sort() function by reading the file into a temporary array, but I would like to implement possibly a regular expression to grab a section of the string to sort by.

The regular expression I use to grab the lines is:

LOGGER_LINE = /([a-zA-Z]{3} \d{1,2}, \d{4} \d{1,2}:\d{2}:\d{2} (AM|PM) (\(SEVERE\)|\(WARNING\)).*)/

And I can produce an output like so:

[FILENAME]
    Feb 16, 2014 1:00:10 AM (SEVERE) Thread: 14 [com.refresh.RefreshActionQueue.write] Could not write RefreshAction checkpoint due to error
    Feb 16, 2014 1:00:10 AM (SEVERE) Thread: 14 [com.refresh.RefreshActionQueue.write] Could not write RefreshAction checkpoint due to error
    Feb 16, 2014 1:00:10 AM (SEVERE) Thread: 14 [com.refresh.RefreshActionQueue.write] Could not write RefreshAction checkpoint due to error
    Feb 16, 2014 1:00:10 AM (SEVERE) Thread: 14 [com.refresh.RefreshActionQueue.write] Could not write RefreshAction checkpoint due to error
    Feb 16, 2014 1:00:20 AM (SEVERE) Thread: 14 [com.refresh.RefreshActionQueue.write] Could not write RefreshAction checkpoint due to error
    Feb 17, 2014 1:00:00 AM (SEVERE) Thread: 18 [com.refresh.RefreshActionQueue.write] Could not write RefreshAction checkpoint due to error
    Feb 17, 2014 1:00:00 AM (SEVERE) Thread: 14 [com.refresh.RefreshActionQueue.write] Could not write RefreshAction checkpoint due to error
    Feb 17, 2014 1:00:00 AM (SEVERE) Thread: 14 [com.refresh.RefreshActionQueue.write] Could not write RefreshAction checkpoint due to error
    Feb 17, 2014 1:00:00 AM (SEVERE) Thread: 14 [com.refresh.RefreshActionQueue.write] Could not write RefreshAction checkpoint due to error
    Feb 17, 2014 1:00:10 AM (SEVERE) Thread: 14 [com.refresh.RefreshActionQueue.write] Could not write RefreshAction checkpoint due to error
    Feb 17, 2014 1:00:10 AM (SEVERE) Thread: 14 [com.refresh.RefreshActionQueue.write] Could not write RefreshAction checkpoint due to error
    Feb 17, 2014 1:00:10 AM (SEVERE) Thread: 14 [com.refresh.RefreshActionQueue.write] Could not write RefreshAction checkpoint due to error
    Feb 17, 2014 1:00:10 AM (SEVERE) Thread: 14 [com.refresh.RefreshActionQueue.write] Could not write RefreshAction checkpoint due to error
    Feb 17, 2014 1:00:20 AM (SEVERE) Thread: 14 [com.refresh.RefreshActionQueue.write] Could not write RefreshAction checkpoint due to error
    Feb 18, 2014 1:00:00 AM (SEVERE) Thread: 18 [com.refresh.RefreshActionQueue.write] Could not write RefreshAction checkpoint due to error
    Feb 18, 2014 1:00:00 AM (SEVERE) Thread: 14 [com.refresh.RefreshActionQueue.write] Could not write RefreshAction checkpoint due to error
    Feb 18, 2014 1:00:00 AM (SEVERE) Thread: 14 [com.refresh.RefreshActionQueue.write] Could not write RefreshAction checkpoint due to error
    Feb 18, 2014 1:00:00 AM (SEVERE) Thread: 14 [com.refresh.RefreshActionQueue.write] Could not write RefreshAction checkpoint due to error
    Feb 18, 2014 1:00:10 AM (SEVERE) Thread: 14 [com.refresh.RefreshActionQueue.write] Could not write RefreshAction checkpoint due to error
    Feb 18, 2014 1:00:10 AM (SEVERE) Thread: 14 [com.refresh.RefreshActionQueue.write] Could not write RefreshAction checkpoint due to error
    Feb 18, 2014 1:00:10 AM (SEVERE) Thread: 14 [com.refresh.RefreshActionQueue.write] Could not write RefreshAction checkpoint due to error
    Feb 18, 2014 1:00:10 AM (SEVERE) Thread: 14 [com.refresh.RefreshActionQueue.write] Could not write RefreshAction checkpoint due to error
    Feb 18, 2014 1:00:20 AM (SEVERE) Thread: 14 [com.refresh.RefreshActionQueue.write] Could not write RefreshAction checkpoint due to error
[FILENAME_2]
    Feb 14, 2014 9:29:01 AM (WARNING) Thread: 26 [com.queue.lookupUtility.keyValueListAsMap] Failed to process standard key/value pair format.
    Feb 14, 2014 9:33:50 AM (WARNING) Thread: 26 [com.queue.lookupUtility.keyValueListAsMap] Failed to process standard key/value pair format.
    Feb 14, 2014 10:22:31 AM (WARNING) Thread: 27 [com.queue.lookupUtility.keyValueListAsMap] Failed to process standard key/value pair format.
    Feb 14, 2014 10:39:31 AM (WARNING) Thread: 28 [com.queue.lookupUtility.keyValueListAsMap] Failed to process standard key/value pair format.
    Feb 14, 2014 10:40:31 AM (WARNING) Thread: 28 [com.queue.lookupUtility.keyValueListAsMap] Failed to process standard key/value pair format.
    Feb 18, 2014 8:43:45 AM (WARNING) Thread: 13 [com.nioHandler]Closing socket to endpoint Address[127.0.0.1:5703], Cause:java.io.EOFException

However my end goal is to sort the timestamps and their according error in descending order.

Might there be a way I can sort the lines according to the timestamp that is matched by the LOGGER_LINE regex? Other suggestions on sorting the timestamp would be excellent.

Answer 1

You should not reinvent the wheel. The time library parses the strings that you have. For example, given the line:

l = "Feb 16, 2014 1:00:10 AM (SEVERE) Thread: 14 [com.refresh.RefreshActionQueue.write] Could not write RefreshAction checkpoint due to error"

The time can be extracted like this:

require "time"
Time.parse(l)
# => 2014-02-16 01:00:10 +0900

So, if you have an array say, array_of_lines of such lines, you can do:

require "time"
array_of_lines.sort_by{|l| Time.parse(l)}.reverse