This crate / package is a rust module that handles streaming input and output. It's purpose is to tally or accumulate values for a streaming set of keys. It is designed to be stupidly simple and consume / produce whitespace seperate values.

Key Value Counts

I use this library to parse simple journal-like logs where each line is of the form:

2021-03-01 warnings:3 error ... (other items with optional counts)

Supposing I wanted to do some processing on this data. This is a very readable / writeable format, but is not standard.

We can use kvc-stream to covert it into something more lika a stream of k-value pairs or kvc-df to convert it to a pandas dataframe

Spec

The kvc journal format is very simple.

• Each line is a "frame"
• A frame has an optional "date header"
• A frame is composed of a string of whitespace-seperated keys with optional counts per key
• A '#' ends the frame, and is useful for comments

These are valid frames, one per line:

a
event event
2021-04-01 april_fools_pranks:4
2021-03-01 key another_key a-third-key <weird-symbols_ar_ok!> this_has_occured_three_times:3 this_twice this_twice
2021-04-02 # Nothing happened that day

Suppose that's stored in data.txt. (try it!)

Running <data.txt kvc-stream produces:

1 a 1
2 event 2
3 Date 2021-04-01
3 april_fools_pranks 4
4 Date 2021-03-01
4 <weird-symbols_ar_ok!> 1
4 a-third-key 1
4 this_has_occured_three_times 3
4 this_twice 2
4 key 1
4 another_key 1
5 Date 2021-04-02

Running cat data.txt | kvc-df (or < data.txt kvc-df ) produces:

index  april_fools_pranks  this_twice  a  <weird-symbols_ar_ok!>  event  Date        a-third-key  key  this_has_occured_three_times  another_key
1      0                   0           1  0                       0      0           0            0    0                             0
2      0                   0           0  0                       2      0           0            0    0                             0
3      4                   0           0  0                       0      2021-04-01  0            0    0                             0
4      0                   2           0  1                       0      2021-03-01  1            1    3                             1
5      0                   0           0  0                       0      2021-04-02  0            0    0                             0

OK, so I actually aligned the text and output an index with cat data.txt | kvc-df -i | column -t

I use this to keep a journal of events and easily scrape it for analysis in other programs or databases.