Suggestion: Give us option to change format from [Jul '17] to something else, like [6/10/2017-7/9/2017]

[hub2git]

Dear dev,

My vnstat report looks like this:

root@LEDE:~# vnstat 

                      rx      /      tx      /     total    /   estimated
 wlan1:
       Jul '17     57.83 MiB  /  497.46 MiB  /  555.29 MiB
       Aug '17     50.55 MiB  /  369.29 MiB  /  419.84 MiB  /  540.00 MiB
     yesterday         0 KiB  /    2.49 MiB  /    2.49 MiB
         today         0 KiB  /      44 KiB  /      44 KiB  /      --    

 wlan0:
       Jul '17    186.26 MiB  /    1.31 GiB  /    1.49 GiB
       Aug '17    536.69 MiB  /    3.82 GiB  /    4.34 GiB  /    5.60 GiB
     yesterday     39.56 MiB  /  290.88 MiB  /  330.45 MiB
         today      1.94 MiB  /    3.10 MiB  /    5.03 MiB  /     197 MiB

I sometimes find myself looking at the monthly report and seeing something like Jul '17 and wondering, Hmmm... is that
A) the July 10 to August 9 cycle
or
B) the June 10 to July 9 cycle?

Might I suggest giving us the option of renaming them?
Some possible formats:
(Words) July 10, 2017 -- Aug. 9, 2017
or
(Pure numbers) 06/10 - 07/09/2017.

[vergoh]

You could achieve something close to that by kind of cheating a little bit. It's possible to modify MonthFormat in the configuration file to contain hardcoded characters like the "10" in your case. However, getting the end of the cycle would be a little bit trickier as even the database doesn't really have that information available.

[tolysz]

On that note could we have an option to show dates in "ISO 8601" format?

[vergoh]

The ISO 8601 format is the default starting from b6aaf0b.

[vergoh]

Some updates / notes (finally):

• The end date of the cycle is likely less of an issue with the version 2.x database format as the timestamp of each month points to the first day and first hour of each month / cycle so it would be enough to subtract one hour from the timestamp of the next cycle to get the last day of the previous cycle and if the next cycle doesn't exist then use the database update timestamp
• Getting the lengthy text to fit with rx + tx + total data on the same line while trying to keep within 80 characters is one issue. In ISO 8601 format, something like 2025-08-02/09-01 can be made to fit, "06/10 - 07/09/2017" most likely but "July 10, 2017 - Aug. 9, 2017" really doesn't want to fit.
• The second issue is configurability. Most likely it would need to be something like current DayFormat + some new configuration key for the other date so that it can be made shorter. But then comes the problem of "2025-08-02/09-01" and "06/10 - 07/09/2017" where one has the longer string first and shorter second while the other is the opposite, and obviously those separator characters would also likely need some sort of configurability. Something like CycleFormat with value like %Y-%m-%d/%m-%d could be the other option but that can't be fed directly to any date formatting function and would be problematic to parse anyway for guessing which part is supposed to be the beginning and which the end of the cycle.
• In addition to the summary output, the implementation would need to handle also monthly output + same in the image output, which is even less flexible.

[vergoh]

There's actually a far more simple solution than what I've been thinking above. The problem statement is about not knowing what the indicated month string represents when MonthRotate has a non-default value. For getting to know that, it's not necessary to repeat the information on each monthly row. Instead, it could be something as simple as:

                      rx      /      tx      /     total    /   estimated
 wlan1:
       Jul '17     57.83 MiB  /  497.46 MiB  /  555.29 MiB
       Aug '17     50.55 MiB  /  369.29 MiB  /  419.84 MiB  /  540.00 MiB
     yesterday         0 KiB  /    2.49 MiB  /    2.49 MiB
         today         0 KiB  /      44 KiB  /      44 KiB  /      --    

 wlan0:
       Jul '17    186.26 MiB  /    1.31 GiB  /    1.49 GiB
       Aug '17    536.69 MiB  /    3.82 GiB  /    4.34 GiB  /    5.60 GiB
     yesterday     39.56 MiB  /  290.88 MiB  /  330.45 MiB
         today      1.94 MiB  /    3.10 MiB  /    5.03 MiB  /     197 MiB

Monthly data begins on the 10th of each indicated month.

That extra line would be visible whenever months are shown and MonthRotate has a value other than 1. For supporting different user preferences, there would be a new configuration option for allowing to hide the line or make it permanently visible regardless of the configured MonthRotate value.

The database doesn't store the information when the month actually began from data perspective. That database field always points to the first day and hour of each month. As a result, if MonthRotate is changed then information isn't available when the change was done and how many times it was changed. That information always comes from the configuration file, not the database.