[rrd-developers] rrdtool fetch / JSON-Output

Michael Markstaller mm at elabnet.de
Thu Jan 12 23:53:58 CET 2012


my first post to the list and to be honest: I havent followed this list 
and rrdtool development for many years though using it widely & every 
single day. It just worked to well ;)

I created a little patch to make "rrdtool fetchj .." simply output json 
instead of text, attached.

Intentions, the answers to why etc:
- Target-Platforms are rather low-end (AMD Geode, OpenWRT Routers), so 
with rrdtool 1.3, 1.4 was dead slow in graphing on these low-ends during 
my tests.
- avoid (another) shellscript or CGI to wrap "rrdtool fetch" output into 
JSON what I needed to feed jQuery/Flot in this case.
- but "rrdtool fetch" does exactly what I need, with all it's benefits, 
fast, small data to transfer, right data, autoscaling etc.pp.

Please let me know your thoughts, if it makes sense at all.
I know for sure that a patch against an rather old version isn't perfect 
but it was as mentioned chosen precisely..

Could also do it for current 1.4/trunk but it's currently not my goal 
because of serious performance-problems (which might have many other 
causes than rrdtool itself for sure!)

best regards

Michael Markstaller

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