Simple data logging to COSM for online graphs

[bgirardot]

I wanted to try out COSM, a website that allows you to feed it data and it stores and graphs the data. I still don't quite know all the details, I am only using the free version.

Anyway, I created a simple feed of the load averages of my RPi, which runs nothing but the stock raspbian 09-18-2012 image and does nothing but run my little shell script. Eventually I will be using COSM to log current and voltage data from a portable solar generator.

The feed is located here:
https://cosm.com/feeds/82165

Here are the steps I followed if anyone is interested in doing something similar:

1. Created a COSM account
2. Created a COSM feed, "something else", push data to feed
3. Created 3 datastreams in that feed
4. Generated an API key in COSM for the feed with 'update' permissions
5. Wrote a 1 line sed "script" on my RPi to transform /proc/loadavg to JSON format for COSM. I am not sure how this will display, but here is the one line:

Code: Select all

s/\([0-9]*\.[0-9][0-9]\) \([0-9]*\.[0-9][0-9]\) \([0-9]*\.[0-9][0-9]\)\(.*\)/{"datastreams":[ {"id":"5min","current_value":"\1"},{"id":"10min","current_value":"\2"},{"id":"15min","current_value":"\3"} ]}/

6. I made a two line shell script to transform /proc/loadavg to JSON and save it out to a file and the use curl to send it to COSM

Code: Select all

sed -f cosm-test.sed /proc/loadavg > cosm-test.json
curl --request PUT --data-binary @cosm-test.json --header "X-ApiKey: api_key_I_generated_here" http://api.cosm.com/v2/feeds/82165

7. Created a crontab entry to call my shell script once a minute

I just wanted to create a post about it because I have so far found COSM to be pretty easy to use and a nice service.

[joan]

It might also be worth considring gnuplot for generating graphs. Feed it a series of numbers or number pairs and it usually comes up with a sensible graph.

[Tafkas]

I will definitily look into cosm. So far I have been generating my charts using munin:

[bgirardot]

Thank you for the heads up on gnuplot and munin, I was just thinking that cosm didn't seem to offer a lot of options for different types of graphs, but that may just be my unfamiliarity with it still.

Cosm does make it easier for me in the sense that I don't have to run a web server anywhere to make my data public and they have a bit of a renewable energy community focus. Cosm lets you pull the data back via json, xml or csv so maybe I end up with an upload to cosm just for storage and public access and then nicer, more flexible local graphs via gnuplot or munin.

Thanks again.