I have used my own HTML5/Javascript page to visualize data over time but without logging. I have used a trailing 16 sample plot window for temperature, for instance. The downside is that data is gone when your browsers closes, but for looking at trends this is sometimes OK.
If you don’t need visualization, just logging then there are lots of other alternatives.
I tend to use Librato Metrics https://www.librato.com/ and just have a small python script getting the data from the Spark Cloud or MQTT and submitting it to Librato.