Figure out how to clamp JSON values

[lbussy]

Different events (opening fridge to check on things, dry hopping, etc) can result in an abnormal spike or dip in values which are brief but which skew the scale of the chart. Figure out a way to clamp those values.

This could be done at the source (script) for "sane" values to avoid sensor errors (85°/185°F), but it would be desirable to allow a configurable clamp after the fact for display purposes.

Have to decide if this is going to be a destructive clamp (edit the JSON) or inline to the dygraph.

[lbussy]

Possible path:

Use jq to clamp the values of a given column:

jq --arg col 'FridgeSet' --argjson mx 62 --argjson mn 60 'def clamp: if . > $mx then $mx elif . < - $mn then - $mn else . end;(.cols | map(.id) | index($col)) as $ix | .rows[].c[$ix].v |= clamp' input.json

If we do this like a sed -i (inline), need to use something like the GNU moreutils tool sponge along the lines of:

jq --arg col 'FridgeSet' --argjson mx 62 --argjson mn 60 'def clamp: if . > $mx then $mx elif . < - $mn then - $mn else . end;(.cols | map(.id) | index($col)) as $ix | .rows[].c[$ix].v |= clamp' input.json | sponge input.json

[lbussy]

This is done in devel, closing.