JSON Fusioncharts和Shell脚本

Question

Hoping someone can help guide me in the right direction.

We have an open source monitoring system (Nagios) that utilizes rrdtool solution for graphs. While that's great and all I want to be able to rrdfetch or rrdexport data out via the nagios shell scripts and encode those into json to leverage a cleaner looking graphing solution such as Fusioncharts.

I'm not much of a web admin so I am fumbling through looking for the right approach. What I have experimented with:

taking two variable outputs via rrd exports and producing:

echo "$label"

    22:30:00
    23:00:00
    23:30:00
    00:00:00

echo "$value"
    2.47
    2.68
    3.40
    2.43

What is the best way to get that into a json format so a solution like fusioncharts can consume it?

I have been looking at a solution called jq , which seems promising when I test / google some examples but in all honesty it's a little over my head.

jq -n "{label:\"$cat1\"}"
jq -n "{value:\"$avg1\"}"

{
  "label": "22:30:00 23:00:00 23:30:00 00:00:00"
}

{
  "value": "2.47 2.68 3.40 2.43"
}

In jsfiddle I was trying to get the shell script to output a json format like this fusionchart example.

FusionCharts.ready(function() {
    var revenueChart = new FusionCharts({
        type: 'line',
        renderAt: 'chart-container',
        width: '500',
        height: '300',
        dataFormat: 'json',
        id: 'revenue-chart',
        dataSource: {
            "chart": {
                "caption": "Sample avg times",
                "subCaption": "Sample avg times",
                "xAxisName": "time",
                "yAxisName": "avg",
                "theme": "fint",
                "rotateValues": "0"
            },

            "data": [{
                "label": "22:30:00",
                "value": "2.47"
            }, {
                "label": "23:00:00",
                "value": "2.68"
            }, {
                "label": "23:30:00",
                "value": "3.40"
            }, {
                "label": "00:00:00",
                "value": "2.43"
            },]
        }
    });

Answer 1

If you want to interpolate some values into a static piece of text, have a look at here documents.

cat <<HERE
  some static text here;
  $label
  some more static text;
  or even $(code to dynamically extract value) in the middle
  of some other text
HERE

You can easily glue together parts, too:

printf 'static\nheader\ntext'
jq something |
while read -r snippet; do  # reads one line from jq at a time
    printf 'stuff around %s goes here\n' "$snippet"
done
echo 'static
tail
can be multi-line string, too!'
tr ':' '\n' <<<"multi:line:string:with:$value:in:it"  # here string, bash only

Whether you use cat with a here document, or a printf (or just plain echo , or, say, date with a creative format string -- actually, anything which produces text on standard output) to produce the string doesn't really matter from a performance or usability point of view; use whichever feels the most natural.