Added text collector conversion for ipmitool output. (#746)

* Added text collector conversion for ipmitool output.

* Sort metrics before exporting, add namespace.

* Added HELP string, tidy up a bit.

* Make status a gauge.

text_collector_examples/ipmitool

+#!/usr/bin/awk -nf
+
+#
+# Converts output of `ipmitool sensor` to prometheus format.
+#
+# With GNU awk:
+#   ipmitool sensor | ./ipmitool > ipmitool.prom
+#
+# With BSD awk:
+#   ipmitool sensor | awk -f ./ipmitool > ipmitool.prom
+#
+
+function export(values, name) {
+	if (values["metric_count"] < 1) {
+		return
+	}
+	delete values["metric_count"]
+
+	printf("# HELP %s%s %s sensor reading from ipmitool\n", namespace, name, help[name]);
+	printf("# TYPE %s%s gauge\n", namespace, name);
+	for (sensor in values) {
+		printf("%s%s{sensor=\"%s\"} %f\n", namespace, name, sensor, values[sensor]);
+	}
+}
+
+# Fields are Bar separated, with space padding.
+BEGIN {
+	FS = "[ ]*[|][ ]*";
+	namespace = "node_ipmi_";
+
+	# Friendly description of the type of sensor for HELP.
+	help["temperature_celcius"] = "Temperature";
+	help["volts"] = "Voltage";
+	help["power_watts"] = "Power";
+	help["speed_rpm"] = "Fan";
+	help["status"] = "Chassis status";
+
+	temperature_celcius["metric_count"] = 0;
+	volts["metric_count"] = 0;
+	power_watts["metric_count"] = 0;
+	speed_rpm["metric_count"] = 0;
+	status["metric_count"] = 0;
+}
+
+# Not a valid line.
+{
+	if (NF < 3) {
+		next
+	}
+}
+
+# $2 is value field.
+$2 ~ /na/ {
+	next
+}
+
+# $3 is type field.
+$3 ~ /degrees C/ {
+	temperature_celcius[$1] = $2;
+	temperature_celcius["metric_count"]++;
+}
+
+$3 ~ /Volts/ {
+	volts[$1] = $2;
+	volts["metric_count"]++;
+}
+
+$3 ~ /Watts/ {
+	power_watts[$1] = $2;
+	power_watts["metric_count"]++;
+}
+
+$3 ~ /RPM/ {
+	speed_rpm[$1] = $2;
+	speed_rpm["metric_count"]++;
+}
+
+$3 ~ /discrete/ {
+	status[$1] = $2;
+	status["metric_count"]++;
+}
+
+END {
+	export(temperature_celcius, "temperature_celcius");
+	export(volts, "volts");
+	export(power_watts, "power_watts");
+	export(speed_rpm, "speed_rpm");
+	export(status, "status");
+}