Class Collector

This class provides methods to collect metrics with no label, one label, or multiple labels, using overloaded definitions of the collect method.

class Collector ;

Once the desired stats have been collected, the accumulated response string can be collected using the getCollection method.

Additionally, the reset method can be used to reset stat collection, when the desired stats have been collected from a Collector instance.

Methods

NameDescription
collect (values) Collect stats from the data members of a struct or a class and prepare them to be fetched upon the next call to getCollection. The specifications of the format of the collected stats can be found at https://prometheus.io/docs/instrumenting/exposition_formats/.
collect (values, label_val) Collect stats from the data members of a struct or a class, annotate them with a given label name and value, and prepare them to be fetched upon the next call to getCollection. The specifications of the format of the collected stats can be found at https://prometheus.io/docs/instrumenting/exposition_formats/.
collect (values, labels) Collect stats from the data members of a struct or a class, annotate them with labels from the data members of another struct or class, and prepare them to be fetched upon the next call to getCollection. The specifications of the format of the collected stats can be found at https://prometheus.io/docs/instrumenting/exposition_formats/.
getCollection ()
reset () Reset the length of the stat collection buffer to 0.

Example

Test collecting populated stats, but without any label. 

auto test_collector = new Collector();
test_collector.collect(Statistics(3600, 347, 3.14, 6.023, 0.43));

assert(test_collector.getCollection() ==
    "up_time_s 3600\ncount 347\nratio 3.14\nfraction 6.023\n" ~
    "very_real 0.43\n");

Example

Test collecting populated stats with one label 

auto test_collector = new Collector();
test_collector.collect!("id")(
    Statistics(3600, 347, 3.14, 6.023, 0.43), 123.034);

assert(test_collector.getCollection() ==
    "up_time_s {id=\"123.034\"} 3600\ncount {id=\"123.034\"} 347\n" ~
    "ratio {id=\"123.034\"} 3.14\nfraction {id=\"123.034\"} 6.023\n" ~
    "very_real {id=\"123.034\"} 0.43\n");

Example

Test collecting stats having initial values with multiple labels 

auto test_collector = new Collector();
test_collector.collect(Statistics(3600, 347, 3.14, 6.023, 0.43),
    Labels(1_235_813, "ocean", 3.14159));

assert(test_collector.getCollection() ==
    "up_time_s {id=\"1235813\",job=\"ocean\",perf=\"3.14159\"} 3600\n" ~
    "count {id=\"1235813\",job=\"ocean\",perf=\"3.14159\"} 347\n" ~
    "ratio {id=\"1235813\",job=\"ocean\",perf=\"3.14159\"} 3.14\n" ~
    "fraction {id=\"1235813\",job=\"ocean\",perf=\"3.14159\"} 6.023\n" ~
    "very_real {id=\"1235813\",job=\"ocean\",perf=\"3.14159\"} 0.43\n");

Example

Test resetting collected stats 

auto test_collector = new Collector();
test_collector.collect!("id")(Statistics.init, 123);

assert(test_collector.getCollection() ==
    "up_time_s {id=\"123\"} 0\ncount {id=\"123\"} 0\n" ~
    "ratio {id=\"123\"} 0\nfraction {id=\"123\"} 0\n" ~
    "very_real {id=\"123\"} 0\n");

test_collector.reset();

assert(test_collector.getCollection() == "");