Add quantiles to summary using quantiles_estimator package. (#116)

* Add quantiles to summary using quantiles_estimator package.

* Move quantile based summary to a separate module.

* Remove separate fsum and isum from quantile_summary

* quantile_summary: Add configurable targets and compress limit

Author: hairyhum

include/prometheus.hrl

@@ -2,6 +2,7 @@
 -define(PROMETHEUS_COUNTER_TABLE, prometheus_counter_table).
 -define(PROMETHEUS_GAUGE_TABLE, prometheus_gauge_table).
 -define(PROMETHEUS_SUMMARY_TABLE, prometheus_summary_table).
+-define(PROMETHEUS_QUANTILE_SUMMARY_TABLE, prometheus_quantile_summary_table).
 -define(PROMETHEUS_HISTOGRAM_TABLE, prometheus_histogram_table).
 -define(PROMETHEUS_BOOLEAN_TABLE, prometheus_boolean_table).
 
@@ -10,6 +11,7 @@
 -define(PROMETHEUS_STANDARD_METRICS, [prometheus_counter,
                                       prometheus_gauge,
                                       prometheus_summary,
+                                      prometheus_quantile_summary,
                                       prometheus_histogram,
                                       prometheus_boolean_table]).
 

rebar.config

@@ -17,7 +17,7 @@
             %% warn_untyped_record,
             {platform_define, "^(2|3)", recent_otp}]}.
 
-{deps, []}.
+{deps, [{quantile_estimator, {git, "https://github.com/odo/quantile_estimator"}}]}.
 {shell, [{apps, [prometheus]}]}.
 {cover_enabled, true}.
 {cover_export_enabled, true}.

rebar.lock

@@ -1 +1,4 @@
-[].
+[{<<"quantile_estimator">>,
+  {git,"https://github.com/odo/quantile_estimator",
+       {ref,"eeea7c7dba2f406a41c70b0f59afcf4a6b2fc4fc"}},
+  0}].

src/formats/prometheus_text_format.erl

@@ -110,9 +110,17 @@ emit_metric(Fd, Name, #'Metric'{label=Labels,
   emit_series(Fd, Name, Labels, Value);
 emit_metric(Fd, Name, #'Metric'{label=Labels,
                                 summary=#'Summary'{sample_count=Count,
-                                                   sample_sum=Sum}}) ->
+                                                   sample_sum=Sum,
+                                                   quantile=Quantiles}}) ->
   emit_series(Fd, [Name, "_count"], Labels, Count),
-  emit_series(Fd, [Name, "_sum"], Labels, Sum);
+  emit_series(Fd, [Name, "_sum"], Labels, Sum),
+  [
+    emit_series(
+      Fd, [Name],
+      Labels ++ [#'LabelPair'{name="quantile", value=io_lib:format("~p", [QN])}],
+      QV)
+    || #'Quantile'{quantile = QN, value = QV} <- Quantiles
+  ];
 emit_metric(Fd, Name, #'Metric'{label=Labels,
                                 histogram=#'Histogram'{sample_count=Count,
                                                        sample_sum=Sum,