dashboard: fill with none for InfluxDB

On lower timescales data with "fill(null)" seems like a scattered set
of dots. Data with "fill(none)" seems fine like a line string. I don't
remember these issues on older Grafana versions, so it is possible
that something had changed with visualization even for deprecated graph
panels.

CHANGELOG.md

@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   It affects all custom-built dashboards which had used `replication` (#224)
 - Remove deprecated `build-static-*` targets from `make` (#224)
 - Make default template use Tarantool 3 sections (#224)
+- Use `fill(none)` in InfluxQL requests (PR #229)
 
 ### Fixed
 - Removed extra quotation mark for TDG jobs_average_panel query (#220)

dashboard/panels/common.libsonnet

@@ -102,7 +102,7 @@ local influxdb_query_filters(filters) = std.join(' AND ', std.map(
           measurement=cfg.measurement,
           group_tags=group_tags,
           alias=legend[cfg.type],
-          fill='null',
+          fill='none',
         ).where('metric_name', '=', std.format('%s%s', [cfg.metrics_prefix, metric_name]))
       ).selectField('value').addConverter(converter);
       if rate then target.addConverter('non_negative_derivative', ['1s']) else target,

dashboard/panels/tdg/graphql.libsonnet

@@ -62,7 +62,7 @@ local prometheus = grafana.prometheus;
           WHERE ("metric_name" = '%(metrics_prefix)s%(metric_name_count)s' %(filters)s)
           AND $timeFilter)
           GROUP BY time($__interval), "label_pairs_alias", "label_pairs_operation_name",
-          "label_pairs_schema", "label_pairs_entity" fill(null)
+          "label_pairs_schema", "label_pairs_entity" fill(none)
         |||, {
           metrics_prefix: cfg.metrics_prefix,
           metric_name_sum: std.join('_', [metric_name, 'sum']),

dashboard/panels/tdg/tasks.libsonnet

@@ -107,7 +107,7 @@ local prometheus = grafana.prometheus;
           (SELECT "value" as "%(metrics_prefix)s%(metric_name_count)s" FROM %(policy_prefix)s"%(measurement)s"
           WHERE ("metric_name" = '%(metrics_prefix)s%(metric_name_count)s' %(filters)s)
           AND $timeFilter)
-          GROUP BY time($__interval), "label_pairs_alias", "label_pairs_name" fill(null)
+          GROUP BY time($__interval), "label_pairs_alias", "label_pairs_name" fill(none)
         |||, {
           metrics_prefix: cfg.metrics_prefix,
           metric_name_sum: std.join('_', [metric_name, 'sum']),
@@ -221,7 +221,7 @@ local prometheus = grafana.prometheus;
           WHERE ("metric_name" = '%(metrics_prefix)s%(metric_name_count)s' %(filters)s)
           AND $timeFilter)
           GROUP BY time($__interval), "label_pairs_alias", "label_pairs_name",
-          "label_pairs_kind" fill(null)
+          "label_pairs_kind" fill(none)
         |||, {
           metrics_prefix: cfg.metrics_prefix,
           metric_name_sum: std.join('_', [metric_name, 'sum']),

dashboard/panels/tdg/tuples.libsonnet

@@ -40,7 +40,7 @@ local prometheus = grafana.prometheus;
           WHERE ("metric_name" = '%(metrics_prefix)s%(metric_name_sum)s' %(filters)s) AND $timeFilter),
           (SELECT "value" as "%(metrics_prefix)s%(metric_name_count)s" FROM %(policy_prefix)s"%(measurement)s"
           WHERE ("metric_name" = '%(metrics_prefix)s%(metric_name_count)s' %(filters)s) AND $timeFilter)
-          GROUP BY time($__interval), "label_pairs_alias", "label_pairs_type_name" fill(null)
+          GROUP BY time($__interval), "label_pairs_alias", "label_pairs_type_name" fill(none)
         |||, {
           metrics_prefix: cfg.metrics_prefix,
           metric_name_sum: std.join('_', [metric_name, 'sum']),