Ensure that all dashboards are using 'defaults.datasource'

Some dashboards were still explicitly specifying 'Prometheus' as the
datasource, which leads to issues when trying to import the dashboards
into a grafana instance where the prometheus datasource has a different
name.

Change-Id: I13135af32a6f312a4feb32ab828f906f7b13edfe

dashboards/gerrit/healthcheck/gerrit-healthcheck.jsonnet

@@ -37,7 +37,7 @@ dashboard.new(
 .addTemplate(
   template.new(
     name='check',
-    datasource='Prometheus',
+    datasource=defaults.datasource,
     query='metrics(^plugins_healthcheck_.+_failure_total$)',
     regex='plugins_healthcheck_(.+)_failure_total',
     label='Check',

dashboards/gerrit/latency/gerrit-rest-api-latency.jsonnet

@@ -27,7 +27,7 @@ dashboard.new(
 .addTemplate(
   template.new(
     name='endpoint',
-    datasource='Prometheus',
+    datasource=defaults.datasource,
     query='metrics(^http_server_rest_api_server_latency_restapi_.+$)',
     regex='^http_server_rest_api_server_latency_restapi_([^_]+)_.+$',
     label='Endpoint',
@@ -37,7 +37,7 @@ dashboard.new(
 .addTemplate(
   template.new(
     name='action',
-    datasource='Prometheus',
+    datasource=defaults.datasource,
     query='metrics(^http_server_rest_api_server_latency_restapi_$endpoint.+$)',
     regex='^http_server_rest_api_server_latency_restapi_[^_]+_([^_]+)_.+$',
     label='Action',

dashboards/gerrit/latency/gerrit-ui-actions-latency.jsonnet

@@ -27,7 +27,7 @@ dashboard.new(
 .addTemplate(
   template.new(
     name='action',
-    datasource='Prometheus',
+    datasource=defaults.datasource,
     query='metrics(^http_server_rest_api_ui_actions_latency_[^_]+$)',
     regex='^http_server_rest_api_ui_actions_latency_(.+)$',
     label='Action',

dashboards/gerrit/overview/panels/availability.libsonnet

@@ -2,9 +2,11 @@ local grafana = import '../../../../vendor/grafonnet/grafana.libsonnet';
 local prometheus = grafana.prometheus;
 local stat = grafana.singlestat;
 
+local defaults = import '../../../globals/defaults.libsonnet';
+
 stat.new(
   title='Gerrit Availability [last 24h]',
-  datasource='Prometheus',
+  datasource=defaults.datasource,
   colorBackground=true,
   colors=[
     "red",

dashboards/gerrit/overview/panels/cpu-usage.libsonnet

@@ -2,9 +2,11 @@ local grafana = import '../../../../vendor/grafonnet/grafana.libsonnet';
 local prometheus = grafana.prometheus;
 local gauge = grafana.gaugePanel;
 
+local defaults = import '../../../globals/defaults.libsonnet';
+
 gauge.new(
   title='CPU Usage',
-  datasource='Prometheus',
+  datasource=defaults.datasource,
 )
 .addTarget(
   target=prometheus.target(

dashboards/gerrit/overview/panels/heap-usage.libsonnet

@@ -2,9 +2,11 @@ local grafana = import '../../../../vendor/grafonnet/grafana.libsonnet';
 local prometheus = grafana.prometheus;
 local gauge = grafana.gaugePanel;
 
+local defaults = import '../../../globals/defaults.libsonnet';
+
 gauge.new(
   title='Heap Memory Usage',
-  datasource='Prometheus',
+  datasource=defaults.datasource,
 )
 .addTarget(
   target=prometheus.target(

dashboards/gerrit/overview/panels/request-errors.libsonnet

@@ -2,9 +2,11 @@ local grafana = import '../../../../vendor/grafonnet/grafana.libsonnet';
 local prometheus = grafana.prometheus;
 local gauge = grafana.gaugePanel;
 
+local defaults = import '../../../globals/defaults.libsonnet';
+
 gauge.new(
   title='HTTP Request Error Rate (last 5 min)',
-  datasource='Prometheus',
+  datasource=defaults.datasource,
   description='Excludes 404 and 401, since these error codes are caused by client behaviour and are overrepresented in the data.',
   min=0,
   max=100,

dashboards/gerrit/overview/panels/rest-latency.libsonnet

@@ -2,9 +2,11 @@ local grafana = import '../../../../vendor/grafonnet/grafana.libsonnet';
 local prometheus = grafana.prometheus;
 local gauge = grafana.gaugePanel;
 
+local defaults = import '../../../globals/defaults.libsonnet';
+
 gauge.new(
   title='REST API latency (0.99 quantile)',
-  datasource='Prometheus',
+  datasource=defaults.datasource,
   unit='ms',
   min=0,
   max=50,

dashboards/gerrit/overview/panels/threads.libsonnet

@@ -2,9 +2,11 @@ local grafana = import '../../../../vendor/grafonnet/grafana.libsonnet';
 local prometheus = grafana.prometheus;
 local gauge = grafana.barGaugePanel;
 
+local defaults = import '../../../globals/defaults.libsonnet';
+
 gauge.new(
   title='Live Threads',
-  datasource='Prometheus',
+  datasource=defaults.datasource,
   thresholds=[{
     color: 'green',
     value: null,

dashboards/gerrit/overview/panels/version-table.libsonnet

@@ -2,9 +2,11 @@ local grafana = import '../../../../vendor/grafonnet/grafana.libsonnet';
 local prometheus = grafana.prometheus;
 local table = grafana.tablePanel;
 
+local defaults = import '../../../globals/defaults.libsonnet';
+
 table.new(
   title='Gerrit Version',
-  datasource='Prometheus',
+  datasource=defaults.datasource,
   transform='table',
   transparent=false,
 )

dashboards/gerrit/replication/gerrit-replication.jsonnet

@@ -27,7 +27,7 @@ dashboard.new(
 .addTemplate(
   template.new(
     name='target',
-    datasource='Prometheus',
+    datasource=defaults.datasource,
     query='metrics(plugins_replication_replication_latency_.*_count)',
     regex='^plugins_replication_replication_latency_(.*)_count$',
     label='Replication Target',