dashboard: set InfluxDB policy dynamically

After this patch, user may choose InfluxDB policy from the list of
policies instead of manually setting up a constant policy on import.

Part of #185

Author: DifferentialOrange

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Replace LuaJit deprecated metrics with new ones
 - Set Prometheus `job` dynamically
 - Set InfluxDB `measurement` dynamically
+- Set InfluxDB `policy` dynamically
 
 
 ## [1.5.0] - 2022-09-22

README.md

@@ -40,18 +40,12 @@ Refer to dashboard [documentation page](https://www.tarantool.io/en/doc/latest/b
     - paste the dashboard JSON file contents, or
     - upload the dashboard JSON file.
 
-3. Set dashboard name, folder, uid, choose corresponding datasource from drop-down list and set datasource-related query parameters.
+3. Set dashboard name, folder, uid and choose corresponding datasource from drop-down list.
 
     ![Dashboard import variables](doc/monitoring/images/grafana_import_setup.png)
 
-    You need to set the following variables for InfluxDB datasource:
-
-    - `Policy` (default valie is `autogen`).
-
-    Datasource variables can be obtained from your datasource configuration.
     You can choose `job` variable value for Prometheus datasource after import.
-    You can choose `measurement` variable value for InfluxDB datasource after import.
-    Variables for example monitoring cluster are described in [Monitoring cluster](#monitoring-cluster) section.
+    You can choose `policy` and `measurement` variable values for InfluxDB datasource after import.
 
 
 ## Monitoring cluster
@@ -70,10 +64,6 @@ We recommend using the exact versions we use in experimental cluster (e.g. Grafa
 After start, Grafana UI will be available at [localhost:3000](http://localhost:3000/).
 You can also interact with Prometheus at [localhost:9090](http://localhost:9090/) and InfluxDB at [localhost:8086](http://localhost:8086/).
 
-To set up an InfluxDB dashboard for monitoring example app, use the following variables:
-
-- `Policy`: `default`.
-
 ### Monitoring local app
 
 If you want to monitor Tarantool cluster deployed on your local host, you can use monitoring cluster similar to example app one.

dashboard/build/influxdb/dashboard.libsonnet

@@ -15,12 +15,14 @@ dashboard_raw(
   pluginId='influxdb',
   pluginName='InfluxDB',
   description='InfluxDB Tarantool metrics bank'
-).addInput(
-  name='INFLUXDB_POLICY',
-  label='Policy',
-  type='constant',
-  value='autogen',
-  description='InfluxDB Tarantool metrics policy'
+).addTemplate(
+  grafana.template.new(
+    name='policy',
+    datasource=variable.datasource.influxdb,
+    query='SHOW RETENTION POLICIES',
+    label='Retention policy',
+    refresh='load',
+  )
 ).addTemplate(
   grafana.template.new(
     name='measurement',

dashboard/build/influxdb/tdg_dashboard.libsonnet

@@ -15,12 +15,14 @@ tdg_dashboard_raw(
   pluginId='influxdb',
   pluginName='InfluxDB',
   description='InfluxDB Tarantool metrics bank'
-).addInput(
-  name='INFLUXDB_POLICY',
-  label='Policy',
-  type='constant',
-  value='autogen',
-  description='InfluxDB Tarantool metrics policy'
+).addTemplate(
+  grafana.template.new(
+    name='policy',
+    datasource=variable.datasource.influxdb,
+    query='SHOW RETENTION POLICIES',
+    label='Retention policy',
+    refresh='load',
+  )
 ).addTemplate(
   grafana.template.new(
     name='measurement',

dashboard/variable.libsonnet

@@ -12,7 +12,7 @@
     alias: '$alias',
   },
   influxdb: {
-    policy: '${INFLUXDB_POLICY}',
+    policy: '$policy',
     measurement: '$measurement',
     alias: '/^$alias$/',
   },

doc/monitoring/grafana_dashboard.rst

@@ -207,8 +207,7 @@ To import a specific dashboard, choose one of the following options:
 - paste the dashboard JSON file contents, or
 - upload the dashboard JSON file.
 
-Set dashboard name, folder, uid (if needed), and datasource-related query parameters
-(InfluxDB source and policy or Prometheus source).
+Set dashboard name, folder, uid (if needed) and datasource.
 
 ..  image:: images/grafana_import_setup.png
     :align: left