dashboard: set Prometheus job dynamically

After this patch, user may choose Prometheus job from the list of jobs
with Tarantool metrics instead of manually setting up a constant job
on import.

Part of #185

Author: DifferentialOrange

CHANGELOG.md

@@ -8,6 +8,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 - Replace LuaJit deprecated metrics with new ones
+- Set Prometheus `job` dynamically
 
 
 ## [1.5.0] - 2022-09-22

README.md

@@ -49,11 +49,8 @@ Refer to dashboard [documentation page](https://www.tarantool.io/en/doc/latest/b
     - `Measurement`,
     - `Policy` (default valie is `autogen`).
 
-    You need to set the following variables for Prometheus datasource:
-
-    - `Job`.
-
     Datasource variables can be obtained from your datasource configuration.
+    You can choose `job` variable value for Prometheus datasource after import.
     Variables for example monitoring cluster are described in [Monitoring cluster](#monitoring-cluster) section.
 
 
@@ -78,10 +75,6 @@ To set up an InfluxDB dashboard for monitoring example app, use the following va
 - `Measurement`: `tarantool_http`;
 - `Policy`: `default`.
 
-To set up an Prometheus dashboard for monitoring example app, use the following variables:
-
-- `Job`: `tarantool`.
-
 ### 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/prometheus/dashboard.libsonnet

@@ -14,25 +14,19 @@ dashboard_raw(
   pluginId='prometheus',
   pluginName='Prometheus',
   description='Prometheus Tarantool metrics bank'
-).addInput(
-  name='PROMETHEUS_JOB',
-  label='Job',
-  type='constant',
-  value='tarantool',
-  description='Prometheus Tarantool metrics job'
 ).addTemplate(
-  grafana.template.custom(
+  grafana.template.new(
     name='job',
-    query='${PROMETHEUS_JOB}',
-    current='${PROMETHEUS_JOB}',
-    hide='variable',
+    datasource=variable.datasource.prometheus,
+    query=std.format('label_values(%s,job)', variable.metrics.tarantool_indicator),
     label='Prometheus job',
+    refresh='load',
   )
 ).addTemplate(
   grafana.template.new(
     name='alias',
     datasource=variable.datasource.prometheus,
-    query=std.format('label_values(tnt_info_uptime{job=~"%s"},alias)', variable.prometheus.job),
+    query=std.format('label_values(%s{job=~"%s"},alias)', [variable.metrics.tarantool_indicator, variable.prometheus.job]),
     includeAll=true,
     multi=true,
     current='all',

dashboard/build/prometheus/dashboard_static.jsonnet

@@ -16,7 +16,7 @@ if WITH_INSTANCE_VARIABLE then
     grafana.template.new(
       name='alias',
       datasource=DATASOURCE,
-      query=std.format('label_values(tnt_info_uptime{job="%s"},alias)', JOB),
+      query=std.format('label_values(%s{job="%s"},alias)', [variable.metrics.tarantool_indicator, JOB]),
       includeAll=true,
       multi=true,
       current='all',

dashboard/build/prometheus/tdg_dashboard.libsonnet

@@ -14,25 +14,19 @@ tdg_dashboard_raw(
   pluginId='prometheus',
   pluginName='Prometheus',
   description='Prometheus Tarantool metrics bank'
-).addInput(
-  name='PROMETHEUS_JOB',
-  label='Job',
-  type='constant',
-  value='tarantool',
-  description='Prometheus Tarantool metrics job'
 ).addTemplate(
-  grafana.template.custom(
+  grafana.template.new(
     name='job',
-    query='${PROMETHEUS_JOB}',
-    current='${PROMETHEUS_JOB}',
-    hide='variable',
+    datasource=variable.datasource.prometheus,
+    query=std.format('label_values(%s,job)', variable.metrics.tarantool_indicator),
     label='Prometheus job',
+    refresh='load',
   )
 ).addTemplate(
   grafana.template.new(
     name='alias',
     datasource=variable.datasource.prometheus,
-    query='label_values(tnt_info_uptime{job=~"$job"},alias)',
+    query=std.format('label_values(%s{job=~"%s"},alias)', [variable.metrics.tarantool_indicator, variable.prometheus.job]),
     includeAll=true,
     multi=true,
     current='all',

dashboard/build/prometheus/tdg_dashboard_static.jsonnet

@@ -16,7 +16,7 @@ if WITH_INSTANCE_VARIABLE then
     grafana.template.new(
       name='alias',
       datasource=DATASOURCE,
-      query=std.format('label_values(tnt_info_uptime{job="%s"},alias)', JOB),
+      query=std.format('label_values(%s{job="%s"},alias)', [variable.metrics.tarantool_indicator, JOB]),
       includeAll=true,
       multi=true,
       current='all',

dashboard/variable.libsonnet

@@ -16,4 +16,8 @@
     measurement: '${INFLUXDB_MEASUREMENT}',
     alias: '/^$alias$/',
   },
+  metrics: {
+    // It is expected that every job/measurement with Tarantool metrics would have this one.
+    tarantool_indicator: 'tnt_info_uptime',
+  },
 }

doc/monitoring/grafana_dashboard.rst

@@ -208,7 +208,7 @@ To import a specific dashboard, choose one of the following options:
 - upload the dashboard JSON file.
 
 Set dashboard name, folder, uid (if needed), and datasource-related query parameters
-(InfluxDB source, measurement and policy or Prometheus source and job).
+(InfluxDB source, measurement and policy or Prometheus source).
 
 ..  image:: images/grafana_import_setup.png
     :align: left
@@ -219,7 +219,7 @@ Set dashboard name, folder, uid (if needed), and datasource-related query parame
 Troubleshooting
 -------------------------------------------------------------------------------
 
-If there's no data on the graphs, make sure that you have set up datasource and job/measurement correctly.
+If there are no data on the graphs, make sure that you have set up datasource and picked job/measurement correctly.
 
 If some Prometheus graphs show no data because of ``parse error: missing unit character in duration``,
 ensure that you use Grafana 7.2 or newer.

tests/Prometheus/dashboard_compiled.json

@@ -7,13 +7,6 @@
          "pluginId": "prometheus",
          "pluginName": "Prometheus",
          "type": "datasource"
-      },
-      {
-         "description": "Prometheus Tarantool metrics job",
-         "label": "Job",
-         "name": "PROMETHEUS_JOB",
-         "type": "constant",
-         "value": "tarantool"
       }
    ],
    "__requires": [
@@ -15174,24 +15167,23 @@
       "list": [
          {
             "allValue": null,
-            "current": {
-               "text": "${PROMETHEUS_JOB}",
-               "value": "${PROMETHEUS_JOB}"
-            },
-            "hide": 2,
+            "current": { },
+            "datasource": "${DS_PROMETHEUS}",
+            "hide": 0,
             "includeAll": false,
             "label": "Prometheus job",
             "multi": false,
             "name": "job",
-            "options": [
-               {
-                  "text": "${PROMETHEUS_JOB}",
-                  "value": "${PROMETHEUS_JOB}"
-               }
-            ],
-            "query": "${PROMETHEUS_JOB}",
-            "refresh": 0,
-            "type": "custom"
+            "options": [ ],
+            "query": "label_values(tnt_info_uptime,job)",
+            "refresh": 1,
+            "regex": "",
+            "sort": 0,
+            "tagValuesQuery": "",
+            "tags": [ ],
+            "tagsQuery": "",
+            "type": "query",
+            "useTags": false
          },
          {
             "allValue": null,

tests/Prometheus/dashboard_tdg_compiled.json

@@ -7,13 +7,6 @@
          "pluginId": "prometheus",
          "pluginName": "Prometheus",
          "type": "datasource"
-      },
-      {
-         "description": "Prometheus Tarantool metrics job",
-         "label": "Job",
-         "name": "PROMETHEUS_JOB",
-         "type": "constant",
-         "value": "tarantool"
       }
    ],
    "__requires": [
@@ -20485,24 +20478,23 @@
       "list": [
          {
             "allValue": null,
-            "current": {
-               "text": "${PROMETHEUS_JOB}",
-               "value": "${PROMETHEUS_JOB}"
-            },
-            "hide": 2,
+            "current": { },
+            "datasource": "${DS_PROMETHEUS}",
+            "hide": 0,
             "includeAll": false,
             "label": "Prometheus job",
             "multi": false,
             "name": "job",
-            "options": [
-               {
-                  "text": "${PROMETHEUS_JOB}",
-                  "value": "${PROMETHEUS_JOB}"
-               }
-            ],
-            "query": "${PROMETHEUS_JOB}",
-            "refresh": 0,
-            "type": "custom"
+            "options": [ ],
+            "query": "label_values(tnt_info_uptime,job)",
+            "refresh": 1,
+            "regex": "",
+            "sort": 0,
+            "tagValuesQuery": "",
+            "tags": [ ],
+            "tagsQuery": "",
+            "type": "query",
+            "useTags": false
          },
          {
             "allValue": null,