74 lines
2.9 KiB
Markdown
74 lines
2.9 KiB
Markdown
---
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title: Use and manage variables
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seotitle: Use and manage dashboard variables
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description: >
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Dashboard variables allow you to alter specific components of cells' queries
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without having to edit the queries, making it easy to interact with your dashboard cells and explore your data.
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menu:
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influxdb_2_1:
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parent: Visualize data
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weight: 103
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influxdb/v2.1/tags: [variables]
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---
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Dashboard variables let you alter specific components of cells' queries without having to edit the queries,
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making it easy to interact with your dashboard cells and explore your data.
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Variables are scoped by organization.
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## Use dashboard variables
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Both [predefined dashboard variables](#predefined-dashboard-variables) and [custom dashboard variables](#custom-dashboard-variables)
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are stored in a `v` record associated with each dashboard.
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Reference each variable using dot-notation (e.g. `v.variableName`).
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```js
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from(bucket: v.bucket)
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|> range(start: v.timeRangeStart, stop: v.timeRangeStop)
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|> filter(fn: (r) => r._measurement == v.measurement and r._field == v.field)
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|> aggregateWindow(every: v.windowPeriod, fn: mean)
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```
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When building Flux queries for dashboard cells, view available dashboard variables
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in the **Variables** tab next to the Functions tab.
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{{< img-hd src="/img/influxdb/2-0-variables-data-explorer-view.png" />}}
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Click a variable name to add it to your query and select a value from the **Value** dropdown.
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## Link to dashboards with variables defined in the URL
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When you apply a variable to your dashboard, `&vars[variable_name]=value` is appended to the URL so you can share the link with the variables included.
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## Predefined dashboard variables
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The InfluxDB user interface (UI) provides the following predefined dashboard variables:
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#### v.timeRangeStart
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Specifies the beginning of the queried time range.
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This variable is typically used to define the [`start` parameter](/{{< latest "flux" >}}/stdlib/universe/range#start)
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of the `range()` function.
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The **Time Range** selector defines the value of this variable.
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#### v.timeRangeStop
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Specifies the end of the queried time range.
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This variable is typically used to define the [`stop` parameter](/{{< latest "flux" >}}/stdlib/universe/range#stop)
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of the `range()` function.
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The **Time Range** selector defines the value of this variable.
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It defaults to `now`.
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#### v.windowPeriod
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Specifies the period of windowed data.
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This variable is typically used to define the `every` or `period` parameters of the
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[`window()` function](/{{< latest "flux" >}}/stdlib/universe/window)
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in data aggregation operations.
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The value of this variable is calculated by analyzing the duration of the Flux
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query it is used within. Queries that fetch data from a longer time range will
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have a larger `v.windowPeriod` duration.
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## Custom dashboard variables
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Create, manage, and use custom dashboard variables in the InfluxDB user interface (UI).
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{{< children >}}
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