Variable Types

This page describes the types of variables, their use cases, and the configuration required for each type.

OpenObserve supports the following variable types:

1. Query Values

This variable dynamically fetches values from a selected field in a stream. It supports both single-select and multi-select options.

When to use: When the available values depend on data already ingested, such as identifiers, names, or categories.

Use Case: Filter the dashboard panels by Pod name using values from logs.

Result:

• This configuration allows users to dynamically select one or more Kubernetes pod names from the logs stream to apply that selection across dashboard panels.
• The variable dropdown will display up to 20 pod names retrieved from the k8s_pod_name field in the default log stream. These values are based on the most recently ingested records.
• The multi-selection option is enabled. Users can select more than one value, and all dashboard panels using $pod will update accordingly.

2. Constant

This variable allows you to set a fixed value that cannot be changed by dashboard users. The constant variables are shown on the dashboard as plain text.

When to use: When the value should always stay the same and must not be changed by anyone using the dashboard.

Use case: Building a dashboard that focuses only on logs from a specific Kubernetes namespace named ziox.

Result:

• After saving, this variable always uses ziox as the namespace value during query execution. Users cannot modify it from the dashboard interface.
• All queries referencing $constant-ziox will consistently apply the ziox namespace filter.

3. Textbox

This variable provides a free-form text input field on the dashboard.

When to use: When users need to manually enter a value that may not exist in the dropdown, such as custom IDs or strings.

Use Case: You want users to manually enter the cluster name they want to filter logs by.

Result:

• Users will see a text input field labeled Enter Cluster Name on the dashboard.
• The default value is _o2_all_, but users can replace it with any cluster name, such as prod or dev, at runtime.
• All queries using $input-cluster-name will include the user-provided input when executed.

What is _o2_all_?

• _o2_all_ is a special keyword used to match all values during query execution.
• If this is set as the default value, the dashboard will include data from all clusters unless the user enters a specific one.

4. Custom

This variable lets you predefine a list of selectable values.

When to use: When values are known in advance and should not be fetched from data.

Use Case: You want to allow users to select a predefined service from a list, such as openobserve or ingress-nginx. This is useful when the possible values are known and limited, and you want to control what the user can select.

Result:

• Users will see a dropdown named Service Name with the default selection set to openobserve.
• They can switch to ingress-nginx if needed. The multiple selection option is disabled, so only one option can be selected.
• All queries using $service-name will include the selected value when executed.

Next Steps

• Learn how to apply variables to a panel.
• Learn about variable dependencies.