Manage targeting rules

Overview

This topic explains how to manage flag targeting rules.

LaunchDarkly evaluates targeting rules after any flag prerequisites. You use flag prerequisites to make flags depend on other flags being enabled to take effect. To learn more, read Flag prerequisites.

Evaluation order

Evaluation order determines which variation a context receives when multiple targeting rules or targets could apply. Flags evaluate flag prerequisites and rules from top to bottom.

This diagram represents rule matching behavior:

At each step in the process, if the context instance matches the rule, it receives the appropriate variation. If it does not match the rule, it moves on to the next rule.

Here is how a context instance moves through a flag evaluation:

1. If your app can’t connect to LaunchDarkly, the context receives the fallback value. Otherwise, it moves to the next step.
2. If targeting is off, the context receives the default off variation. Otherwise, it moves to the next step.
3. If the flag has prerequisites, and the context doesn’t meet the prerequisites, it receives the default off variation. Otherwise, it moves to the next step.
4. If the context matches one individual targeting rule, it is served the variation in that rule. If it doesn’t match an individual targeting rule, it moves to the next step.
5. If the context is a multi-context, and the multi-context matches multiple individual targeting rules, then it is served the variation with the lowest index number. If it doesn’t match any individual targeting rules, it moves to the next step.
   • For boolean flags, the index of true is always 0 and the index of false is always 1. This means that if a multi-context is individually targeted multiple times with different variations, the multi-context will always receive true.
   • For multivariate flags, the index of the variation matches the order that you created the variations in. For example, if you create the variation red first, it will have an index of 0, and if you create the variation blue second, it will have an index of 1.
6. If the context meets a flag rule, it receives the chosen variation. Otherwise, it moves to the next step. If there are multiple flag rules, the context moves through the rules from top to bottom.
7. If the context doesn’t meet any of the previous criteria, it receives the default on variation. To learn more, read Set default values.

Here is an image of two targeting rules:

In this example, the first rule (if the segment is not in Beta users) is evaluated before the second rule (if the organization key is Beta).

Reorder targeting rules

You can reorder mobile targeting, segment targeting, and custom rules by clicking and dragging them into different positions. Alternatively, you can click the overflow menu of the flag targeting rule you want to move. Then, select Move rule up or Move rule down.

You cannot reorder prerequisites or individual targets. Only mobile targeting, segment targeting, and custom rules can be reordered.

Duplicate targeting rules

You can create new targeting rules by duplicating a flag’s existing targeting rule and modifying the new rule.

To duplicate an existing targeting rule:

1. Click on the flag rule’s three-dot overflow menu and choose “Duplicate rule.” A new rule appears.
   • If the flag is off and the rules are hidden, click View targeting rules.
2. Make at least one change to the existing rule or the new rule.
3. Click Review and save.

Here is an image of the “Duplicate rule” option in the rule menu:

The new rule appears below the original rule. You must make at least one change to either the existing rule or the new rule before saving your changes, to prevent two exact duplicate rules on the same flag.

Disable targeting rules

You can disable a targeting rule without deleting it. This lets you maintain the rule for later use. LaunchDarkly skips disabled rules during flag evaluation.

To disable a targeting rule:

1. Click on the flag rule’s three-dot overflow menu.
   • If the flag is off and the rules are hidden, click View targeting rules.
2. Select Disable rule.
3. Click Review and save.

The rule is now disabled. To re-enable the rule, click the three-dot overflow menu and select Enable rule.