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mirror of https://github.com/Unleash/unleash.git synced 2024-12-22 19:07:54 +01:00
unleash.unleash/website/docs/reference/custom-activation-strategies.md
Thomas Heartman d5fbd0b743
refactor: move docs into new structure / fix links for SEO (#2416)
## What

This (admittedly massive) PR updates the "physical" documentation
structure and fixes url inconsistencies and SEO problems reported by
marketing. The main points are:

- remove or move directories : advanced, user_guide, deploy, api
- move the files contained within to the appropriate one of topics,
how-to, tutorials, or reference
- update internal doc links and product links to the content
- create client-side redirects for all the urls that have changed.

A number of the files have been renamed in small ways to better match
their url and to make them easier to find. Additionally, the top-level
api directory has been moved to /reference/api/legacy/unleash (see the
discussion points section for more on this).

## Why

When moving our doc structure to diataxis a while back, we left the
"physical' files lying where they were, because it didn't matter much to
the new structure. However, that did introduce some inconsistencies with
where you place docs and how we organize them.

There's also the discrepancies in whether urls us underscores or hyphens
(which isn't necessarily the same as their file name), which has been
annoying me for a while, but now has also been raised by marketing as an
issue in terms of SEO.

## Discussion points

The old, hand-written API docs have been moved from /api to
/reference/api/legacy/unleash. There _is_ a /reference/api/unleash
directory, but this is being populated by the OpenAPI plugin, and mixing
those could only cause trouble. However, I'm unsure about putting
/legacy/ in the title, because the API isn't legacy, the docs are. Maybe
we could use another path? Like /old-docs/ or something? I'd appreciate
some input on this.
2022-11-22 09:05:30 +00:00

5.1 KiB

title
Custom Activation Strategies

:::tip

This document is a reference for custom activation strategies. If you're looking for a guide on how to use them, see the how to use custom strategies guide.

:::

Custom activation strategies let you define your own activation strategies to use with Unleash. When the built-in activation strategies aren't enough, custom activation strategies are there to provide you with the flexibility you need.

Custom activation strategies work exactly like the built-in activation strategies when working in the admin UI.

Definition

A strategy creation form. It has fields labeled "strategy name" — "TimeStamp" — and "description" — "activate toggle after a given timestamp". It also has fields for a parameter named "enableAfter". The parameter is of type "string" and the parameter description is "Expected format: YYYY-MM-DD HH:MM". The parameter is required.

You define custom activation strategies on your Unleash instance, either via the admin UI or via the API. A strategy contains:

  • A strategy name: You'll use this to refer to the strategy in the UI and in code. The strategy name should make it easy to understand what the strategy does. For instance, if a strategy uses contact numbers to determine whether a feature should be enabled, then ContactNumbers would be a good name.
  • An optional description: Use this to describe what the strategy should do.
  • An optional list of parameters: The parameter list lets you pass arguments to your custom activation strategy. These will be made available to your custom strategy implementation. How you interact with them differs between SDKs, but refer to the Node.js example in the how-to guide for a rough idea.

The strategy name is the only required parameter, but adding a good description will make it easier to remember what a strategy should do. The list of parameters lets you pass data from the Unleash instance to the strategy implementation.

Parameters

A strategy with five parameters, one of each type.

Parameters let you provide arguments to your strategy that it can access for evaluation. When creating a strategy, each parameter can be either required or optional. This marking is to help the user understand what they need to fill out; they can still save the strategy without filling out a required field.

Each parameter consists of three parts:

  • a name: must be unique among the strategy's parameters.
  • an optional description: describe the purpose or format of the parameter.
  • a parameter type: dictates the kind of input field the user will see in the admin UI and the type of the value in the implementation code.

Parameter types

Each parameter has one of five different parameter types. A parameter's type impacts the kind of controls shown in the admin UI and how it's represented in code.

The below table lists the types and how they're represented in the JSON payload returned from the Unleash server. When parsed, the exact types will vary based on your programming language's type system.

All values have an empty string ("") as the default value. As such, if you don't interact with a control or otherwise set a value, the value will be an empty string.

type name code representation example value UI control
string string "a string" A standard input field
percentage a string representing a number between 0 and 100 (inclusive) "99" A value slider
list string (values are comma-separated) "one,two" A multi-input text field
number string "123" A numeric text field
boolean a string: one of "true" or "false" "true" An on/off toggle

Implementation

:::note

If you have not implemented the strategy in your client SDK, the check will always return false because the client doesn't recognize the strategy.

:::

While custom strategies are defined on the Unleash server, they must be implemented on the client. All official Unleash client SDKs provide a way for you to implement custom strategies. You should refer to the individual SDK's documentation for specifics, but for an example, you can have a look at the Node.js client implementation section in the how to use custom strategies guide.

The exact method for implementing custom strategies will vary between SDKs, but the server SDKs follow the same patterns. For front-end client SDKs (Android, JavaScript, React, iOS), the custom activation strategy must be implemented in the Unleash Proxy.

When implementing a strategy in your client, you will get access to the strategy's parameters and the Unleash Context. Again, refer to your specific SDK's documentation for more details.