Apigee provides two primary techniques for dynamically selecting a target endpoint at runtime. The first is a declarative approach using conditional RouteRules within the ProxyEndpoint. Apigee evaluates these rules sequentially, and the first rule whose condition evaluates to true directs the flow to the specified TargetEndpoint. The second is a programmatic approach, typically using a JavaScript policy. This policy can execute code to determine the appropriate target URL and then dynamically set the target.url flow variable, which overrides the statically configured URL in the TargetEndpoint definition.

A: "Routing tables" is not a standard Apigee configuration object. While you use the Management API to configure RouteRules, the API itself is a configuration tool, not the runtime mechanism that makes the dynamic choice.

D: By default, an API proxy has a static route to a single, pre-configured target endpoint. Dynamic routing requires explicit configuration and is not a default behavior.

1. Google Cloud Apigee Documentation

"Conditional routing": This document explicitly describes the use of RouteRule elements with conditions to achieve dynamic routing. It states

"You can add routing logic to your API proxy flow by adding conditional routes to your TargetEndpoint configuration... A RouteRule forwards a request to a particular TargetEndpoint if the condition in the route rule evaluates to true." (See the section on "Conditional routes").

2. Google Cloud Apigee Documentation

"Flow variables reference": The documentation for the target.url variable states

"In a JavaScript policy

you can read and set this variable." This confirms that scripts can programmatically alter the target URL at runtime.

3. Google Cloud Apigee Documentation

"Route requests to the proper backend server": This guide provides a clear example of dynamic routing. Under the section "Dynamically routing to a target with a script

" it demonstrates using a JavaScript policy to set the target.url variable. It states

"You can dynamically set a target URL with code... the script overrides the static URL... configured in the TargetEndpoint XML block."