ai-search-api-policy.xml

<policies>
    <inbound>
        <base />
        <!-- AAD Authorization -->
        <!-- Enabled if entra-validate named value is set to true -->
        <include-fragment fragment-id="aad-auth" />
        <set-header name="api-key" exists-action="delete" />
        <!-- Setting cache keys -->
        <set-variable name="deployment-id" value="@((string)context.Request.MatchedParameters["index-name"])" />
        <set-variable name="routesCacheKey" value="@((string)context.Variables["deployment-id"] + "Routes" + context.Deployment.Region + context.Api.Revision)" />
        <set-variable name="oaClustersCacheKey" value="@("aiSearchInstance" + context.Deployment.Region + context.Api.Revision)" />
        <cache-lookup-value key="@((string)context.Variables.GetValueOrDefault<string>("oaClustersCacheKey", "ALL-SEARCH"))" variable-name="oaClusters" />
        <!-- If we can't find the configuration cached, it will be loaded -->
        <choose>
            <when condition="@(context.Variables.ContainsKey("oaClusters") == false)">
                <set-variable name="oaClusters" value="@{
                        // route is an Azure AI Search endpoint
                        JArray routes = new JArray();
                        // cluster is a group of routes that are capable of serving a specific index name
                        JArray clusters = new JArray();
                        // Update the below if condition when using multiple APIM gateway regions/SHGW to get different configurations for each region
                        if(context.Deployment.Region == "West Europe" || true)
                        {
                            // Adding all Azure AI Search endpoints routes (which are set as APIM Backend)
                            routes.Add(new JObject()
                            {
                                { "name", "Contoso Insurance KB" },
                                { "location", "Switzerland North" },
                                { "backend-id", "ai-search-swn" },
                                { "priority", 1},
                                { "isThrottling", false }, 
                                { "retryAfter", DateTime.MinValue } 
                            });

                            routes.Add(new JObject()
                            {
                                { "name", "Northwind Outdoor KB" },
                                { "location", "Sweden Central" },
                                { "backend-id", "ai-search-sec" },
                                { "priority", 1},
                                { "isThrottling", false }, 
                                { "retryAfter", DateTime.MinValue } 
                            });

                            // For each index, create a cluster with the routes that can serve it
                            clusters.Add(new JObject()
                            {
                                { "deploymentName", "gptkbindex" },
                                { "routes", new JArray(routes[0]) }
                            });

                            clusters.Add(new JObject()
                            {
                                { "deploymentName", "product-info" },
                                { "routes", new JArray(routes[1]) }
                            });
                        }
                        else
                        {
                            //No clusters found for selected region, either return error (default behavior) or set default cluster in the else section
                        }
                        
                        return clusters;   
                    }" />
                <!-- Add cluster configurations to cache -->
                <cache-store-value key="@((string)context.Variables.GetValueOrDefault<string>("oaClustersCacheKey", "ALL-SEARCH"))" value="@((JArray)context.Variables["oaClusters"])" duration="86400" />
            </when>
        </choose>
        <include-fragment fragment-id="validate-routes" />
        <authentication-managed-identity resource="https://search.azure.com" output-token-variable-name="msi-access-token" client-id="{{uami-client-id}}" ignore-error="false" />
        <set-header name="Authorization" exists-action="override">
            <value>@("Bearer " + (string)context.Variables["msi-access-token"])</value>
        </set-header>
    </inbound>
    <backend>
        <include-fragment fragment-id="backend-routing" />
    </backend>
    <outbound>
        <base />
        <set-variable name="idPrefix" value="search" />
        <set-variable name="targetService" value="AI-Search" />
        <set-variable name="model" value="@((string)context.Variables.GetValueOrDefault<string>("deployment-id", "AI-SEARCH-INDEX"))" />
        <set-variable name="deploymentName" value="@((string)context.Variables.GetValueOrDefault<string>("deployment-id", "AI-SEARCH-SERVICE"))" />
        <include-fragment fragment-id="ai-usage" />
    </outbound>
    <on-error>
        <base />
        <set-variable name="service-name" value="Azure AI Search" />
        <set-variable name="target-deployment" value="@((string)context.Request.MatchedParameters["index-name"])" />
        <include-fragment fragment-id="throttling-events" />
    </on-error>
</policies>