Azure Data Explorer input bindings for Azure Functions (preview)

The Azure Data Explorer input binding retrieves data from a database.

Examples

A C# function can be created by using one of the following C# modes:

• Isolated worker model: Compiled C# function that runs in a worker process that's isolated from the runtime. Isolated worker process is required to support C# functions running on LTS and non-LTS versions .NET and the .NET Framework.
• In-process model: Compiled C# function that runs in the same process as the Functions runtime.
• C# script: Used primarily when you create C# functions in the Azure portal.

Important

Support will end for the in-process model on November 10, 2026. We highly recommend that you migrate your apps to the isolated worker model for full support.

Isolated worker model

More samples for the Azure Data Explorer input binding (out of process) are available in the GitHub repository.

This section contains the following examples:

• HTTP trigger, get row by ID from query string
• HTTP trigger, get multiple rows from route data

The examples refer to a Product class and the Products table, both of which are defined in the previous sections.

HTTP trigger, get row by ID from query string

The following example shows a C# function that retrieves a single record. The function is triggered by an HTTP request that uses a query string to specify the ID. That ID is used to retrieve a Product record with the specified query.

Note

The HTTP query string parameter is case sensitive.

using System.Text.Json.Nodes;
using Microsoft.Azure.Functions.Worker;
using Microsoft.Azure.Functions.Worker.Extensions.Kusto;
using Microsoft.Azure.Functions.Worker.Http;
using Microsoft.Azure.WebJobs.Extensions.Kusto.SamplesOutOfProc.OutputBindingSamples.Common;

namespace Microsoft.Azure.WebJobs.Extensions.Kusto.SamplesOutOfProc.InputBindingSamples
{
    public static class GetProductsQuery
    {
        [Function("GetProductsQuery")]
        public static JsonArray Run(
            [HttpTrigger(AuthorizationLevel.Anonymous, "get", Route = "getproductsquery")] HttpRequestData req,
            [KustoInput(Database: "productsdb",
            KqlCommand = "declare query_parameters (productId:long);Products | where ProductID == productId",
            KqlParameters = "@productId={Query.productId}",Connection = "KustoConnectionString")] JsonArray products)
        {
            return products;
        }
    }
}

HTTP trigger, get multiple rows from route parameter

The following example shows a C# function that retrieves records returned by the query (based on the name of the product, in this case). The function is triggered by an HTTP request that uses route data to specify the value of a query parameter. That parameter is used to filter the Product records in the specified query.

using Microsoft.Azure.Functions.Worker;
using Microsoft.Azure.Functions.Worker.Extensions.Kusto;
using Microsoft.Azure.Functions.Worker.Http;
using Microsoft.Azure.WebJobs.Extensions.Kusto.SamplesOutOfProc.OutputBindingSamples.Common;

namespace Microsoft.Azure.WebJobs.Extensions.Kusto.SamplesOutOfProc.InputBindingSamples
{
    public static class GetProductsFunction
    {
        [Function("GetProductsFunction")]
        public static IEnumerable<Product> Run(
            [HttpTrigger(AuthorizationLevel.Anonymous, "get", Route = "getproductsfn/{name}")] HttpRequestData req,
            [KustoInput(Database: "productsdb",
            KqlCommand = "declare query_parameters (name:string);GetProductsByName(name)",
            KqlParameters = "@name={name}",Connection = "KustoConnectionString")] IEnumerable<Product> products)
        {
            return products;
        }
    }
}

In-process model

More samples for the Azure Data Explorer input binding are available in the GitHub repository.

This section contains the following examples:

• HTTP trigger, get rows by ID from query string
• HTTP trigger, get multiple rows from route data

The examples refer to Product class and a corresponding database table:

public class Product
{
    [JsonProperty(nameof(ProductID))]
    public long ProductID { get; set; }

    [JsonProperty(nameof(Name))]
    public string Name { get; set; }

    [JsonProperty(nameof(Cost))]
    public double Cost { get; set; }
}

.create-merge table Products (ProductID:long, Name:string, Cost:double)

HTTP trigger, get row by ID from query string

The following example shows a C# function that retrieves a list of products given a product ID. The function is triggered by an HTTP request that uses a parameter for the ID. That ID is used to retrieve a Product list that matches the query.

Note

The HTTP query string parameter is case sensitive.

using System.Collections.Generic;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.Azure.WebJobs.Extensions.Kusto.Samples.Common;
using Microsoft.Azure.WebJobs.Kusto;

namespace Microsoft.Azure.WebJobs.Extensions.Kusto.Samples.InputBindingSamples
{
    public static class GetProducts
    {
        [FunctionName("GetProductsList")]
        public static async Task<IActionResult> RunAsync(
            [HttpTrigger(AuthorizationLevel.Anonymous, "get", Route = "getproducts")]
            HttpRequest req,
            [Kusto(Database:"productsdb" ,
            KqlCommand = "declare query_parameters (productId:long);Products | where ProductID == productId" ,
            KqlParameters = "@productId={Query.productId}", // get the value of the query parameter "productId"
            Connection = "KustoConnectionString")]
            IAsyncEnumerable<Product> products)
        {
            IAsyncEnumerator<Product> enumerator = products.GetAsyncEnumerator();
            var productList = new List<Product>();
            while (await enumerator.MoveNextAsync())
            {
                productList.Add(enumerator.Current);
            }
            await enumerator.DisposeAsync();
            return new OkObjectResult(productList);
        }
    }
}

HTTP trigger, get multiple rows from route parameter

The following example shows a C# function that retrieves documents returned by the query. The function is triggered by an HTTP request that uses route data to specify the value of a KQL function parameter. The simple function GetProductsByName retrieves a set of products that match a product name.

.create function ifnotexists GetProductsByName(name:string)
{
    Products | where Name == name
}

using System.Collections.Generic;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;

namespace Microsoft.Azure.WebJobs.Extensions.Kusto.Samples.InputBindingSamples
{
  public static class GetProductsFunction
      {
          [FunctionName("GetProductsFunction")]
          public static IActionResult Run(
              [HttpTrigger(AuthorizationLevel.Anonymous, "get", Route = "getproductsfn/{name}")]
              HttpRequest req,
              [Kusto(Database:"productsdb" ,
              KqlCommand = "declare query_parameters (name:string);GetProductsByName(name)" ,
              KqlParameters = "@name={name}",
              Connection = "KustoConnectionString")]
              IEnumerable<Product> products)
          {
              return new OkObjectResult(products);
          }
      }
}

More samples for the Java Azure Data Explorer input binding are available in the GitHub repository.

This section contains the following examples:

• HTTP trigger, get multiple rows
• HTTP trigger, get row by ID from query string

The examples refer to a Product class (in a separate file Product.java) and a corresponding database table.

package com.microsoft.azure.kusto.common;

import com.fasterxml.jackson.annotation.JsonProperty;

public class Product {
    @JsonProperty("ProductID")
    public long ProductID;
    @JsonProperty("Name")
    public String Name;
    @JsonProperty("Cost")
    public double Cost;

    public Product() {
    }

    public Product(long ProductID, String name, double Cost) {
        this.ProductID = ProductID;
        this.Name = name;
        this.Cost = Cost;
    }
}

HTTP trigger, get multiple rows

The example uses a route parameter to specify the name of the ID of the products. All matching products are retrieved from the products table.

package com.microsoft.azure.kusto.inputbindings;

import com.microsoft.azure.functions.HttpMethod;
import com.microsoft.azure.functions.HttpRequestMessage;
import com.microsoft.azure.functions.HttpResponseMessage;
import com.microsoft.azure.functions.HttpStatus;
import com.microsoft.azure.functions.annotation.AuthorizationLevel;
import com.microsoft.azure.functions.annotation.FunctionName;
import com.microsoft.azure.functions.annotation.HttpTrigger;
import com.microsoft.azure.functions.kusto.annotation.KustoInput;
import com.microsoft.azure.kusto.common.Product;


import java.util.Optional;

public class GetProducts {
    @FunctionName("GetProducts")
    public HttpResponseMessage run(
        @HttpTrigger(name = "req", methods = {
            HttpMethod.GET}, authLevel = AuthorizationLevel.ANONYMOUS, route = "getproducts/{productId}") HttpRequestMessage<Optional<String>> request,
            @KustoInput(name = "getjproducts", kqlCommand = "declare query_parameters (productId:long);Products | where ProductID == productId",
                    kqlParameters = "@productId={productId}", database = "productsdb", connection = "KustoConnectionString") Product[] products) {
        return request.createResponseBuilder(HttpStatus.OK).header("Content-Type", "application/json").body(products)
                .build();
    }
}

HTTP trigger, get row by ID from query string

The following example shows a query for the products table by the product name. The function is triggered by an HTTP request that uses a query string to specify the value of a query parameter. That parameter is used to filter the Product records in the specified query.

package com.microsoft.azure.kusto.inputbindings;

import com.microsoft.azure.functions.HttpMethod;
import com.microsoft.azure.functions.HttpRequestMessage;
import com.microsoft.azure.functions.HttpResponseMessage;
import com.microsoft.azure.functions.HttpStatus;
import com.microsoft.azure.functions.annotation.AuthorizationLevel;
import com.microsoft.azure.functions.annotation.FunctionName;
import com.microsoft.azure.functions.annotation.HttpTrigger;
import com.microsoft.azure.functions.kusto.annotation.KustoInput;
import com.microsoft.azure.kusto.common.Product;

import java.util.Optional;

public class GetProductsQueryString {
    @FunctionName("GetProductsQueryString")
    public HttpResponseMessage run(@HttpTrigger(name = "req", methods = {
            HttpMethod.GET}, authLevel = AuthorizationLevel.ANONYMOUS, route = "getproducts") HttpRequestMessage<Optional<String>> request,
            @KustoInput(name = "getjproductsquery", kqlCommand = "declare query_parameters (name:string);GetProductsByName(name)",
                    kqlParameters = "@name={Query.name}", database = "productsdb", connection = "KustoConnectionString") Product[] products) {
        return request.createResponseBuilder(HttpStatus.OK).header("Content-Type", "application/json").body(products)
                .build();
    }
}

More samples for the Azure Data Explorer input binding are available in the GitHub repository.

This section contains the following examples:

• HTTP trigger, get multiple rows
• HTTP trigger, get row by ID from query string

The examples refer to a database table:

HTTP trigger, get multiple rows

The following example shows an Azure Data Explorer input binding in a function.json file and a JavaScript function that reads from a query and returns the results in the HTTP response.

The following binding data is in the function.json file:

{
  "bindings": [
    {
      "authLevel": "function",
      "name": "req",
      "direction": "in",
      "type": "httpTrigger",
      "methods": [
        "get"
      ],
      "route": "getproducts/{productId}"
    },
    {
      "name": "$return",
      "type": "http",
      "direction": "out"
    },
    {
      "name": "productget",
      "type": "kusto",
      "database": "productsdb",
      "direction": "in",
      "kqlCommand": "declare query_parameters (productId:long);Products | where ProductID == productId",
      "kqlParameters": "@productId={productId}",
      "connection": "KustoConnectionString"
    }
  ],
  "disabled": false
}

The configuration section explains these properties.

The following snippet is sample JavaScript code:

module.exports = async function (context, req, productget) {
    return {
        status: 200,
        body: productget
    };
}

HTTP trigger, get row by name from query string

The following example shows a query for the products table by the product name. The function is triggered by an HTTP request that uses a query string to specify the value of a query parameter. That parameter is used to filter the Product records in the specified query.

The following binding data is in the function.json file:

{
  "bindings": [
    {
      "authLevel": "function",
      "name": "req",
      "direction": "in",
      "type": "httpTrigger",
      "methods": [
        "get"
      ],
      "route": "getproductsfn"
    },
    {
      "name": "$return",
      "type": "http",
      "direction": "out"
    },
    {
      "name": "productfnget",
      "type": "kusto",
      "database": "productsdb",
      "direction": "in",
      "kqlCommand": "declare query_parameters (name:string);GetProductsByName(name)",
      "kqlParameters": "@name={Query.name}",
      "connection": "KustoConnectionString"
    }
  ],
  "disabled": false
}

The configuration section explains these properties.

The following snippet is sample JavaScript code:

module.exports = async function (context, req, producproductfngettget) {
    return {
        status: 200,
        body: productfnget
    };
}

More samples for the Azure Data Explorer input binding are available in the GitHub repository.

This section contains the following examples:

• HTTP trigger, get multiple rows
• HTTP trigger, get records by using a KQL function

HTTP trigger, get multiple rows

The following example shows an Azure Data Explorer input binding in a function.json file and a Python function that reads from a query and returns the results in the HTTP response.

The following binding data is in the function.json file:

{
  "scriptFile": "__init__.py",
  "bindings": [
    {
      "authLevel": "Anonymous",
      "type": "httpTrigger",
      "direction": "in",
      "name": "req",
      "methods": [
        "get"
      ],
      "route": "getproducts/{productId}"
    },
    {
      "type": "http",
      "direction": "out",
      "name": "$return"
    },
    {
      "name": "productsdb",
      "type": "kusto",
      "database": "sdktestsdb",
      "direction": "in",
      "kqlCommand": "declare query_parameters (productId:long);Products | where ProductID == productId",
      "kqlParameters": "@productId={Query.productId}",
      "connection": "KustoConnectionString"
    }
  ]
}

The configuration section explains these properties.

The following snippet is sample Python code:

import azure.functions as func
from Common.product import Product


def main(req: func.HttpRequest, products: str) -> func.HttpResponse:
    return func.HttpResponse(
        products,
        status_code=200,
        mimetype="application/json"
    )

HTTP trigger, get row by ID from query string

The following example shows a query for the products table by the product name. The function is triggered by an HTTP request that uses a query string to specify the value of a query parameter. That parameter is used to filter the Product records in the specified query.

The following binding data is in the function.json file:

{
  "bindings": [
    {
      "authLevel": "function",
      "name": "req",
      "direction": "in",
      "type": "httpTrigger",
      "methods": [
        "get"
      ],
      "route": "getproductsfn"
    },
    {
      "name": "$return",
      "type": "http",
      "direction": "out"
    },
    {
      "name": "productfnget",
      "type": "kusto",
      "database": "productsdb",
      "direction": "in",
      "kqlCommand": "declare query_parameters (name:string);GetProductsByName(name)",
      "kqlParameters": "@name={Query.name}",
      "connection": "KustoConnectionString"
    }
  ],
  "disabled": false
}

The configuration section explains these properties.

The following snippet is sample Python code:

import azure.functions as func

def main(req: func.HttpRequest, products: str) -> func.HttpResponse:
    return func.HttpResponse(
        products,
        status_code=200,
        mimetype="application/json"
    )

Attributes

The C# library uses the KustoAttribute attribute to declare the Azure Data Explorer bindings on the function, which has the following properties.

Attribute property	Description
Database	Required. The database against which the query must be executed.
Connection	Required. The name of the variable that holds the connection string, resolved through environment variables or through function app settings. Defaults to look up on the variable KustoConnectionString. At runtime, this variable is looked up against the environment. Documentation on the connection string is at Kusto connection strings. For example:"KustoConnectionString": "Data Source=https://your_cluster.kusto.windows.net;Database=your_Database;Fed=True;AppClientId=your_AppId;AppKey=your_AppKey;Authority Id=your_TenantId.
KqlCommand	Required. The KqlQuery parameter that must be executed. Can be a KQL query or a KQL function call.
KqlParameters	Optional. Parameters that act as predicate variables for KqlCommand. For example, "@name={name},@Id={id}", where {name} and {id} are substituted at runtime with actual values acting as predicates. The parameter name and the parameter value can't contain a comma (,) or an equal sign (=).
ManagedServiceIdentity	Optional. You can use a managed identity to connect to Azure Data Explorer. To use a system managed identity, use "system." Any other identity names are interpreted as a user managed identity.

Annotations

The Java functions runtime library uses the @KustoInput annotation (com.microsoft.azure.functions.kusto.annotation.KustoInput).

Element	Description
name	Required. The name of the variable that represents the query results in function code.
database	Required. The database against which the query must be executed.
connection	Required. The name of the variable that holds the connection string, resolved through environment variables or through function app settings. Defaults to look up on the variable KustoConnectionString. At runtime, this variable is looked up against the environment. Documentation on the connection string is at Kusto connection strings. For example:"KustoConnectionString": "Data Source=https://your_cluster.kusto.windows.net;Database=your_Database;Fed=True;AppClientId=your_AppId;AppKey=your_AppKey;Authority Id=your_TenantId.
kqlCommand	Required. The KqlQuery parameter that must be executed. Can be a KQL query or a KQL function call.
kqlParameters	Optional. Parameters that act as predicate variables for KqlCommand. For example, "@name={name},@Id={id}", where {name} and {id} are substituted at runtime with actual values acting as predicates. The parameter name and the parameter value can't contain a comma (,) or an equal sign (=).
managedServiceIdentity	A managed identity can be used to connect to Azure Data Explorer. To use a system managed identity, use "system." Any other identity names are interpreted as a user managed identity.

Configuration

The following table explains the binding configuration properties that you set in the function.json file.

function.json property	Description
type	Required. Must be set to kusto.
direction	Required. Must be set to in.
name	Required. The name of the variable that represents the query results in function code.
database	Required. The database against which the query must be executed.
connection	Required. The name of the variable that holds the connection string, resolved through environment variables or through function app settings. Defaults to look up on the variable KustoConnectionString. At runtime, this variable is looked up against the environment. Documentation on the connection string is at Kusto connection strings. For example:"KustoConnectionString": "Data Source=https://your_cluster.kusto.windows.net;Database=your_Database;Fed=True;AppClientId=your_AppId;AppKey=your_AppKey;Authority Id=your_TenantId.
kqlCommand	Required. The KqlQuery parameter that must be executed. Can be a KQL query or a KQL function call.
kqlParameters	Optional. Parameters that act as predicate variables for KqlCommand. For example, "@name={name},@Id={id}", where {name} and {id} are substituted at runtime with actual values acting as predicates. The parameter name and the parameter value can't contain a comma (,) or an equal sign (=).
managedServiceIdentity	A managed identity can be used to connect to Azure Data Explorer. To use a system managed identity, use "system." Any other identity names are interpreted as a user managed identity.

When you're developing locally, add your application settings in the local.settings.json file in the Values collection.

Usage

The attribute's constructor takes the database and the attributes KQLCommand and KQLParameters and the connection setting name. The KQL command can be a KQL statement or a KQL function. The connection string setting name corresponds to the application setting (in local.settings.json for local development) that contains the Kusto connection strings. For example: "KustoConnectionString": "Data Source=https://your_cluster.kusto.windows.net;Database=your_Database;Fed=True;AppClientId=your_AppId;AppKey=your_AppKey;Authority Id=your_TenantId. Queries executed by the input binding are parameterized. The values provided in the KQL parameters are used at runtime.

Next steps

Save data to a table (output binding)