State management

• 1: State management overview
• 2: How-To: Save and get state
• 3: How-To: Query state
• 4: How-To: Build a stateful service
• 5: How-To: Enable the transactional outbox pattern
• 6: How-To: Share state between applications
• 7: How-To: Encrypt application state
• 8: Work with backend state stores
• 8.1: Azure Cosmos DB
• 8.2: Redis
• 8.3: SQL server
• 9: State Time-to-Live (TTL)

1 - State management overview

Your application can use Dapr’s state management API to save, read, and query key/value pairs in the supported state stores. Using a state store component, you can build stateful, long running applications that save and retrieve their state (like a shopping cart or a game’s session state). For example, in the diagram below:

• Use HTTP POST to save or query key/value pairs.
• Use HTTP GET to read a specific key and have its value returned.

The following overview video and demo demonstrates how Dapr state management works.

Features

With the state management API building block, your application can leverage features that are typically complicated and error-prone to build, including:

• Setting the choices on concurrency control and data consistency.
• Performing bulk update operations CRUD including multiple transactional operations.
• Querying and filtering the key/value data.

These are the features available as part of the state management API:

Pluggable state stores

Dapr data stores are modeled as components, which can be swapped out without any changes to your service code. See supported state stores to see the list.

Configurable state store behaviors

With Dapr, you can include additional metadata in a state operation request that describes how you expect the request to be handled. You can attach:

• Concurrency requirements
• Consistency requirements

By default, your application should assume a data store is eventually consistent and uses a last-write-wins concurrency pattern.

Not all stores are created equal. To ensure your application’s portability, you can query the metadata capabilities of the store and make your code adaptive to different store capabilities.

Concurrency

Dapr supports Optimistic Concurrency Control (OCC) using ETags. When a state value is requested, Dapr always attaches an ETag property to the returned state. When the user code:

• Updates a state, it’s expected to attach the ETag through the request body.
• Deletes a state, it’s expected to attach the ETag through the If-Match header.

The write operation succeeds when the provided ETag matches the ETag in the state store.

Why Dapr chooses optimistic concurrency control (OCC)

Data update conflicts are rare in many applications, since clients are naturally partitioned by business contexts to operate on different data. However, if your application chooses to use ETags, mismatched ETags may cause a request rejection. It’s recommended you use a retry policy in your code to compensate for conflicts when using ETags.

If your application omits ETags in writing requests, Dapr skips ETag checks while handling the requests. This enables the last-write-wins pattern, compared to the first-write-wins pattern with ETags.

Read the API reference to learn how to set concurrency options.

Consistency

Dapr supports both strong consistency and eventual consistency, with eventual consistency as the default behavior.

• Strong consistency: Dapr waits for all replicas (or designated quorums) to acknowledge before it acknowledges a write request.
• Eventual consistency: Dapr returns as soon as the write request is accepted by the underlying data store, even if this is a single replica.

Read the API reference to learn how to set consistency options.

Setting content type

State store components may maintain and manipulate data differently, depending on the content type. Dapr supports passing content type in state management API as part of request metadata.

Setting the content type is optional, and the component decides whether to make use of it. Dapr only provides the means of passing this information to the component.

• With the HTTP API: Set content type via URL query parameter metadata.contentType. For example, http://localhost:3500/v1.0/state/store?metadata.contentType=application/json.
• With the gRPC API: Set content type by adding key/value pair "contentType" : <content type> to the request metadata.

Multiple operations

Dapr supports two types of multi-read or multi-write operations: bulk or transactional. Read the API reference to learn how use bulk and multi options.

Bulk read operations

You can group multiple read requests into a bulk (or batch) operation. In the bulk operation, Dapr submits the read requests as individual requests to the underlying data store, and returns them as a single result.

Transactional operations

You can group write, update, and delete operations into a request, which are then handled as an atomic transaction. The request will succeed or fail as a transactional set of operations.

Actor state

Transactional state stores can be used to store actor state. To specify which state store to use for actors, specify value of property actorStateStore as true in the state store component’s metadata section. Actors state is stored with a specific scheme in transactional state stores, allowing for consistent querying. Only a single state store component can be used as the state store for all actors. Read the state API reference and the actors API reference to learn more about state stores for actors.

Time to Live (TTL) on actor state

You should always set the TTL metadata field (ttlInSeconds), or the equivalent API call in your chosen SDK when saving actor state to ensure that state eventually removed. Read actors overview for more information.

State encryption

Dapr supports automatic client encryption of application state with support for key rotations. This is supported on all Dapr state stores. For more info, read the How-To: Encrypt application state topic.

Shared state between applications

Different applications’ needs vary when it comes to sharing state. In one scenario, you may want to encapsulate all state within a given application and have Dapr manage the access for you. In another scenario, you may want two applications working on the same state to get and save the same keys.

Dapr enables states to be:

• Isolated to an application.
• Shared in a state store between applications.
• Shared between multiple applications across different state stores.

For more details read How-To: Share state between applications,

Enabling the outbox pattern

Dapr enables developers to use the outbox pattern for achieving a single transaction across a transactional state store and any message broker. For more information, read How to enable transactional outbox messaging

Querying state

There are two ways to query the state:

• Using the state management query API provided in Dapr runtime.
• Querying state store directly with the store’s native SDK.

Query API

Using the optional state management query API, you can query the key/value data saved in state stores, regardless of underlying database or storage technology. With the state management query API, you can filter, sort, and paginate the key/value data. For more details read How-To: Query state.

Querying state store directly

Dapr saves and retrieves state values without any transformation. You can query and aggregate state directly from the underlying state store. For example, to get all state keys associated with an application ID “myApp” in Redis, use:

KEYS "myApp*"

Querying actor state

If the data store supports SQL queries, you can query an actor’s state using SQL queries. For example:

SELECT * FROM StateTable WHERE Id='<app-id>||<actor-type>||<actor-id>||<key>'

You can also avoid the common turn-based concurrency limitations of actor frameworks by performing aggregate queries across actor instances. For example, to calculate the average temperature of all thermometer actors, use:

SELECT AVG(value) FROM StateTable WHERE Id LIKE '<app-id>||<thermometer>||*||temperature'

State Time-to-Live (TTL)

Dapr enables per state set request time-to-live (TTL). This means that applications can set time-to-live per state stored, and these states cannot be retrieved after expiration.

State management API

The state management API can be found in the state management API reference, which describes how to retrieve, save, delete, and query state values by providing keys.

Try out state management

Quickstarts and tutorials

Want to put the Dapr state management API to the test? Walk through the following quickstart and tutorials to see state management in action:

Start using state management directly in your app

Want to skip the quickstarts? Not a problem. You can try out the state management building block directly in your application. After Dapr is installed, you can begin using the state management API starting with the state management how-to guide.

Next steps

• Start working through the state management how-to guides, starting with:
  • How-To: Save and get state
  • How-To: Build a stateful service
• Review the list of state store components
• Read the state management API reference
• Read the actors API reference

2 - How-To: Save and get state

State management is one of the most common needs of any new, legacy, monolith, or microservice application. Dealing with and testing different database libraries and handling retries and faults can be both difficult and time consuming.

In this guide, you’ll learn the basics of using the key/value state API to allow an application to save, get, and delete state.

The code example below loosely describes an application that processes orders with an order processing service which has a Dapr sidecar. The order processing service uses Dapr to store state in a Redis state store.

Set up a state store

A state store component represents a resource that Dapr uses to communicate with a database.

For the purpose of this guide we’ll use a Redis state store, but any state store from the supported list will work.

• Self-Hosted (CLI)
• Kubernetes

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
  name: statestore
spec:
  type: state.redis
  version: v1
  metadata:
  - name: redisHost
    value: localhost:6379
  - name: redisPassword
    value: ""

Save and retrieve a single state

The following example shows how to save and retrieve a single key/value pair using the Dapr state management API.

• .NET
• Java
• Python
• Go
• JavaScript
• HTTP API (Bash)
• HTTP API (PowerShell)

using System.Text;
using System.Threading.Tasks;
using Dapr.Client;

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddDaprClient();
var app = builder.Build();

var random = new Random();
//Resolve the DaprClient from its dependency injection registration
using var client = app.Services.GetRequiredService<DaprClient>();

while(true) 
{
    await Task.Delay(TimeSpan.FromSeconds(5));
    var orderId = random.Next(1,1000);
    //Using Dapr SDK to save and get state
    await client.SaveStateAsync(DAPR_STORE_NAME, "order_1", orderId.ToString());
    await client.SaveStateAsync(DAPR_STORE_NAME, "order_2", orderId.ToString());
    var result = await client.GetStateAsync<string>(DAPR_STORE_NAME, "order_1");
    Console.WriteLine($"Result after get: {result}");
}

dapr run --app-id orderprocessing --app-port 6001 --dapr-http-port 3601 --dapr-grpc-port 60001 dotnet run

//dependencies
import io.dapr.client.DaprClient;
import io.dapr.client.DaprClientBuilder;
import io.dapr.client.domain.State;
import io.dapr.client.domain.TransactionalStateOperation;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import reactor.core.publisher.Mono;
import java.util.Random;
import java.util.concurrent.TimeUnit;

//code
@SpringBootApplication
public class OrderProcessingServiceApplication {

	private static final Logger log = LoggerFactory.getLogger(OrderProcessingServiceApplication.class);

	private static final String STATE_STORE_NAME = "statestore";

	public static void main(String[] args) throws InterruptedException{
		while(true) {
			TimeUnit.MILLISECONDS.sleep(5000);
			Random random = new Random();
			int orderId = random.nextInt(1000-1) + 1;
			DaprClient client = new DaprClientBuilder().build();
            //Using Dapr SDK to save and get state
			client.saveState(STATE_STORE_NAME, "order_1", Integer.toString(orderId)).block();
			client.saveState(STATE_STORE_NAME, "order_2", Integer.toString(orderId)).block();
			Mono<State<String>> result = client.getState(STATE_STORE_NAME, "order_1", String.class);
			log.info("Result after get" + result);
		}
	}

}

dapr run --app-id orderprocessing --app-port 6001 --dapr-http-port 3601 --dapr-grpc-port 60001 mvn spring-boot:run

#dependencies
import random
from time import sleep    
import requests
import logging
from dapr.clients import DaprClient
from dapr.clients.grpc._state import StateItem
from dapr.clients.grpc._request import TransactionalStateOperation, TransactionOperationType

#code
logging.basicConfig(level = logging.INFO)
DAPR_STORE_NAME = "statestore"
while True:
    sleep(random.randrange(50, 5000) / 1000)
    orderId = random.randint(1, 1000)
    with DaprClient() as client:
        #Using Dapr SDK to save and get state
        client.save_state(DAPR_STORE_NAME, "order_1", str(orderId)) 
        result = client.get_state(DAPR_STORE_NAME, "order_1")
        logging.info('Result after get: ' + result.data.decode('utf-8'))

dapr run --app-id orderprocessing --app-port 6001 --dapr-http-port 3601 --dapr-grpc-port 60001 -- python3 OrderProcessingService.py

// dependencies
import (
	"context"
	"log"
	"math/rand"
	"strconv"
	"time"

	dapr "github.com/dapr/go-sdk/client"
)

// code
func main() {
	const STATE_STORE_NAME = "statestore"
	rand.Seed(time.Now().UnixMicro())
	for i := 0; i < 10; i++ {
		orderId := rand.Intn(1000-1) + 1
		client, err := dapr.NewClient()
		if err != nil {
			panic(err)
		}
		defer client.Close()
		ctx := context.Background()
		err = client.SaveState(ctx, STATE_STORE_NAME, "order_1", []byte(strconv.Itoa(orderId)), nil)
		if err != nil {
			panic(err)
		}
		result, err := client.GetState(ctx, STATE_STORE_NAME, "order_1", nil)
		if err != nil {
			panic(err)
		}
		log.Println("Result after get:", string(result.Value))
		time.Sleep(2 * time.Second)
	}
}

dapr run --app-id orderprocessing --app-port 6001 --dapr-http-port 3601 --dapr-grpc-port 60001 go run OrderProcessingService.go

//dependencies
import { DaprClient, HttpMethod, CommunicationProtocolEnum } from '@dapr/dapr'; 

//code
const daprHost = "127.0.0.1"; 
var main = function() {
    for(var i=0;i<10;i++) {
        sleep(5000);
        var orderId = Math.floor(Math.random() * (1000 - 1) + 1);
        start(orderId).catch((e) => {
            console.error(e);
            process.exit(1);
        });
    }
}

async function start(orderId) {
    const client = new DaprClient({
        daprHost,
        daprPort: process.env.DAPR_HTTP_PORT,
        communicationProtocol: CommunicationProtocolEnum.HTTP,
    });
    const STATE_STORE_NAME = "statestore";
    //Using Dapr SDK to save and get state
    await client.state.save(STATE_STORE_NAME, [
        {
            key: "order_1",
            value: orderId.toString()
        },
        {
            key: "order_2",
            value: orderId.toString()
        }
    ]);
    var result = await client.state.get(STATE_STORE_NAME, "order_1");
    console.log("Result after get: " + result);
}

function sleep(ms) {
    return new Promise(resolve => setTimeout(resolve, ms));
}

main();

dapr run --app-id orderprocessing --app-port 6001 --dapr-http-port 3601 --dapr-grpc-port 60001 npm start

dapr run --app-id orderprocessing --dapr-http-port 3601

curl -X POST -H "Content-Type: application/json" -d '[{ "key": "order_1", "value": "250"}]' http://localhost:3601/v1.0/state/statestore

curl http://localhost:3601/v1.0/state/statestore/order_1

dapr --app-id orderprocessing --dapr-http-port 3601 run

Invoke-RestMethod -Method Post -ContentType 'application/json' -Body '[{"key": "order_1", "value": "250"}]' -Uri 'http://localhost:3601/v1.0/state/statestore'

Invoke-RestMethod -Uri 'http://localhost:3601/v1.0/state/statestore/order_1'

Delete state

Below are code examples that leverage Dapr SDKs for deleting the state.

• .NET
• Java
• Python
• Go
• JavaScript
• HTTP API (Bash)
• HTTP API (PowerShell)

using Dapr.Client;
using System.Threading.Tasks;

const string DAPR_STORE_NAME = "statestore";

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddDaprClient();
var app = builder.Build();

//Resolve the DaprClient from the dependency injection registration
using var client = app.Services.GetRequiredService<DaprClient>();

//Use the DaprClient to delete the state
await client.DeleteStateAsync(DAPR_STORE_NAME, "order_1", cancellationToken: cancellationToken);

dapr run --app-id orderprocessing --app-port 6001 --dapr-http-port 3601 --dapr-grpc-port 60001 dotnet run

//dependencies
import io.dapr.client.DaprClient;
import io.dapr.client.DaprClientBuilder;
import org.springframework.boot.autoconfigure.SpringBootApplication;

//code
@SpringBootApplication
public class OrderProcessingServiceApplication {
	public static void main(String[] args) throws InterruptedException{
        String STATE_STORE_NAME = "statestore";

        //Using Dapr SDK to delete the state
        DaprClient client = new DaprClientBuilder().build();
        String storedEtag = client.getState(STATE_STORE_NAME, "order_1", String.class).block().getEtag();
        client.deleteState(STATE_STORE_NAME, "order_1", storedEtag, null).block();
	}
}

dapr run --app-id orderprocessing --app-port 6001 --dapr-http-port 3601 --dapr-grpc-port 60001 mvn spring-boot:run

#dependencies
from dapr.clients.grpc._request import TransactionalStateOperation, TransactionOperationType

#code
logging.basicConfig(level = logging.INFO)
DAPR_STORE_NAME = "statestore"

#Using Dapr SDK to delete the state
with DaprClient() as client:
    client.delete_state(store_name=DAPR_STORE_NAME, key="order_1")

dapr run --app-id orderprocessing --app-port 6001 --dapr-http-port 3601 --dapr-grpc-port 60001 -- python3 OrderProcessingService.py

//dependencies
import (
	"context"
	dapr "github.com/dapr/go-sdk/client"

)

//code
func main() {
    STATE_STORE_NAME := "statestore"
    //Using Dapr SDK to delete the state
    client, err := dapr.NewClient()
    if err != nil {
        panic(err)
    }
    defer client.Close()
    ctx := context.Background()

    if err := client.DeleteState(ctx, STATE_STORE_NAME, "order_1"); err != nil {
        panic(err)
    }
}

dapr run --app-id orderprocessing --app-port 6001 --dapr-http-port 3601 --dapr-grpc-port 60001 go run OrderProcessingService.go

//dependencies
import { DaprClient, HttpMethod, CommunicationProtocolEnum } from '@dapr/dapr'; 

//code
const daprHost = "127.0.0.1"; 
var main = function() {
    const STATE_STORE_NAME = "statestore";
    //Using Dapr SDK to save and get state
    const client = new DaprClient({
        daprHost,
        daprPort: process.env.DAPR_HTTP_PORT,
        communicationProtocol: CommunicationProtocolEnum.HTTP,
    });
    
    await client.state.delete(STATE_STORE_NAME, "order_1"); 
}

main();

dapr run --app-id orderprocessing --app-port 6001 --dapr-http-port 3601 --dapr-grpc-port 60001 npm start

curl -X DELETE 'http://localhost:3601/v1.0/state/statestore/order_1'

Invoke-RestMethod -Method Delete -Uri 'http://localhost:3601/v1.0/state/statestore/order_1'

Save and retrieve multiple states

Below are code examples that leverage Dapr SDKs for saving and retrieving multiple states.

• .NET
• Java
• Python
• Go
• JavaScript
• HTTP API (Bash)
• HTTP API (PowerShell)

using Dapr.Client;
using System.Threading.Tasks;

const string DAPR_STORE_NAME = "statestore";

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddDaprClient();
var app = builder.Build();

//Resolve the DaprClient from the dependency injection registration
using var client = app.Services.GetRequiredService<DaprClient>();

IReadOnlyList<BulkStateItem> multipleStateResult = await client.GetBulkStateAsync(DAPR_STORE_NAME, new List<string> { "order_1", "order_2" }, parallelism: 1);

dapr run --app-id orderprocessing --app-port 6001 --dapr-http-port 3601 --dapr-grpc-port 60001 dotnet run

using Dapr.Client;
using System.Threading.Tasks;

const string DAPR_STORE_NAME = "statestore";

var builder = WebApplication.CreateBuilder(args);
builder.Serivces.AddDaprClient();
var app = builder.Build();

//Resolve the DaprClient from the dependency injection registration
using var client = app.Services.GetRequiredService<DaprClient>();

IReadOnlyList<BulkStateItem<Widget>> mulitpleStateResult = await client.GetBulkStateAsync<Widget>(DAPR_STORE_NAME, new List<string> { "widget_1", "widget_2" }, parallelism: 1);

record Widget(string Size, string Color);

//dependencies
import io.dapr.client.DaprClient;
import io.dapr.client.DaprClientBuilder;
import io.dapr.client.domain.State;
import java.util.Arrays;

//code
@SpringBootApplication
public class OrderProcessingServiceApplication {

	private static final Logger log = LoggerFactory.getLogger(OrderProcessingServiceApplication.class);

	public static void main(String[] args) throws InterruptedException{
        String STATE_STORE_NAME = "statestore";
        //Using Dapr SDK to retrieve multiple states
        DaprClient client = new DaprClientBuilder().build();
        Mono<List<State<String>>> resultBulk = client.getBulkState(STATE_STORE_NAME,
        Arrays.asList("order_1", "order_2"), String.class);
	}
}

dapr run --app-id orderprocessing --app-port 6001 --dapr-http-port 3601 --dapr-grpc-port 60001 mvn spring-boot:run

#dependencies
from dapr.clients import DaprClient
from dapr.clients.grpc._state import StateItem

#code
logging.basicConfig(level = logging.INFO)
DAPR_STORE_NAME = "statestore"
orderId = 100
#Using Dapr SDK to save and retrieve multiple states
with DaprClient() as client:
    client.save_bulk_state(store_name=DAPR_STORE_NAME, states=[StateItem(key="order_2", value=str(orderId))])
    result = client.get_bulk_state(store_name=DAPR_STORE_NAME, keys=["order_1", "order_2"], states_metadata={"metakey": "metavalue"}).items
    logging.info('Result after get bulk: ' + str(result)) 

dapr run --app-id orderprocessing --app-port 6001 --dapr-http-port 3601 --dapr-grpc-port 60001 -- python3 OrderProcessingService.py

// dependencies
import (
	"context"
	"log"
	"math/rand"
	"strconv"
	"time"

	dapr "github.com/dapr/go-sdk/client"
)

// code
func main() {
	const STATE_STORE_NAME = "statestore"
	rand.Seed(time.Now().UnixMicro())
	for i := 0; i < 10; i++ {
		orderId := rand.Intn(1000-1) + 1
		client, err := dapr.NewClient()
		if err != nil {
			panic(err)
		}
		defer client.Close()
		ctx := context.Background()
		err = client.SaveState(ctx, STATE_STORE_NAME, "order_1", []byte(strconv.Itoa(orderId)), nil)
		if err != nil {
			panic(err)
		}
		keys := []string{"key1", "key2", "key3"}
        items, err := client.GetBulkState(ctx, STATE_STORE_NAME, keys, nil, 100)
		if err != nil {
			panic(err)
		}
		for _, item := range items {
			log.Println("Item from GetBulkState:", string(item.Value))
		}
	}
} 

dapr run --app-id orderprocessing --app-port 6001 --dapr-http-port 3601 --dapr-grpc-port 60001 go run OrderProcessingService.go

//dependencies
import { DaprClient, HttpMethod, CommunicationProtocolEnum } from '@dapr/dapr'; 

//code
const daprHost = "127.0.0.1"; 
var main = function() {
    const STATE_STORE_NAME = "statestore";
    var orderId = 100;
    //Using Dapr SDK to save and retrieve multiple states
    const client = new DaprClient({
        daprHost,
        daprPort: process.env.DAPR_HTTP_PORT,
        communicationProtocol: CommunicationProtocolEnum.HTTP,
    });

    await client.state.save(STATE_STORE_NAME, [
        {
            key: "order_1",
            value: orderId.toString()
        },
        {
            key: "order_2",
            value: orderId.toString()
        }
    ]);
    result = await client.state.getBulk(STATE_STORE_NAME, ["order_1", "order_2"]);
}

main();

dapr run --app-id orderprocessing --app-port 6001 --dapr-http-port 3601 --dapr-grpc-port 60001 npm start

curl -X POST -H "Content-Type: application/json" -d '[{ "key": "order_1", "value": "250"}, { "key": "order_2", "value": "550"}]' http://localhost:3601/v1.0/state/statestore

curl -X POST -H "Content-Type: application/json" -d '{"keys":["order_1", "order_2"]}' http://localhost:3601/v1.0/state/statestore/bulk

Invoke-RestMethod -Method Post -ContentType 'application/json' -Body '[{ "key": "order_1", "value": "250"}, { "key": "order_2", "value": "550"}]' -Uri 'http://localhost:3601/v1.0/state/statestore'

Invoke-RestMethod -Method Post -ContentType 'application/json' -Body '{"keys":["order_1", "order_2"]}' -Uri 'http://localhost:3601/v1.0/state/statestore/bulk'

Perform state transactions

Below are code examples that leverage Dapr SDKs for performing state transactions.

• .NET
• Java
• Python
• Go
• JavaScript
• HTTP API (Bash)
• HTTP API (PowerShell)

using Dapr.Client;
using System.Threading.Tasks;

const string DAPR_STORE_NAME = "statestore";

var builder = WebApplication.CreateBuilder(args);
builder.Serivces.AddDaprClient();
var app = builder.Build();

//Resolve the DaprClient from the dependency injection registration
using var client = app.Services.GetRequiredService<DaprClient>();

var random = new Random();

while (true)
{
   await Task.Delay(TimeSpan.FromSeconds(5));
   var orderId = random.Next(1, 1000);
   var requests = new List<StateTransactionRequest> 
   {
        new StateTransactionRequest("order_3", JsonSerializer.SerializeToUtf8Bytes(orderId.ToString()), StateOperationType.Upsert),
        new StateTransactionRequest("order_2", null, StateOperationType.Delete)
   };
   var cancellationTokenSource = new CancellationTokenSource();
   var cancellationToken = cancellationTokenSource.Token;
   
   //Use the DaprClient to perform the state transactions
   await client.ExecuteStateTransactionAsync(DAPR_STORE_NAME, requests, cancellationToken: cancellationToken);
   Console.WriteLine($"Order requested: {orderId}");
   Console.WriteLine($"Result: {result}");
}

dapr run --app-id orderprocessing --app-port 6001 --dapr-http-port 3601 --dapr-grpc-port 60001 dotnet run

//dependencies
import io.dapr.client.DaprClient;
import io.dapr.client.DaprClientBuilder;
import io.dapr.client.domain.State;
import io.dapr.client.domain.TransactionalStateOperation;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import reactor.core.publisher.Mono;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import java.util.concurrent.TimeUnit;

//code
@SpringBootApplication
public class OrderProcessingServiceApplication {

	private static final Logger log = LoggerFactory.getLogger(OrderProcessingServiceApplication.class);

	private static final String STATE_STORE_NAME = "statestore";

	public static void main(String[] args) throws InterruptedException{
		while(true) {
			TimeUnit.MILLISECONDS.sleep(5000);
			Random random = new Random();
			int orderId = random.nextInt(1000-1) + 1;
			DaprClient client = new DaprClientBuilder().build();
			List<TransactionalStateOperation<?>> operationList = new ArrayList<>();
			operationList.add(new TransactionalStateOperation<>(TransactionalStateOperation.OperationType.UPSERT,
					new State<>("order_3", Integer.toString(orderId), "")));
			operationList.add(new TransactionalStateOperation<>(TransactionalStateOperation.OperationType.DELETE,
					new State<>("order_2")));
            //Using Dapr SDK to perform the state transactions
			client.executeStateTransaction(STATE_STORE_NAME, operationList).block();
			log.info("Order requested: " + orderId);
		}
	}

}

dapr run --app-id orderprocessing --app-port 6001 --dapr-http-port 3601 --dapr-grpc-port 60001 mvn spring-boot:run

#dependencies
import random
from time import sleep    
import requests
import logging
from dapr.clients import DaprClient
from dapr.clients.grpc._state import StateItem
from dapr.clients.grpc._request import TransactionalStateOperation, TransactionOperationType

#code
logging.basicConfig(level = logging.INFO)    
DAPR_STORE_NAME = "statestore"
while True:
    sleep(random.randrange(50, 5000) / 1000)
    orderId = random.randint(1, 1000)
    with DaprClient() as client:
        #Using Dapr SDK to perform the state transactions
        client.execute_state_transaction(store_name=DAPR_STORE_NAME, operations=[
            TransactionalStateOperation(
                operation_type=TransactionOperationType.upsert,
                key="order_3",
                data=str(orderId)),
            TransactionalStateOperation(key="order_3", data=str(orderId)),
            TransactionalStateOperation(
                operation_type=TransactionOperationType.delete,
                key="order_2",
                data=str(orderId)),
            TransactionalStateOperation(key="order_2", data=str(orderId))
        ])

    client.delete_state(store_name=DAPR_STORE_NAME, key="order_1")
    logging.basicConfig(level = logging.INFO)
    logging.info('Order requested: ' + str(orderId))
    logging.info('Result: ' + str(result))

dapr run --app-id orderprocessing --app-port 6001 --dapr-http-port 3601 --dapr-grpc-port 60001 -- python3 OrderProcessingService.py

// dependencies
package main

import (
	"context"
	"log"
	"math/rand"
	"strconv"
	"time"

	dapr "github.com/dapr/go-sdk/client"
)

// code
func main() {
	const STATE_STORE_NAME = "statestore"
	rand.Seed(time.Now().UnixMicro())
	for i := 0; i < 10; i++ {
		orderId := rand.Intn(1000-1) + 1
		client, err := dapr.NewClient()
		if err != nil {
			panic(err)
		}
		defer client.Close()
		ctx := context.Background()
		err = client.SaveState(ctx, STATE_STORE_NAME, "order_1", []byte(strconv.Itoa(orderId)), nil)
		if err != nil {
			panic(err)
		}
		result, err := client.GetState(ctx, STATE_STORE_NAME, "order_1", nil)
		if err != nil {
			panic(err)
		}

        ops := make([]*dapr.StateOperation, 0)
        data1 := "data1"
        data2 := "data2"

        op1 := &dapr.StateOperation{
            Type: dapr.StateOperationTypeUpsert,
            Item: &dapr.SetStateItem{
                Key:   "key1",
                Value: []byte(data1),
            },
        }
        op2 := &dapr.StateOperation{
            Type: dapr.StateOperationTypeDelete,
            Item: &dapr.SetStateItem{
                Key:   "key2",
                Value: []byte(data2),
            },
        }
        ops = append(ops, op1, op2)
        meta := map[string]string{}
        err = client.ExecuteStateTransaction(ctx, STATE_STORE_NAME, meta, ops)

		log.Println("Result after get:", string(result.Value))
		time.Sleep(2 * time.Second)
	}
}

dapr run --app-id orderprocessing --app-port 6001 --dapr-http-port 3601 --dapr-grpc-port 60001 go run OrderProcessingService.go

//dependencies
import { DaprClient, HttpMethod, CommunicationProtocolEnum } from '@dapr/dapr'; 

//code
const daprHost = "127.0.0.1"; 
var main = function() {
    for(var i=0;i<10;i++) {
        sleep(5000);
        var orderId = Math.floor(Math.random() * (1000 - 1) + 1);
        start(orderId).catch((e) => {
            console.error(e);
            process.exit(1);
        });
    }
}

async function start(orderId) {
    const client = new DaprClient({
        daprHost,
        daprPort: process.env.DAPR_HTTP_PORT,
        communicationProtocol: CommunicationProtocolEnum.HTTP,
    });

    const STATE_STORE_NAME = "statestore";
    //Using Dapr SDK to save and retrieve multiple states
    await client.state.transaction(STATE_STORE_NAME, [
        {
        operation: "upsert",
        request: {
            key: "order_3",
            value: orderId.toString()
        }
        },
        {
        operation: "delete",
        request: {
            key: "order_2"
        }
        }
    ]);
}

function sleep(ms) {
    return new Promise(resolve => setTimeout(resolve, ms));
}

main();

dapr run --app-id orderprocessing --app-port 6001 --dapr-http-port 3601 --dapr-grpc-port 60001 npm start

curl -X POST -H "Content-Type: application/json" -d '{"operations": [{"operation":"upsert", "request": {"key": "order_1", "value": "250"}}, {"operation":"delete", "request": {"key": "order_2"}}]}' http://localhost:3601/v1.0/state/statestore/transaction

curl -X POST -H "Content-Type: application/json" -d '{"keys":["order_1", "order_2"]}' http://localhost:3601/v1.0/state/statestore/bulk

Invoke-RestMethod -Method Post -ContentType 'application/json' -Body '{"operations": [{"operation":"upsert", "request": {"key": "order_1", "value": "250"}}, {"operation":"delete", "request": {"key": "order_2"}}]}' -Uri 'http://localhost:3601/v1.0/state/statestore/transaction'

Invoke-RestMethod -Method Post -ContentType 'application/json' -Body '{"keys":["order_1", "order_2"]}' -Uri 'http://localhost:3601/v1.0/state/statestore/bulk'

Next steps

• Read the full State API reference
• Try one of the Dapr SDKs
• Build a stateful service

3 - How-To: Query state

With the state query API, you can retrieve, filter, and sort the key/value data stored in state store components. The query API is not a replacement for a complete query language.

Even though the state store is a key/value store, the value might be a JSON document with its own hierarchy, keys, and values. The query API allows you to use those keys/values to retrieve corresponding documents.

Querying the state

Submit query requests via HTTP POST/PUT or gRPC. The body of the request is the JSON map with 3 entries:

• filter
• sort
• page

filter

The filter specifies the query conditions in the form of a tree, where each node represents either unary or multi-operand operation.

The following operations are supported:

The key in the operand is similar to the JSONPath notation. Each dot in the key indicates a nested JSON structure. For example, consider this structure:

{
  "shape": {
    "name": "rectangle",
    "dimensions": {
      "height": 24,
      "width": 10
    },
    "color": {
      "name": "red",
      "code": "#FF0000"
    }
  }
}

To compare the value of the color code, the key will be shape.color.code.

If the filter section is omitted, the query returns all entries.

sort

The sort is an ordered array of key:order pairs, where:

• key is a key in the state store
• order is an optional string indicating sorting order:
  • "ASC" for ascending
  • "DESC" for descending
    If omitted, ascending order is the default.

page

The page contains limit and token parameters.

• limit sets the page size.
• token is an iteration token returned by the component, used in subsequent queries.

Behind the scenes, this query request is translated into the native query language and executed by the state store component.

Example data and query

Let’s look at some real examples, ranging from simple to complex.

As a dataset, consider a collection of employee records containing employee ID, organization, state, and city. Notice that this dataset is an array of key/value pairs, where:

• key is the unique ID
• value is the JSON object with employee record.

To better illustrate functionality, organization name (org) and employee ID (id) are a nested JSON person object.

Get started by creating an instance of MongoDB, which is your state store.

docker run -d --rm -p 27017:27017 --name mongodb mongo:5

Next, start a Dapr application. Refer to the component configuration file, which instructs Dapr to use MongoDB as its state store.

dapr run --app-id demo --dapr-http-port 3500 --resources-path query-api-examples/components/mongodb

Populate the state store with the employee dataset, so you can query it later.

curl -X POST -H "Content-Type: application/json" -d @query-api-examples/dataset.json http://localhost:3500/v1.0/state/statestore

Once populated, you can examine the data in the state store. In the image below, a section of the MongoDB UI displays employee records.

Each entry has the _id member as a concatenated object key, and the value member containing the JSON record.

The query API allows you to select records from this JSON structure.

Now you can run the example queries.

Example 1

First, find all employees in the state of California and sort them by their employee ID in descending order.

This is the query:

{
    "filter": {
        "EQ": { "state": "CA" }
    },
    "sort": [
        {
            "key": "person.id",
            "order": "DESC"
        }
    ]
}

An equivalent of this query in SQL is:

SELECT * FROM c WHERE
  state = "CA"
ORDER BY
  person.id DESC

Execute the query with the following command:

• HTTP API (Bash)
• HTTP API (PowerShell)

curl -s -X POST -H "Content-Type: application/json" -d @query-api-examples/query1.json http://localhost:3500/v1.0-alpha1/state/statestore/query | jq .

Invoke-RestMethod -Method Post -ContentType 'application/json' -InFile query-api-examples/query1.json -Uri 'http://localhost:3500/v1.0-alpha1/state/statestore/query'

The query result is an array of matching key/value pairs in the requested order:

{
  "results": [
    {
      "key": "3",
      "data": {
        "person": {
          "org": "Finance",
          "id": 1071
        },
        "city": "Sacramento",
        "state": "CA"
      },
      "etag": "44723d41-deb1-4c23-940e-3e6896c3b6f7"
    },
    {
      "key": "7",
      "data": {
        "city": "San Francisco",
        "state": "CA",
        "person": {
          "id": 1015,
          "org": "Dev Ops"
        }
      },
      "etag": "0e69e69f-3dbc-423a-9db8-26767fcd2220"
    },
    {
      "key": "5",
      "data": {
        "state": "CA",
        "person": {
          "org": "Hardware",
          "id": 1007
        },
        "city": "Los Angeles"
      },
      "etag": "f87478fa-e5c5-4be0-afa5-f9f9d75713d8"
    },
    {
      "key": "9",
      "data": {
        "person": {
          "org": "Finance",
          "id": 1002
        },
        "city": "San Diego",
        "state": "CA"
      },
      "etag": "f5cf05cd-fb43-4154-a2ec-445c66d5f2f8"
    }
  ]
}

Example 2

Now, find all employees from the “Dev Ops” and “Hardware” organizations.

This is the query:

{
    "filter": {
        "IN": { "person.org": [ "Dev Ops", "Hardware" ] }
    }
}

An equivalent of this query in SQL is:

SELECT * FROM c WHERE
  person.org IN ("Dev Ops", "Hardware")

Execute the query with the following command:

• HTTP API (Bash)
• HTTP API (PowerShell)

curl -s -X POST -H "Content-Type: application/json" -d @query-api-examples/query2.json http://localhost:3500/v1.0-alpha1/state/statestore/query | jq .

Invoke-RestMethod -Method Post -ContentType 'application/json' -InFile query-api-examples/query2.json -Uri 'http://localhost:3500/v1.0-alpha1/state/statestore/query'

Similar to the previous example, the result is an array of matching key/value pairs.

Example 3

In this example, find:

• All employees from the “Dev Ops” department.
• Employees from the “Finance” departing residing in the states of Washington and California.

In addition, sort the results first by state in descending alphabetical order, then by employee ID in ascending order. Let’s process up to 3 records at a time.

This is the query:

{
    "filter": {
        "OR": [
            {
                "EQ": { "person.org": "Dev Ops" }
            },
            {
                "AND": [
                    {
                        "EQ": { "person.org": "Finance" }
                    },
                    {
                        "IN": { "state": [ "CA", "WA" ] }
                    }
                ]
            }
        ]
    },
    "sort": [
        {
            "key": "state",
            "order": "DESC"
        },
        {
            "key": "person.id"
        }
    ],
    "page": {
        "limit": 3
    }
}

An equivalent of this query in SQL is:

SELECT * FROM c WHERE
  person.org = "Dev Ops" OR
  (person.org = "Finance" AND state IN ("CA", "WA"))
ORDER BY
  state DESC,
  person.id ASC
LIMIT 3

Execute the query with the following command:

• HTTP API (Bash)
• HTTP API (PowerShell)

curl -s -X POST -H "Content-Type: application/json" -d @query-api-examples/query3.json http://localhost:3500/v1.0-alpha1/state/statestore/query | jq .

Invoke-RestMethod -Method Post -ContentType 'application/json' -InFile query-api-examples/query3.json -Uri 'http://localhost:3500/v1.0-alpha1/state/statestore/query'

Upon successful execution, the state store returns a JSON object with a list of matching records and the pagination token:

{
  "results": [
    {
      "key": "1",
      "data": {
        "person": {
          "org": "Dev Ops",
          "id": 1036
        },
        "city": "Seattle",
        "state": "WA"
      },
      "etag": "6f54ad94-dfb9-46f0-a371-e42d550adb7d"
    },
    {
      "key": "4",
      "data": {
        "person": {
          "org": "Dev Ops",
          "id": 1042
        },
        "city": "Spokane",
        "state": "WA"
      },
      "etag": "7415707b-82ce-44d0-bf15-6dc6305af3b1"
    },
    {
      "key": "10",
      "data": {
        "person": {
          "org": "Dev Ops",
          "id": 1054
        },
        "city": "New York",
        "state": "NY"
      },
      "etag": "26bbba88-9461-48d1-8a35-db07c374e5aa"
    }
  ],
  "token": "3"
}

The pagination token is used “as is” in the subsequent query to get the next batch of records:

{
    "filter": {
        "OR": [
            {
                "EQ": { "person.org": "Dev Ops" }
            },
            {
                "AND": [
                    {
                        "EQ": { "person.org": "Finance" }
                    },
                    {
                        "IN": { "state": [ "CA", "WA" ] }
                    }
                ]
            }
        ]
    },
    "sort": [
        {
            "key": "state",
            "order": "DESC"
        },
        {
            "key": "person.id"
        }
    ],
    "page": {
        "limit": 3,
        "token": "3"
    }
}

• HTTP API (Bash)
• HTTP API (PowerShell)

curl -s -X POST -H "Content-Type: application/json" -d @query-api-examples/query3-token.json http://localhost:3500/v1.0-alpha1/state/statestore/query | jq .

Invoke-RestMethod -Method Post -ContentType 'application/json' -InFile query-api-examples/query3-token.json -Uri 'http://localhost:3500/v1.0-alpha1/state/statestore/query'

And the result of this query is:

{
  "results": [
    {
      "key": "9",
      "data": {
        "person": {
          "org": "Finance",
          "id": 1002
        },
        "city": "San Diego",
        "state": "CA"
      },
      "etag": "f5cf05cd-fb43-4154-a2ec-445c66d5f2f8"
    },
    {
      "key": "7",
      "data": {
        "city": "San Francisco",
        "state": "CA",
        "person": {
          "id": 1015,
          "org": "Dev Ops"
        }
      },
      "etag": "0e69e69f-3dbc-423a-9db8-26767fcd2220"
    },
    {
      "key": "3",
      "data": {
        "person": {
          "org": "Finance",
          "id": 1071
        },
        "city": "Sacramento",
        "state": "CA"
      },
      "etag": "44723d41-deb1-4c23-940e-3e6896c3b6f7"
    }
  ],
  "token": "6"
}

That way you can update the pagination token in the query and iterate through the results until no more records are returned.

Limitations

The state query API has the following limitations:

• To query actor states stored in a state store, you need to use the query API for the specific database. See querying actor state.
• The API does not work with Dapr encrypted state stores capability. Since the encryption is done by the Dapr runtime and stored as encrypted data, then this effectively prevents server side querying.

You can find additional information in the related links section.

Related links

• Refer to the query API reference.
• See the state store components that implement query support.
• View the state store query API implementation guide.
• See how to query Redis state store.

4 - How-To: Build a stateful service

In this article, you’ll learn how to create a stateful service which can be horizontally scaled, using opt-in concurrency and consistency models. Consuming the state management API frees developers from difficult state coordination, conflict resolution, and failure handling.

Set up a state store

A state store component represents a resource that Dapr uses to communicate with a database. For the purpose of this guide, we’ll use the default Redis state store.

Using the Dapr CLI

When you run dapr init in self-hosted mode, Dapr creates a default Redis statestore.yaml and runs a Redis state store on your local machine, located:

• On Windows, under %UserProfile%\.dapr\components\statestore.yaml
• On Linux/MacOS, under ~/.dapr/components/statestore.yaml

With the statestore.yaml component, you can easily swap out underlying components without application code changes.

See a list of supported state stores.

Kubernetes

See how to setup different state stores on Kubernetes.

Strong and eventual consistency

Using strong consistency, Dapr makes sure that the underlying state store:

• Returns the response once the data has been written to all replicas.
• Receives an ACK from a quorum before writing or deleting state.

For get requests, Dapr ensures the store returns the most up-to-date data consistently among replicas. The default is eventual consistency, unless specified otherwise in the request to the state API.

The following examples illustrate how to save, get, and delete state using strong consistency. The example is written in Python, but is applicable to any programming language.

Saving state

import requests
import json

store_name = "redis-store" # name of the state store as specified in state store component yaml file
dapr_state_url = "http://localhost:3500/v1.0/state/{}".format(store_name)
stateReq = '[{ "key": "k1", "value": "Some Data", "options": { "consistency": "strong" }}]'
response = requests.post(dapr_state_url, json=stateReq)

Getting state

import requests
import json

store_name = "redis-store" # name of the state store as specified in state store component yaml file
dapr_state_url = "http://localhost:3500/v1.0/state/{}".format(store_name)
response = requests.get(dapr_state_url + "/key1", headers={"consistency":"strong"})
print(response.headers['ETag'])

Deleting state

import requests
import json

store_name = "redis-store" # name of the state store as specified in state store component yaml file
dapr_state_url = "http://localhost:3500/v1.0/state/{}".format(store_name)
response = requests.delete(dapr_state_url + "/key1", headers={"consistency":"strong"})

If the concurrency option hasn’t been specified, the default is last-write concurrency mode.

First-write-wins and last-write-wins

Dapr allows developers to opt-in for two common concurrency patterns when working with data stores:

• First-write-wins: useful in situations where you have multiple instances of an application, all writing to the same key concurrently.
• Last-write-wins: Default mode for Dapr.

Dapr uses version numbers to determine whether a specific key has been updated. You can:

1. Retain the version number when reading the data for a key.
2. Use the version number during updates such as writes and deletes.

If the version information has changed since the version number was retrieved, an error is thrown, requiring you to perform another read to get the latest version information and state.

Dapr utilizes ETags to determine the state’s version number. ETags are returned from state requests in an ETag header. Using ETags, your application knows that a resource has been updated since the last time they checked by erroring during an ETag mismatch.

The following example shows how to:

• Get an ETag.
• Use the ETag to save state.
• Delete the state.

The following example is written in Python, but is applicable to any programming language.

import requests
import json

store_name = "redis-store" # name of the state store as specified in state store component yaml file
dapr_state_url = "http://localhost:3500/v1.0/state/{}".format(store_name)
response = requests.get(dapr_state_url + "/key1", headers={"concurrency":"first-write"})
etag = response.headers['ETag']
newState = '[{ "key": "k1", "value": "New Data", "etag": {}, "options": { "concurrency": "first-write" }}]'.format(etag)

requests.post(dapr_state_url, json=newState)
response = requests.delete(dapr_state_url + "/key1", headers={"If-Match": "{}".format(etag)})

Handling version mismatch failures

In the following example, you’ll see how to retry a save state operation when the version has changed:

import requests
import json

# This method saves the state and returns false if failed to save state
def save_state(data):
    try:
        store_name = "redis-store" # name of the state store as specified in state store component yaml file
        dapr_state_url = "http://localhost:3500/v1.0/state/{}".format(store_name)
        response = requests.post(dapr_state_url, json=data)
        if response.status_code == 200:
            return True
    except:
        return False
    return False

# This method gets the state and returns the response, with the ETag in the header -->
def get_state(key):
    response = requests.get("http://localhost:3500/v1.0/state/<state_store_name>/{}".format(key), headers={"concurrency":"first-write"})
    return response

# Exit when save state is successful. success will be False if there's an ETag mismatch -->
success = False
while success != True:
    response = get_state("key1")
    etag = response.headers['ETag']
    newState = '[{ "key": "key1", "value": "New Data", "etag": {}, "options": { "concurrency": "first-write" }}]'.format(etag)

    success = save_state(newState)

5 - How-To: Enable the transactional outbox pattern

The transactional outbox pattern is a well known design pattern for sending notifications regarding changes in an application’s state. The transactional outbox pattern uses a single transaction that spans across the database and the message broker delivering the notification.

Developers are faced with many difficult technical challenges when trying to implement this pattern on their own, which often involves writing error-prone central coordination managers that, at most, support a combination of one or two databases and message brokers.

For example, you can use the outbox pattern to:

1. Write a new user record to an account database.
2. Send a notification message that the account was successfully created.

With Dapr’s outbox support, you can notify subscribers when an application’s state is created or updated when calling Dapr’s transactions API.

The diagram below is an overview of how the outbox feature works:

1. Service A saves/updates state to the state store using a transaction.
2. A message is written to the broker under the same transaction. When the message is successfully delivered to the message broker, the transaction completes, ensuring the state and message are transacted together.
3. The message broker delivers the message topic to any subscribers - in this case, Service B.

Requirements

The outbox feature can be used with using any transactional state store supported by Dapr. All pub/sub brokers are supported with the outbox feature.

Learn more about the transactional methods you can use.

Enable the outbox pattern

To enable the outbox feature, add the following required and optional fields on a state store component:

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
  name: mysql-outbox
spec:
  type: state.mysql
  version: v1
  metadata:
  - name: connectionString
    value: "<CONNECTION STRING>"
  - name: outboxPublishPubsub # Required
    value: "mypubsub"
  - name: outboxPublishTopic # Required
    value: "newOrder"
  - name: outboxPubsub # Optional
    value: "myOutboxPubsub"
  - name: outboxDiscardWhenMissingState #Optional. Defaults to false
    value: false

Metadata fields

Additional configurations

Combining outbox and non-outbox messages on the same state store

If you want to use the same state store for sending both outbox and non-outbox messages, simply define two state store components that connect to the same state store, where one has the outbox feature and the other does not.

MySQL state store without outbox

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
  name: mysql
spec:
  type: state.mysql
  version: v1
  metadata:
  - name: connectionString
    value: "<CONNECTION STRING>"

MySQL state store with outbox

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
  name: mysql-outbox
spec:
  type: state.mysql
  version: v1
  metadata:
  - name: connectionString
    value: "<CONNECTION STRING>"
  - name: outboxPublishPubsub # Required
    value: "mypubsub"
  - name: outboxPublishTopic # Required
    value: "newOrder"

Shape the outbox pattern message

You can override the outbox pattern message published to the pub/sub broker by setting another transaction that is not be saved to the database and is explicitly mentioned as a projection. This transaction is added a metadata key named outbox.projection with a value set to true. When added to the state array saved in a transaction, this payload is ignored when the state is written and the data is used as the payload sent to the upstream subscriber.

To use correctly, the key values must match between the operation on the state store and the message projection. If the keys do not match, the whole transaction fails.

If you have two or more outbox.projection enabled state items for the same key, the first one defined is used and the others are ignored.

Learn more about default and custom CloudEvent messages.

• Python
• JavaScript
• .NET
• Java
• Go
• HTTP

DAPR_STORE_NAME = "statestore"

async def main():
    client = DaprClient()

    # Define the first state operation to save the value "2"
    op1 = StateItem(
        key="key1",
        value=b"2"
    )

    # Define the second state operation to publish the value "3" with metadata
    op2 = StateItem(
        key="key1",
        value=b"3",
        options=StateOptions(
            metadata={
                "outbox.projection": "true"
            }
        )
    )

    # Create the list of state operations
    ops = [op1, op2]

    # Execute the state transaction
    await client.state.transaction(DAPR_STORE_NAME, operations=ops)
    print("State transaction executed.")

const { DaprClient, StateOperationType } = require('@dapr/dapr');

const DAPR_STORE_NAME = "statestore";

async function main() {
  const client = new DaprClient();

  // Define the first state operation to save the value "2"
  const op1 = {
    operation: StateOperationType.UPSERT,
    request: {
      key: "key1",
      value: "2"
    }
  };

  // Define the second state operation to publish the value "3" with metadata
  const op2 = {
    operation: StateOperationType.UPSERT,
    request: {
      key: "key1",
      value: "3",
      metadata: {
        "outbox.projection": "true"
      }
    }
  };

  // Create the list of state operations
  const ops = [op1, op2];

  // Execute the state transaction
  await client.state.transaction(DAPR_STORE_NAME, ops);
  console.log("State transaction executed.");
}

main().catch(err => {
  console.error(err);
});