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Quickstart: Configuration

Get started with Dapr’s Configuration building block

Let’s take a look at Dapr’s Configuration building block. A configuration item is often dynamic in nature and tightly coupled to the needs of the application that consumes it. Configuration items are key/value pairs containing configuration data, such as:

  • App ids
  • Partition keys
  • Database names, etc

In this quickstart, you’ll run an order-processor microservice that utilizes the Configuration API. The service:

  1. Gets configuration items from the configuration store.
  2. Subscribes for configuration updates.
Diagram that demonstrates the flow of the configuration API quickstart with key/value pairs used.

Select your preferred language-specific Dapr SDK before proceeding with the Quickstart.


Pre-requisites

For this example, you will need:

Step 1: Set up the environment

Clone the sample provided in the Quickstarts repo.

git clone https://github.com/dapr/quickstarts.git

Once cloned, open a new terminal and run the following command to set values for configuration items orderId1 and orderId2.

docker exec dapr_redis redis-cli MSET orderId1 "101" orderId2 "102"

Step 2: Run the order-processor service

From the root of the Quickstarts clone directory, navigate to the order-processor directory.

cd configuration/python/sdk/order-processor

Install the dependencies:

pip3 install -r requirements.txt

Run the order-processor service alongside a Dapr sidecar.

dapr run --app-id order-processor --resources-path ../../../components/ --app-port 6001 -- python3 app.py

Note: Since Python3.exe is not defined in Windows, you may need to use python app.py instead of python3 app.py.

The expected output:

== APP == Configuration for orderId1 : value: "101"
== APP ==
== APP == Configuration for orderId2 : value: "102"
== APP ==
== APP == App unsubscribed from config changes

(Optional) Step 3: Update configuration item values

Once the app has unsubscribed, try updating the configuration item values. Change the orderId1 and orderId2 values using the following command:

docker exec dapr_redis redis-cli MSET orderId1 "103" orderId2 "104"

Run the order-processor service again:

dapr run --app-id order-processor --resources-path ../../../components/ --app-port 6001 -- python3 app.py

Note: Since Python3.exe is not defined in Windows, you may need to use python app.py instead of python3 app.py.

The app will return the updated configuration values:

== APP == Configuration for orderId1 : value: "103"
== APP ==
== APP == Configuration for orderId2 : value: "104"
== APP ==

The order-processor service

The order-processor service includes code for:

  • Getting the configuration items from the config store
  • Subscribing to configuration updates (which you made in the CLI earlier)
  • Unsubscribing from configuration updates and exiting the app after 20 seconds of inactivity.

Get configuration items:

# Get config items from the config store
for config_item in CONFIGURATION_ITEMS:
    config = client.get_configuration(store_name=DAPR_CONFIGURATION_STORE, keys=[config_item], config_metadata={})
    print(f"Configuration for {config_item} : {config.items[config_item]}", flush=True)

Subscribe to configuration updates:

# Subscribe for configuration changes
configuration = await client.subscribe_configuration(DAPR_CONFIGURATION_STORE, CONFIGURATION_ITEMS)

Unsubscribe from configuration updates and exit the application:

# Unsubscribe from configuration updates
unsubscribed = True
for config_item in CONFIGURATION_ITEMS:
    unsub_item = client.unsubscribe_configuration(DAPR_CONFIGURATION_STORE, config_item)
    #...
if unsubscribed == True:
    print("App unsubscribed from config changes", flush=True)

Pre-requisites

For this example, you will need:

Step 1: Set up the environment

Clone the sample provided in the Quickstarts repo.

git clone https://github.com/dapr/quickstarts.git

Once cloned, open a new terminal and run the following command to set values for configuration items orderId1 and orderId2.

docker exec dapr_redis redis-cli MSET orderId1 "101" orderId2 "102"

Step 2: Run the order-processor service

From the root of the Quickstarts clone directory, navigate to the order-processor directory.

cd configuration/javascript/sdk/order-processor

Install the dependencies:

npm install

Run the order-processor service alongside a Dapr sidecar.

dapr run --app-id order-processor --resources-path ../../../components/ --app-protocol grpc --dapr-grpc-port 3500 -- node index.js

The expected output:

== APP == Configuration for orderId1: {"key":"orderId1","value":"101","version":"","metadata":{}}
== APP == Configuration for orderId2: {"key":"orderId2","value":"102","version":"","metadata":{}}
== APP == App unsubscribed to config changes

(Optional) Step 3: Update configuration item values

Once the app has unsubscribed, try updating the configuration item values. Change the orderId1 and orderId2 values using the following command:

docker exec dapr_redis redis-cli MSET orderId1 "103" orderId2 "104"

Run the order-processor service again:

dapr run --app-id order-processor --resources-path ../../../components/ --app-protocol grpc --dapr-grpc-port 3500 -- node index.js

The app will return the updated configuration values:

== APP == Configuration for orderId1: {"key":"orderId1","value":"103","version":"","metadata":{}}
== APP == Configuration for orderId2: {"key":"orderId2","value":"104","version":"","metadata":{}}

The order-processor service

The order-processor service includes code for:

  • Getting the configuration items from the config store
  • Subscribing to configuration updates (which you made in the CLI earlier)
  • Unsubscribing from configuration updates and exiting the app after 20 seconds of inactivity.

Get configuration items:

// Get config items from the config store
//...
  const config = await client.configuration.get(DAPR_CONFIGURATION_STORE, CONFIGURATION_ITEMS);
  Object.keys(config.items).forEach((key) => {
    console.log("Configuration for " + key + ":", JSON.stringify(config.items[key]));
  });

Subscribe to configuration updates:

// Subscribe to config updates
try {
  const stream = await client.configuration.subscribeWithKeys(
    DAPR_CONFIGURATION_STORE,
    CONFIGURATION_ITEMS,
    (config) => {
      console.log("Configuration update", JSON.stringify(config.items));
    }
  );

Unsubscribe from configuration updates and exit the application:

// Unsubscribe to config updates and exit app after 20 seconds
setTimeout(() => {
  stream.stop();
  console.log("App unsubscribed to config changes");
  process.exit(0);
},

Pre-requisites

For this example, you will need:

Step 1: Set up the environment

Clone the sample provided in the Quickstarts repo.

git clone https://github.com/dapr/quickstarts.git

Once cloned, open a new terminal and run the following command to set values for configuration items orderId1 and orderId2.

docker exec dapr_redis redis-cli MSET orderId1 "101" orderId2 "102"

Step 2: Run the order-processor service

From the root of the Quickstarts clone directory, navigate to the order-processor directory.

cd configuration/csharp/sdk/order-processor

Recall NuGet packages:

dotnet restore
dotnet build

Run the order-processor service alongside a Dapr sidecar.

dapr run --app-id order-processor-http --resources-path ../../../components/ --app-port 7001 -- dotnet run --project .

The expected output:

== APP == Configuration for orderId1: {"Value":"101","Version":"","Metadata":{}}
== APP == Configuration for orderId2: {"Value":"102","Version":"","Metadata":{}}
== APP == App unsubscribed from config changes

(Optional) Step 3: Update configuration item values

Once the app has unsubscribed, try updating the configuration item values. Change the orderId1 and orderId2 values using the following command:

docker exec dapr_redis redis-cli MSET orderId1 "103" orderId2 "104"

Run the order-processor service again:

dapr run --app-id order-processor-http --resources-path ../../../components/ --app-port 7001 -- dotnet run --project .

The app will return the updated configuration values:

== APP == Configuration for orderId1: {"Value":"103","Version":"","Metadata":{}}
== APP == Configuration for orderId2: {"Value":"104","Version":"","Metadata":{}}

The order-processor service

The order-processor service includes code for:

  • Getting the configuration items from the config store
  • Subscribing to configuration updates (which you made in the CLI earlier)
  • Unsubscribing from configuration updates and exiting the app after 20 seconds of inactivity.

Get configuration items:

// Get config from configuration store
GetConfigurationResponse config = await client.GetConfiguration(DAPR_CONFIGURATION_STORE, CONFIGURATION_ITEMS);
foreach (var item in config.Items)
{
  var cfg = System.Text.Json.JsonSerializer.Serialize(item.Value);
  Console.WriteLine("Configuration for " + item.Key + ": " + cfg);
}

Subscribe to configuration updates:

// Subscribe to config updates
SubscribeConfigurationResponse subscribe = await client.SubscribeConfiguration(DAPR_CONFIGURATION_STORE, CONFIGURATION_ITEMS);

Unsubscribe from configuration updates and exit the application:

// Unsubscribe to config updates and exit the app
try
{
  client.UnsubscribeConfiguration(DAPR_CONFIGURATION_STORE, subscriptionId);
  Console.WriteLine("App unsubscribed from config changes");
  Environment.Exit(0);
}

Pre-requisites

For this example, you will need:

Step 1: Set up the environment

Clone the sample provided in the Quickstarts repo.

git clone https://github.com/dapr/quickstarts.git

Once cloned, open a new terminal and run the following command to set values for configuration items orderId1 and orderId2.

docker exec dapr_redis redis-cli MSET orderId1 "101" orderId2 "102"

Step 2: Run the order-processor service

From the root of the Quickstarts clone directory, navigate to the order-processor directory.

cd configuration/java/sdk/order-processor

Install the dependencies:

mvn clean install

Run the order-processor service alongside a Dapr sidecar.

dapr run --app-id order-processor --resources-path ../../../components -- java -jar target/OrderProcessingService-0.0.1-SNAPSHOT.jar

The expected output:

== APP == Configuration for orderId1: {'value':'101'}
== APP == Configuration for orderId2: {'value':'102'}
== APP == App unsubscribed to config changes

(Optional) Step 3: Update configuration item values

Once the app has unsubscribed, try updating the configuration item values. Change the orderId1 and orderId2 values using the following command:

docker exec dapr_redis redis-cli MSET orderId1 "103" orderId2 "104"

Run the order-processor service again:

dapr run --app-id order-processor --resources-path ../../../components -- java -jar target/OrderProcessingService-0.0.1-SNAPSHOT.jar

The app will return the updated configuration values:

== APP == Configuration for orderId1: {'value':'103'}
== APP == Configuration for orderId2: {'value':'104'}

The order-processor service

The order-processor service includes code for:

  • Getting the configuration items from the config store
  • Subscribing to configuration updates (which you made in the CLI earlier)
  • Unsubscribing from configuration updates and exiting the app after 20 seconds of inactivity.

Get configuration items:

// Get config items from the config store
try (DaprPreviewClient client = (new DaprClientBuilder()).buildPreviewClient()) {
    for (String configurationItem : CONFIGURATION_ITEMS) {
        ConfigurationItem item = client.getConfiguration(DAPR_CONFIGURATON_STORE, configurationItem).block();
        System.out.println("Configuration for " + configurationItem + ": {'value':'" + item.getValue() + "'}");
    }

Subscribe to configuration updates:

// Subscribe for config changes
Flux<SubscribeConfigurationResponse> subscription = client.subscribeConfiguration(DAPR_CONFIGURATON_STORE,
        CONFIGURATION_ITEMS.toArray(String[]::new));

Unsubscribe from configuration updates and exit the application:

// Unsubscribe from config changes
UnsubscribeConfigurationResponse unsubscribe = client
        .unsubscribeConfiguration(subscriptionId, DAPR_CONFIGURATON_STORE).block();
if (unsubscribe.getIsUnsubscribed()) {
    System.out.println("App unsubscribed to config changes");
}

Pre-requisites

For this example, you will need:

Step 1: Set up the environment

Clone the sample provided in the Quickstarts repo.

git clone https://github.com/dapr/quickstarts.git

Once cloned, open a new terminal and run the following command to set values for configuration items orderId1 and orderId2.

docker exec dapr_redis redis-cli MSET orderId1 "101" orderId2 "102"

Step 2: Run the order-processor service

From the root of the Quickstarts clone directory, navigate to the order-processor directory.

cd configuration/go/sdk/order-processor

Run the order-processor service alongside a Dapr sidecar.

dapr run --app-id order-processor --app-port 6001 --resources-path ../../../components -- go run .

The expected output:

== APP == Configuration for orderId1: {"Value":"101","Version":"","Metadata":null}
== APP == Configuration for orderId2: {"Value":"102","Version":"","Metadata":null}
== APP == dapr configuration subscribe finished.
== APP == App unsubscribed to config changes

(Optional) Step 3: Update configuration item values

Once the app has unsubscribed, try updating the configuration item values. Change the orderId1 and orderId2 values using the following command:

docker exec dapr_redis redis-cli MSET orderId1 "103" orderId2 "104"

Run the order-processor service again:

dapr run --app-id order-processor --app-port 6001 --resources-path ../../../components -- go run .

The app will return the updated configuration values:

== APP == Configuration for orderId1: {"Value":"103","Version":"","Metadata":null}
== APP == Configuration for orderId2: {"Value":"104","Version":"","Metadata":null}

The order-processor service

The order-processor service includes code for:

  • Getting the configuration items from the config store
  • Subscribing to configuration updates (which you made in the CLI earlier)
  • Unsubscribing from configuration updates and exiting the app after 20 seconds of inactivity.

Get configuration items:

// Get config items from config store
for _, item := range CONFIGURATION_ITEMS {
	config, err := client.GetConfigurationItem(ctx, DAPR_CONFIGURATION_STORE, item)
	//...
	c, _ := json.Marshal(config)
	fmt.Println("Configuration for " + item + ": " + string(c))
}

Subscribe to configuration updates:

// Subscribe for config changes
err = client.SubscribeConfigurationItems(ctx, DAPR_CONFIGURATION_STORE, CONFIGURATION_ITEMS, func(id string, config map[string]*dapr.ConfigurationItem) {
	// First invocation when app subscribes to config changes only returns subscription id
	if len(config) == 0 {
		fmt.Println("App subscribed to config changes with subscription id: " + id)
		subscriptionId = id
		return
	}
})

Unsubscribe from configuration updates and exit the application:

// Unsubscribe to config updates and exit app after 20 seconds
select {
case <-ctx.Done():
	err = client.UnsubscribeConfigurationItems(context.Background(), DAPR_CONFIGURATION_STORE, subscriptionId)
    //...
	{
		fmt.Println("App unsubscribed to config changes")
	}

Demo

Watch this video demoing the Configuration API quickstart:

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Next steps

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Last modified May 25, 2023: Add demos to docs (#3452) (0d714b58)