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.

  1. 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.

  1. 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.

  1. cd configuration/python/sdk/order-processor

Install the dependencies:

  1. pip3 install -r requirements.txt

Run the order-processor service alongside a Dapr sidecar.

  1. dapr run --app-id order-processor --components-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:

  1. == APP == Configuration for orderId1 : value: "101"
  2. == APP ==
  3. == APP == Configuration for orderId2 : value: "102"
  4. == APP ==
  5. == 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:

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

Run the order-processor service again:

  1. dapr run --app-id order-processor --components-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:

  1. == APP == Configuration for orderId1 : value: "103"
  2. == APP ==
  3. == APP == Configuration for orderId2 : value: "104"
  4. == 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:

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

Subscribe to configuration updates:

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

Unsubscribe from configuration updates and exit the application:

  1. # Unsubscribe from configuration updates
  2. unsubscribed = True
  3. for config_item in CONFIGURATION_ITEMS:
  4.     unsub_item = client.unsubscribe_configuration(DAPR_CONFIGURATION_STORE, config_item)
  5.     #...
  6. if unsubscribed == True:
  7.     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.

  1. 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.

  1. 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.

  1. cd configuration/javascript/sdk/order-processor

Install the dependencies:

  1. npm install

Run the order-processor service alongside a Dapr sidecar.

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

The expected output:

  1. == APP == Configuration for orderId1: {"key":"orderId1","value":"101","version":"","metadata":{}}
  2. == APP == Configuration for orderId2: {"key":"orderId2","value":"102","version":"","metadata":{}}
  3. == 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:

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

Run the order-processor service again:

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

The app will return the updated configuration values:

  1. == APP == Configuration for orderId1: {"key":"orderId1","value":"103","version":"","metadata":{}}
  2. == 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:

  1. // Get config items from the config store
  2. //...
  3.   const config = await client.configuration.get(DAPR_CONFIGURATION_STORE, CONFIGURATION_ITEMS);
  4.   Object.keys(config.items).forEach((key) => {
  5.     console.log("Configuration for " + key + ":", JSON.stringify(config.items[key]));
  6.   });

Subscribe to configuration updates:

  1. // Subscribe to config updates
  2. try {
  3.   const stream = await client.configuration.subscribeWithKeys(
  4.     DAPR_CONFIGURATION_STORE,
  5.     CONFIGURATION_ITEMS,
  6.     (config) => {
  7.       console.log("Configuration update", JSON.stringify(config.items));
  8.     }
  9.   );

Unsubscribe from configuration updates and exit the application:

  1. // Unsubscribe to config updates and exit app after 20 seconds
  2. setTimeout(() => {
  3.   stream.stop();
  4.   console.log("App unsubscribed to config changes");
  5.   process.exit(0);
  6. },

Pre-requisites

For this example, you will need:

Step 1: Set up the environment

Clone the sample provided in the Quickstarts repo.

  1. 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.

  1. 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.

  1. cd configuration/csharp/sdk/order-processor

Recall NuGet packages:

  1. dotnet restore
  2. dotnet build

Run the order-processor service alongside a Dapr sidecar.

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

The expected output:

  1. == APP == Configuration for orderId1: {"Value":"101","Version":"","Metadata":{}}
  2. == APP == Configuration for orderId2: {"Value":"102","Version":"","Metadata":{}}
  3. == 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:

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

Run the order-processor service again:

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

The app will return the updated configuration values:

  1. == APP == Configuration for orderId1: {"Value":"103","Version":"","Metadata":{}}
  2. == 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:

  1. // Get config from configuration store
  2. GetConfigurationResponse config = await client.GetConfiguration(DAPR_CONFIGURATION_STORE, CONFIGURATION_ITEMS);
  3. foreach (var item in config.Items)
  4. {
  5.   var cfg = System.Text.Json.JsonSerializer.Serialize(item.Value);
  6.   Console.WriteLine("Configuration for " + item.Key + ": " + cfg);
  7. }

Subscribe to configuration updates:

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

Unsubscribe from configuration updates and exit the application:

  1. // Unsubscribe to config updates and exit the app
  2. try
  3. {
  4.   client.UnsubscribeConfiguration(DAPR_CONFIGURATION_STORE, subscriptionId);
  5.   Console.WriteLine("App unsubscribed from config changes");
  6.   Environment.Exit(0);
  7. }

Pre-requisites

For this example, you will need:

Step 1: Set up the environment

Clone the sample provided in the Quickstarts repo.

  1. 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.

  1. 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.

  1. cd configuration/java/sdk/order-processor

Install the dependencies:

  1. mvn clean install

Run the order-processor service alongside a Dapr sidecar.

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

The expected output:

  1. == APP == Configuration for orderId1: {'value':'101'}
  2. == APP == Configuration for orderId2: {'value':'102'}
  3. == 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:

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

Run the order-processor service again:

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

The app will return the updated configuration values:

  1. == APP == Configuration for orderId1: {'value':'103'}
  2. == 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:

  1. // Get config items from the config store
  2. try (DaprPreviewClient client = (new DaprClientBuilder()).buildPreviewClient()) {
  3.     for (String configurationItem : CONFIGURATION_ITEMS) {
  4.         ConfigurationItem item = client.getConfiguration(DAPR_CONFIGURATON_STORE, configurationItem).block();
  5.         System.out.println("Configuration for " + configurationItem + ": {'value':'" + item.getValue() + "'}");
  6.     }

Subscribe to configuration updates:

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

Unsubscribe from configuration updates and exit the application:

  1. // Unsubscribe from config changes
  2. UnsubscribeConfigurationResponse unsubscribe = client
  3.         .unsubscribeConfiguration(subscriptionId, DAPR_CONFIGURATON_STORE).block();
  4. if (unsubscribe.getIsUnsubscribed()) {
  5.     System.out.println("App unsubscribed to config changes");
  6. }

Pre-requisites

For this example, you will need:

Step 1: Set up the environment

Clone the sample provided in the Quickstarts repo.

  1. 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.

  1. 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.

  1. cd configuration/go/sdk/order-processor

Run the order-processor service alongside a Dapr sidecar.

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

The expected output:

  1. == APP == Configuration for orderId1: {"Value":"101","Version":"","Metadata":null}
  2. == APP == Configuration for orderId2: {"Value":"102","Version":"","Metadata":null}
  3. == APP == dapr configuration subscribe finished.
  4. == 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:

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

Run the order-processor service again:

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

The app will return the updated configuration values:

  1. == APP == Configuration for orderId1: {"Value":"103","Version":"","Metadata":null}
  2. == 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:

  1. // Get config items from config store
  2. for _, item := range CONFIGURATION_ITEMS {
  3.     config, err := client.GetConfigurationItem(ctx, DAPR_CONFIGURATION_STORE, item)
  4.     //...
  5.     c, _ := json.Marshal(config)
  6.     fmt.Println("Configuration for " + item + ": " + string(c))
  7. }

Subscribe to configuration updates:

  1. // Subscribe for config changes
  2. err = client.SubscribeConfigurationItems(ctx, DAPR_CONFIGURATION_STORE, CONFIGURATION_ITEMS, func(id string, config map[string]*dapr.ConfigurationItem) {
  3.     // First invocation when app subscribes to config changes only returns subscription id
  4.     if len(config) == 0 {
  5.         fmt.Println("App subscribed to config changes with subscription id: " + id)
  6.         subscriptionId = id
  7.         return
  8.     }
  9. })

Unsubscribe from configuration updates and exit the application:

  1. // Unsubscribe to config updates and exit app after 20 seconds
  2. select {
  3. case <-ctx.Done():
  4.     err = client.UnsubscribeConfigurationItems(context.Background(), DAPR_CONFIGURATION_STORE, subscriptionId)
  5.     //...
  6.     {
  7.         fmt.Println("App unsubscribed to config changes")
  8.     }

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Last modified January 16, 2023: docs: improve consistency on directory mvment prefix (#3061) (05bf098c)