Use the Dapr API

Running dapr init loads your local environment with:

• The Dapr sidecar binaries.
• Default Redis component definitions for both:
  • State management, and
  • A message broker.

With this setup, run Dapr using the Dapr CLI and try out the state API to store and retrieve a state. Learn more about the state building block and how it works in our concept docs.

In this guide, you will simulate an application by running the sidecar and calling the API directly. For the purpose of this tutorial you’ll run the sidecar without an application.

Step 1: Run the Dapr sidecar

One of the most useful Dapr CLI commands is dapr run. This command launches an application, together with a sidecar.

Launch a Dapr sidecar that will listen on port 3500 for a blank application named myapp:

dapr run --app-id myapp --dapr-http-port 3500

Since no custom component folder was defined with the above command, Dapr uses the default component definitions created during the dapr init flow, found:

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

These tell Dapr to use the local Docker container for Redis as a state store and message broker.

Step 2: Save state

Update the state with an object. The new state will look like this:

[
  {
    "key": "name",
    "value": "Bruce Wayne"
  }
]

Notice, the object contained in the state has a key assigned with the value name. You will use the key in the next step.

Store the new state using the following command:

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

curl -X POST -H "Content-Type: application/json" -d '[{ "key": "name", "value": "Bruce Wayne"}]' http://localhost:3500/v1.0/state/statestore

Invoke-RestMethod -Method Post -ContentType 'application/json' -Body '[{ "key": "name", "value": "Bruce Wayne"}]' -Uri 'http://localhost:3500/v1.0/state/statestore'

Step 3: Get state

Retrieve the object you just stored in the state by using the state management API with the key name. Run the following code with the same Dapr instance you ran earlier. :

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

curl http://localhost:3500/v1.0/state/statestore/name

Invoke-RestMethod -Uri 'http://localhost:3500/v1.0/state/statestore/name'

Step 4: See how the state is stored in Redis

Look in the Redis container and verify Dapr is using it as a state store. Use the Redis CLI with the following command:

docker exec -it dapr_redis redis-cli

List the Redis keys to see how Dapr created a key value pair with the app-id you provided to dapr run as the key’s prefix:

keys *

Output:
1) "myapp||name"

View the state value by running:

hgetall "myapp||name"

Output:
1) "data"
2) "\"Bruce Wayne\""
3) "version"
4) "1"

Exit the redis-cli with:

exit