Use the Dapr API

Run a Dapr sidecar and try out the state API

In this guide, you’ll simulate an application by running the sidecar and calling the API directly. After running Dapr using the Dapr CLI, you’ll:

  • Save a state object.
  • Read/get the state object.
  • Delete the state object.

Learn more about the state building block and how it works in our concept docs.

Pre-requisites

Step 1: Run the Dapr sidecar

The dapr run command launches an application, together with a sidecar.

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

  1. 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.

Step 2: Save state

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

  1. [
  2.   {
  3.     "key": "name",
  4.     "value": "Bruce Wayne"
  5.   }
  6. ]

Notice, that objects contained in the state each have a key assigned with the value name. You will use the key in the next step.

Save a new state object using the following command:

  1. curl -X POST -H "Content-Type: application/json" -d '[{ "key": "name", "value": "Bruce Wayne"}]' http://localhost:3500/v1.0/state/statestore
  1. 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. In the same terminal window, run the following command:

  1. curl http://localhost:3500/v1.0/state/statestore/name
  1. 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:

  1. 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:

  1. keys *

Output:
1) "myapp||name"

View the state values by running:

  1. hgetall "myapp||name"

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

Exit the Redis CLI with:

  1. exit

Step 5: Delete state

In the same terminal window, delete thename state object from the state store.

  1. curl -v -X DELETE -H "Content-Type: application/json" http://localhost:3500/v1.0/state/statestore/name
  1. Invoke-RestMethod -Method Delete -ContentType 'application/json' -Uri 'http://localhost:3500/v1.0/state/statestore/name'

Next step: Dapr Quickstarts >>

Last modified May 18, 2022: Upmerge of v1.7 into v1.8 20220518 (#2446) (e1f6e886)