3.7 KiB
type | title | linkTitle | weight | description |
---|---|---|---|---|
docs | Use the Dapr API | Use the Dapr API | 30 | Run a Dapr sidecar and try out the state management API |
In this guide, you'll simulate an application by running the sidecar and calling the state management 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]({{< ref state-management >}}).
Pre-requisites
- [Install Dapr CLI]({{< ref install-dapr-cli.md >}}).
- [Run
dapr init
]({{< ref install-dapr-selfhost.md>}}).
Step 1: Run the Dapr sidecar
The [dapr run
]({{< ref dapr-run.md >}}) command normally runs your application and a Dapr sidecar. In this case,
it only runs the sidecar since you are interacting with the state management API directly.
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]({{< ref "install-dapr-selfhost.md#step-5-verify-components-directory-has-been-initialized" >}}).
Step 2: Save state
Update the state with an object. The new state will look like this:
[
{
"key": "name",
"value": "Bruce Wayne"
}
]
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:
{{< tabs "HTTP API (Bash)" "HTTP API (PowerShell)">}} {{% codetab %}}
curl -X POST -H "Content-Type: application/json" -d '[{ "key": "name", "value": "Bruce Wayne"}]' http://localhost:3500/v1.0/state/statestore
{{% /codetab %}}
{{% codetab %}}
Invoke-RestMethod -Method Post -ContentType 'application/json' -Body '[{ "key": "name", "value": "Bruce Wayne"}]' -Uri 'http://localhost:3500/v1.0/state/statestore'
{{% /codetab %}}
{{< /tabs >}}
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:
{{< tabs "HTTP API (Bash)" "HTTP API (PowerShell)">}}
{{% codetab %}}
curl http://localhost:3500/v1.0/state/statestore/name
{{% /codetab %}}
{{% codetab %}}
Invoke-RestMethod -Uri 'http://localhost:3500/v1.0/state/statestore/name'
{{% /codetab %}}
{{< /tabs >}}
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 values by running:
hgetall "myapp||name"
Output:
1) "data"
2) "\"Bruce Wayne\""
3) "version"
4) "1"
Exit the Redis CLI with:
exit
Step 5: Delete state
In the same terminal window, delete thename
state object from the state store.
{{< tabs "HTTP API (Bash)" "HTTP API (PowerShell)">}}
{{% codetab %}}
curl -v -X DELETE -H "Content-Type: application/json" http://localhost:3500/v1.0/state/statestore/name
{{% /codetab %}}
{{% codetab %}}
Invoke-RestMethod -Method Delete -ContentType 'application/json' -Uri 'http://localhost:3500/v1.0/state/statestore/name'
{{% /codetab %}}
{{< /tabs >}}
{{< button text="Next step: Dapr Quickstarts >>" page="getting-started/quickstarts" >}}