Redis

Detailed information on the Redis state store component

Component format

To setup Redis state store create a component of type state.redis. See this guide on how to create and apply a state store configuration.

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
  name: <NAME>
  namespace: <NAMESPACE>
spec:
  type: state.redis
  version: v1
  metadata:
  - name: redisHost
    value: <HOST>
  - name: redisPassword
    value: <PASSWORD>
  - name: enableTLS
    value: <bool> # Optional. Allowed: true, false.
  - name: failover
    value: <bool> # Optional. Allowed: true, false.
  - name: sentinelMasterName
    value: <string> # Optional
  - name: maxRetries
    value: # Optional
  - name: maxRetryBackoff
    value: # Optional
  - name: ttlInSeconds
    value: <int> # Optional
  - name: queryIndexes
    value: <string> # Optional

Warning

The above example uses secrets as plain strings. It is recommended to use a secret store for the secrets as described here.

If you wish to use Redis as an actor store, append the following to the yaml.

  - name: actorStateStore
    value: "true"

Spec metadata fields

Setup Redis

Dapr can use any Redis instance - containerized, running on your local dev machine, or a managed cloud service.

• Self-Hosted
• Kubernetes
• Azure
• AWS
• GCP

A Redis instance is automatically created as a Docker container when you run dapr init

We can use Helm to quickly create a Redis instance in our Kubernetes cluster. This approach requires Installing Helm.

1. Install Redis into your cluster. Note that we’re explicitly setting an image tag to get a version greater than 5, which is what Dapr’ pub/sub functionality requires. If you’re intending on using Redis as just a state store (and not for pub/sub), you do not have to set the image version.

   helm repo add bitnami https://charts.bitnami.com/bitnami
   helm install redis bitnami/redis

2. Run kubectl get pods to see the Redis containers now running in your cluster.

3. Add redis-master:6379 as the redisHost in your redis.yaml file. For example:

       metadata:
       - name: redisHost
         value: redis-master:6379

4. Next, we’ll get the Redis password, which is slightly different depending on the OS we’re using:

   • Windows: Run kubectl get secret --namespace default redis -o jsonpath="{.data.redis-password}" > encoded.b64, which will create a file with your encoded password. Next, run certutil -decode encoded.b64 password.txt, which will put your redis password in a text file called password.txt. Copy the password and delete the two files.

   • Linux/MacOS: Run kubectl get secret --namespace default redis -o jsonpath="{.data.redis-password}" | base64 --decode and copy the outputted password.

   Add this password as the redisPassword value in your redis.yaml file. For example:

       metadata:
       - name: redisPassword
         value: lhDOkwTlp0

Note: this approach requires having an Azure Subscription.

1. Open this link to start the Azure Cache for Redis creation flow. Log in if necessary.
2. Fill out necessary information and check the “Unblock port 6379” box, which will allow us to persist state without SSL.
3. Click “Create” to kickoff deployment of your Redis instance.
4. Once your instance is created, you’ll need to grab the Host name (FQDN) and your access key.
   • for the Host name navigate to the resources “Overview” and copy “Host name”
   • for your access key navigate to “Access Keys” under “Settings” and copy your key.
5. Finally, we need to add our key and our host to a redis.yaml file that Dapr can apply to our cluster. If you’re running a sample, you’ll add the host and key to the provided redis.yaml. If you’re creating a project from the ground up, you’ll create a redis.yaml file as specified in Configuration. Set the redisHost key to [HOST NAME FROM PREVIOUS STEP]:6379 and the redisPassword key to the key you copied in step 4. Note: In a production-grade application, follow secret management instructions to securely manage your secrets.

NOTE: Dapr pub/sub uses Redis Streams that was introduced by Redis 5.0, which isn’t currently available on Azure Managed Redis Cache. Consequently, you can use Azure Managed Redis Cache only for state persistence.

AWS Redis

GCP Cloud MemoryStore

Querying JSON objects (optional)

In addition to supporting storing and querying state data as key/value pairs, the Redis state store optionally supports querying of JSON objects to meet more complex querying or filtering requirements. To enable this feature, the following steps are required:

1. The Redis store must support Redis modules and specifically both Redisearch and RedisJson. If you are deploying and running Redis then load redisearch and redisjson modules when deploying the Redis service. ``
2. Specify queryIndexes entry in the metadata of the component config. The value of the queryIndexes is a JSON array of the following format:

[
  {
    "name": "<indexing name>",
    "indexes": [
      {
        "key": "<JSONPath-like syntax for selected element inside documents>",
        "type": "<value type (supported types: TEXT, NUMERIC)>",
      },
      ...
    ]
  },
  ...
]

1. When calling state management API, add the following metadata to the API calls:

• Save State, Get State, Delete State:
  • add metadata.contentType=application/json URL query parameter to HTTP API request
  • add "contentType": "application/json" pair to the metadata of gRPC API request
• Query State:
  • add metadata.contentType=application/json&metadata.queryIndexName=<indexing name> URL query parameters to HTTP API request
  • add "contentType" : "application/json" and "queryIndexName" : "<indexing name>" pairs to the metadata of gRPC API request

Consider an example where you store documents like that:

{
  "key": "1",
  "value": {
    "person": {
      "org": "Dev Ops",
      "id": 1036
    },
    "city": "Seattle",
    "state": "WA"
}

The component config file containing corresponding indexing schema looks like that:

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
  name: statestore
spec:
  type: state.redis
  version: v1
  initTimeout: 1m
  metadata:
  - name: redisHost
    value: "localhost:6379"
  - name: redisPassword
    value: ""
  - name: queryIndexes
    value: |
      [
        {
          "name": "orgIndx",
          "indexes": [
            {
              "key": "person.org",
              "type": "TEXT"
            },
            {
              "key": "person.id",
              "type": "NUMERIC"
            },
            {
              "key": "state",
              "type": "TEXT"
            },
            {
              "key": "city",
              "type": "TEXT"
            }
          ]
        }
      ]

Consecutively, you can now store, retrieve, and query these documents.

Consider the example from “How-To: Query state” guide. Let’s run it with Redis.

• Self-Hosted
• Kubernetes
• Azure
• AWS
• GCP
• Redis Enterprise Cloud
• Alibaba Cloud

If you are using a self-hosted deployment of Dapr, a Redis instance without the JSON module is automatically created as a Docker container when you run dapr init.

Alternatively, you can create an instance of Redis by running the following command:

docker run -p 6379:6379 --name redis --rm redis

The Redis container that gets created on dapr init or via the above command, cannot be used with state store query API alone. You can run redislabs/rejson docker image on a different port(than the already installed Redis is using) to work with they query API.

Note: redislabs/rejson has support only for amd64 architecture.

Use following command to create an instance of redis compatiable with query API.

docker run -p 9445:9445 --name rejson --rm redislabs/rejson:2.0.6

Follow instructions for Redis deployment in Kubernetes with one extra detail.

When installing Redis Helm package, provide a configuration file that specifies container image and enables required modules:

helm install redis bitnami/redis -f values.yaml

where values.yaml looks like:

image:
  repository: redislabs/rejson
  tag: 2.0.6
master:
  extraFlags:
   - --loadmodule
   - /usr/lib/redis/modules/rejson.so
   - --loadmodule
   - /usr/lib/redis/modules/redisearch.so

Note

Azure Redis managed service does not support the RedisJson module and cannot be used with query.

Follow instructions for Redis deployment in AWS.

Note

For query support you need to enable RediSearch and RedisJson.

Note

Memory Store does not support modules and cannot be used with query.

Redis Enterprise Cloud

Alibaba Cloud

Next is to start a Dapr application. Refer to this component configuration file, which contains query indexing schemas. Make sure to modify the redisHost to reflect the local forwarding port which redislabs/rejson uses.

dapr run --app-id demo --dapr-http-port 3500 --components-path query-api-examples/components/redis

Now populate the state store with the employee dataset, so you can then query it later.

curl -X POST -H "Content-Type: application/json" -d @query-api-examples/dataset.json \
  http://localhost:3500/v1.0/state/querystatestore?metadata.contentType=application/json

To make sure the data has been properly stored, you can retrieve a specific object

curl http://localhost:3500/v1.0/state/querystatestore/1?metadata.contentType=application/json

The result will be:

{
  "city": "Seattle",
  "state": "WA",
  "person": {
    "org": "Dev Ops",
    "id": 1036
  }
}

Now, let’s find all employees in the state of California and sort them by their employee ID in descending order.

This is the query:

{
    "filter": {
        "EQ": { "state": "CA" }
    },
    "sort": [
        {
            "key": "person.id",
            "order": "DESC"
        }
    ]
}

Execute the query with the following command:

curl -s -X POST -H "Content-Type: application/json" -d @query-api-examples/query1.json \
  'http://localhost:3500/v1.0-alpha1/state/querystatestore/query?metadata.contentType=application/json&metadata.queryIndexName=orgIndx'

The result will be:

{
  "results": [
    {
      "key": "3",
      "data": {
        "person": {
          "org": "Finance",
          "id": 1071
        },
        "city": "Sacramento",
        "state": "CA"
      },
      "etag": "1"
    },
    {
      "key": "7",
      "data": {
        "person": {
          "org": "Dev Ops",
          "id": 1015
        },
        "city": "San Francisco",
        "state": "CA"
      },
      "etag": "1"
    },
    {
      "key": "5",
      "data": {
        "person": {
          "org": "Hardware",
          "id": 1007
        },
        "city": "Los Angeles",
        "state": "CA"
      },
      "etag": "1"
    },
    {
      "key": "9",
      "data": {
        "person": {
          "org": "Finance",
          "id": 1002
        },
        "city": "San Diego",
        "state": "CA"
      },
      "etag": "1"
    }
  ]
}

The query syntax and documentation is available here

Related links

• Basic schema for a Dapr component
• Read this guide for instructions on configuring state store components
• State management building block

Last modified June 23, 2022: Merge pull request #2550 from ItalyPaleAle/cosmosdb-harcoded-dapr-version (cf03237)