NATS Streaming

Detailed documentation on the NATS Streaming pubsub component

Component format

To set up NATS Streaming pub/sub, create a component of type pubsub.natsstreaming. See the how-to guide on how to create and apply a pubsub configuration.

  1. apiVersion: dapr.io/v1alpha1
  2. kind: Component
  3. metadata:
  4.   name: natsstreaming-pubsub
  5. spec:
  6.   type: pubsub.natsstreaming
  7.   version: v1
  8.   metadata:
  9.   - name: natsURL
  10.     value: "nats://localhost:4222"
  11.   - name: natsStreamingClusterID
  12.     value: "clusterId"
  13.   - name: concurrencyMode
  14.     value: parallel
  15.     # below are subscription configuration.
  16.   - name: subscriptionType
  17.     value: <REPLACE-WITH-SUBSCRIPTION-TYPE> # Required. Allowed values: topic, queue.
  18.   - name: ackWaitTime
  19.     value: "" # Optional.
  20.   - name: maxInFlight
  21.     value: "" # Optional.
  22.   - name: durableSubscriptionName
  23.     value: "" # Optional.
  24.   # following subscription options - only one can be used
  25.   - name: deliverNew
  26.     value: <bool>
  27.   - name: startAtSequence
  28.     value: 1
  29.   - name: startWithLastReceived
  30.     value: false
  31.   - name: deliverAll
  32.     value: false
  33.   - name: startAtTimeDelta
  34.     value: ""
  35.   - name: startAtTime
  36.     value: ""
  37.   - name: startAtTimeFormat
  38.     value: ""

Warning

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

Warning

NATS Streaming has been deprecated. Consider using NATS JetStream going forward.

Spec metadata fields

FieldRequiredDetailsExample
natsURLYNATS server address URL“nats://localhost:4222”
natsStreamingClusterIDYNATS cluster ID“clusterId”
subscriptionTypeYSubscription type. Allowed values “topic”, “queue”“topic”
ackWaitTimeNSee here“300ms”
maxInFlightNSee here“25”
durableSubscriptionNameNDurable subscriptions identification name.“my-durable”
deliverNewNSubscription Options. Only one can be used. Deliver new messages only“true”, “false”
startAtSequenceNSubscription Options. Only one can be used. Sets the desired start sequence position and state“100000”, “230420”
startWithLastReceivedNSubscription Options. Only one can be used. Sets the start position to last received.“true”, “false”
deliverAllNSubscription Options. Only one can be used. Deliver all available messages“true”, “false”
startAtTimeDeltaNSubscription Options. Only one can be used. Sets the desired start time position and state using the delta“10m”, “23s”
startAtTimeNSubscription Options. Only one can be used. Sets the desired start time position and state“Feb 3, 2013 at 7:54pm (PST)”
startAtTimeFormatNMust be used with startAtTime. Sets the format for the time“Jan 2, 2006 at 3:04pm (MST)”
concurrencyModeNCall the subscriber sequentially (“single” message at a time), or concurrently (in “parallel”). Default: “parallel”“single”, “parallel”

Create a NATS server

Run a NATS server locally using Docker:

  1. docker run -d --name nats-streaming -p 4222:4222 -p 8222:8222 nats-streaming

Interact with the server using the client port: localhost:4222.

Install NATS on Kubernetes by using the kubectl:

  1. # Single server NATS
  3. kubectl apply -f https://raw.githubusercontent.com/nats-io/k8s/master/nats-server/single-server-nats.yml
  5. kubectl apply -f https://raw.githubusercontent.com/nats-io/k8s/master/nats-streaming-server/single-server-stan.yml

This installs a single NATS-Streaming and NATS into the default namespace. To interact with NATS, find the service with:

  1. kubectl get svc stan

For example, if installing using the example above, the NATS Streaming address would be:

<YOUR-HOST>:4222

Last modified July 27, 2022: Remove namespace element from component examples (#2647) (ff9de5c8)