NATS Streaming
Detailed documentation on the NATS Streaming pubsub component
Component format
To setup NATS Streaming pubsub create a component of type pubsub.natsstreaming. See this guide on how to create and apply a pubsub configuration.
apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
name: natsstreaming-pubsub
namespace: default
spec:
type: pubsub.natsstreaming
version: v1
metadata:
- name: natsURL
value: "nats://localhost:4222"
- name: natsStreamingClusterID
value: "clusterId"
# below are subscription configuration.
- name: subscriptionType
value: <REPLACE-WITH-SUBSCRIPTION-TYPE> # Required. Allowed values: topic, queue.
- name: ackWaitTime
value: "" # Optional.
- name: maxInFlight
value: "" # Optional.
- name: durableSubscriptionName
value: "" # Optional.
# following subscription options - only one can be used
- name: deliverNew
value: <bool>
- name: startAtSequence
value: 1
- name: startWithLastReceived
value: false
- name: deliverAll
value: false
- name: startAtTimeDelta
value: ""
- name: startAtTime
value: ""
- name: startAtTimeFormat
value: ""
Warning
The above example uses secrets as plain strings. It is recommended to use a secret store for the secrets as described here.Spec metadata fields
| Field | Required | Details | Example |
|---|---|---|---|
| natsURL | Y | NATS server address URL | “nats://localhost:4222” |
| natsStreamingClusterID | Y | NATS cluster ID | "clusterId" |
| subscriptionType | Y | Subscription type. Allowed values "topic", "queue" | "topic" |
| ackWaitTime | N | See here | "300ms" |
| maxInFlight | N | See here | "25" |
| durableSubscriptionName | N | Durable subscriptions identification name. | "my-durable" |
| deliverNew | N | Subscription Options. Only one can be used. Deliver new messages only | "true", "false" |
| startAtSequence | N | Subscription Options. Only one can be used. Sets the desired start sequence position and state | "100000", "230420" |
| startWithLastReceived | N | Subscription Options. Only one can be used. Sets the start position to last received. | "true", "false" |
| deliverAll | N | Subscription Options. Only one can be used. Deliver all available messages | "true", "false" |
| startAtTimeDelta | N | Subscription Options. Only one can be used. Sets the desired start time position and state using the delta | "10m", "23s" |
| startAtTime | N | Subscription Options. Only one can be used. Sets the desired start time position and state | "Feb 3, 2013 at 7:54pm (PST)" |
| startAtTimeDelta | N | Must be used with startAtTime. Sets the format for the time | "Jan 2, 2006 at 3:04pm (MST)" |
Create a NATS server
You can run a NATS server locally using Docker:
docker run -d --name nats-streaming -p 4222:4222 -p 8222:8222 nats-streaming
You can then interact with the server using the client port: localhost:4222.
Install NATS on Kubernetes by using the kubectl:
# Single server NATS
kubectl apply -f https://raw.githubusercontent.com/nats-io/k8s/master/nats-server/single-server-nats.yml
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: kubectl get svc stan.
For example, if installing using the example above, the NATS Streaming address would be:
<YOUR-HOST>:4222
Related links
- Basic schema for a Dapr component
- Read this guide for instructions on configuring pub/sub components
- Pub/Sub building block
Last modified May 22, 2021: docs: clean up white noise (#1491) (fe1ab8eb)