JetStream

Detailed documentation on the NATS JetStream component

Component format

To setup JetStream pubsub create a component of type pubsub.jetstream. See this guide on how to create and apply a pubsub configuration.

  1. apiVersion: dapr.io/v1alpha1
  2. kind: Component
  3. metadata:
  4.   name: jetstream-pubsub
  5. spec:
  6.   type: pubsub.jetstream
  7.   version: v1
  8.   metadata:
  9.   - name: natsURL
  10.     value: "nats://localhost:4222"
  11.   - name: jwt # Optional. Used for decentralized JWT authentication.
  12.     value: "eyJhbGciOiJ...6yJV_adQssw5c"
  13.   - name: seedKey # Optional. Used for decentralized JWT authentication.
  14.     value: "SUACS34K232O...5Z3POU7BNIL4Y"
  15.   - name: tls_client_cert # Optional. Used for TLS Client authentication.
  16.     value: "/path/to/tls.crt"
  17.   - name: tls_client_key # Optional. Used for TLS Client authentication.
  18.     value: "/path/to/tls.key"
  19.   - name: token # Optional. Used for token based authentication.
  20.     value: "my-token"
  21.   - name: name
  22.     value: "my-conn-name"
  23.   - name: streamName
  24.     value: "my-stream"
  25.   - name: durableName 
  26.     value: "my-durable"
  27.   - name: queueGroupName
  28.     value: "my-queue"
  29.   - name: startSequence
  30.     value: 1
  31.   - name: startTime # In Unix format
  32.     value: 1630349391
  33.   - name: flowControl
  34.     value: false
  35.   - name: ackWait
  36.     value: 10s
  37.   - name: maxDeliver
  38.     value: 5
  39.   - name: backOff
  40.     value: "50ms, 1s, 10s"
  41.   - name: maxAckPending
  42.     value: 5000
  43.   - name: replicas
  44.     value: 1
  45.   - name: memoryStorage
  46.     value: false
  47.   - name: rateLimit
  48.     value: 1024
  49.   - name: heartbeat
  50.     value: 15s
  51.   - name: ackPolicy
  52.     value: explicit
  53.   - name: deliverPolicy
  54.     value: all
  55.   - name: domain
  56.     value: hub
  57.   - name: apiPrefix
  58.     value: PREFIX

Spec metadata fields

FieldRequiredDetailsExample
natsURLYNATS server address URL“nats://localhost:4222”
jwtNNATS decentralized authentication JWT“eyJhbGciOiJ…6yJV_adQssw5c”
seedKeyNNATS decentralized authentication seed key“SUACS34K232O…5Z3POU7BNIL4Y”
tls_client_certNNATS TLS Client Authentication Certificate“/path/to/tls.crt”
tls_client_keyNNATS TLS Client Authentication Key“/path/to/tls.key”
tokenNNATS token based authentication“my-token”
nameNNATS connection name“my-conn-name”
streamNameNName of the JetStream Stream to bind to“my-stream”
durableNameNDurable name“my-durable”
queueGroupNameNQueue group name“my-queue”
startSequenceNStart Sequence1
startTimeNStart Time in Unix format1630349391
flowControlNFlow Controltrue
ackWaitNAck Wait10s
maxDeliverNMax Deliver15
backOffNBackOff“50ms, 1s, 5s, 10s”
maxAckPendingNMax Ack Pending5000
replicasNReplicas3
memoryStorageNMemory Storagefalse
rateLimitNRate Limit1024
heartbeatNHeartbeat10s
ackPolicyNAck Policyexplicit
deliverPolicyNOne of: all, last, new, sequence, timeall
domainN[JetStream Leafondes]HUB
apiPrefixN[JetStream Leafnodes]PREFIX

Create a NATS server

You can run a NATS Server with JetStream enabled locally using Docker:

  1. docker run -d -p 4222:4222 nats:latest -js

You can then interact with the server using the client port: localhost:4222.

Install NATS JetStream on Kubernetes by using the helm:

  1. helm repo add nats https://nats-io.github.io/k8s/helm/charts/
  2. helm install --set nats.jetstream.enabled=true my-nats nats/nats

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

  1. kubectl get svc my-nats

For more information on helm chart settings, see the Helm chart documentation.

Create JetStream

It is essential to create a NATS JetStream for a specific subject. For example, for a NATS server running locally use:

  1. nats -s localhost:4222 stream add myStream --subjects mySubject

Last modified January 27, 2023: fix typo (#3082) (3fa9fabe)