nats.docs/jetstream/configuration_mgmt

Configuration Management

In many cases managing the configuration in your application code is the best model, many teams though wish to pre-create Streams and Consumers.

We support a number of tools to assist with this:

• nats CLI with configuration files
• Terraform
• GitHub Actions
• Kubernetes JetStream Controller

nats Admin CLI

The nats CLI can be used to manage Streams and Consumers easily using it's --config flag, for example:

Add a new Stream

This creates a new Stream based on orders.json. The orders.json file can be extracted from an existing stream using nats stream info ORDERS -j | jq .config

$ nats str add ORDERS --config orders.json

Edit an existing Stream

This edits an existing stream ensuring it complies with the configuration in orders.json

$ nats str edit ORDERS --config orders.json

Add a New Consumer

This creates a new Consumer based on orders_new.json. The orders_new.json file can be extracted from an existing stream using nats con info ORDERS NEW -j | jq .config

$ nats con add ORDERS NEW --config orders_new.json

Terraform

Terraform is a Cloud configuration tool from Hashicorp found at terraform.io, we maintain a Provider for Terraform called terraform-provider-jetstream that can maintain JetStream using Terraform.

Setup

Our provider is not hosted by Hashicorp so installation is a bit more complex than typical. Browse to the Release Page and download the release for your platform and extract it into your Terraform plugins directory.

$ unzip -l terraform-provider-jetstream_0.0.2_darwin_amd64.zip
Archive:  terraform-provider-jetstream_0.0.2_darwin_amd64.zip
  Length      Date    Time    Name
---------  ---------- -----   ----
    11357  03-09-2020 10:48   LICENSE
     1830  03-09-2020 12:53   README.md
 24574336  03-09-2020 12:54   terraform-provider-jetstream_v0.0.2

Place the terraform-provider-jetstream_v0.0.2 file in ~/.terraform.d/plugins/terraform-provider-jetstream_v0.0.2

In your project you can configure the Provider like this:

provider "jetstream" {
  servers = "connect.ngs.global"
  credentials = "ngs_jetstream_admin.creds"
}

And start using it, here's an example that create the ORDERS example. Review the Project README for full details.

resource "jetstream_stream" "ORDERS" {
  name     = "ORDERS"
  subjects = ["ORDERS.*"]
  storage  = "file"
  max_age  = 60 * 60 * 24 * 365
}

resource "jetstream_consumer" "ORDERS_NEW" {
  stream_id      = jetstream_stream.ORDERS.id
  durable_name   = "NEW"
  deliver_all    = true
  filter_subject = "ORDERS.received"
  sample_freq    = 100
}

resource "jetstream_consumer" "ORDERS_DISPATCH" {
  stream_id      = jetstream_stream.ORDERS.id
  durable_name   = "DISPATCH"
  deliver_all    = true
  filter_subject = "ORDERS.processed"
  sample_freq    = 100
}

resource "jetstream_consumer" "ORDERS_MONITOR" {
  stream_id        = jetstream_stream.ORDERS.id
  durable_name     = "MONITOR"
  deliver_last     = true
  ack_policy       = "none"
  delivery_subject = "monitor.ORDERS"
}

output "ORDERS_SUBJECTS" {
  value = jetstream_stream.ORDERS.subjects
}