nats-connector

An OpenFaaS event-connector to trigger functions from NATS.

Try it out

Test functions have been created to help you verify the installation of nats-connector. See contrib/test-functions.

Deploy on Kubernetes

The following instructions show how to run and test nats-connector on Kubernetes.

1. Deploy the receiver functions, the receiver function must have the topic annotation:

   export OPENFAAS_URL="http://localhost:8080" # Set your gateway via env variable or the -g flag
   faas-cli deploy --name receive-message --image openfaas/receive-message:latest --fprocess='./handler' --annotation topic="nats-test"

   Or deploy with the stack.yml provided in this repo:

   cd contrib/test-functions
   faas-cli template pull stack
   faas-cli deploy --filter receive-message
   

2. Deploy the connector with:

   kubectl apply -f ./yaml/kubernetes/connector-dep.yaml

3. Deploy the publish-message function

   faas-cli deploy --name publish-message --image openfaas/publish-message:latest --fprocess='./handler' --env nats_url=nats://nats.openfaas:4222

   Or deploy via stack.yml

   cd contrib/test-functions
   faas-cli template pull stack
   faas-cli deploy --filter publish-message
   

4. Now publish a message on the nats-test topic.

   Invoke the publisher

   faas-cli invoke publish-message <<< "test message"

5. Verify that the receiver was invoked by checking the logs

   faas-cli logs receive-message
   
   2019-12-29T19:06:50Z 2019/12/29 19:06:50 received "test message"

Building

Build and release is done via CI, but you can also build your own version locally.

export TAG=0.2.1
make build push

Configuration

Configuration is by environment variable, which can be set in the Kubernetes YAML file: yaml/kubernetes/connector-dep.yaml

Variable	Description	Default
topics	Delimited list of topics	nats-test,
broker_host	The host, but not the port for NATS	nats
async-invocation	Queue the invocation with the built-in OpenFaaS queue-worker and return immediately	false
gateway_url	The URL for the OpenFaaS gateway	http://gateway:8080
upstream_timeout	Timeout to wait for synchronous invocations	60s
rebuild_interval	Interval at which to rebuild the map of topics <> functions	5s
topic_delimiter	Used to separate items in topics variable	,