HTTP~ Fire!
Send request to domain ingress.
POSTdata to target function URL:curl -d '{"hello":"ofn"}' \ -H 'Content-Type: application/json' \ http://openfunction.io/default/sample-node-http-triggerWait a second (may be few more seconds for cold start), you would get results:
See also: OpenFunction 202 - Set up MQTT Broker ↩︎
Haili Zhang
Cloud Platform Director of UISEE© Technology.
Cloud Native focuses: Kubernetes, DevOps, Observability, Service Mesh, Serverless.
Tricky Part of Async Func
Pros
- By leveraging Dapr, async function could nearly connect with everthing …
- Check Dapr Bindings
- Check Dapr PubSub Brokers
Cons
- NEED events to pull the trigger
- Usually coming in from external systems, or interface with external systems
- e.g. message queue, cron, K8s events
- Also rather unfriendly for testing
- We need a MQTT client tool to serve as the event publisher, remember that?
HTTP Comes to the Rescue
Idea
- Use HTTP sync function as trigger
POSTdata to one sync function- Sync function bridge data to event hub
- With async function subscribed to hub
Solution
- Enable Dapr output binding and pub in sync function runtime [1]
- Check the figure aside as an example 👉
Feature introduced in OpenFunction 0.6.0 along with Node.js Function Framework 0.5.0 ↩︎
Invoke Async in A Sync Way!
Same function signature
Exactly the same async function signature.
function (ctx, data) {}
data: Request body data, parsed as JSON by default
Extensions
Specific signature type
New type openfunction ready to work.
- OpenFunction Function CRD:
apiVersion: core.openfunction.io/v1beta1
kind: Function
metadata:
name: func-name
spec:
serving:
# default to knative
runtime: knative
params:
# default to http
FUNCTION_SIGNATURE_TYPE: openfunction- CLI:
--signature-type=openfunction - ENV:
FUNCTION_SIGNATURE_TYPE=openfunction
Lab: HTTP Trigger MQTT Bindings
Sample Function
Another plain forwarder
// Standard Express style HTTP sync function
export const tryKnative = (req, res) => {
res.send(`Hello, ${req.query.u || 'World'}!`);
};
// OpenFunction standard function which could
// set bridge between sync and async function
export const tryKnativeAsync = async (ctx, data) => {
console.log('Data received: %o', data);
// Forward HTTP body to Dapr outputs
await ctx.send(data);
// Send something back as HTTP response
// when necessary
// ctx.res.send(data);
};Remember to build the function, either when applying Function CR manifest or directly via Pack CLI tool
Sample CR Manifest
Check out full content in http-trigger.yml
spec:
image: '<image-repo>/<image-name>:<image-tag>'
serving:
runtime: knative
params:
FUNCTION_TARGET: tryKnativeAsync
FUNCTION_SIGNATURE_TYPE: openfunction
outputs:
- name: mqtt-output
component: mqtt-out
operation: create
bindings:
mqtt-out:
type: bindings.mqtt
version: v1
metadata:
- name: consumerID
value: '{uuid}'
- name: url
value: tcp://admin:public@emqx:1883
- name: topic
value: outDeploy Sample Function
Apply function manifest, and check running states
$ kubectl apply -f http-trigger.yaml function.core.openfunction.io/sample-node-http-trigger created $ kubectl get fn NAME BUILDSTATE SERVINGSTATE BUILDER SERVING URL AGE sample-node-http-trigger Skipped Running serving-7d75d http://openfunction.io/default/sample-node-http-trigger 6d $ kubectl get deploy NAME READY UP-TO-DATE AVAILABLE AGE ... serving-7d75d-ksvc-xn768-v200-deployment 0/0 0 0 6d14h ...
Knative runtime would autoscale the deployment replica to
0, if no incoming request for a period of time.
HTTP~ Fire!
Send request to domain ingress.
POSTdata to target function URL:curl -d '{"hello":"ofn"}' \ -H 'Content-Type: application/json' \ http://openfunction.io/default/sample-node-http-triggerWait a second (may be few more seconds for cold start), you would get results:
See also: OpenFunction 202 - Set up MQTT Broker ↩︎