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Quickstarts
1 - Prerequisites
Registry Credential
When building a function, you’ll need to push your function container image to a container registry like Docker Hub or Quay.io. To do that you’ll need to generate a secret for your container registry first.
You can create this secret by filling in the REGISTRY_SERVER
, REGISTRY_USER
and REGISTRY_PASSWORD
fields, and then run the following command.
REGISTRY_SERVER=https://index.docker.io/v1/
REGISTRY_USER=<your_registry_user>
REGISTRY_PASSWORD=<your_registry_password>
kubectl create secret docker-registry push-secret \
--docker-server=$REGISTRY_SERVER \
--docker-username=$REGISTRY_USER \
--docker-password=$REGISTRY_PASSWORD
Source repository Credential
If your source code is in a private git repository, you’ll need to create a secret containing the private git repo’s username and password:
USERNAME=<your_git_username>
PASSWORD=<your_git_password>
kubectl create secret generic git-repo-secret \
--username=$USERNAME \
--password=$USERNAME
You can then reference this secret in the Function
CR’s spec.build.srcRepo.credentials
apiVersion: core.openfunction.io/v1beta1
kind: Function
metadata:
name: function-sample
spec:
version: "v2.0.0"
image: "openfunctiondev/sample-go-func:v1"
imageCredentials:
name: push-secret
port: 8080 # default to 8080
build:
builder: openfunction/builder-go:latest
env:
FUNC_NAME: "HelloWorld"
FUNC_CLEAR_SOURCE: "true"
srcRepo:
url: "https://github.com/OpenFunction/samples.git"
sourceSubPath: "functions/knative/hello-world-go"
revision: "main"
credentials:
name: git-repo-secret
serving:
template:
containers:
- name: function # DO NOT change this
imagePullPolicy: IfNotPresent
runtime: "knative"
Kafka
Async functions can be triggered by events in message queues like Kafka, here you can find steps to setup a Kafka cluster for demo purpose.
Install strimzi-kafka-operator in the default namespace.
helm repo add strimzi https://strimzi.io/charts/ helm install kafka-operator -n default strimzi/strimzi-kafka-operator
Run the following command to create a Kafka cluster and Kafka Topic in the default namespace. The Kafka and Zookeeper clusters created by this command have a storage type of ephemeral and are demonstrated using emptyDir.
Here we create a 1-replica Kafka server named
<kafka-server>
and a 1-replica topic named<kafka-topic>
with 10 partitionscat <<EOF | kubectl apply -f - apiVersion: kafka.strimzi.io/v1beta2 kind: Kafka metadata: name: <kafka-server> namespace: default spec: kafka: version: 3.1.0 replicas: 1 listeners: - name: plain port: 9092 type: internal tls: false - name: tls port: 9093 type: internal tls: true config: offsets.topic.replication.factor: 1 transaction.state.log.replication.factor: 1 transaction.state.log.min.isr: 1 default.replication.factor: 1 min.insync.replicas: 1 inter.broker.protocol.version: "3.1" storage: type: ephemeral zookeeper: replicas: 1 storage: type: ephemeral entityOperator: topicOperator: {} userOperator: {} --- apiVersion: kafka.strimzi.io/v1beta2 kind: KafkaTopic metadata: name: <kafka-topic> namespace: default labels: strimzi.io/cluster: <kafka-server> spec: partitions: 10 replicas: 1 config: retention.ms: 7200000 segment.bytes: 1073741824 EOF
Run the following command to check Pod status and wait for Kafka and Zookeeper to run and start.
$ kubectl get po NAME READY STATUS RESTARTS AGE <kafka-server>-entity-operator-568957ff84-nmtlw 3/3 Running 0 8m42s <kafka-server>-kafka-0 1/1 Running 0 9m13s <kafka-server>-zookeeper-0 1/1 Running 0 9m46s strimzi-cluster-operator-687fdd6f77-cwmgm 1/1 Running 0 11m
Run the following command to view the metadata for the Kafka cluster.
$ kafkacat -L -b <kafka-server>-kafka-brokers:9092
2 - Create sync functions
Before you creating any functions, make sure you’ve installed all the prerequisites
Sync functions are funtions whose inputs are payloads of HTTP requests, and the output or response are sent to the waiting client immediately after the function logic finishes processing the inputs payload. Below you can find some sync function examples in different languages:
Sync Functions | |
---|---|
Go | Hello World, Multi-functions, Sync function with path parameters, log processing, Sync function with output binding |
Nodejs | Hello World, Sync function with output binding |
Python | Hello World |
Java | Hello World |
DotNet | Hello World |
You can find more function samples here
3 - Create async functions
Before you creating any functions, make sure you’ve installed all the prerequisites
Async functions are event-driven and their inputs are usually events from Non-HTTP event sources like message queues, cron triggers, MQTT brokers etc. and usually the client will not wait for an immediate response after triggering an async function by delivering an event. Below you can find some async function examples in different languages:
Async Functions | |
---|---|
Go | Kafka input & HTTP output binding, Cron input & Kafka output binding, Cron input binding, Kafka input binding, Kafka pubsub |
Nodejs | MQTT binding & pubsub |
Python | |
Java | |
DotNet |
You can find more function samples here