Serverless Function Return Null in Knative

[himadriganguly]

⚠️⚠️ Deployed the sample serverless function from https://www.serverless.com/framework/docs/providers/knative/guide/quick-start/ in Knative on the local machine in minikube. It deployed without any issue but when invoke with serverless invoke -f hello return NULL.

serverless.yml

service: app

provider:
  name: knative
  # optional Docker Hub credentials you need if you're using local Dockerfiles as function handlers
  docker:
    username: ${env:DOCKER_HUB_USERNAME}
    password: ${env:DOCKER_HUB_PASSWORD}

functions:
  hello:
    handler: hello-world.dockerfile
    context: ./code
    # either use a container image URL for your function `handler` as the commented out `handler`
    # below shows or make sure that you update the application code and corresponding Dockerfile
    # to process incoming CloudEvents event data when using the event sources listed below
    # handler: gcr.io/knative-releases/github.com/knative/eventing-contrib/cmd/event_display:latest
    # events:
    #   - custom:
    #       filter:
    #         attributes:
    #           type: greeting
    #   - kafka:
    #       consumerGroup: KAFKA_CONSUMER_GROUP_NAME
    #       bootstrapServers:
    #         - server1
    #         - server2
    #       topics:
    #         - my-topic
    #   - awsSqs:
    #       secretName: aws-credentials
    #       secretKey: credentials
    #       queue: QUEUE_URL
    #   - gcpPubSub:
    #       project: knative-hackathon
    #       topic: foo
    #   - cron:
    #       schedule: '* * * * *'
    #       data: '{"message": "Hello world from a Cron event source!"}'

plugins:
  - serverless-knative

FULL COMMAND NAME output

serverless info

Service Information
service: app
namespace: sls-app-dev
ingress ip: 172.17.0.5

Deployed functions
hello:
  - url: app-hello.sls-app-dev.example.com

serverless invoke -f hello

Return NULL

Installed version

Framework Core: 1.74.1
Plugin: 3.6.15
SDK: 2.3.1
Components: 2.31.12

But the sample application in Knative documentation at https://knative.dev/docs/serving/samples/hello-world/helloworld-python/index.html works exactly fine.

[zhaogaiwen]

can you show ksvc?

[himadriganguly]

Output of kubectl get ksvc -n sls-app-dev

NAME               URL                                                      LATESTCREATED            LATESTREADY   READY   REASON
app-hello   http://app-hello.sls-app-dev.example.com       app-hello-7mdzv                                             False       RevisionMissing