OpenFaaS Functions

This is repository for various function that use OpenFaaS platform.

For more information please see blog post here:

• Going Serverless with OpenFaaS and Golang — The Ultimate Setup and Workflow

Prerequisites

• k3s (k3sup install is preferable):

  # Fastest, easiest and recommended option - using k3sup
  curl -SLsf https://get.k3sup.dev/ | sudo sh
  
  # Manual, more involved option
  curl -sfL https://get.k3s.io | sh -
  
  sudo cat /var/lib/rancher/k3s/server/node-token  # This is K3S_TOKEN
  
  export K3S_URL="http://localhost:6443"
  export K3S_TOKEN="..."
  
  sudo cp /etc/rancher/k3s/k3s.yaml ~/.kube/config
  sudo chown $(id -u):$(id -g) /home/martin/.kube/config
  
  kubectl get node
  kubectl config view
  

  If you get connection refused error try running systemctl restart k3s

  To add worker nodes, ssh into other machine, export variables as shown above and run curl -sfL https://get.k3s.io | sh -

• OpenFaaS CLI:

  curl -sL https://cli.openfaas.com | sudo sh

• OpenFaaS (k3sup install is preferable):

  # Again if using k3sup - simpler, faster option
  k3sup app install openfaas
  
  # Manual, more involved option
  git clone https://github.com/openfaas/faas-netes
  
  kubectl apply -f https://raw.githubusercontent.com/openfaas/faas-netes/master/namespaces.yml
  
  PASSWORD=$(head -c 12 /dev/urandom | shasum| cut -d' ' -f1)
  kubectl -n openfaas create secret generic basic-auth \
  --from-literal=basic-auth-user=admin \
  --from-literal=basic-auth-password="$PASSWORD"
  
  cd faas-netes && \
  kubectl apply -f ./yaml
  
  export OPENFAAS_URL=http://127.0.0.1:31112
  
  kubectl port-forward svc/gateway -n openfaas 31112:8080 &

  Open http://127.0.0.1:31112 in browser and login with admin and echo $PASSWORD

• Task (Taskfile):

  cd ~
  curl -sL https://taskfile.dev/install.sh | sh

  Or depending on your system: https://taskfile.dev/#/installation

Usage

Before deploying functions, the Docker image needs to first be push to remote registry repository, this repository is specified using PREFIX variable in Taskfile.yml. You need to change its value to your Docker Hub username.

• Create:

  Create function with specified name, using some template:

  task create TPL=golang-mod FUNC=my-func

• Build:

  Build specific function (Docker image):

  task build FUNC=my-func

• Run:

  Build, push and deploy function:

  task run FUNC=my-func

• Logs:

  View info and logs of function:

  task logs FUNC=my-func

• Debug:

  Run function locally (in Docker) and attach to watchdog process logs:

  task debug FUNC=my-func

  When the function is running you can hit it with cURL:

  curl -vvv --header "Content-Type: application/json" \
            --request POST \
            --data '{"key":"value"}' \
            127.0.0.1:8081

  You might also want to change timeouts of the function when debugging (template.yml):

  functions:
      func_name:
        ...
        environment:
            read_timeout: 20
            write_timeout: 20

Using Custom Templates

Custom templates are stored in openfaas-templates repository.

These are automatically pulled when running task create ..., if you want to use different template store, then change OPENFAAS_TEMPLATE_STORE_URL in Taskfile.yml

Resources

• Using template from external repository
• OpenFaaS Function Store
• Customise a template
• Deployment Troubleshooting
• https://blog.alexellis.io/serverless-golang-with-openfaas/
• https://blog.alexellis.io/test-drive-k3s-on-raspberry-pi/
• https://rancher.com/docs/k3s/latest/en/configuration/
• https://github.com/openfaas/templates/blob/master/template/dockerfile/function/Dockerfile