OpenFaaS Templates

This repository is used both for development of OpenFaaS templates and well as a OpenFaaS Template Store.

Blog Posts - More Information About This Repo

You can find more information about this project/repository and how to use it in following blog posts:

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

Related Projects/Work

OpenFaaS functions created using templates in this repository can be found in following repository - https://github.com/MartinHeinz/openfaas-functions.

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.

• Verify:

  You can verify that all templates work by running:

  task verify

  This will build all templates in template directory. Ideally test should be included in Docker build, so that test don't need to be ran separately.

• Build:

  You can build the Docker image of the template using:

  task build FUNC=golang-mod

• Run:

  You can run template by building and running function created from it:

  task run FUNC=golang-mod

  The function is ran in Docker container on local accessible on port 8081.

• Debug:

  You can debug template by building and running function created from it and attaching to its watchdog process logs:

  task debug FUNC=golang-mod

  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

• Clean:

  To remove artifacts created during build you can run:

  task clean

Using Local Docker Images

Images need to be pushed to remote registry, because OpenFaaS doesn't recognize local repositories. That's why, you need to specify prefix, which is a username + repository in remote registry.

If you don't want to push images, then you can use helm and pass it openfaasImagePullPolicy and faasnetesd.imagePullPolicy parameters to use local docker images:

helm upgrade openfaas chart/openfaas --install \
  --set "faasnetesd.imagePullPolicy=IfNotPresent" \
  --set "openfaasImagePullPolicy=IfNotPresent" \
  --namespace openfaas  \
  --set functionNamespace=openfaas-fn \
  --set operator.create=true

Create New Template

How you create new templates depends on language you use, therefore please refer to guide at https://github.com/openfaas/faas-cli/blob/master/guide/TEMPLATE.md

For the Golang based templates please use Golang module system.

You can use ./template/golang-mod as a base or example.

Before building image, you first need to download all dependencies with go mod tidy.

Troubleshooting Functions

Apart from task debug you can also use following commands for troubleshooting:

• View functions and their logs:

  $ kubectl get deploy -n openfaas-fn
  NAME             READY     UP-TO-DATE   AVAILABLE    AGE
  <FUNCTION_NAME>   0/1       1            0           11m
  nodeinfo          1/1       1            1           7h3m
  
  kubectl logs -n openfaas-fn deploy/<FUNCTION_ANME>

• See if function failed to start:

  kubectl describe -n openfaas-fn deploy/<FUNCTION_NAME>

Resources

• https://github.com/openfaas/templates/blob/master/template/dockerfile/function/Dockerfile
• https://rancher.com/docs/k3s/latest/en/configuration/
• https://blog.alexellis.io/test-drive-k3s-on-raspberry-pi/
• https://github.com/openfaas-incubator/ofc-bootstrap
• https://github.com/openfaas/faas-cli/blob/master/guide/TEMPLATE.md
• https://docs.openfaas.com/deployment/troubleshooting/#function-execution-logs
• https://blog.alexellis.io/serverless-golang-with-openfaas/