This document introduces serverless functions and OpenFaaS. It discusses what serverless is, examples of serverless use cases, how OpenFaaS works and its benefits. It also provides instructions on how to write and deploy functions with OpenFaaS including using asynchronous invocation and chaining functions together.

1. Serverless Functions Made Simple
OpenFaaS
DOCKER CAMBRIDGE
@alexellisuk

2. What is Serverless?
MicroserviceMicroserviceMicroservice
Monolith
Microservice
Function
Serverless evolu*on

3. OpenFaaS
DRIVING FACTORS

4. “Alexa, how’s
the weather?”
{ “intent”:
“FindWeather” }
{ “speech”:
“It’s 70 degrees” }
Lambda
Function

5. “Alexa, how’s
the weather?”
{ “intent”:
“FindWeather” }
{ “speech”:
“It’s 70 degrees” }
+

6. What are serverless use-cases?
ANYTHING - WINDOWS/LINUX
Image/Video
conversion
Machine
Learning
Mobile Back-
ends / IoT
HTTP API /
Integrations
Chat Bots
Batch Jobs

7. How did OpenFaaS come about?
STORY SO FAR
• “Lambda but with containers for Alexa”
• Dockercon Cool Hacks - “push Docker beyond what it was designed to do”
• Since May
• Top trending Open Source project overall
• > 8k stars
• Industry Award
• Production users
• Kubernetes, Nomad, Hyper.sh, Cattle
Commits: 876, Forks: 372 Stars: 6589

8. OpenFaaS top contributors and influencers
You..
1.3k commits, 60+ contributors, 533 forks

9. Comes in one flavor: Cloud Native
API Gateway Function Watchdog
Prometheus Swarm Kubernetes

10. HTTP
body
stdinrequest
stdoutresponse
“python3
main.py”
headers
body
headers
Forked process
Function watchdog

11. Performance - fork vs After Burn
HELLO-WORLD & APACHE-BENCH

12. OpenFaaS values
Portable
Developer-
First
Unsurprising UNIX-like
Operator-
Friendly
Community-
Centric
Framework
Developer
Love
Mobilized
Cloud Native

13. Building a Twitter bot

14. Building a Twitter bot
@COLORISEBOT
Gateway Colorise
Tweet-pic
Normalise-color
Minio
Tweet-listener

15. Deployed in 60 seconds

16. How do I write a function?
WRITE A HANDLER
def handler(req):
r = requests.get(req)
print(r.status_code)
handler.py
requirements.txt
Python
Template
Docker
Image
requests
$ faas-cli new dockercon --lang python
Container Registry

17. How do I arrange functions?
provider:
name: faas
url-ping:
lang: python
handler: ./sample/url-ping
image: of/url-ping
environment:
http_proxy: http://corp1.com
notify-slack:
lang: python
handler: ./sample/notify-slack
image: of/notify-slack
$ faas-cli build -f ./sample.yml
$ faas-cli deploy -f ./sample.yml
YAML STACK
$ faas-cli new url-ping --lang python

18. Synchronous invocation
IN STORE RETURNS
marshal request
Gateway Func: resizer
HTTP
200
Resize
Image

19. Asynchronous invocation
RETURN A PRODUCT BY MAIL
NATS Queue
marshal request
Gateway Queue-worker
dequeue
Func: resizer
HTTP
200
HTTP
200
Resize
Image

20. Asynchronous invocation
WITH A CALLBACK-URL
Gateway Func: resizer
HTTP
200
http://x.y.z
X-Callback-Url:
hFp://x.y.z
X-Callback-Url
Resize
Image
Queue etc

21. github.com/openfaas/faas
Chaining demo

22. FanClub GetAvatar
hFps://
Twitter
Chaining demo - Fanclub
HOW IT WORKS
Polaroid

23. Chaining / workflows
AS FUNCTIONS
• Should be a function
• A can call B directly
• A can call B via gateway
• Async
• Director pattern (in documentation)
• Helper library available

24. Providers, integrations and users
DON’T TAKE MY WORD FOR IT

25. Follow @openfaas for more
https://www.openfaas.com