Workshop: snap from zero to hero
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This document discusses Snaps, a packaging format for Linux applications that provides confinement and versioning. It begins by explaining the architecture of Snaps and how they isolate applications and provide writable areas. It then demonstrates how to build, install, and update Snaps. It also shows how to create a more complex Snap that includes both a backend service and website. The document guides the reader through cloning the source code, defining the Snap metadata, and building parts for the backend, assets, and website. It explains how to expose the command line interface and web service.
![# Shipping backend assets
parts:
face-detection-backend:
[…]
assets-backend:
source: .
plugin: dump
snap: [images, frontfacedetection.xml]](https://image.slidesharecdn.com/workshopsnapfromzerotohero-170623192950/85/Workshop-snap-from-zero-to-hero-19-320.jpg)
![# And finally, the website part!
parts:
face-detection-backend:
[…]
assets-backend:
[…]
website:
source: https://github.com/ubuntu/face-detection-web.git
plugin: bower
organize:
‘*’: ‘www/’](https://image.slidesharecdn.com/workshopsnapfromzerotohero-170623192950/85/Workshop-snap-from-zero-to-hero-20-320.jpg)
![# Simplifying command name:
apps:
face-detection-demo:
command: face-detection-cli
service:
[…]
# Rebuild, reinstall and check the new command
name!
$ snapcraft
$ sudo snap install *.snap --devmode
$ face-detection-demo --help
# Head over to http://localhost:8080](https://image.slidesharecdn.com/workshopsnapfromzerotohero-170623192950/85/Workshop-snap-from-zero-to-hero-23-320.jpg)
Workshop: snap from zero to hero
- 1. Snaps: from Zero to Hero Dal pacchetto, all’immagine Marco Trevisan marco@ubuntu.com CC BY-SA 3.0
- 2. classic kernel snappy os appapp kernel config os writable files app writable area app writable areaany package can write to any file read-only snaps writable spaces per snap filesystem
- 3. versioned root writable area (for services) $SNAP_DATA common root writable area (for services) $SNAP_COMMON versioned user writable area $SNAP_USER_DATA /tmp (per service and app)/tmp (per service and app) /tmp (per service and app process) snap code & assets (squashfs, RO bind-mounted in /snap/<snap_name>/<version>) $SNAP Service common user writable area $SNAP_USER_COMMON Service CLI GUI
- 4. versioned root writable area (for services) $SNAP_DATA common root writable area (for services) $SNAP_COMMON versioned user writable area $SNAP_USER_DATA /tmp (per service and app)/tmp (per service and app) /tmp (per service and app process) ~ /dev/<device> /sys / (from core snap) /var/lib/snapd/hostfs (/ from host) snap code & assets (squashfs, RO bind-mounted in /snap/<snap_name>/<version>) $SNAP Service common user writable area $SNAP_USER_COMMON Service CLI GUI
- 5. Interazione tra snap app snapapp snap app writable area app writable area Le app sono confinate ed isolate app snap app writable area app snap app writable area
- 6. Ubuntu Core: un sistema all-snaps! Ed un sistema moderno per creare distribuzioni Kernel snap Core snap Gadget snap App snap App snap App snap Content interface snap ● Integrità assicurata da un sistema in sola lettura squashfs ● Non serve riflashare tutto quando cambia un componente
- 7. alla prova di snapd
- 8. Minimum system requirements Processor Architecture x86 or ARMv7+ (Cortex-A7 single core) Memory 256MB Flash Storage 512MB storage Available Connectivity types WiFi, Ethernet, USB, BT4.0 BLE, ..
- 9. # Prerequisito: installa snapd nel sistema # O usa un immagine per KVM di Ubuntu-core # http://snapcraft.io # Installa ed esegui il tuo primo snap $ snap find hello $ sudo snap install hello $ hello $ snap list # Snap può fornire servizi e diversi binari $ hello $ hello.universe
- 10. # Aggiorna gli snap nel sistema (automatico) $ sudo snap refresh # Passa alla versione di “hello” di un altro # canale $ sudo snap refresh hello --beta $ hello # Rimuove uno snap $ sudo snap remove hello
- 11. # Uno snap più complesso! $ sudo snap install face-detection-demo --devmode --beta # Apri http://localhost:8080 (service). # Attiva la webcam via web o da: $ face-detection-demo --enable-camera # Il comando comunica (via Unix socket) # col servizio, che è collegato alla webcam # ed in ascolto sulla rete. # Utilizza le altre opzioni, disponibili anche # nell’interfaccia web
- 12. # Aggiorna all’ultima versione dell’app! $ sudo snap refresh face-detection-demo --devmode --edge # L’interfaccia web non funziona più, # ed i dati son stati eliminati! # facciamo il revert per recuperare servizio (e dati!): $ sudo snap revert face-detection-demo --devmode # La versione è blacklisted, non viene riscaricata $ sudo snap refresh face-detection-demo --devmode --edge $ sudo snap remove face-detection-demo
- 13. Build your first snap
- 14. Build snaps on classic, deploy on Ubuntu Core
- 16. # Creating this first (non trivial) snap! # Ensure you have snapcraft installed $ sudo apt install snapcraft # Clone our source code $ git clone https://github.com/ubuntu/face-detection-demo --branch vanilla # Hint: snapcraft.yaml is available at http://bit.ly/2d9UOKH
- 17. # Creazione metadata $ cd face-detection-demo $ snapcraft init # Apri e modifica lo snapcraft.yaml: name: face-detection-demo version: ‘1.0’ summary: Demo for Face Detection statistics description: | This demo shows face detection statistics with fun heads. grade: devel confinement: devmode
- 18. # Adding golang part parts: face-detection-backend: source: . plugin: go go-importpath: github.com/ubuntu/face-detection-demo build-packages: - build-essential - libopencv-dev
- 19. # Shipping backend assets parts: face-detection-backend: […] assets-backend: source: . plugin: dump snap: [images, frontfacedetection.xml]
- 20. # And finally, the website part! parts: face-detection-backend: […] assets-backend: […] website: source: https://github.com/ubuntu/face-detection-web.git plugin: bower organize: ‘*’: ‘www/’
- 21. # First build and install $ snapcraft $ sudo snap install *.snap --devmode # No http://localhost:8080 service or face-detection-demo CLI! -> We need to expose them explicitly
- 22. # Exposing a command and a service: apps: tool: command: face-detection-cli service: command: face-detection-service daemon: simple restart-condition: always # Rebuild, reinstall and profit! $ snapcraft $ sudo snap install *.snap --devmode $ face-detection-demo.tool --help
- 23. # Simplifying command name: apps: face-detection-demo: command: face-detection-cli service: […] # Rebuild, reinstall and check the new command name! $ snapcraft $ sudo snap install *.snap --devmode $ face-detection-demo --help # Head over to http://localhost:8080
- 24. snapcraft.io/ developer.ubuntu.com/en/snappy github.com/snapcore/snapd github.com/snapcore/snapcraft sudo snap install snap-codelabs # http://localhost:8123