Microservices: Ubuntu Core: Building your own snap application

After the installation of ubuntu core and running caddy webserver from a repository  i was wondering how to build my own snap package.

The tutorial shows how to build GNU Hello into a snap packages:

and this tutorial works fine.
But this does not really help, if you have a command, which you can not build with autotools or ant or ....
A complete list can be found here.

So my plan:

• create a bash script "myapp.sh"
• try to build a snap, which contains this file

My first step was to create a directory "myapp" and create a "snapcraft.yaml" file:

name: myapp
version: "2.13"
summary: My first snap
description: My first snap app
confinement: strict

apps:
          myapp:
                      command: myapp.sh

parts:
          myapp:
                      plugin: nil

 Inside the myapp directory i created "prime/bin/myapp.sh" and "stage/myapp.sh". For both i changed the execution bits:
(With only u+x i got "-bash: ./myapp.sh: Permission denied")

chmod uga+x

Then i ran

$ snapcraft
"grade" property not specified: defaulting to "stable"
Skipping pull myapp (already ran)
Skipping build myapp (already ran)
Skipping stage myapp (already ran)
Skipping prime myapp (already ran)
Snapping 'myapp' |                                                                                                                                            
Snapped myapp_2.13_amd64.snap

This file i transferred to my ubuntu core and installed it with:

$ snap install --dangerous  myapp_2.13_amd64.snap
myapp 2.13 installed

And:

d-schroff@localhost:~$ myapp
This is myapp.

Other posts around this topic: Snapcraft / Snap on ubuntu core

Installing Ubuntu Core on Virtualbox

Creating a snap containing only a shell script

Running a webserver (caddy) with snap