juju reactive charm (by quqi99)

sudo snap install charm --classic
mkdir -p /bak/work/charms/layers
export JUJU_REPOSITORY=/bak/work/charms
export LAYER_PATH=$JUJU_REPOSITORY/layers
cd $LAYER_PATH
charm create simple
cd simple

sudo bash -c 'cat >layer.yaml' <<EOF
includes: ['layer:basic', 'layer:vnfproxy']
options:
    basic:
        use_venv: false
EOF

sudo bash -c 'cat >metadata.yaml' <<EOF
name: simple
summary: a simple vnf proxy charm
maintainer: hua <hua@localhost>
subordinate: false
series: ['xenial']
EOF

sudo bash -c 'cat >actions.yaml' <<EOF
touch:
  description: "Touch a file on the VNF."
  params:
    filename:
        description: "The name of the file to touch."
        type: string
        default: ""
  required:
    - filename
EOF

mkdir -p actions
sudo bash -c 'cat >actions/touch' <<EOF
#!/usr/bin/env python3
import sys
sys.path.append('lib')
from charms.reactive import main, set_flag
from charmhelpers.core.hookenv import action_fail, action_name

set_flag('actions.{}'.format(action_name()))

try:
   main()
except Exception as e:
   action_fail(repr(e))
EOF
sudo chmod +x actions/touch

sudo bash -c 'cat >reactive/simple.py' <<EOF
from charmhelpers.core.hookenv import ( 
     action_get, 
     action_fail, 
     action_set, 
     status_set, 
) 
from charms.reactive import ( 
     clear_flag, 
     set_flag, 
     when, 
     when_not,
) 
import charms.sshproxy
# Set the charm’s state to active so the LCM knows it’s ready to work.
@when_not('simple.installed') 
def install_simple_proxy_charm():     
     set_flag('simple.installed') 
     status_set('active', 'Ready!')
# Define what to do when the `touch` primitive is invoked. 
@when('actions.touch')
def touch(): 
     err = ''
     try: 
          filename = action_get('filename') 
          cmd = ['touch {}'.format(filename)]
          result, err = charms.sshproxy._run(cmd) 
     except: 
         action_fail('command failed:' + err) 
     else: 
         action_set({'output': result})
      finally: 
          clear_flag('actions.touch')
EOF

charm build

vnfd file
vnfd:vnfd-catalog:
    vnfd:
    -   id: hackfest3charmed-vnf
        name: hackfest3charmed-vnf
        vnf-configuration:
            juju:
                charm: simple
            initial-config-primitive:
            -   seq: '1'
                name: config
                parameter:
                -   name: ssh-hostname
                    value: <rw_mgmt_ip>
                -   name: ssh-username
                    value: ubuntu
                -   name: ssh-password
                    value: osm4u
            -   seq: '2'
                name: touch
                parameter:
                -   name: filename
                    value: '/home/ubuntu/first-touch'
            config-primitive:
            -   name: touch
                parameter:
                -   name: filename
                    data-type: STRING
                    default-value: '/home/ubuntu/touched'


Reference
[1] https://osm.etsi.org/wikipub/index.php/Creating_your_VNF_Charm