Merge ~jacekn/prometheus-snmp-exporter-charm/+git/prometheus-snmp-exporter-charm:master into prometheus-snmp-exporter-charm:master

[Jacek Nykis]

Switch snap support to snap layer. Remove deb package support

[Stuart Bishop (stub)]

Looks fine.

Do you want to declare the Juju resource in metadata.yaml, so people can upload the snap as a resource for deployments without network connectivity?

review: Approve

diff --git a/config.yaml b/config.yaml
index c47092e..ed96956 100644
--- a/config.yaml
+++ b/config.yaml
@@ -1,39 +1,10 @@
 options:
-  install_method:
-    default: "snap"
-    type: string
-    description: >
-        How to install prometheus-snmp-exporter package. If set to "apt"
-        the package will be installed using apt-get.
-        If set to "snap", empty string or unset snap package will be installed
   snap_channel:
     default: "stable"
     type: string
     description: |
         If install_method is set to "snap" this option controlls channel name.
         Supported values are: "stable", "candidate", "beta" and "edge"
-  install_sources:
-    default: '[ "ppa:canonical-bootstack/prometheus" ]'
-    type: string
-    description: |
-        YAML list of additional installation sources, as a string. The number of
-        install_sources must match the number of install_keys. For example:
-          install_sources: |
-           - ppa:project1/ppa
-           - ppa:project2/ppa
-  install_keys:
-    default: '[ "" ]'
-    type: string
-    description: |
-        YAML list of GPG keys for installation sources, as a string. For apt repository
-        URLs, use the public key ID used to verify package signatures. For 
-        other sources such as PPA, use empty string. This list must have the 
-        same number of elements as install_sources, even if the key items are 
-        all empty string. An example to go with the above for install_sources:
-          install_keys: |
-           - "ABC"
-           - ""
-
   snmp_community:
     default: "public"
     type: string
diff --git a/layer.yaml b/layer.yaml
index 16a7bcf..c0bb288 100644
--- a/layer.yaml
+++ b/layer.yaml
@@ -1,4 +1,4 @@
-includes: ['layer:basic', 'interface:http']
+includes: ['layer:basic', 'interface:http', 'layer:snap']
 ignore: ['.*.swp' ]
 options:
   basic:
diff --git a/reactive/prometheus-snmp-exporter.py b/reactive/prometheus-snmp-exporter.py
index 36788fb..aad2631 100644
--- a/reactive/prometheus-snmp-exporter.py
+++ b/reactive/prometheus-snmp-exporter.py
@@ -1,18 +1,18 @@
 import yaml
-import subprocess
 
-from charmhelpers import fetch
 from charmhelpers.core import host, hookenv
 from charmhelpers.core.templating import render
 from charms.reactive import (
     when, when_not, set_state, remove_state
 )
 from charms.reactive.helpers import any_file_changed, data_changed
+from charms.layer import snap
 
 
-PKGNAMES = ['prometheus-snmp-exporter']
+SNAP_NAME = 'prometheus-snmp-exporter'
 PORT_DEF = 9116
 SNMP_EXPORTER_YML_TMPL = 'snmp.yaml.j2'
+CONF_FILE_PATH = '/var/snap/prometheus-snmp-exporter/current/snmp.yml'
 
 
 def templates_changed(tmpl_list):
@@ -21,21 +21,12 @@ def templates_changed(tmpl_list):
 
 @when_not('snmp-exporter.installed')
 def install_packages():
-    fetch.configure_sources()
+    hookenv.status_set('maintenance', 'Installing software')
     config = hookenv.config()
-    source = config.get('install_method', 'snap')
-    channel = '--channel={}'.format(config.get('snap_channel', 'stable'))
-    if source == 'snap':
-        # Switch to check_call once LP1622782 is resolved
-        subprocess.call(['snap', 'install'] + PKGNAMES + [channel])
-        set_state('snmp-exporter.installed')
-    elif source == 'apt':
-        fetch.apt_update()
-        fetch.apt_install(PKGNAMES)
-        set_state('snmp-exporter.installed')
-    else:
-        hookenv.status_set('blocked',
-                           'Unsupported install_method: {}'.format(source))
+    channel = config.get('snap_channel', 'stable')
+    snap.install(SNAP_NAME, channel=channel, force_dangerous=False)
+    set_state('snmp-exporter.installed')
+    set_state('snmp-exporter.do-check-reconfig')
 
 
 def validate_config(filename):
@@ -46,27 +37,16 @@ def validate_config(filename):
 @when('snmp-exporter.do-reconfig-yaml')
 def write_snmp_exporter_config_yaml():
     config = hookenv.config()
-    if config.get('install_method', 'snap') == 'snap':
-        config_file = '/var/snap/prometheus-snmp-exporter/current/snmp.yml'
-    else:
-        config_file = '/etc/prometheus/snmp.yaml'
     render(source=SNMP_EXPORTER_YML_TMPL,
-           target=config_file,
+           target=CONF_FILE_PATH,
            context={'config': config}
            )
-    validate_config(config_file)
+    validate_config(CONF_FILE_PATH)
     hookenv.open_port(PORT_DEF)
     set_state('snmp-exporter.do-restart')
     remove_state('snmp-exporter.do-reconfig-yaml')
 
 
-@when_not('snmp-exporter.started')
-def setup_snmp_exporter():
-    hookenv.status_set('maintenance', 'Installing software')
-    install_packages()
-    set_state('snmp-exporter.do-check-reconfig')
-
-
 @when('snmp-exporter.started')
 def check_config():
     set_state('snmp-exporter.do-check-reconfig')
@@ -75,9 +55,6 @@ def check_config():
 @when('snmp-exporter.do-check-reconfig')
 def check_reconfig_snmp_exporter():
     config = hookenv.config()
-    install_opts = ('install_sources', 'install_keys', 'install_method')
-    if any(config.changed(opt) for opt in install_opts):
-        remove_state('snmp-exporter.installed')
 
     if data_changed('snmp-exporter.config', config):
         set_state('snmp-exporter.do-reconfig-yaml')