Merge lp:~jacekn/charms/xenial/prometheus-snmp-exporter/layer-prometheus-snmp-exporter-snap into lp:~canonical-is-sa/charms/xenial/prometheus-snmp-exporter/layer-prometheus-snmp-exporter

[Jacek Nykis]

Add snap package support

[Stuart Bishop (stub)]

A couple of issues inline, but nothing that will require a second review. Mostly good.

review: Approve

=== modified file 'config.yaml'
--- config.yaml	2016-05-18 16:31:08 +0000
+++ config.yaml	2016-09-13 21:43:17 +0000
@@ -1,4 +1,17 @@
 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

=== modified file 'reactive/prometheus-snmp-exporter.py'
--- reactive/prometheus-snmp-exporter.py	2016-05-18 15:27:05 +0000
+++ reactive/prometheus-snmp-exporter.py	2016-09-13 21:43:17 +0000
@@ -1,4 +1,5 @@
 import yaml
+import subprocess
 
 from charmhelpers import fetch
 from charmhelpers.core import host, hookenv
@@ -9,10 +10,8 @@
 from charms.reactive.helpers import any_file_changed, data_changed
 
 
-SVCNAME = 'prometheus-snmp-exporter'
 PKGNAMES = ['prometheus-snmp-exporter']
 PORT_DEF = 9116
-SNMP_EXPORTER_YML = '/etc/prometheus/snmp.yaml'
 SNMP_EXPORTER_YML_TMPL = 'snmp.yaml.j2'
 
 
@@ -20,33 +19,50 @@
     return any_file_changed(['templates/{}'.format(x) for x in tmpl_list])
 
 
-@when('snmp-exporter.do-install')
+@when_not('snmp-exporter.installed')
 def install_packages():
     fetch.configure_sources()
-    fetch.apt_update()
-    fetch.apt_install(PKGNAMES)
-    remove_state('snmp-exporter.do-install')
-
-
-def validate_config():
-    return yaml.safe_load(open(SNMP_EXPORTER_YML))
-
-
-@when('alertmanager.do-reconfig-yaml')
-def write_alertmanager_config_yaml():
-    config = hookenv.config()
+    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))
+        raise Exception('Unsupported install_method: {}'.format(source))
+
+
+def validate_config(filename):
+    return yaml.safe_load(open(filename))
+
+
+@when('snmp-exporter.installed')
+@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=SNMP_EXPORTER_YML,
+           target=config_file,
            context={'config': config}
            )
-    validate_config()
+    validate_config(config_file)
     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_alertmanager():
+def setup_snmp_exporter():
     hookenv.status_set('maintenance', 'Installing software')
     install_packages()
     set_state('snmp-exporter.do-check-reconfig')
@@ -58,14 +74,14 @@
 
 
 @when('snmp-exporter.do-check-reconfig')
-def check_reconfig_alertmanager():
+def check_reconfig_snmp_exporter():
     config = hookenv.config()
-    install_opts = ('install_sources', 'install_keys')
+    install_opts = ('install_sources', 'install_keys', 'install_method')
     if any(config.changed(opt) for opt in install_opts):
-        set_state('snmp-exporter.do-install')
+        remove_state('snmp-exporter.installed')
 
     if data_changed('snmp-exporter.config', config):
-        set_state('alertmanager.do-reconfig-yaml')
+        set_state('snmp-exporter.do-reconfig-yaml')
 
     if templates_changed([SNMP_EXPORTER_YML_TMPL]):
         set_state('snmp-exporter.do-reconfig-yaml')
@@ -74,13 +90,18 @@
 
 
 @when('snmp-exporter.do-restart')
-def restart_alertmanager():
-    if not host.service_running(SVCNAME):
-        hookenv.log('Starting {}...'.format(SVCNAME))
-        host.service_start(SVCNAME)
-    else:
-        hookenv.log('Restarting {}, config file changed...'.format(SVCNAME))
-        host.service_restart(SVCNAME)
+def restart_snmp_exporter():
+    config = hookenv.config()
+    if config.get('install_method', 'snap'):
+        svcname = 'snap.prometheus-snmp-exporter.snmp-exporter'
+    else:
+        svcname = 'prometheus-snmp-exporter'
+    if not host.service_running(svcname):
+        hookenv.log('Starting {}...'.format(svcname))
+        host.service_start(svcname)
+    else:
+        hookenv.log('Restarting {}, config file changed...'.format(svcname))
+        host.service_restart(svcname)
     hookenv.status_set('active', 'Ready')
     set_state('snmp-exporter.started')
     remove_state('snmp-exporter.do-restart')

=== modified file 'templates/snmp.yaml.j2'
--- templates/snmp.yaml.j2	2016-05-27 10:14:37 +0000
+++ templates/snmp.yaml.j2	2016-09-13 21:43:17 +0000
@@ -1,7 +1,9 @@
 ---
 # Default module: interface stats and uptime.
 default:
-  community: {{ config.snmp_community }}
+  version: 2
+  auth:
+    community: {{ config.snmp_community }}
   walk:
     - 1.3.6.1.2.1.1.3
     - 1.3.6.1.2.1.2