Merge lp:~ricardokirkner/charms/trusty/logstash/logstash2-extra-plugins into lp:~canonical-is-sa/charms/trusty/logstash/logstash2

[Ricardo Kirkner]

added support for installing extra plugins

update logstash plugins during config-changed hook to allow for updating after installed

[Guillermo Gonzalez (verterok)]

+1

review: Approve

[Alexandre Gomes (alejdg)]

+1

review: Approve

[lp:~ricardokirkner/charms/trusty/logstash/logstash2-extra-plugins]

74. By Ricardo Kirkner on 2018-01-19

added workaround to avoid uninstall process from hanging

75. By Ricardo Kirkner on 2018-01-19

fixed typo

=== modified file 'config.yaml'
--- config.yaml	2017-12-04 14:43:22 +0000
+++ config.yaml	2018-01-19 16:20:49 +0000
@@ -11,6 +11,16 @@
     type: string
     default: ''
     description: Space separated list of extra apt packages to install.
+  extra-plugins:
+    type: string
+    default: ''
+    descripion: |
+      Space separated list of plugins to install.
+      Format for each item is name:version.
+  extra-plugins-repo:
+    type: string
+    default: "https://archive.admin.canonical.com/other/logstash"
+    description: "Location to download logstash plugins from."
   ssl_cert:
     default: ""
     type: string

=== modified file 'hooks/config-changed'
--- hooks/config-changed	2017-11-30 13:53:27 +0000
+++ hooks/config-changed	2018-01-19 16:20:49 +0000
@@ -1,13 +1,15 @@
 #!/usr/bin/python
 
+import base64
+import grp
 import os
+import pwd
+import re
 import shlex
 import subprocess
 import sys
-import pwd
-import grp
-import base64
 
+import requests
 
 sys.path.insert(0, os.path.join(os.environ['CHARM_DIR'], 'lib'))
 
@@ -21,6 +23,7 @@
 
 SERVICE = 'logstash-indexer'
 BASEPATH = os.path.join(os.path.sep, 'opt', 'logstash')
+PLUGIN_CMD = os.path.join(BASEPATH, 'bin', 'plugin')
 
 
 @hooks.hook('config-changed')
@@ -36,6 +39,12 @@
     copy_config()
     place_upstart_template()
 
+    extra_plugins = config.get('extra-plugins', '').split()
+    if extra_plugins:
+        log('Updating logstash plugins')
+        plugins = dict(map(lambda x: x.split(':'), extra_plugins))
+        update_plugins(plugins)
+
     # This only actually opens the port if we've exposed the service in juju
     # open port for lumberjack
     hookenv.open_port(5043)
@@ -132,6 +141,70 @@
         p.write(render('{}.conf'.format(SERVICE), opts, template_dir=templ))
 
 
+def update_plugins(plugins):
+    """Make sure all requested plugins are installed at the right versions."""
+    fetch_plugins(plugins)
+
+    for (name, version) in plugins.items():
+        current_version = get_plugin_version(name)
+        if current_version == version:
+            log('Plugin {} already at version {}'.format(name, version))
+            continue
+        elif current_version is not None:
+            uninstall_plugin(name)
+        install_plugin(name, version)
+
+
+def fetch_plugins(plugins):
+    """Download plugin gems from repository."""
+    config = hookenv.config()
+    repo_url = config.get('extra-plugins-repo')
+    if repo_url:
+        for (name, version) in plugins.items():
+            filename = '{}-{}.gem'.format(name, version)
+            fpath = os.path.join(os.path.sep, 'tmp', filename)
+            if os.path.exists(fpath):
+                log("Plugin {} already fetched, skipping".format(filename))
+                continue
+
+            response = requests.get('{}/{}'.format(repo_url, filename))
+            with open(fpath, 'wb') as handle:
+                for block in response.iter_content(1024):
+                    if not block:
+                        break
+                    handle.write(block)
+
+
+def get_plugin_version(name):
+    """Return version for named plugin.
+
+    Return None if version can not be found.
+    """
+    try:
+        output = subprocess.check_output([PLUGIN_CMD, "list", "--verbose", name])
+    except subprocess.CalledProcessError:
+        return
+
+    match = re.match('.*\((.*)\)$', output)
+    if match:
+        return match.groups()[0]
+
+
+def uninstall_plugin(name):
+    """Uninstall plugin by name."""
+    # make sure to specify a fake proxy to avoid the uninstall process
+    # try to reach out to https://rubygems.org to fetch specs
+    env = dict(os.environ, http_proxy="http://localhost:3128"env)
+    subprocess.call([PLUGIN_CMD, "uninstall", name], env=env)
+
+
+def install_plugin(name, version):
+    """Install plugin from local file."""
+    filename = '{}-{}.gem'.format(name, version)
+    fpath = os.path.join(os.path.sep, 'tmp', filename)
+    subprocess.check_call([PLUGIN_CMD, "install", "--no-verify", fpath])
+
+
 if __name__ == "__main__":
     # execute a hook based on the name the program is called by
     hooks.execute(sys.argv)