Initial attempt at discovery plugin

[johann8384]

Attempting to build a framework for startup plugins.

Testing with this skeleton plugin that I intend to turn into an Apache Curator plugin.

Fixes #716

[johann8384]

Loaded my test plugin:

2016-03-02 22:17:34,277 INFO  [main] CuratorPlugin: Apache Curator ServiceDiscovery Plugin Initialized
2016-03-02 22:17:34,277 INFO  [main] TSDMain: Successfully initialized startup plugin [io.tsdb.opentsdb.discoveryplugins.CuratorPlugin] version: 2.0.0

[johann8384]

Configuration values:

tsd.startup.enabled = true
tsd.startup.plugin = io.tsdb.opentsdb.discoveryplugins.CuratorPlugin
tsd.core.plugin_path = /tmp/plugins

[johann8384]

Notes for me, I need to add a few things to this:

• Fix build
• I would like to add a "ready()" call for when the TSDB is open (about when it prints "listening on 4242" in the logs)
• Add tests

[johann8384]

My test plugin loads cleanly:

2016-03-14 15:33:20,580 DEBUG [main] TSDMain: Startup Plugin is Enabled
2016-03-14 15:33:20,580 DEBUG [main] TSDMain: Plugin Path: /tmp
2016-03-14 15:33:20,587 DEBUG [main] PluginLoader: Found a jar: /tmp/DiscoveryPlugins-1.0-SNAPSHOT.jar
2016-03-14 15:33:20,587 DEBUG [main] PluginLoader: Found a jar: /tmp/DiscoveryPlugins-all-1.0-SNAPSHOT.jar
2016-03-14 15:33:20,587 WARN  [main] PluginLoader: Access denied to directory: /tmp/launchd-1290.iITGIm
2016-03-14 15:33:20,587 WARN  [main] PluginLoader: Access denied to directory: /tmp/launchd-751.hEI1uL
2016-03-14 15:33:20,591 DEBUG [main] PluginLoader: Successfully added JAR to class loader: /tmp/DiscoveryPlugins-1.0-SNAPSHOT.jar
2016-03-14 15:33:20,591 DEBUG [main] TSDMain: Attempt to Load: io.tsdb.opentsdb.discoveryplugins.IdentityPlugin
2016-03-14 15:33:20,594 DEBUG [main] CuratorPlugin: constructor called
2016-03-14 15:33:20,595 INFO  [main] CuratorPlugin: Apache Curator ServiceDiscovery Plugin Initialized
2016-03-14 15:33:20,595 DEBUG [main] CuratorPlugin: Finished with config
2016-03-14 15:33:20,595 INFO  [main] TSDMain: Successfully initialized startup plugin [io.tsdb.opentsdb.discoveryplugins.IdentityPlugin] version: 2.0.0

[johann8384]

Documentation PR added: OpenTSDB/opentsdb.net#79