llnw/collectd — pull request #9 by kev009 (2014-06-02 22:01:01+00:00)
Title: [METRICS-390] Add global host tags and add tag writing from metadata using target_set 

1) A global HostTags is added to write_tsdb that apply to all values sent from this instance of collectd.

2) Tagging and prefixing:
See https://collectd.org/wiki/index.php/Chains

See https://github.com/llnw/collectd/pull/8 for the target_set tagging implementation.

The global metric name prefix is removed and can be set using a match on Plugin name, including a wildcard.

The first rule simply prepends 'sys' to the all metric names but can be overridden later in the chain. The second rule uses TypeInstance to pass in a value, and target_set strips it and sets a TSDB tag instead.
```

Host "localhost"
Port "4242"
HostTags "status=production deviceclass=www"

Plugin "*"

TSDBPrefix "sys"

Plugin "^someperlplugin$"
TypeInstance "^8080$"

TypeInstance ""
TSDBPrefix "app"
TSDBTags "port=8080"

```