README
¶
Telegraf Execd Go Shim
The goal of this shim is to make it trivial to extract an internal input, processor, or output plugin from the main Telegraf repo out to a stand-alone repo. This allows anyone to build and run it as a separate app using one of the execd plugins:
Steps to externalize a plugin
- Move the project to an external repo, it's recommended to preserve the path
structure, (but not strictly necessary). eg if your plugin was at
plugins/inputs/cpu
, it's recommended that it also be underplugins/inputs/cpu
in the new repo. For a further example of what this might look like, take a look at ssoroka/rand or danielnelson/telegraf-plugins - Copy main.go into your project under the
cmd
folder. This will be the entrypoint to the plugin when run as a stand-alone program, and it will call the shim code for you to make that happen. It's recommended to have only one plugin per repo, as the shim is not designed to run multiple plugins at the same time (it would vastly complicate things). - Edit the main.go file to import your plugin. Within Telegraf this would have
been done in an all.go file, but here we don't split the two apart, and the change
just goes in the top of main.go. If you skip this step, your plugin will do nothing.
eg:
_ "github.com/me/my-plugin-telegraf/plugins/inputs/cpu"
- Optionally add a plugin.conf for configuration specific to your plugin. Note that this config file must be separate from the rest of the config for Telegraf, and must not be in a shared directory where Telegraf is expecting to load all configs. If Telegraf reads this config file it will not know which plugin it relates to. Telegraf instead uses an execd config block to look for this plugin.
Steps to build and run your plugin
- Build the cmd/main.go. For my rand project this looks like
go build -o rand cmd/main.go
- If you're building an input, you can test out the binary just by running it.
eg
./rand -config plugin.conf
Depending on your polling settings and whether you implemented a service plugin or an input gathering plugin, you may see data right away, or you may have to hit enter first, or wait for your poll duration to elapse, but the metrics will be written to STDOUT. Ctrl-C to end your test. If you're testig a processor or output manually, you can still do this but you will need to feed valid metrics in on STDIN to verify that it is doing what you want. This can be a very valuable debugging technique before hooking it up to Telegraf. - Configure Telegraf to call your new plugin binary. For an input, this would look something like:
[[inputs.execd]]
command = ["/path/to/rand", "-config", "/path/to/plugin.conf"]
signal = "none"
Refer to the execd plugin readmes for more information.
Congratulations
You've done it! Consider publishing your plugin to github and open a Pull Request back to the Telegraf repo letting us know about the availability of your external plugin.
Documentation
¶
Index ¶
- Constants
- func DefaultImportedPlugins() config
- func LoadConfig(filePath *string) (loaded loadedConfig, err error)
- type Logger
- func (l *Logger) Debug(args ...interface{})
- func (l *Logger) Debugf(format string, args ...interface{})
- func (l *Logger) Error(args ...interface{})
- func (l *Logger) Errorf(format string, args ...interface{})
- func (l *Logger) Info(args ...interface{})
- func (l *Logger) Infof(format string, args ...interface{})
- func (l *Logger) Warn(args ...interface{})
- func (l *Logger) Warnf(format string, args ...interface{})
- type Shim
- func (s *Shim) AddInput(input telegraf.Input) error
- func (s *Shim) AddOutput(output telegraf.Output) error
- func (s *Shim) AddProcessor(processor telegraf.Processor) error
- func (s *Shim) AddStreamingProcessor(processor telegraf.StreamingProcessor) error
- func (s *Shim) LoadConfig(filePath *string) error
- func (s *Shim) Log() telegraf.Logger
- func (s *Shim) LogName() string
- func (s *Shim) MakeMetric(m telegraf.Metric) telegraf.Metric
- func (s *Shim) Run(pollInterval time.Duration) error
- func (s *Shim) RunInput(pollInterval time.Duration) error
- func (s *Shim) RunOutput() error
- func (s *Shim) RunProcessor() error
Constants ¶
const ( // PollIntervalDisabled is used to indicate that you want to disable polling, // as opposed to duration 0 meaning poll constantly. PollIntervalDisabled = time.Duration(0) )
Variables ¶
This section is empty.
Functions ¶
func DefaultImportedPlugins ¶
func DefaultImportedPlugins() config
DefaultImportedPlugins defaults to whatever plugins happen to be loaded and have registered themselves with the registry. This makes loading plugins without having to define a config dead easy.
func LoadConfig ¶
LoadConfig loads the config and returns inputs that later need to be loaded.
Types ¶
type Logger ¶
type Logger struct{}
Logger defines a logging structure for plugins. external plugins can only ever write to stderr and writing to stdout would interfere with input/processor writing out of metrics.
func (*Logger) Debug ¶
func (l *Logger) Debug(args ...interface{})
Debug logs a debug message, patterned after log.Print.
func (*Logger) Error ¶
func (l *Logger) Error(args ...interface{})
Error logs an error message, patterned after log.Print.
func (*Logger) Info ¶
func (l *Logger) Info(args ...interface{})
Info logs an information message, patterned after log.Print.
type Shim ¶
type Shim struct { Input telegraf.Input Processor telegraf.StreamingProcessor Output telegraf.Output // contains filtered or unexported fields }
Shim allows you to wrap your inputs and run them as if they were part of Telegraf, except built externally.
func (*Shim) AddInput ¶
AddInput adds the input to the shim. Later calls to Run() will run this input.
func (*Shim) AddProcessor ¶
AddProcessor adds the processor to the shim. Later calls to Run() will run this.
func (*Shim) AddStreamingProcessor ¶
func (s *Shim) AddStreamingProcessor(processor telegraf.StreamingProcessor) error
AddStreamingProcessor adds the processor to the shim. Later calls to Run() will run this.
func (*Shim) LoadConfig ¶
LoadConfig Adds plugins to the shim
func (*Shim) MakeMetric ¶
MakeMetric satisfies the MetricMaker interface