cc-metric-collector/sinks/README.md
Thomas Gruber fdb58b0be2
Sink specific configuration maps (#25)
* Use sink-specific configurations to have more flexibility. Adjust sample sink configuration files

* Add documentation

* Add links to individual sink readmes

* Fix link in README

* HTTPS for HttpSink

* If no CPU die id available, use the socket id instead
2022-02-04 18:12:24 +01:00

2.8 KiB

CCMetric sinks

This folder contains the SinkManager and sink implementations for the cc-metric-collector.

Available sinks:

Configuration

The configuration file for the sinks is a list of configurations. The type field in each specifies which sink to initialize.

[
  "mystdout" : {
    "type" : "stdout",
    "meta_as_tags" : false
  },
  "metricstore" : {
    "type" : "http",
    "host" : "localhost",
    "port" : "4123",
    "database" : "ccmetric",
    "password" : "<jwt token>"
  }
]

Contributing own sinks

A sink contains four functions and is derived from the type sink:

  • Init(config json.RawMessage) error
  • Write(point CCMetric) error
  • Flush() error
  • Close()

The data structures should be set up in Init() like opening a file or server connection. The Write() function writes/sends the data. For non-blocking sinks, the Flush() method tells the sink to drain its internal buffers. The Close() function should tear down anything created in Init().

Finally, the sink needs to be registered in the sinkManager.go. There is a list of sinks called AvailableSinks which is a map (sink_type_string -> pointer to sink interface). Add a new entry with a descriptive name and the new sink.

Sample sink

package sinks

import (
	"encoding/json"
	"log"
	lp "github.com/ClusterCockpit/cc-metric-collector/internal/ccMetric"
)

type SampleSinkConfig struct {
	defaultSinkConfig  // defines JSON tags for 'name' and 'meta_as_tags'
}

type SampleSink struct {
	sink              // declarate 'name' and 'meta_as_tags'
	config StdoutSinkConfig // entry point to the SampleSinkConfig
}

// Initialize the sink by giving it a name and reading in the config JSON
func (s *SampleSink) Init(config json.RawMessage) error {
	s.name = "SampleSink"   // Always specify a name here
  // Read in the config JSON
	if len(config) > 0 {
		err := json.Unmarshal(config, &s.config)
		if err != nil {
			return err
		}
	}
	return nil
}

// Code to submit a single CCMetric to the sink
func (s *SampleSink) Write(point lp.CCMetric) error {
	log.Print(point)
	return nil
}

// If the sink uses batched sends internally, you can tell to flush its buffers
func (s *SampleSink) Flush() error {
	return nil
}


// Close sink: close network connection, close files, close libraries, ...
func (s *SampleSink) Close() {}