metrics-collector.go

package metrics

import (
	"encoding/json"

	"fmt"
	"os"

	"github.com/devopsfaith/krakend/config"
	"github.com/devopsfaith/krakend/logging"
	newrelic "github.com/newrelic/go-agent"
)

// Namespace for krakend_newrelic
const Namespace = "github_com/letgoapp/krakend_newrelic"

var (
	app            *Application
	isDebugEnabled bool
)

// Config struct for NewRelic
type Config struct {
	newrelic.Config
	InstrumentationRate int `json:"rate"`
}

type Application struct {
	newrelic.Application
	Config Config
}

// ConfigGetter gets config for NewRelic
func ConfigGetter(cfg config.ExtraConfig) (Config, error) {
	result := Config{}
	v, ok := cfg[Namespace]
	if !ok {
		return result, fmt.Errorf("unknown Namespace %s", Namespace)
	}
	tmp, ok := v.(map[string]interface{})
	if !ok {
		return result, fmt.Errorf("Cannot map config to map string interface")
	}

	// check whether compulsory fields are present
	if _, ok := tmp["license"]; !ok {
		return result, fmt.Errorf("Config should have the field license defined")
	}

	if _, ok = tmp["appName"]; !ok {
		return result, fmt.Errorf("Config should have the field appName defined")
	}

	// check whether debug enabled
	var val interface{}
	if val, ok = tmp["debugEnabled"]; !ok {
		isDebugEnabled = false
	} else {
		valB, ok := val.(bool)
		if !ok || !valB {
			isDebugEnabled = false
		} else {
			isDebugEnabled = true
		}
	}

	marshaledConf, err := json.Marshal(tmp)
	if err != nil {
		return result, err
	}

	err = json.Unmarshal(marshaledConf, &result)

	return result, err
}

// Register registers the NewRelic app
func Register(cfg config.ExtraConfig, logger logging.Logger) {
	conf, err := ConfigGetter(cfg)
	if err != nil {
		logger.Debug("no config for the NR module:", err.Error())
		return
	}

	if isDebugEnabled {
		conf.Config.Logger = newrelic.NewDebugLogger(os.Stdout)
	}

	nrApp, err := newrelic.NewApplication(conf.Config)
	if err != nil {
		logger.Debug("unable to start the NR module:", err.Error())
		return
	}

	app = &Application{nrApp, conf}
}