event.go

// (c) Copyright IBM Corp. 2021
// (c) Copyright Instana Inc. 2017

package instana

import (
	"time"
)

// EventData is the construct serialized for the host agent
type EventData struct {
	Title string `json:"title"`
	Text  string `json:"text"`
	// Duration in milliseconds
	Duration int `json:"duration"`
	// Severity with value of -1, 5, 10 : see type severity
	Severity int    `json:"severity"`
	Plugin   string `json:"plugin,omitempty"`
	ID       string `json:"id,omitempty"`
	Host     string `json:"host"`
}

type severity int

// Severity values for events sent to the instana agent
const (
	SeverityChange   severity = -1
	SeverityWarning  severity = 5
	SeverityCritical severity = 10
)

// Defaults for the Event API
const (
	ServicePlugin = "com.instana.forge.connection.http.logical.LogicalWebApp"
	ServiceHost   = ""
)

// SendDefaultServiceEvent sends a default event which already contains the service and host
func SendDefaultServiceEvent(title string, text string, sev severity, duration time.Duration) {
	var service string

	if s, err := getSensor(); err != nil {
		defaultLogger.Warn("error retrieving sensor", err.Error())
	} else {
		service = s.serviceOrBinaryName()
	}

	// If the sensor is not yet initialized, there is no default service (as
	// configured on the sensor) so we will send blank instead
	SendServiceEvent(service, title, text, sev, duration)
}

// SendServiceEvent sends an event on a specific service
func SendServiceEvent(service string, title string, text string, sev severity, duration time.Duration) {
	sendEvent(&EventData{
		Title:    title,
		Text:     text,
		Severity: int(sev),
		Plugin:   ServicePlugin,
		ID:       service,
		Host:     ServiceHost,
		Duration: int(duration / time.Millisecond),
	})
}

// SendHostEvent sends an event on the current host
func SendHostEvent(title string, text string, sev severity, duration time.Duration) {
	sendEvent(&EventData{
		Title:    title,
		Text:     text,
		Duration: int(duration / time.Millisecond),
		Severity: int(sev),
	})
}

func sendEvent(event *EventData) {
	s, err := getSensor()
	if err != nil {
		// If the sensor hasn't initialized we do so here so that we properly
		// discover where the host agent may be as it varies between a
		// normal host, docker, kubernetes etc..
		InitSensor(&Options{})
	}

	// we do fire & forget here, because the whole pid dance isn't necessary to send events
	go func(e *EventData) {
		_ = s.Agent().SendEvent(e)
	}(event)
}