graphicek/server/integrations/ntfy.go

package integrations

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"strconv"
	"strings"
	"time"
)

type NtfyIntegration struct{}

var ntfyHTTPClient = &http.Client{
	Timeout: 15 * time.Second,
}

type NtfyNotificationChannelConfig struct {
	Endpoint  string `json:"endpoint"`
	AuthToken string `json:"authToken"`
}

func (s NtfyIntegration) ProcessEvent(evt *ContactPointEvent, rawConfig string) error {
	config := NtfyNotificationChannelConfig{}
	err := json.Unmarshal([]byte(rawConfig), &config)

	if err != nil {
		return fmt.Errorf("failed to parse ntfy integration config - %w", err)
	}

	if err := s.validate(config); err != nil {
		return err
	}

	switch evt.Type {
	case ContactPointEventAlertTriggered:
		data := evt.AlertTriggeredEvent

		if data.SensorValueCondition != nil {
			text := fmt.Sprintf("%s is at {value}", data.Sensor.Name)

			if data.Alert.CustomMessage != "" {
				text = data.Alert.CustomMessage
			}

			text = strings.Replace(text, "{value}", strconv.FormatFloat(data.LastValue, 'f', -1, 64), -1)

			return s.send(config, "Alert Triggered", text)
		}

		if data.SensorLastContactCondition != nil {
			text := fmt.Sprintf(
				"%s has not reported in for last %s %s",
				data.Sensor.Name,
				strconv.FormatFloat(data.SensorLastContactCondition.Value, 'f', -1, 64),
				data.SensorLastContactCondition.ValueUnit,
			)

			if data.Alert.CustomMessage != "" {
				text = data.Alert.CustomMessage
			}

			return s.send(config, "Alert Triggered", text)
		}

		return nil

	case ContactPointEventAlertResolved:
		data := evt.AlertResolvedEvent

		if data.SensorValueCondition != nil {
			text := fmt.Sprintf("%s is at {value}", data.Sensor.Name)

			if data.Alert.CustomResolvedMessage != "" {
				text = data.Alert.CustomResolvedMessage
			}

			text = strings.Replace(text, "{value}", strconv.FormatFloat(data.LastValue, 'f', -1, 64), -1)

			return s.send(config, "Alert Resolved", text)
		}

		if data.SensorLastContactCondition != nil {
			text := fmt.Sprintf(
				"%s has reported in last %s %s",
				data.Sensor.Name,
				strconv.FormatFloat(data.SensorLastContactCondition.Value, 'f', -1, 64),
				data.SensorLastContactCondition.ValueUnit,
			)

			if data.Alert.CustomResolvedMessage != "" {
				text = data.Alert.CustomResolvedMessage
			}

			return s.send(config, "Alert Resolved", text)
		}

		return nil

	case ContactPointEventTest:
		return s.send(config, "Test", "Test message from Basic Sensor Receiver")
	}

	return nil
}

func (s NtfyIntegration) ValidateConfig(rawConfig string) error {
	config := NtfyNotificationChannelConfig{}
	err := json.Unmarshal([]byte(rawConfig), &config)

	if err != nil {
		return err
	}

	return s.validate(config)
}

func (s NtfyIntegration) validate(config NtfyNotificationChannelConfig) error {
	if strings.TrimSpace(config.Endpoint) == "" {
		return fmt.Errorf("ntfy endpoint is required")
	}

	return nil
}

func (s NtfyIntegration) send(config NtfyNotificationChannelConfig, title string, text string) error {
	url := strings.TrimSpace(config.Endpoint)

	req, err := http.NewRequest(http.MethodPost, url, strings.NewReader(text))
	if err != nil {
		return fmt.Errorf("failed to create ntfy request - %w", err)
	}

	req.Header.Set("Content-Type", "text/plain; charset=utf-8")
	req.Header.Set("Title", title)

	if config.AuthToken != "" {
		req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", config.AuthToken))
	}

	resp, err := ntfyHTTPClient.Do(req)
	if err != nil {
		return fmt.Errorf("failed to send ntfy notification - %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode < 200 || resp.StatusCode > 299 {
		body, readErr := io.ReadAll(resp.Body)
		if readErr != nil {
			return fmt.Errorf("ntfy returned status %d", resp.StatusCode)
		}

		return fmt.Errorf("ntfy returned status %d: %s", resp.StatusCode, strings.TrimSpace(string(body)))
	}

	return nil
}