event.go

// Copyright (c) Microsoft Corporation.
// Licensed under the MIT license.

package bootstrap

import (
	"encoding/json"
	"fmt"
	"os"
	"path/filepath"
	"time"

	"github.com/Azure/aks-secure-tls-bootstrap/client/internal/telemetry"
)

const (
	performSecureTLSBootstrappingGuestAgentEventName = "AKS.Bootstrap.SecureTLSBootstrapping"
)

func getGuestAgentEventsPath() string {
	if isWindows() {
		return guestAgentEventsPathWindows
	}
	return guestAgentEventsPathLinux
}

func getEventVersion() string {
	if isWindows() {
		// corresponds to Microsoft.Compute.CustomScriptExtension-1.10
		return "1.10"
	}
	// corresponds to Microsoft.Azure.Extensions.CustomScript-1.23
	return "1.23"
}

type Status string

const (
	StatusSuccess Status = "Success"
	StatusFailure Status = "Failure"
)

type Result struct {
	// Status is the terminal status of the bootstrapping event.
	Status Status `json:"Status"`
	// ElapsedMilliseconds measures how long the bootstrapping event took to execute, in milliseconds.
	ElapsedMilliseconds int64 `json:"ElapsedMilliseconds"`
	// Trace maps individual span names to their respective durations.
	Trace telemetry.Trace `json:"Trace,omitempty"`
	// FinalErrorType indicates the type of error last encountered before the bootstrapping event entered a failed terminal state.
	FinalErrorType ErrorType `json:"FinalErrorType,omitempty"`
	// FinalError stores the last encountered error before the bootstrapping event entered a failed terminal state.
	FinalError string `json:"FinalError,omitempty"`
	// ClientVersion stores the client version string.
	ClientVersion string `json:"ClientVersion,omitempty"`
}

type Event struct {
	Level   string
	Message string
	Start   time.Time
	End     time.Time
}

var _ json.Marshaler = (*Event)(nil)

// Event instances are marshaled according to the GuestAgentGenericLogsSchema object used
// by the azure guest agent (WALinuxAgent).
// For details, see: https://github.com/Azure/WALinuxAgent/blob/master/azurelinuxagent/common/telemetryevent.py#L49
func (e *Event) MarshalJSON() ([]byte, error) {
	return json.Marshal(struct {
		TaskName    string `json:"TaskName"`
		OperationID string `json:"OperationId"`
		Timestamp   string `json:"Timestamp"`
		Version     string `json:"Version"`
		EventLevel  string `json:"EventLevel"`
		Message     string `json:"Message"`
		EventPID    string `json:"EventPid"`
		EventTID    string `json:"EventTid"`
	}{
		TaskName:    performSecureTLSBootstrappingGuestAgentEventName,
		Timestamp:   e.Start.Format("2006-01-02 15:04:05.000"),
		OperationID: e.End.Format("2006-01-02 15:04:05.000"),
		Message:     e.Message,
		Version:     getEventVersion(),
		EventLevel:  e.Level,
		EventPID:    "0",
		EventTID:    "0",
	})
}

func (e *Event) WriteWithResult(result *Result) (string, error) {
	e.Level = "Informational"
	if result.Status == StatusFailure {
		e.Level = "Error"
	}
	resultBytes, err := json.Marshal(result)
	if err != nil {
		e.Message = "Completed"
	} else {
		e.Message = string(resultBytes)
	}
	return e.write()
}

func (e *Event) write() (string, error) {
	guestAgentEventsPath := getGuestAgentEventsPath()
	if _, err := os.Stat(guestAgentEventsPath); err != nil {
		if os.IsNotExist(err) {
			return "", nil
		}
		return "", fmt.Errorf("stating guest agent event path %s: %w", guestAgentEventsPath, err)
	}
	eventFilePath := filepath.Join(guestAgentEventsPath, fmt.Sprintf("%d.json", e.Start.UnixNano()))
	eventBytes, err := json.Marshal(e)
	if err != nil {
		return "", fmt.Errorf("marshalling bootstrap event data: %w", err)
	}
	if err := os.WriteFile(eventFilePath, eventBytes, 0600); err != nil {
		return "", fmt.Errorf("writing bootstrap event data to disk: %w", err)
	}
	return eventFilePath, nil
}