akms-simulator.go

package main

import (
	"crypto/tls"
	"crypto/x509"
	"encoding/json"
	"flag"
	"io"
	"net/http"
	"os"

	"github.com/sirupsen/logrus"
)

const (
	// LogFile is the file where the log is stored.
	LogFilePath = "/logs/akms-simulator.log"
)

type LogFile struct {
	Source string            `json:"source"`
	Body   PushKSAKeyRequest `json:"body"`
}
type PushKSAKeyRequest struct {
	RequestID string   `json:"request_ID"`
	ProcessID string   `json:"process_ID"`
	KSAKeys   []KSAKey `json:"ksa_keys"`
}

type KSAKey struct {
	KeyID string `json:"key_ID"`
	Key   string `json:"key"`
}

func main() {
	tlsCAFile := flag.String("ca", "", "Path to CA certificate file")
	tlsCertFile := flag.String("cert", "", "Path to certificate file")
	tlsKeyFile := flag.String("key", "", "Path to key file")
	flag.Parse()

	logrus.Info("Starting AKMS Simulator...")

	router := http.NewServeMux()

	router.HandleFunc("/api/v1/keys/push_ksa_key", handlePushKsaKey)
	router.HandleFunc("/debug/get_log_file", logFileRequest)

	server := &http.Server{
		Addr:    ":4444",
		Handler: router,
	}

	if *tlsCAFile != "" && *tlsCertFile != "" && *tlsKeyFile != "" {
		logrus.Info("TLS enabled")
		cp := x509.NewCertPool()
		b, err := os.ReadFile(*tlsCAFile)
		if err != nil {
			logrus.Fatalf("Error reading CA file: %s", err)
		}

		if !cp.AppendCertsFromPEM(b) {
			logrus.Fatalf("Error appending certs from PEM")
		}

		cert, err := tls.LoadX509KeyPair(*tlsCertFile, *tlsKeyFile)
		if err != nil {
			logrus.Fatalf("Error loading X509 key pair: %s", err)
		}

		tlsConfig := &tls.Config{
			MinVersion:   tls.VersionTLS13,
			ClientCAs:    cp,
			Certificates: []tls.Certificate{cert},
			ClientAuth:   tls.RequireAndVerifyClientCert,
		}

		server.TLSConfig = tlsConfig

		logrus.Fatal(server.ListenAndServeTLS("", ""))
	} else {
		logrus.Fatal(server.ListenAndServe())
	}
}

func logFileRequest(w http.ResponseWriter, r *http.Request) {
	if r.Method == http.MethodDelete {
		if _, err := os.Stat(LogFilePath); err == nil {
			err := os.Remove(LogFilePath)
			if err != nil {
				logrus.Errorf("Error deleting log file: %s", err)
				w.WriteHeader(http.StatusInternalServerError)
				return
			}
		}
		logrus.Info("Log file deleted or never existed in the first place")
		w.WriteHeader(http.StatusNoContent)
		return
	} else if r.Method != http.MethodGet {
		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
		logrus.Errorf("Method not allowed: %s", r.Method)
		return
	}

	logrus.Info("Log file requested")
	http.ServeFile(w, r, LogFilePath)
}

func handlePushKsaKey(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
		logrus.Errorf("Method not allowed: %s", r.Method)
		return
	}

	body, err := io.ReadAll(r.Body)
	if err != nil {
		http.Error(w, "Failed to read request body", http.StatusInternalServerError)
		logrus.Errorf("Failed to read request body: %s", err)
		return
	}

	ip := r.RemoteAddr
	logstring := "Request came from: " + ip + "; Body: " + string(body)
	logrus.Info(logstring)

	var bodyObject PushKSAKeyRequest
	err = json.Unmarshal(body, &bodyObject)
	if err != nil {
		logrus.Errorf("Error parsing body into PushKSAKeyRequest: %s", err)
		return
	}

	logFile := LogFile{Source: ip, Body: bodyObject}
	jsonLogFile, err := json.Marshal(logFile)
	if err != nil {
		logrus.Errorf("Error marshaling logFile: %s", err)
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	// Append jsonLogFile to akms-logfile.log
	f, err := os.OpenFile(LogFilePath, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
	if err != nil {
		logrus.Errorf("Error opening log file: %s", err)
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	defer f.Close() //nolint:errcheck
	if _, err := f.Write(jsonLogFile); err != nil {
		logrus.Errorf("Error writing to log file: %s", err)
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	// Write the newline character
	if _, err := f.Write([]byte("\n")); err != nil {
		logrus.Errorf("Error writing newline to log file: %s", err)
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	w.WriteHeader(http.StatusNoContent)
}