サーバーレス アーキテクチャにおける Java 機能のセキュリティに関する考慮事項

import com.google.gson.Gson;
import com.google.gson.JsonObject;
import functions.eventpojos.PubsubMessage;
import functions.eventpojos.PubsubMessage.PubsubAttributes;
import java.io.IOException;
import java.io.PrintWriter;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.nio.charset.StandardCharsets;
import java.time.Duration;

public class ProtectedApiFunction {
  private static final HttpClient httpClient =
      HttpClient
          .newBuilder()
          .connectTimeout(Duration.ofSeconds(10))
          .build();

  public static void handlePubSubMessage(
      PubsubMessage message, PubsubAttributes attributes, PrintWriter out) throws IOException {

    String apiKey = System.getenv("API_KEY");
    if (apiKey == null) {
      out.println("API_KEY environment variable must be set");
      return;
    }

    JsonObject requestBody =
        new Gson().fromJson(new String(message.getData(), StandardCharsets.UTF_8), JsonObject.class);
    String url = "https://example.com/api";
    HttpRequest.Builder requestBuilder =
        HttpRequest.newBuilder()
            .uri(URI.create(url))
            .header("Authorization", String.format("Bearer %s", apiKey))
            .POST(HttpRequest.BodyPublishers.ofString(requestBody.toString()));

    HttpResponse<String> response =
        httpClient.send(requestBuilder.build(), HttpResponse.BodyHandlers.ofString());

    out.println(response.body());
  }
}