feat: disable dynamic code loading properties by default

google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/ConnectionOptions.java

@@ -36,6 +36,7 @@
 import com.google.cloud.spanner.SpannerOptions;
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Preconditions;
+import com.google.common.base.Strings;
 import com.google.common.collect.Sets;
 import com.google.spanner.v1.ExecuteSqlRequest.QueryOptions;
 import java.io.IOException;
@@ -205,8 +206,14 @@ public String[] getValidValues() {
   public static final String CREDENTIALS_PROPERTY_NAME = "credentials";
   /** Name of the 'encodedCredentials' connection property. */
   public static final String ENCODED_CREDENTIALS_PROPERTY_NAME = "encodedCredentials";
+
+  public static final String ENABLE_ENCODED_CREDENTIALS_SYSTEM_PROPERTY =
+      "ENABLE_ENCODED_CREDENTIALS";
   /** Name of the 'credentialsProvider' connection property. */
   public static final String CREDENTIALS_PROVIDER_PROPERTY_NAME = "credentialsProvider";
+
+  public static final String ENABLE_CREDENTIALS_PROVIDER_SYSTEM_PROPERTY =
+      "ENABLE_CREDENTIALS_PROVIDER";
   /**
    * OAuth token to use for authentication. Cannot be used in combination with a credentials file.
    */
@@ -219,6 +226,8 @@ public String[] getValidValues() {
   public static final String NUM_CHANNELS_PROPERTY_NAME = "numChannels";
   /** Name of the 'channelProvider' connection property. */
   public static final String CHANNEL_PROVIDER_PROPERTY_NAME = "channelProvider";
+
+  public static final String ENABLE_CHANNEL_PROVIDER_SYSTEM_PROPERTY = "ENABLE_CHANNEL_PROVIDER";
   /** Custom user agent string is only for other Google libraries. */
   private static final String USER_AGENT_PROPERTY_NAME = "userAgent";
   /** Query optimizer version to use for a connection. */
@@ -248,6 +257,19 @@ public String[] getValidValues() {
   public static final String MAX_PARTITIONED_PARALLELISM_PROPERTY_NAME =
       "maxPartitionedParallelism";
 
+  private static final String GUARDED_CONNECTION_PROPERTY_ERROR_MESSAGE =
+      "%s can only be used if the system property %s has been set to true. "
+          + "Start the application with the JVM command line option -D%s=true";
+
+  private static String generateGuardedConnectionPropertyError(
+      String systemPropertyName, String connectionPropertyName) {
+    return String.format(
+        GUARDED_CONNECTION_PROPERTY_ERROR_MESSAGE,
+        connectionPropertyName,
+        systemPropertyName,
+        systemPropertyName);
+  }
+
   /** All valid connection properties. */
   public static final Set<ConnectionProperty> VALID_PROPERTIES =
       Collections.unmodifiableSet(
@@ -846,40 +868,64 @@ static boolean parseRetryAbortsInternally(String uri) {
 
   @VisibleForTesting
   static @Nullable String parseEncodedCredentials(String uri) {
-    return parseUriProperty(uri, ENCODED_CREDENTIALS_PROPERTY_NAME);
+    String encodedCredentials = parseUriProperty(uri, ENCODED_CREDENTIALS_PROPERTY_NAME);
+    checkGuardedProperty(
+        encodedCredentials,
+        ENABLE_ENCODED_CREDENTIALS_SYSTEM_PROPERTY,
+        ENCODED_CREDENTIALS_PROPERTY_NAME);
+    return encodedCredentials;
   }
 
   @VisibleForTesting
   static @Nullable CredentialsProvider parseCredentialsProvider(String uri) {
-    String name = parseUriProperty(uri, CREDENTIALS_PROVIDER_PROPERTY_NAME);
-    if (name != null) {
+    String credentialsProviderName = parseUriProperty(uri, CREDENTIALS_PROVIDER_PROPERTY_NAME);
+    checkGuardedProperty(
+        credentialsProviderName,
+        ENABLE_CREDENTIALS_PROVIDER_SYSTEM_PROPERTY,
+        CREDENTIALS_PROVIDER_PROPERTY_NAME);
+    if (!Strings.isNullOrEmpty(credentialsProviderName)) {
       try {
         Class<? extends CredentialsProvider> clazz =
-            (Class<? extends CredentialsProvider>) Class.forName(name);
+            (Class<? extends CredentialsProvider>) Class.forName(credentialsProviderName);
         Constructor<? extends CredentialsProvider> constructor = clazz.getDeclaredConstructor();
         return constructor.newInstance();
       } catch (ClassNotFoundException classNotFoundException) {
         throw SpannerExceptionFactory.newSpannerException(
             ErrorCode.INVALID_ARGUMENT,
-            "Unknown or invalid CredentialsProvider class name: " + name,
+            "Unknown or invalid CredentialsProvider class name: " + credentialsProviderName,
             classNotFoundException);
       } catch (NoSuchMethodException noSuchMethodException) {
         throw SpannerExceptionFactory.newSpannerException(
             ErrorCode.INVALID_ARGUMENT,
-            "Credentials provider " + name + " does not have a public no-arg constructor.",
+            "Credentials provider "
+                + credentialsProviderName
+                + " does not have a public no-arg constructor.",
             noSuchMethodException);
       } catch (InvocationTargetException
           | InstantiationException
           | IllegalAccessException exception) {
         throw SpannerExceptionFactory.newSpannerException(
             ErrorCode.INVALID_ARGUMENT,
-            "Failed to create an instance of " + name + ": " + exception.getMessage(),
+            "Failed to create an instance of "
+                + credentialsProviderName
+                + ": "
+                + exception.getMessage(),
             exception);
       }
     }
     return null;
   }
 
+  private static void checkGuardedProperty(
+      String value, String systemPropertyName, String connectionPropertyName) {
+    if (!Strings.isNullOrEmpty(value)
+        && !Boolean.parseBoolean(System.getProperty(systemPropertyName))) {
+      throw SpannerExceptionFactory.newSpannerException(
+          ErrorCode.FAILED_PRECONDITION,
+          generateGuardedConnectionPropertyError(systemPropertyName, connectionPropertyName));
+    }
+  }
+
   @VisibleForTesting
   static @Nullable String parseOAuthToken(String uri) {
     String value = parseUriProperty(uri, OAUTH_TOKEN_PROPERTY_NAME);
@@ -907,6 +953,8 @@ static String parseNumChannels(String uri) {
   @VisibleForTesting
   static String parseChannelProvider(String uri) {
     String value = parseUriProperty(uri, CHANNEL_PROVIDER_PROPERTY_NAME);
+    checkGuardedProperty(
+        value, ENABLE_CHANNEL_PROVIDER_SYSTEM_PROPERTY, CHANNEL_PROVIDER_PROPERTY_NAME);
     return value != null ? value : DEFAULT_CHANNEL_PROVIDER;
   }