feat: add grpc-validation-utils module (#41)

Author: GurtejSohi

grpc-validation-utils/build.gradle.kts

@@ -0,0 +1,9 @@
+plugins {
+  `java-library`
+}
+
+dependencies {
+  api(project(":grpc-context-utils"))
+  api("io.grpc:grpc-api")
+  implementation("com.google.protobuf:protobuf-java-util:3.21.7")
+}

grpc-validation-utils/src/main/java/org/hypertrace/core/grpcutils/validation/GrpcValidatorUtils.java

@@ -0,0 +1,58 @@
+package org.hypertrace.core.grpcutils.validation;
+
+import com.google.protobuf.Descriptors.FieldDescriptor;
+import com.google.protobuf.Message;
+import com.google.protobuf.util.JsonFormat;
+import io.grpc.Status;
+import org.hypertrace.core.grpcutils.context.RequestContext;
+
+public class GrpcValidatorUtils {
+  private static final JsonFormat.Printer JSON_PRINTER = JsonFormat.printer();
+
+  private GrpcValidatorUtils() {}
+
+  public static void validateRequestContextOrThrow(RequestContext requestContext) {
+    if (requestContext.getTenantId().isEmpty()) {
+      throw Status.INVALID_ARGUMENT
+          .withDescription("Missing expected Tenant ID")
+          .asRuntimeException();
+    }
+  }
+
+  public static <T extends Message> void validateNonDefaultPresenceOrThrow(
+      T source, int fieldNumber) {
+    FieldDescriptor descriptor = source.getDescriptorForType().findFieldByNumber(fieldNumber);
+
+    if (descriptor.isRepeated()) {
+      validateNonDefaultPresenceRepeatedOrThrow(source, descriptor);
+    } else if (!source.hasField(descriptor)
+        || source.getField(descriptor).equals(descriptor.getDefaultValue())) {
+      throw Status.INVALID_ARGUMENT
+          .withDescription(
+              String.format(
+                  "Expected field value %s but not present:%n %s",
+                  descriptor.getFullName(), printMessage(source)))
+          .asRuntimeException();
+    }
+  }
+
+  private static <T extends Message> void validateNonDefaultPresenceRepeatedOrThrow(
+      T source, FieldDescriptor descriptor) {
+    if (source.getRepeatedFieldCount(descriptor) == 0) {
+      throw Status.INVALID_ARGUMENT
+          .withDescription(
+              String.format(
+                  "Expected at least 1 value for repeated field %s but not present:%n %s",
+                  descriptor.getFullName(), printMessage(source)))
+          .asRuntimeException();
+    }
+  }
+
+  public static String printMessage(Message message) {
+    try {
+      return JSON_PRINTER.print(message);
+    } catch (Exception exception) {
+      return message.toString();
+    }
+  }
+}

settings.gradle.kts

@@ -17,3 +17,4 @@ include(":grpc-client-rx-utils")
 include(":grpc-server-rx-utils")
 include(":grpc-context-utils")
 include(":grpc-server-utils")
+include(":grpc-validation-utils")