Merge pull request #3 from venasolutions/refurbish-metadata

MongoDriver "path" metadata field

bosk-mongo/src/main/java/io/vena/bosk/drivers/mongo/Formatter.java

@@ -55,6 +55,7 @@ final class Formatter {
 	 * No field name should be a prefix of any other.
 	 */
 	enum DocumentFields {
+		path,
 		state,
 		echo,
 	}

bosk-mongo/src/main/java/io/vena/bosk/drivers/mongo/MongoDriver.java

@@ -41,6 +41,7 @@
 
 import static com.mongodb.ErrorCategory.DUPLICATE_KEY;
 import static io.vena.bosk.drivers.mongo.Formatter.DocumentFields.echo;
+import static io.vena.bosk.drivers.mongo.Formatter.DocumentFields.path;
 import static io.vena.bosk.drivers.mongo.Formatter.DocumentFields.state;
 import static io.vena.bosk.drivers.mongo.Formatter.dottedFieldNameOf;
 import static io.vena.bosk.drivers.mongo.Formatter.enclosingReference;
@@ -115,7 +116,7 @@ public R initialRoot(Type rootType) throws InvalidTypeException, IOException, In
 		}
 
 		R root = receiver.initialRoot(rootType);
-		ensureTenantDocumentExists(formatter.object2bsonValue(root, rootType));
+		ensureDocumentExists(formatter.object2bsonValue(root, rootType), "$setOnInsert");
 		return root;
 	}
 
@@ -219,8 +220,17 @@ public void refurbish() {
 					return;
 				}
 
+				// Round trip via state tree nodes
 				R root = formatter.document2object(newState, rootRef);
-				doUpdate(replacementDoc(rootRef, root), documentFilter());
+				BsonValue initialState = formatter.object2bsonValue(root, rootRef.targetType());
+
+				// Start with a blank document so subsequent changes become update events instead of inserts
+				// TODO: should we do this for initialization too? We want those to be updates as well, right?
+				collection.replaceOne(documentFilter(), new Document());
+
+				// Set all the same fields we set on initialization
+				ensureDocumentExists(initialState, "$set");
+
 				session.commitTransaction();
 			} finally {
 				if (session.hasActiveTransaction()) {
@@ -269,9 +279,9 @@ private <T> BsonDocument deletionDoc(Reference<T> target) {
 		return new BsonDocument("$unset", new BsonDocument(key, new BsonNull())); // Value is ignored
 	}
 
-	private void ensureTenantDocumentExists(BsonValue initialState) {
+	private void ensureDocumentExists(BsonValue initialState, String updateCommand) {
+		BsonDocument update = new BsonDocument(updateCommand, initialDocument(initialState));
 		BsonDocument filter = documentFilter();
-		BsonDocument update = initialTenantUpsert(initialState);
 		UpdateOptions options = new UpdateOptions();
 		options.upsert(true);
 		LOGGER.debug("** Initial tenant upsert for {}", documentID);
@@ -285,6 +295,9 @@ private void ensureTenantDocumentExists(BsonValue initialState) {
 			if (DUPLICATE_KEY == ErrorCategory.fromErrorCode(e.getCode())) {
 				// This can happen in MongoDB 4.0 if two upserts occur in parallel.
 				// https://docs.mongodb.com/v4.0/reference/method/db.collection.update/
+				// As of MongoDB 4.2, this is no longer required. Since 4.0 is not longer
+				// supported, we could presumably delete this code.
+				// https://www.mongodb.com/docs/manual/core/retryable-writes/#std-label-retryable-update-upsert
 				LOGGER.debug("| Retrying: {}", e.getMessage());
 				result = collection.updateOne(filter, update, options);
 			} else {
@@ -294,11 +307,12 @@ private void ensureTenantDocumentExists(BsonValue initialState) {
 		LOGGER.debug("| Result: {}", result);
 	}
 
-	BsonDocument initialTenantUpsert(BsonValue initialState) {
+	private BsonDocument initialDocument(BsonValue initialState) {
 		BsonDocument fieldValues = new BsonDocument("_id", documentID);
+		fieldValues.put(path.name(), new BsonString("/"));
 		fieldValues.put(state.name(), initialState);
 		fieldValues.put(echo.name(), new BsonString(uniqueEchoToken()));
-		return new BsonDocument("$setOnInsert", fieldValues);
+		return fieldValues;
 	}
 
 	/**

bosk-mongo/src/test/java/io/vena/bosk/drivers/mongo/MongoDriverSpecialTest.java

@@ -1,6 +1,8 @@
 package io.vena.bosk.drivers.mongo;
 
 import com.mongodb.MongoException;
+import com.mongodb.client.MongoCollection;
+import com.mongodb.client.MongoCursor;
 import io.vena.bosk.Bosk;
 import io.vena.bosk.BoskDriver;
 import io.vena.bosk.Catalog;
@@ -26,16 +28,22 @@
 import java.util.concurrent.LinkedBlockingDeque;
 import lombok.Value;
 import lombok.experimental.Accessors;
+import org.bson.BsonDocument;
+import org.bson.BsonNull;
+import org.bson.BsonString;
+import org.bson.Document;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 import static io.vena.bosk.ListingEntry.LISTING_ENTRY;
+import static io.vena.bosk.drivers.mongo.Formatter.DocumentFields.path;
 import static java.lang.Long.max;
 import static java.lang.System.currentTimeMillis;
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
 /**
@@ -380,6 +388,54 @@ void refurbish_createsField() throws IOException, InterruptedException {
 		assertEquals(Optional.of(TestValues.blank()), after); // Now it's there
 	}
 
+	@Test
+	@UsesMongoService
+	void refurbish_fixesMetadata() throws IOException, InterruptedException {
+		// Set up the database so it looks basically right
+		Bosk<TestEntity> initialBosk = new Bosk<TestEntity>(
+			"Initial",
+			TestEntity.class,
+			this::initialRoot,
+			createDriverFactory()
+		);
+
+		// (Close this so it doesn't crash when we delete the "path" field)
+		((MongoDriver<TestEntity>)initialBosk.driver()).close();
+
+		// Remove the `path` metadata field
+		MongoCollection<Document> collection = mongoService.client()
+			.getDatabase(driverSettings.database())
+			.getCollection(driverSettings.collection());
+		BsonDocument filterDoc = new BsonDocument("_id", new BsonString("boskDocument"));
+		BsonDocument deletionDoc = new BsonDocument("$unset", new BsonDocument(path.name(), new BsonNull())); // Value is ignored
+		collection.updateOne(filterDoc, deletionDoc);
+
+		// Make the bosk we want to test
+		Bosk<TestEntity> bosk = new Bosk<TestEntity>(
+			"bosk",
+			TestEntity.class,
+			this::initialRoot,
+			createDriverFactory()
+		);
+
+		// Verify that the path field is indeed missing
+		bosk.driver().flush();
+		try (MongoCursor<Document> cursor = collection.find(filterDoc).cursor()) {
+			Document doc = cursor.next();
+			assertNull(doc.get(path.name()));
+		}
+
+		// Refurbish
+		((MongoDriver<?>)bosk.driver()).refurbish();
+
+		// Verify that it's there now
+		try (MongoCursor<Document> cursor = collection.find(filterDoc).cursor()) {
+			Document doc = cursor.next();
+			assertEquals("/", doc.get(path.name()));
+		}
+
+	}
+
 	private <E extends Entity> DriverFactory<E> createDriverFactory() {
 		return (bosk, downstream) -> {
 			MongoDriver<E> driver = new MongoDriver<E>(