From 3a0909368cc10e41ef9f6a444cbb6e70bd499a37 Mon Sep 17 00:00:00 2001
From: Sandip Gahlot <sgahlot@redhat.com>
Date: Wed, 28 Jul 2021 10:11:36 -0400
Subject: [PATCH] DBAAS-42: Added support for MongoDB service binding by
 reading the given mandatory/optional properties (+ tests) and making the
 correct connection string

DBAAS-42: Using correct property for quarkus mongodb connection string. Removed MockitoExtension
---
 extensions/mongodb-client/deployment/pom.xml  |   2 +-
 .../deployment/MongoClientProcessor.java      |  15 +-
 extensions/mongodb-client/runtime/pom.xml     |  19 +-
 .../runtime/MongoServiceBindingConverter.java | 140 ++++++++++++
 ...ce.binding.runtime.ServiceBindingConverter |   1 +
 .../MongoServiceBindingConverterTest.java     | 213 ++++++++++++++++++
 .../org.mockito.plugins.MockMaker             |   1 +
 .../service-binding/all-props/database        |   1 +
 .../resources/service-binding/all-props/host  |   1 +
 .../service-binding/all-props/password        |   1 +
 .../resources/service-binding/all-props/port  |   1 +
 .../service-binding/all-props/provider        |   1 +
 .../resources/service-binding/all-props/type  |   1 +
 .../service-binding/all-props/username        |   1 +
 .../service-binding/no-port/database          |   1 +
 .../resources/service-binding/no-port/host    |   1 +
 .../service-binding/no-port/password          |   1 +
 .../service-binding/no-port/provider          |   1 +
 .../resources/service-binding/no-port/type    |   1 +
 .../service-binding/no-port/username          |   1 +
 .../service-binding/no-user/database          |   1 +
 .../resources/service-binding/no-user/host    |   1 +
 .../resources/service-binding/no-user/port    |   1 +
 .../service-binding/no-user/provider          |   1 +
 .../resources/service-binding/no-user/type    |   1 +
 25 files changed, 406 insertions(+), 3 deletions(-)
 create mode 100644 extensions/mongodb-client/runtime/src/main/java/io/quarkus/mongodb/runtime/MongoServiceBindingConverter.java
 create mode 100644 extensions/mongodb-client/runtime/src/main/resources/META-INF/services/io.quarkus.kubernetes.service.binding.runtime.ServiceBindingConverter
 create mode 100644 extensions/mongodb-client/runtime/src/test/java/io/quarkus/mongodb/runtime/MongoServiceBindingConverterTest.java
 create mode 100644 extensions/mongodb-client/runtime/src/test/resources/mockito-extensions/org.mockito.plugins.MockMaker
 create mode 100644 extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/database
 create mode 100644 extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/host
 create mode 100644 extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/password
 create mode 100644 extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/port
 create mode 100644 extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/provider
 create mode 100644 extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/type
 create mode 100644 extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/username
 create mode 100644 extensions/mongodb-client/runtime/src/test/resources/service-binding/no-port/database
 create mode 100644 extensions/mongodb-client/runtime/src/test/resources/service-binding/no-port/host
 create mode 100644 extensions/mongodb-client/runtime/src/test/resources/service-binding/no-port/password
 create mode 100644 extensions/mongodb-client/runtime/src/test/resources/service-binding/no-port/provider
 create mode 100644 extensions/mongodb-client/runtime/src/test/resources/service-binding/no-port/type
 create mode 100644 extensions/mongodb-client/runtime/src/test/resources/service-binding/no-port/username
 create mode 100644 extensions/mongodb-client/runtime/src/test/resources/service-binding/no-user/database
 create mode 100644 extensions/mongodb-client/runtime/src/test/resources/service-binding/no-user/host
 create mode 100644 extensions/mongodb-client/runtime/src/test/resources/service-binding/no-user/port
 create mode 100644 extensions/mongodb-client/runtime/src/test/resources/service-binding/no-user/provider
 create mode 100644 extensions/mongodb-client/runtime/src/test/resources/service-binding/no-user/type

diff --git a/extensions/mongodb-client/deployment/pom.xml b/extensions/mongodb-client/deployment/pom.xml
index 9def469e33a9f..926c3f95a13c1 100644
--- a/extensions/mongodb-client/deployment/pom.xml
+++ b/extensions/mongodb-client/deployment/pom.xml
@@ -123,4 +123,4 @@
         </plugins>
     </build>
 
-</project>
+</project>
\ No newline at end of file
diff --git a/extensions/mongodb-client/deployment/src/main/java/io/quarkus/mongodb/deployment/MongoClientProcessor.java b/extensions/mongodb-client/deployment/src/main/java/io/quarkus/mongodb/deployment/MongoClientProcessor.java
index 3eb4fd9546eb4..700c5173ce642 100644
--- a/extensions/mongodb-client/deployment/src/main/java/io/quarkus/mongodb/deployment/MongoClientProcessor.java
+++ b/extensions/mongodb-client/deployment/src/main/java/io/quarkus/mongodb/deployment/MongoClientProcessor.java
@@ -51,6 +51,7 @@
 import io.quarkus.deployment.builditem.FeatureBuildItem;
 import io.quarkus.deployment.builditem.SslNativeConfigBuildItem;
 import io.quarkus.deployment.builditem.nativeimage.ReflectiveClassBuildItem;
+import io.quarkus.deployment.builditem.nativeimage.ServiceProviderBuildItem;
 import io.quarkus.deployment.metrics.MetricsCapabilityBuildItem;
 import io.quarkus.mongodb.MongoClientName;
 import io.quarkus.mongodb.reactive.ReactiveMongoClient;
@@ -58,6 +59,7 @@
 import io.quarkus.mongodb.runtime.MongoClientRecorder;
 import io.quarkus.mongodb.runtime.MongoClientSupport;
 import io.quarkus.mongodb.runtime.MongoClients;
+import io.quarkus.mongodb.runtime.MongoServiceBindingConverter;
 import io.quarkus.mongodb.runtime.MongodbConfig;
 import io.quarkus.runtime.metrics.MetricsFactory;
 import io.quarkus.smallrye.health.deployment.spi.HealthBuildItem;
@@ -69,6 +71,8 @@ public class MongoClientProcessor {
     private static final DotName MONGO_CLIENT = DotName.createSimple(MongoClient.class.getName());
     private static final DotName REACTIVE_MONGO_CLIENT = DotName.createSimple(ReactiveMongoClient.class.getName());
 
+    private static final String SERVICE_BINDING_INTERFACE_NAME = "io.quarkus.kubernetes.service.binding.runtime.ServiceBindingConverter";
+
     @BuildStep
     AdditionalIndexedClassesBuildItem includeBsonTypesToIndex() {
         return new AdditionalIndexedClassesBuildItem(
@@ -371,4 +375,13 @@ HealthBuildItem addHealthCheck(MongoClientBuildTimeConfig buildTimeConfig) {
         return new HealthBuildItem("io.quarkus.mongodb.health.MongoHealthCheck",
                 buildTimeConfig.healthEnabled);
     }
-}
+
+    @BuildStep
+    void registerServiceBinding(Capabilities capabilities, BuildProducer<ServiceProviderBuildItem> buildProducer) {
+        if (capabilities.isPresent(Capability.KUBERNETES_SERVICE_BINDING)) {
+            buildProducer.produce(
+                    new ServiceProviderBuildItem(SERVICE_BINDING_INTERFACE_NAME,
+                            MongoServiceBindingConverter.class.getName()));
+        }
+    }
+}
\ No newline at end of file
diff --git a/extensions/mongodb-client/runtime/pom.xml b/extensions/mongodb-client/runtime/pom.xml
index 06c4edf05a1ae..47534584f7d90 100644
--- a/extensions/mongodb-client/runtime/pom.xml
+++ b/extensions/mongodb-client/runtime/pom.xml
@@ -44,6 +44,11 @@
             <groupId>org.mongodb</groupId>
             <artifactId>mongodb-crypt</artifactId>
         </dependency>
+        <dependency>
+            <groupId>io.quarkus</groupId>
+            <artifactId>quarkus-kubernetes-service-binding</artifactId>
+            <optional>true</optional>
+        </dependency>
 
         <!-- Add the health extension as optional as we will produce the health check only if it's included -->
         <dependency>
@@ -100,6 +105,18 @@
             <artifactId>awaitility</artifactId>
             <scope>test</scope>
         </dependency>
+
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-core</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-junit-jupiter</artifactId>
+            <scope>test</scope>
+        </dependency>
+
         <!--
         We need this dependency to make MP context propagation work. As these tests do not
         actually start Quarkus the MP CP extension does not run, so it does not exclude the
@@ -139,4 +156,4 @@
     </build>
 
 
-</project>
+</project>
\ No newline at end of file
diff --git a/extensions/mongodb-client/runtime/src/main/java/io/quarkus/mongodb/runtime/MongoServiceBindingConverter.java b/extensions/mongodb-client/runtime/src/main/java/io/quarkus/mongodb/runtime/MongoServiceBindingConverter.java
new file mode 100644
index 0000000000000..7931f9a686d8b
--- /dev/null
+++ b/extensions/mongodb-client/runtime/src/main/java/io/quarkus/mongodb/runtime/MongoServiceBindingConverter.java
@@ -0,0 +1,140 @@
+package io.quarkus.mongodb.runtime;
+
+import static java.lang.String.format;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+
+import org.jboss.logging.Logger;
+
+import io.quarkus.kubernetes.service.binding.runtime.ServiceBinding;
+import io.quarkus.kubernetes.service.binding.runtime.ServiceBindingConfigSource;
+import io.quarkus.kubernetes.service.binding.runtime.ServiceBindingConverter;
+
+/**
+ * ServiceBindingConverter for MongoDB to support SBO (Service Binding Operator) in Quarkus.
+ *
+ * This class supports both the <b>Standard</b> and <b>SRV</b> connection string format for
+ * MongoDB depending on whether port is provided or not.
+ *
+ * <br>
+ * Following individual properties are supported to make the connection string:
+ * <ul>
+ * <li>username</li>
+ * <li>password</li>
+ * <li>host</li>
+ * <li>port</li>
+ * <li>database</li>
+ * </ul>
+ * <i>Other than host all other properties are optinoal</i>
+ *
+ * <br>
+ * <br>
+ * Only following options are supported by default:
+ * <ul>
+ * <li>retryWrites=true</li>
+ * <li>w=majority</li>
+ * </ul>
+ *
+ */
+public class MongoServiceBindingConverter implements ServiceBindingConverter {
+    private static final Logger LOGGER = Logger.getLogger(MongoServiceBindingConverter.class);
+
+    private static final String BINDING_TYPE = "mongodb";
+    public static final String BINDING_CONFIG_SOURCE_NAME = BINDING_TYPE + "-k8s-service-binding-source";
+    public static final String MONGO_DB_CONNECTION_STRING = "quarkus.mongodb.connection-string";
+
+    // DB properties
+    public static final String DB_USER = "username";
+    public static final String DB_PASSWORD = "password";
+    public static final String DB_HOST = "host";
+    public static final String DB_PORT = "port";
+    public static final String DB_DATABASE = "database";
+    public static final String DB_PREFIX_STANDARD = "mongodb://";
+    public static final String DB_PREFIX_SRV = "mongodb+srv://";
+    public static final String DB_DEFAULT_OPTIONS = "?retryWrites=true&w=majority";
+
+    private static final String CONNECTION_STRING_WITH_USER = "%s%s:%s@%s/%s" + DB_DEFAULT_OPTIONS; // user:pass@hostPort/database
+    private static final String CONNECTION_STRING_WITH_USER_NO_DB = "%s%s:%s@%s" + DB_DEFAULT_OPTIONS; // user:pass@hostPort
+    private static final String CONNECTION_STRING_WITHOUT_USER = "%s%s/%s" + DB_DEFAULT_OPTIONS; // hostPort/database
+    private static final String CONNECTION_STRING_WITHOUT_USER_NO_DB = "%s%s" + DB_DEFAULT_OPTIONS; // hostPort
+
+    @Override
+    public Optional<ServiceBindingConfigSource> convert(List<ServiceBinding> serviceBindings) {
+        Optional<ServiceBinding> matchingByType = ServiceBinding.singleMatchingByType(BINDING_TYPE, serviceBindings);
+        if (matchingByType.isEmpty()) {
+            return Optional.empty();
+        }
+
+        Map<String, String> properties = new HashMap<>();
+
+        properties.put(MONGO_DB_CONNECTION_STRING, getConnectionString(matchingByType.get()));
+
+        return Optional.of(new ServiceBindingConfigSource(BINDING_CONFIG_SOURCE_NAME, properties));
+    }
+
+    private String getConnectionString(ServiceBinding binding) {
+        String user = getDbProperty(binding, DB_USER);
+        String password = getDbProperty(binding, DB_PASSWORD);
+        String hostPort = getHostPort(binding);
+        String database = getDbProperty(binding, DB_DATABASE);
+        String prefix = isPortProvided(hostPort) ? DB_PREFIX_STANDARD : DB_PREFIX_SRV;
+
+        String connectionString;
+        if (isBlank(user)) {
+            if (isBlank(database)) {
+                connectionString = format(CONNECTION_STRING_WITHOUT_USER_NO_DB, prefix, hostPort);
+            } else {
+                connectionString = format(CONNECTION_STRING_WITHOUT_USER, prefix, hostPort, database);
+            }
+        } else {
+            if (isBlank(database)) {
+                connectionString = format(CONNECTION_STRING_WITH_USER_NO_DB, prefix, user, password, hostPort);
+            } else {
+                connectionString = format(CONNECTION_STRING_WITH_USER, prefix, user, password, hostPort, database);
+            }
+        }
+
+        LOGGER.info(format("MongoDB connection string: [%s]", connectionString));
+        return connectionString;
+    }
+
+    private String getDbProperty(ServiceBinding binding, String dbPropertyKey) {
+        String dbPropertyValue = binding.getProperties().get(dbPropertyKey);
+        if (isBlank(dbPropertyValue)) {
+            LOGGER.debug(format("Property '%s' not found", dbPropertyKey));
+        }
+
+        return dbPropertyValue;
+    }
+
+    private String getHostPort(ServiceBinding binding) {
+        String host = getDbProperty(binding, DB_HOST);
+        String port = getDbProperty(binding, DB_PORT);
+
+        String hostPort = host;
+        if (isNotBlank(host)) {
+            if (isNotBlank(port)) {
+                hostPort = host + ":" + port;
+            }
+        } else {
+            LOGGER.warn("Unable to get the host property. Connection string won't be correct");
+        }
+
+        return hostPort;
+    }
+
+    private boolean isPortProvided(String hostPort) {
+        return hostPort != null && hostPort.contains(":");
+    }
+
+    private boolean isBlank(String value) {
+        return value == null || value.trim().length() == 0;
+    }
+
+    private boolean isNotBlank(String value) {
+        return !isBlank(value);
+    }
+}
\ No newline at end of file
diff --git a/extensions/mongodb-client/runtime/src/main/resources/META-INF/services/io.quarkus.kubernetes.service.binding.runtime.ServiceBindingConverter b/extensions/mongodb-client/runtime/src/main/resources/META-INF/services/io.quarkus.kubernetes.service.binding.runtime.ServiceBindingConverter
new file mode 100644
index 0000000000000..fbb2732ba35e4
--- /dev/null
+++ b/extensions/mongodb-client/runtime/src/main/resources/META-INF/services/io.quarkus.kubernetes.service.binding.runtime.ServiceBindingConverter
@@ -0,0 +1 @@
+io.quarkus.mongodb.runtime.MongoServiceBindingConverter
\ No newline at end of file
diff --git a/extensions/mongodb-client/runtime/src/test/java/io/quarkus/mongodb/runtime/MongoServiceBindingConverterTest.java b/extensions/mongodb-client/runtime/src/test/java/io/quarkus/mongodb/runtime/MongoServiceBindingConverterTest.java
new file mode 100644
index 0000000000000..db650ef0a3477
--- /dev/null
+++ b/extensions/mongodb-client/runtime/src/test/java/io/quarkus/mongodb/runtime/MongoServiceBindingConverterTest.java
@@ -0,0 +1,213 @@
+package io.quarkus.mongodb.runtime;
+
+import static io.quarkus.mongodb.runtime.MongoServiceBindingConverter.BINDING_CONFIG_SOURCE_NAME;
+import static io.quarkus.mongodb.runtime.MongoServiceBindingConverter.DB_DATABASE;
+import static io.quarkus.mongodb.runtime.MongoServiceBindingConverter.DB_DEFAULT_OPTIONS;
+import static io.quarkus.mongodb.runtime.MongoServiceBindingConverter.DB_HOST;
+import static io.quarkus.mongodb.runtime.MongoServiceBindingConverter.DB_PASSWORD;
+import static io.quarkus.mongodb.runtime.MongoServiceBindingConverter.DB_PORT;
+import static io.quarkus.mongodb.runtime.MongoServiceBindingConverter.DB_PREFIX_SRV;
+import static io.quarkus.mongodb.runtime.MongoServiceBindingConverter.DB_PREFIX_STANDARD;
+import static io.quarkus.mongodb.runtime.MongoServiceBindingConverter.DB_USER;
+import static io.quarkus.mongodb.runtime.MongoServiceBindingConverter.MONGO_DB_CONNECTION_STRING;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.spy;
+
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Optional;
+
+import org.assertj.core.util.Lists;
+import org.junit.jupiter.api.Test;
+
+import io.quarkus.kubernetes.service.binding.runtime.ServiceBinding;
+import io.quarkus.kubernetes.service.binding.runtime.ServiceBindingConfigSource;
+
+public class MongoServiceBindingConverterTest {
+    private final static Path rootPath = Paths.get("src/test/resources/service-binding");
+    private final static String BINDING_DIRECTORY_ALL_PROPS = "all-props";
+    private final static String BINDING_DIRECTORY_NO_PORT = "no-port";
+    private final static String BINDING_DIRECTORY_NO_USER = "no-user";
+
+    private static final String EXPECTED_USERNAME = "someUserName";
+    private static final String EXPECTED_PASSWORD = "password123 isItAGoodPassword";
+    private static final String EXPECTED_HOST = "mongodb0.example.com";
+    private static final String EXPECTED_DB = "random-DB";
+    private static final String EXPECTED_PORT = "11010";
+
+    @Test
+    public void testBindingWithAllProperties() {
+        String bindingDirectory = BINDING_DIRECTORY_ALL_PROPS;
+        ServiceBinding serviceBinding = new ServiceBinding(rootPath.resolve(bindingDirectory));
+        assertThat(serviceBinding.getName()).isEqualTo(bindingDirectory);
+        assertThat(serviceBinding.getType()).isEqualTo("mongodb");
+        assertThat(serviceBinding.getProvider()).isEqualTo("atlas");
+        assertThat(serviceBinding.getProperties().get(DB_USER)).isEqualTo(EXPECTED_USERNAME);
+        assertThat(serviceBinding.getProperties().get(DB_PASSWORD)).isEqualTo(EXPECTED_PASSWORD);
+        assertThat(serviceBinding.getProperties().get(DB_HOST)).isEqualTo(EXPECTED_HOST);
+        assertThat(serviceBinding.getProperties().get(DB_PORT)).isEqualTo(EXPECTED_PORT);
+        assertThat(serviceBinding.getProperties().get(DB_DATABASE)).isEqualTo(EXPECTED_DB);
+    }
+
+    @Test
+    public void testBindingWithMissingProperties() {
+        String bindingDirectory = BINDING_DIRECTORY_NO_PORT;
+        ServiceBinding serviceBinding = new ServiceBinding(rootPath.resolve(bindingDirectory));
+        assertThat(serviceBinding.getName()).isEqualTo(bindingDirectory);
+        assertThat(serviceBinding.getType()).isEqualTo("mongodb");
+        assertThat(serviceBinding.getProvider()).isEqualTo("atlas");
+        assertThat(serviceBinding.getProperties().get(DB_USER)).isEqualTo(EXPECTED_USERNAME);
+        assertThat(serviceBinding.getProperties().get(DB_PASSWORD)).isEqualTo(EXPECTED_PASSWORD);
+        assertThat(serviceBinding.getProperties().get(DB_HOST)).isEqualTo(EXPECTED_HOST);
+        assertThat(serviceBinding.getProperties().get(DB_PORT)).isNull();
+        assertThat(serviceBinding.getProperties().get(DB_DATABASE)).isEqualTo(EXPECTED_DB);
+    }
+
+    @Test
+    public void testConnectionStringWithPortPresent() {
+        ServiceBindingConfigSource serviceBindingConfigSource = readBindingAndVerifyConfigSource(BINDING_DIRECTORY_ALL_PROPS);
+
+        String expectedConnString = DB_PREFIX_STANDARD + EXPECTED_USERNAME + ":" + EXPECTED_PASSWORD +
+                "@" + EXPECTED_HOST + ":" + EXPECTED_PORT + "/" + EXPECTED_DB + DB_DEFAULT_OPTIONS;
+        verifyConnectionString(serviceBindingConfigSource, DB_PREFIX_STANDARD, expectedConnString);
+    }
+
+    @Test
+    public void testConnectionStringWithPortMissing() {
+        ServiceBindingConfigSource serviceBindingConfigSource = readBindingAndVerifyConfigSource(BINDING_DIRECTORY_NO_PORT);
+
+        String expectedConnString = DB_PREFIX_SRV + EXPECTED_USERNAME + ":" + EXPECTED_PASSWORD +
+                "@" + EXPECTED_HOST + "/" + EXPECTED_DB + DB_DEFAULT_OPTIONS;
+        verifyConnectionString(serviceBindingConfigSource, DB_PREFIX_SRV, expectedConnString);
+    }
+
+    @Test
+    public void testConnectionStringWithPortAndDatabaseMissing() {
+        HashMap<String, String> properties = getMapWithAllValuesPopulated();
+        properties.remove(DB_PORT); // BindingDirectory doesn't have this property, but removing it since it's put back in the map
+        properties.remove(DB_DATABASE); // This is what we actually want to test out
+
+        ServiceBindingConfigSource serviceBindingConfigSource = readBindingAsSpyAndVerifyConfigSource(
+                BINDING_DIRECTORY_NO_PORT, properties);
+
+        String expectedConnString = DB_PREFIX_SRV + EXPECTED_USERNAME + ":" + EXPECTED_PASSWORD +
+                "@" + EXPECTED_HOST + DB_DEFAULT_OPTIONS;
+        verifyConnectionString(serviceBindingConfigSource, DB_PREFIX_SRV, expectedConnString);
+    }
+
+    @Test
+    public void testConnectionStringWithUserMissing() {
+        ServiceBindingConfigSource serviceBindingConfigSource = readBindingAndVerifyConfigSource(BINDING_DIRECTORY_NO_USER);
+
+        String expectedConnString = DB_PREFIX_STANDARD + EXPECTED_HOST + ":" + EXPECTED_PORT + "/" + EXPECTED_DB
+                + DB_DEFAULT_OPTIONS;
+        verifyConnectionString(serviceBindingConfigSource, DB_PREFIX_STANDARD, expectedConnString);
+    }
+
+    @Test
+    public void testConnectionStringWithUserAndPortMissing() {
+        HashMap<String, String> properties = getMapWithAllValuesPopulated();
+        properties.remove(DB_USER); // BindingDirectory doesn't have this property, but removing it since it's put back in the map
+        properties.remove(DB_PORT); // This is what we actually want to test out
+
+        ServiceBindingConfigSource serviceBindingConfigSource = readBindingAsSpyAndVerifyConfigSource(
+                BINDING_DIRECTORY_NO_USER, properties);
+
+        String expectedConnString = DB_PREFIX_SRV + EXPECTED_HOST + "/" + EXPECTED_DB + DB_DEFAULT_OPTIONS;
+        verifyConnectionString(serviceBindingConfigSource, DB_PREFIX_SRV, expectedConnString);
+    }
+
+    @Test
+    public void testConnectionStringWithUserAndPortAndDatabaseMissing() {
+        HashMap<String, String> properties = getMapWithAllValuesPopulated();
+        properties.remove(DB_USER); // BindingDirectory doesn't have this property, but removing it since it's put back in the map
+        properties.remove(DB_PORT); // This is what we actually want to test out
+        properties.remove(DB_DATABASE); // This is what we actually want to test out
+
+        ServiceBindingConfigSource serviceBindingConfigSource = readBindingAsSpyAndVerifyConfigSource(
+                BINDING_DIRECTORY_NO_USER, properties);
+
+        String expectedConnString = DB_PREFIX_SRV + EXPECTED_HOST + DB_DEFAULT_OPTIONS;
+        verifyConnectionString(serviceBindingConfigSource, DB_PREFIX_SRV, expectedConnString);
+    }
+
+    @Test
+    public void testConnectionStringWithUserAndDatabaseMissing() {
+        HashMap<String, String> properties = getMapWithAllValuesPopulated();
+        properties.remove(DB_USER); // BindingDirectory doesn't have this property, but removing it since it's put back in the map
+        properties.remove(DB_DATABASE); // This is what we actually want to test out
+
+        ServiceBindingConfigSource serviceBindingConfigSource = readBindingAsSpyAndVerifyConfigSource(
+                BINDING_DIRECTORY_NO_USER, properties);
+
+        String expectedConnString = DB_PREFIX_STANDARD + EXPECTED_HOST + ":" + EXPECTED_PORT + DB_DEFAULT_OPTIONS;
+        verifyConnectionString(serviceBindingConfigSource, DB_PREFIX_STANDARD, expectedConnString);
+    }
+
+    @Test
+    public void testConnectionStringWithDatabaseMissing() {
+        HashMap<String, String> properties = getMapWithAllValuesPopulated();
+        properties.remove(DB_DATABASE); // This is what we actually want to test out
+
+        ServiceBindingConfigSource serviceBindingConfigSource = readBindingAsSpyAndVerifyConfigSource(
+                BINDING_DIRECTORY_ALL_PROPS, properties);
+
+        String expectedConnString = DB_PREFIX_STANDARD + EXPECTED_USERNAME + ":" + EXPECTED_PASSWORD +
+                "@" + EXPECTED_HOST + ":" + EXPECTED_PORT + DB_DEFAULT_OPTIONS;
+        verifyConnectionString(serviceBindingConfigSource, DB_PREFIX_STANDARD, expectedConnString);
+    }
+
+    private ServiceBindingConfigSource readBindingAndVerifyConfigSource(String bindingDirectory) {
+        ServiceBinding serviceBinding = new ServiceBinding(rootPath.resolve(bindingDirectory));
+        assertThat(serviceBinding.getName()).isEqualTo(bindingDirectory);
+
+        return verifyConfigSource(serviceBinding);
+    }
+
+    /*
+     * ServiceBinding will be created as a {@link Mockito.spy} so that we can return the given bindingProperties from
+     * that object when getProperties is invoked.
+     * This is to facilitate testing any scenario where we don't want to read from binding
+     */
+    private ServiceBindingConfigSource readBindingAsSpyAndVerifyConfigSource(String bindingDirectory,
+            Map<String, String> bindingProperties) {
+        ServiceBinding serviceBinding = spy(new ServiceBinding(rootPath.resolve(bindingDirectory)));
+        assertThat(serviceBinding.getName()).isEqualTo(bindingDirectory);
+
+        doReturn(bindingProperties).when(serviceBinding).getProperties();
+
+        return verifyConfigSource(serviceBinding);
+    }
+
+    private ServiceBindingConfigSource verifyConfigSource(ServiceBinding serviceBinding) {
+        Optional<ServiceBindingConfigSource> result = new MongoServiceBindingConverter()
+                .convert(Lists.newArrayList(serviceBinding));
+        assertThat(result.isPresent()).isTrue();
+
+        ServiceBindingConfigSource serviceBindingConfigSource = result.get();
+        assertThat(serviceBindingConfigSource).isNotNull();
+        assertThat(serviceBindingConfigSource.getName()).isEqualTo(BINDING_CONFIG_SOURCE_NAME);
+
+        return serviceBindingConfigSource;
+    }
+
+    private void verifyConnectionString(ServiceBindingConfigSource serviceBindingConfigSource, String expectedPrefix,
+            String expectedConnString) {
+        assertThat(serviceBindingConfigSource.getProperties().get(MONGO_DB_CONNECTION_STRING)).startsWith(expectedPrefix);
+        assertThat(serviceBindingConfigSource.getProperties().get(MONGO_DB_CONNECTION_STRING)).isEqualTo(expectedConnString);
+    }
+
+    private HashMap<String, String> getMapWithAllValuesPopulated() {
+        HashMap<String, String> map = new HashMap<>();
+        map.put(DB_USER, EXPECTED_USERNAME);
+        map.put(DB_PASSWORD, EXPECTED_PASSWORD);
+        map.put(DB_HOST, EXPECTED_HOST);
+        map.put(DB_PORT, EXPECTED_PORT);
+        map.put(DB_DATABASE, EXPECTED_DB);
+
+        return map;
+    }
+}
\ No newline at end of file
diff --git a/extensions/mongodb-client/runtime/src/test/resources/mockito-extensions/org.mockito.plugins.MockMaker b/extensions/mongodb-client/runtime/src/test/resources/mockito-extensions/org.mockito.plugins.MockMaker
new file mode 100644
index 0000000000000..ca6ee9cea8ec1
--- /dev/null
+++ b/extensions/mongodb-client/runtime/src/test/resources/mockito-extensions/org.mockito.plugins.MockMaker
@@ -0,0 +1 @@
+mock-maker-inline
\ No newline at end of file
diff --git a/extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/database b/extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/database
new file mode 100644
index 0000000000000..699e929642ed9
--- /dev/null
+++ b/extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/database
@@ -0,0 +1 @@
+random-DB
\ No newline at end of file
diff --git a/extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/host b/extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/host
new file mode 100644
index 0000000000000..bee4cd9950942
--- /dev/null
+++ b/extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/host
@@ -0,0 +1 @@
+mongodb0.example.com
\ No newline at end of file
diff --git a/extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/password b/extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/password
new file mode 100644
index 0000000000000..b4a5888fa99a2
--- /dev/null
+++ b/extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/password
@@ -0,0 +1 @@
+password123 isItAGoodPassword
\ No newline at end of file
diff --git a/extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/port b/extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/port
new file mode 100644
index 0000000000000..d0c0a5740ae48
--- /dev/null
+++ b/extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/port
@@ -0,0 +1 @@
+11010
\ No newline at end of file
diff --git a/extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/provider b/extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/provider
new file mode 100644
index 0000000000000..98c8f47051d4b
--- /dev/null
+++ b/extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/provider
@@ -0,0 +1 @@
+atlas
\ No newline at end of file
diff --git a/extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/type b/extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/type
new file mode 100644
index 0000000000000..e73baecce656b
--- /dev/null
+++ b/extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/type
@@ -0,0 +1 @@
+mongodb
\ No newline at end of file
diff --git a/extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/username b/extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/username
new file mode 100644
index 0000000000000..88e8fbc39a4f6
--- /dev/null
+++ b/extensions/mongodb-client/runtime/src/test/resources/service-binding/all-props/username
@@ -0,0 +1 @@
+someUserName
\ No newline at end of file
diff --git a/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-port/database b/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-port/database
new file mode 100644
index 0000000000000..699e929642ed9
--- /dev/null
+++ b/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-port/database
@@ -0,0 +1 @@
+random-DB
\ No newline at end of file
diff --git a/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-port/host b/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-port/host
new file mode 100644
index 0000000000000..bee4cd9950942
--- /dev/null
+++ b/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-port/host
@@ -0,0 +1 @@
+mongodb0.example.com
\ No newline at end of file
diff --git a/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-port/password b/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-port/password
new file mode 100644
index 0000000000000..b4a5888fa99a2
--- /dev/null
+++ b/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-port/password
@@ -0,0 +1 @@
+password123 isItAGoodPassword
\ No newline at end of file
diff --git a/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-port/provider b/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-port/provider
new file mode 100644
index 0000000000000..98c8f47051d4b
--- /dev/null
+++ b/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-port/provider
@@ -0,0 +1 @@
+atlas
\ No newline at end of file
diff --git a/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-port/type b/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-port/type
new file mode 100644
index 0000000000000..e73baecce656b
--- /dev/null
+++ b/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-port/type
@@ -0,0 +1 @@
+mongodb
\ No newline at end of file
diff --git a/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-port/username b/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-port/username
new file mode 100644
index 0000000000000..88e8fbc39a4f6
--- /dev/null
+++ b/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-port/username
@@ -0,0 +1 @@
+someUserName
\ No newline at end of file
diff --git a/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-user/database b/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-user/database
new file mode 100644
index 0000000000000..699e929642ed9
--- /dev/null
+++ b/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-user/database
@@ -0,0 +1 @@
+random-DB
\ No newline at end of file
diff --git a/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-user/host b/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-user/host
new file mode 100644
index 0000000000000..bee4cd9950942
--- /dev/null
+++ b/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-user/host
@@ -0,0 +1 @@
+mongodb0.example.com
\ No newline at end of file
diff --git a/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-user/port b/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-user/port
new file mode 100644
index 0000000000000..d0c0a5740ae48
--- /dev/null
+++ b/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-user/port
@@ -0,0 +1 @@
+11010
\ No newline at end of file
diff --git a/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-user/provider b/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-user/provider
new file mode 100644
index 0000000000000..98c8f47051d4b
--- /dev/null
+++ b/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-user/provider
@@ -0,0 +1 @@
+atlas
\ No newline at end of file
diff --git a/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-user/type b/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-user/type
new file mode 100644
index 0000000000000..e73baecce656b
--- /dev/null
+++ b/extensions/mongodb-client/runtime/src/test/resources/service-binding/no-user/type
@@ -0,0 +1 @@
+mongodb
\ No newline at end of file