feat(spanner): add jdbc support for external hosts (googleapis#3536)

* feat(spanner): add jdbc support for external hosts

* feat(spanner): added default port value and unit tests

* feat(spanner): fixed redundant class name typo

Author: sagnghos

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

@@ -628,11 +628,16 @@ private Builder() {}
     public static final String SPANNER_URI_FORMAT =
         "(?:cloudspanner:)(?<HOSTGROUP>//[\\w.-]+(?:\\.[\\w\\.-]+)*[\\w\\-\\._~:/?#\\[\\]@!\\$&'\\(\\)\\*\\+,;=.]+)?/projects/(?<PROJECTGROUP>(([a-z]|[-.:]|[0-9])+|(DEFAULT_PROJECT_ID)))(/instances/(?<INSTANCEGROUP>([a-z]|[-]|[0-9])+)(/databases/(?<DATABASEGROUP>([a-z]|[-]|[_]|[0-9])+))?)?(?:[?|;].*)?";
 
+    public static final String EXTERNAL_HOST_FORMAT =
+        "(?:cloudspanner:)(?<HOSTGROUP>//[\\w.-]+(?::\\d+)?)(/instances/(?<INSTANCEGROUP>[a-z0-9-]+))?(/databases/(?<DATABASEGROUP>[a-z0-9_-]+))(?:[?;].*)?";
     private static final String SPANNER_URI_REGEX = "(?is)^" + SPANNER_URI_FORMAT + "$";
 
     @VisibleForTesting
     static final Pattern SPANNER_URI_PATTERN = Pattern.compile(SPANNER_URI_REGEX);
 
+    @VisibleForTesting
+    static final Pattern EXTERNAL_HOST_PATTERN = Pattern.compile(EXTERNAL_HOST_FORMAT);
+
     private static final String HOST_GROUP = "HOSTGROUP";
     private static final String PROJECT_GROUP = "PROJECTGROUP";
     private static final String INSTANCE_GROUP = "INSTANCEGROUP";
@@ -643,6 +648,10 @@ private boolean isValidUri(String uri) {
       return SPANNER_URI_PATTERN.matcher(uri).matches();
     }
 
+    private boolean isValidExternalHostUri(String uri) {
+      return EXTERNAL_HOST_PATTERN.matcher(uri).matches();
+    }
+
     /**
      * Sets the URI of the Cloud Spanner database to connect to. A connection URI must be specified
      * in this format:
@@ -700,9 +709,11 @@ private boolean isValidUri(String uri) {
      * @return this builder
      */
     public Builder setUri(String uri) {
-      Preconditions.checkArgument(
-          isValidUri(uri),
-          "The specified URI is not a valid Cloud Spanner connection URI. Please specify a URI in the format \"cloudspanner:[//host[:port]]/projects/project-id[/instances/instance-id[/databases/database-name]][\\?property-name=property-value[;property-name=property-value]*]?\"");
+      if (!isValidExternalHostUri(uri)) {
+        Preconditions.checkArgument(
+            isValidUri(uri),
+            "The specified URI is not a valid Cloud Spanner connection URI. Please specify a URI in the format \"cloudspanner:[//host[:port]]/projects/project-id[/instances/instance-id[/databases/database-name]][\\?property-name=property-value[;property-name=property-value]*]?\"");
+      }
       ConnectionPropertyValue<Boolean> value =
           cast(ConnectionProperties.parseValues(uri).get(LENIENT.getKey()));
       checkValidProperties(value != null && value.getValue(), uri);
@@ -829,7 +840,14 @@ public static Builder newBuilder() {
   private final SpannerOptionsConfigurator configurator;
 
   private ConnectionOptions(Builder builder) {
-    Matcher matcher = Builder.SPANNER_URI_PATTERN.matcher(builder.uri);
+    Matcher matcher;
+    boolean isExternalHost = false;
+    if (builder.isValidExternalHostUri(builder.uri)) {
+      matcher = Builder.EXTERNAL_HOST_PATTERN.matcher(builder.uri);
+      isExternalHost = true;
+    } else {
+      matcher = Builder.SPANNER_URI_PATTERN.matcher(builder.uri);
+    }
     Preconditions.checkArgument(
         matcher.find(), String.format("Invalid connection URI specified: %s", builder.uri));
 
@@ -947,12 +965,18 @@ && getInitialConnectionPropertyValue(OAUTH_TOKEN) == null
       this.sessionPoolOptions = SessionPoolOptions.newBuilder().setAutoDetectDialect(true).build();
     }
 
-    String projectId = matcher.group(Builder.PROJECT_GROUP);
+    String projectId = "default";
+    String instanceId = matcher.group(Builder.INSTANCE_GROUP);
+    if (!isExternalHost) {
+      projectId = matcher.group(Builder.PROJECT_GROUP);
+    } else if (instanceId == null) {
+      instanceId = "default";
+    }
     if (Builder.DEFAULT_PROJECT_ID_PLACEHOLDER.equalsIgnoreCase(projectId)) {
       projectId = getDefaultProjectId(this.credentials);
     }
     this.projectId = projectId;
-    this.instanceId = matcher.group(Builder.INSTANCE_GROUP);
+    this.instanceId = instanceId;
     this.databaseName = matcher.group(Builder.DATABASE_GROUP);
   }
 
@@ -981,6 +1005,10 @@ static String determineHost(
       // The leading '//' is already included in the regex for the connection URL, so we don't need
       // to add the leading '//' to the host name here.
       host = matcher.group(Builder.HOST_GROUP);
+      if (Builder.EXTERNAL_HOST_FORMAT.equals(matcher.pattern().pattern())
+          && !host.matches(".*:\\d+$")) {
+        host = String.format("%s:15000", host);
+      }
     }
     if (usePlainText) {
       return PLAIN_TEXT_PROTOCOL + host;

google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/ConnectionOptionsTest.java

@@ -16,6 +16,7 @@
 
 package com.google.cloud.spanner.connection;
 
+import static com.google.cloud.spanner.connection.ConnectionOptions.Builder.EXTERNAL_HOST_PATTERN;
 import static com.google.cloud.spanner.connection.ConnectionOptions.Builder.SPANNER_URI_PATTERN;
 import static com.google.cloud.spanner.connection.ConnectionOptions.DEFAULT_ENDPOINT;
 import static com.google.cloud.spanner.connection.ConnectionOptions.determineHost;
@@ -1211,4 +1212,40 @@ public void testEnableApiTracing() {
             .build()
             .isEnableApiTracing());
   }
+
+  @Test
+  public void testExternalHostPatterns() {
+    Matcher matcherWithoutInstance =
+        EXTERNAL_HOST_PATTERN.matcher("cloudspanner://localhost:15000/databases/test-db");
+    assertTrue(matcherWithoutInstance.matches());
+    assertNull(matcherWithoutInstance.group("INSTANCEGROUP"));
+    assertEquals("test-db", matcherWithoutInstance.group("DATABASEGROUP"));
+    Matcher matcherWithProperty =
+        EXTERNAL_HOST_PATTERN.matcher(
+            "cloudspanner://localhost:15000/instances/default/databases/singers-db?usePlainText=true");
+    assertTrue(matcherWithProperty.matches());
+    assertEquals("default", matcherWithProperty.group("INSTANCEGROUP"));
+    assertEquals("singers-db", matcherWithProperty.group("DATABASEGROUP"));
+    Matcher matcherWithoutPort =
+        EXTERNAL_HOST_PATTERN.matcher(
+            "cloudspanner://localhost/instances/default/databases/test-db");
+    assertTrue(matcherWithoutPort.matches());
+    assertEquals("default", matcherWithoutPort.group("INSTANCEGROUP"));
+    assertEquals("test-db", matcherWithoutPort.group("DATABASEGROUP"));
+    assertEquals(
+        "http://localhost:15000",
+        determineHost(
+            matcherWithoutPort,
+            DEFAULT_ENDPOINT,
+            /* autoConfigEmulator= */ true,
+            /* usePlainText= */ true,
+            ImmutableMap.of()));
+    Matcher matcherWithProject =
+        EXTERNAL_HOST_PATTERN.matcher(
+            "cloudspanner://localhost:15000/projects/default/instances/default/databases/singers-db");
+    assertFalse(matcherWithProject.matches());
+    Matcher matcherWithoutHost =
+        EXTERNAL_HOST_PATTERN.matcher("cloudspanner:/instances/default/databases/singers-db");
+    assertFalse(matcherWithoutHost.matches());
+  }
 }