feat: Track PG Adapter usage from user-agent headers (#1711)

* Added the string "pg-adapter" in the list of allowed client library token, so that when PG Adapter connects via client library by passing the string "pg-adapter" in the user-agent header, it doesn't get discarded.

* Added an additional test case for the testSetClientLibToken test.

* Changed assertThat to assertEquals

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

* Changed assertThat to assertEquals

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

google-cloud-spanner/src/main/java/com/google/cloud/spanner/SpannerOptions.java

@@ -80,6 +80,7 @@ public class SpannerOptions extends ServiceOptions<Spanner, SpannerOptions> {
   private static final String JDBC_API_CLIENT_LIB_TOKEN = "sp-jdbc";
   private static final String HIBERNATE_API_CLIENT_LIB_TOKEN = "sp-hib";
   private static final String LIQUIBASE_API_CLIENT_LIB_TOKEN = "sp-liq";
+  private static final String PG_ADAPTER_CLIENT_LIB_TOKEN = "pg-adapter";
 
   private static final String API_SHORT_NAME = "Spanner";
   private static final String DEFAULT_HOST = "https://spanner.googleapis.com";
@@ -657,7 +658,8 @@ public static class Builder
             ServiceOptions.getGoogApiClientLibName(),
             JDBC_API_CLIENT_LIB_TOKEN,
             HIBERNATE_API_CLIENT_LIB_TOKEN,
-            LIQUIBASE_API_CLIENT_LIB_TOKEN);
+            LIQUIBASE_API_CLIENT_LIB_TOKEN,
+            PG_ADAPTER_CLIENT_LIB_TOKEN);
     private TransportChannelProvider channelProvider;
 
     @SuppressWarnings("rawtypes")

google-cloud-spanner/src/test/java/com/google/cloud/spanner/SpannerOptionsTest.java

@@ -19,6 +19,7 @@
 import static com.google.common.truth.Truth.assertThat;
 import static org.hamcrest.CoreMatchers.is;
 import static org.hamcrest.MatcherAssert.assertThat;
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertSame;
 import static org.junit.Assert.assertThrows;
 import static org.mockito.Mockito.mock;
@@ -502,6 +503,7 @@ public void testDoNotCacheClosedSpannerInstance() {
   public void testSetClientLibToken() {
     final String jdbcToken = "sp-jdbc";
     final String hibernateToken = "sp-hib";
+    final String pgAdapterToken = "pg-adapter";
     SpannerOptions options =
         SpannerOptions.newBuilder()
             .setProjectId("some-project")
@@ -522,8 +524,16 @@ public void testSetClientLibToken() {
         SpannerOptions.newBuilder()
             .setProjectId("some-project")
             .setCredentials(NoCredentials.getInstance())
+            .setClientLibToken(pgAdapterToken)
             .build();
-    assertThat(options.getClientLibToken()).isEqualTo(ServiceOptions.getGoogApiClientLibName());
+    assertEquals(options.getClientLibToken(), pgAdapterToken);
+
+    options =
+        SpannerOptions.newBuilder()
+            .setProjectId("some-project")
+            .setCredentials(NoCredentials.getInstance())
+            .build();
+    assertEquals(options.getClientLibToken(), ServiceOptions.getGoogApiClientLibName());
   }
 
   @Test(expected = IllegalArgumentException.class)