feat: log version and settings on startup (#3601)

Add some informative log messages about the client on startup. A similar feature existed in 1x, but got lost in the upgrade 2.0. Will print the artifact name, version and settings for each new connection

Author: igorbernstein2

bigtable-client-core-parent/bigtable-hbase/src/main/java/com/google/cloud/bigtable/hbase/wrappers/BigtableHBaseSettings.java

@@ -87,4 +87,6 @@ protected String getRequiredValue(String key, String displayName) {
         !isNullOrEmpty(value), String.format("%s must be supplied via %s", displayName, key));
     return value;
   }
+
+  public abstract String toDebugString();
 }

bigtable-client-core-parent/bigtable-hbase/src/main/java/com/google/cloud/bigtable/hbase/wrappers/veneer/BigtableHBaseVeneerSettings.java

@@ -85,6 +85,7 @@
 import com.google.cloud.bigtable.hbase.wrappers.BigtableHBaseSettings;
 import com.google.cloud.bigtable.hbase.wrappers.veneer.metrics.MetricsApiTracerAdapterFactory;
 import com.google.common.base.Joiner;
+import com.google.common.base.MoreObjects;
 import com.google.common.base.Optional;
 import com.google.common.base.Preconditions;
 import com.google.common.base.Strings;
@@ -257,6 +258,15 @@ public BigtableInstanceAdminSettings getInstanceAdminSettings() {
     return instanceAdminSettings;
   }
 
+  @Override
+  public String toDebugString() {
+    return MoreObjects.toStringHelper(this)
+        .add("dataSettings", dataSettings)
+        .add("tableAdminSettings", tableAdminSettings)
+        .add("instanceAdminSettings", instanceAdminSettings)
+        .toString();
+  }
+
   // ************** Private Helpers **************
   private BigtableDataSettings buildBigtableDataSettings(ClientOperationTimeouts clientTimeouts)
       throws IOException {

bigtable-client-core-parent/bigtable-hbase/src/main/java/org/apache/hadoop/hbase/client/AbstractBigtableConnection.java

@@ -18,6 +18,7 @@
 
 import com.google.api.core.InternalApi;
 import com.google.cloud.bigtable.hbase.BigtableBufferedMutator;
+import com.google.cloud.bigtable.hbase.BigtableHBaseVersion;
 import com.google.cloud.bigtable.hbase.BigtableRegionLocator;
 import com.google.cloud.bigtable.hbase.adapters.Adapters;
 import com.google.cloud.bigtable.hbase.adapters.HBaseRequestAdapter;
@@ -30,10 +31,12 @@
 import java.io.Closeable;
 import java.io.IOException;
 import java.util.HashSet;
+import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.CopyOnWriteArraySet;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hbase.ServerName;
 import org.apache.hadoop.hbase.TableName;
@@ -114,11 +117,43 @@ protected AbstractBigtableConnection(
       throw ioe;
     }
 
+    logStartup(LOG, conf, settings);
+
     this.batchPool = pool;
     this.closed = false;
     this.bigtableApi = BigtableApi.create(settings);
   }
 
+  private static final AtomicBoolean firstConnection = new AtomicBoolean();
+
+  private void logStartup(Logger logger, Configuration userConfig, BigtableHBaseSettings settings) {
+    if (firstConnection.compareAndSet(false, true)) {
+      String jarPath;
+      try {
+        jarPath = getClass().getProtectionDomain().getCodeSource().getLocation().toString();
+      } catch (RuntimeException e) {
+        jarPath = "<unknown>";
+      }
+
+      logger.info(
+          "Using bigtable-hbase client from jar %s. Version: %s",
+          jarPath, BigtableHBaseVersion.getVersion());
+    }
+    // Dump user configuration
+    if (logger.getLog().isDebugEnabled()) {
+      MoreObjects.ToStringHelper configHelper = MoreObjects.toStringHelper("BigtableConfiguration");
+
+      for (Map.Entry<String, String> entry : userConfig) {
+        if (!entry.getKey().startsWith("google.bigtable")) {
+          continue;
+        }
+        configHelper.add(entry.getKey(), entry.getValue());
+      }
+      logger.debug("User Configuration: " + configHelper);
+      logger.debug("Effective settings: " + settings.toDebugString());
+    }
+  }
+
   /** {@inheritDoc} */
   @Override
   public Configuration getConfiguration() {