feat(bigtable): cheap Table creation with different resource name (#8172

)

Customers can now produce a copy of a Table with a modified resource name, without needing to make a new connection to the service.

google/cloud/bigtable/metadata_update_policy_test.cc

@@ -67,6 +67,28 @@ TEST_F(MetadataUpdatePolicyTest, RunWithEmbeddedServerParamTableName) {
   EXPECT_EQ(expected, range.first->second);
 }
 
+/// @test A test for setting metadata when table is known.
+TEST_F(MetadataUpdatePolicyTest, ModifiedTableName) {
+  std::string const other_project_id = "other-project";
+  std::string const other_instance_id = "other-instance";
+  std::string const other_table_id = "other-table";
+  auto other_table = table_->WithNewTarget(other_project_id, other_instance_id,
+                                           other_table_id);
+
+  grpc::string expected =
+      "table_name=" +
+      TableName(other_project_id, other_instance_id, other_table_id);
+  auto reader =
+      other_table.ReadRows(RowSet("row1"), 1, Filter::PassAllFilter());
+  // lets make the RPC call to send metadata
+  reader.begin();
+  // Get metadata from embedded server
+  auto client_metadata = bigtable_service_.client_metadata();
+  auto range = client_metadata.equal_range("x-goog-request-params");
+  ASSERT_EQ(1, std::distance(range.first, range.second));
+  EXPECT_EQ(expected, range.first->second);
+}
+
 /// @test A cloning test for normal construction of metadata .
 TEST_F(MetadataUpdatePolicyTest, SimpleDefault) {
   auto const x_google_request_params = "parent=" + std::string(kInstanceName);

google/cloud/bigtable/table.h

@@ -22,6 +22,7 @@
 #include "google/cloud/bigtable/idempotent_mutation_policy.h"
 #include "google/cloud/bigtable/mutations.h"
 #include "google/cloud/bigtable/read_modify_write_rule.h"
+#include "google/cloud/bigtable/resource_names.h"
 #include "google/cloud/bigtable/row_key_sample.h"
 #include "google/cloud/bigtable/row_reader.h"
 #include "google/cloud/bigtable/row_set.h"
@@ -212,7 +213,9 @@ class Table {
         std::string const& table_id)
       : client_(std::move(client)),
         app_profile_id_(std::move(app_profile_id)),
-        table_name_(TableName(client_, table_id)),
+        project_id_(client_->project_id()),
+        instance_id_(client_->instance_id()),
+        table_name_(TableName(project_id_, instance_id_, table_id)),
         table_id_(table_id),
         rpc_retry_policy_prototype_(
             bigtable::DefaultRPCRetryPolicy(internal::kBigtableLimits)),
@@ -351,10 +354,40 @@ class Table {
 
   std::string const& table_name() const { return table_name_; }
   std::string const& app_profile_id() const { return app_profile_id_; }
-  std::string const& project_id() const { return client_->project_id(); }
-  std::string const& instance_id() const { return client_->instance_id(); }
+  std::string const& project_id() const { return project_id_; }
+  std::string const& instance_id() const { return instance_id_; }
   std::string const& table_id() const { return table_id_; }
 
+  /**
+   * Returns a Table that reuses the connection and configuration of this
+   * Table, but with a different resource name.
+   *
+   * @note The app profile id is copied from this Table.
+   */
+  Table WithNewTarget(std::string project_id, std::string instance_id,
+                      std::string table_id) const {
+    return WithNewTarget(std::move(project_id), std::move(instance_id),
+                         app_profile_id_, std::move(table_id));
+  }
+
+  /**
+   * Returns a Table that reuses the connection and configuration of this
+   * Table, but with a different resource name.
+   */
+  Table WithNewTarget(std::string project_id, std::string instance_id,
+                      std::string app_profile_id, std::string table_id) const {
+    auto table = *this;
+    table.instance_id_ = std::move(instance_id);
+    table.project_id_ = std::move(project_id);
+    table.table_id_ = std::move(table_id);
+    table.app_profile_id_ = std::move(app_profile_id);
+    table.table_name_ =
+        TableName(table.project_id_, table.instance_id_, table.table_id_);
+    table.metadata_update_policy_ =
+        MetadataUpdatePolicy(table.table_name_, MetadataParamTypes::TABLE_NAME);
+    return table;
+  }
+
   /**
    * Attempts to apply the mutation to a row.
    *
@@ -936,6 +969,8 @@ class Table {
   friend class MutationBatcher;
   std::shared_ptr<DataClient> client_;
   std::string app_profile_id_;
+  std::string project_id_;
+  std::string instance_id_;
   std::string table_name_;
   std::string table_id_;
   std::shared_ptr<RPCRetryPolicy const> rpc_retry_policy_prototype_;

google/cloud/bigtable/table_test.cc

@@ -54,6 +54,51 @@ TEST_F(TableTest, StandaloneTableName) {
 
 TEST_F(TableTest, TableName) { EXPECT_EQ(kTableName, table_.table_name()); }
 
+TEST_F(TableTest, WithNewTarget) {
+  Table table(client_, "original-profile", kTableId);
+  EXPECT_EQ(table.project_id(), kProjectId);
+  EXPECT_EQ(table.instance_id(), kInstanceId);
+  EXPECT_EQ(table.table_id(), kTableId);
+  EXPECT_EQ(table.table_name(), TableName(kProjectId, kInstanceId, kTableId));
+  EXPECT_EQ(table.app_profile_id(), "original-profile");
+
+  std::string const other_project_id = "other-project";
+  std::string const other_instance_id = "other-instance";
+  std::string const other_table_id = "other-table";
+  auto other_table =
+      table.WithNewTarget(other_project_id, other_instance_id, other_table_id);
+
+  EXPECT_EQ(other_table.project_id(), other_project_id);
+  EXPECT_EQ(other_table.instance_id(), other_instance_id);
+  EXPECT_EQ(other_table.table_id(), other_table_id);
+  EXPECT_EQ(other_table.table_name(),
+            TableName(other_project_id, other_instance_id, other_table_id));
+  EXPECT_EQ(other_table.app_profile_id(), "original-profile");
+}
+
+TEST_F(TableTest, WithNewTargetProfile) {
+  Table table(client_, "original-profile", kTableId);
+  EXPECT_EQ(table.project_id(), kProjectId);
+  EXPECT_EQ(table.instance_id(), kInstanceId);
+  EXPECT_EQ(table.table_id(), kTableId);
+  EXPECT_EQ(table.table_name(), TableName(kProjectId, kInstanceId, kTableId));
+  EXPECT_EQ(table.app_profile_id(), "original-profile");
+
+  std::string const other_project_id = "other-project";
+  std::string const other_instance_id = "other-instance";
+  std::string const other_table_id = "other-table";
+  std::string const other_profile_id = "other-profile";
+  auto other_table = table.WithNewTarget(other_project_id, other_instance_id,
+                                         other_profile_id, other_table_id);
+
+  EXPECT_EQ(other_table.project_id(), other_project_id);
+  EXPECT_EQ(other_table.instance_id(), other_instance_id);
+  EXPECT_EQ(other_table.table_id(), other_table_id);
+  EXPECT_EQ(other_table.table_name(),
+            TableName(other_project_id, other_instance_id, other_table_id));
+  EXPECT_EQ(other_table.app_profile_id(), other_profile_id);
+}
+
 TEST_F(TableTest, TableConstructor) {
   std::string const other_table_id = "my-table";
   std::string const other_table_name = TableName(client_, other_table_id);