[refactor](ingester-example): reorganize project structure and improve database connection configuration. (#86)

* refactor(ingester-example): reorganize project structure and improve database connection

- Rename packages to better reflect their purpose (e.g., quickstart, benchmark)
- Move database connection logic to a central DBConnector class
- Use properties file for database connection details
- Update logging and error handling
- Improve code readability and maintainability

* docs(ingester-example): update README and reorganize imports

- Update README with correct file paths for examples- Reorganize import statements in Java files for better readability

* docs(bench): remove redundant environment variables from benchmark classes

- Remove db_endpoint and db_name from BulkWriteBenchmark and StreamingWriteBenchmark
- Update class comments to reflect the removal of these environment variables

* docs(bench): remove unnecessary db endpoint and name comments

- Remove comments about db_endpoint and db_name as they are not relevant to the batching write benchmark- Keep existing information about batch_size_per_request, zstd_compression, and max_points_per_second

Author: zqr10159

README.md

@@ -225,7 +225,7 @@ Context ctx = Context.newDefault();
 // Add a hint to make the database create a table with the specified TTL (time-to-live)
 ctx = ctx.withHint("ttl", "3d");
 // Set the compression algorithm to Zstd.
-ctx = ctx.withCompression(Compression.Zstd)
+ctx = ctx.withCompression(Compression.Zstd);
 // Use the ctx when writing data to GreptimeDB
 CompletableFuture<Result<WriteOk, Err>> future = client.write(Arrays.asList(table1, table2), WriteOp.Insert, ctx);
 ```

ingester-example/README.md

@@ -34,15 +34,15 @@ These batching approaches can dramatically improve performance compared to makin
 
 #### Examples
 
-- [LowLevelApiWriteQuickStart.java](src/main/java/io/greptime/LowLevelApiWriteQuickStart.java)
+- [LowLevelApiWriteQuickStart.java](src/main/java/io/greptime/quickstart/write/LowLevelApiWriteQuickStart.java)
 
   This example demonstrates how to use the low-level API to write data to GreptimeDB. It covers:
   * Defining table schemas with tags, timestamps, and fields
   * Writing multiple rows of data to different tables
   * Processing write results using the Result pattern
   * Deleting data using the `WriteOp.Delete` operation
 
-- [HighLevelApiWriteQuickStart.java](src/main/java/io/greptime/HighLevelApiWriteQuickStart.java)
+- [HighLevelApiWriteQuickStart.java](src/main/java/io/greptime/quickstart/write/HighLevelApiWriteQuickStart.java)
 
   This example demonstrates how to use the high-level API to write data to GreptimeDB. It covers:
   * Writing data using POJO objects with annotations
@@ -61,15 +61,15 @@ This API is particularly well-suited for:
 
 #### Examples
 
-- [LowLevelApiStreamWriteQuickStart.java](src/main/java/io/greptime/LowLevelApiStreamWriteQuickStart.java)
+- [LowLevelApiStreamWriteQuickStart.java](src/main/java/io/greptime/quickstart/write/LowLevelApiStreamWriteQuickStart.java)
 
   This example demonstrates how to use the low-level API to write data to GreptimeDB using stream. It covers:
   * Defining table schemas with tags, timestamps, and fields
   * Writing multiple rows of data to different tables via streaming
   * Finalizing the stream and retrieving write results
   * Deleting data using the `WriteOp.Delete` operation
 
-- [HighLevelApiStreamWriteQuickStart.java](src/main/java/io/greptime/HighLevelApiStreamWriteQuickStart.java)
+- [HighLevelApiStreamWriteQuickStart.java](src/main/java/io/greptime/quickstart/write/HighLevelApiStreamWriteQuickStart.java)
 
   This example demonstrates how to use the high-level API to write data to GreptimeDB using stream. It covers:
   * Writing POJO objects directly to the stream
@@ -99,7 +99,7 @@ This API is ideal for scenarios such as:
 
 ### Examples
 
-- [BulkWriteApiQuickStart.java](src/main/java/io/greptime/BulkWriteApiQuickStart.java)
+- [BulkWriteApiQuickStart.java](src/main/java/io/greptime/quickstart/write/BulkWriteApiQuickStart.java)
 
   This example demonstrates how to use the bulk write API to write large volumes of data to a single table with maximum efficiency. It covers:
   * Configuring the bulk writer for optimal performance

ingester-example/src/main/java/io/greptime/bench/DBConnector.java

@@ -18,18 +18,36 @@
 
 import io.greptime.GreptimeDB;
 import io.greptime.options.GreptimeOptions;
+import io.greptime.quickstart.query.QueryJDBCQuickStart;
+import java.io.IOException;
+import java.util.Properties;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * DBConnector is a helper class to connect to a GreptimeDB instance.
  */
 public class DBConnector {
 
-    public static GreptimeDB connectTo(String[] endpoints, String dbname) {
-        GreptimeOptions opts = GreptimeOptions.newBuilder(endpoints, dbname)
+    private static final Logger LOG = LoggerFactory.getLogger(DBConnector.class);
+
+    public static GreptimeDB connect() {
+        Properties prop = new Properties();
+        try {
+            prop.load(QueryJDBCQuickStart.class.getResourceAsStream("/db-connection.properties"));
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+        String database = (String) prop.get("db.database");
+        String endpointsStr = prop.getProperty("db.endpoints");
+        String[] endpoints = endpointsStr.split(",");
+        GreptimeOptions opts = GreptimeOptions.newBuilder(endpoints, database)
                 .writeMaxRetries(0)
                 .defaultStreamMaxWritePointsPerSecond(Integer.MAX_VALUE)
                 .useZeroCopyWriteInBulkWrite(true)
                 .build();
+        LOG.info("Connect to db: {}, endpoint: {}", database, endpointsStr);
+
         return GreptimeDB.create(opts);
     }
 }

ingester-example/src/main/java/io/greptime/bench/BatchingWriteBenchmark.java renamed to ingester-example/src/main/java/io/greptime/bench/benchmark/BatchingWriteBenchmark.java

@@ -14,10 +14,12 @@
  * limitations under the License.
  */
 
-package io.greptime.bench;
+package io.greptime.bench.benchmark;
 
 import io.greptime.GreptimeDB;
 import io.greptime.WriteOp;
+import io.greptime.bench.DBConnector;
+import io.greptime.bench.TableDataProvider;
 import io.greptime.common.util.MetricsUtil;
 import io.greptime.common.util.ServiceLoader;
 import io.greptime.common.util.SystemPropertyUtil;
@@ -40,8 +42,6 @@
  * BatchingWriteBenchmark is a benchmark for the batching write API of GreptimeDB.
  *
  * Env:
- * - db_endpoint: the endpoint of the GreptimeDB server
- * - db_name: the name of the database
  * - batch_size_per_request: the batch size per request
  * - zstd_compression: whether to use zstd compression
  * - max_points_per_second: the max number of points that can be written per second, exceeding which may cause blockage
@@ -51,21 +51,18 @@ public class BatchingWriteBenchmark {
     private static final Logger LOG = LoggerFactory.getLogger(BatchingWriteBenchmark.class);
 
     public static void main(String[] args) throws Exception {
-        String endpoint = SystemPropertyUtil.get("db_endpoint", "127.0.0.1:4001");
-        String dbName = SystemPropertyUtil.get("db_name", "public");
         boolean zstdCompression = SystemPropertyUtil.getBool("zstd_compression", true);
         int batchSize = SystemPropertyUtil.getInt("batch_size_per_request", 64 * 1024);
         int maxPointsPerSecond = SystemPropertyUtil.getInt("max_points_per_second", Integer.MAX_VALUE);
-        LOG.info("Connect to db: {}, endpoint: {}", dbName, endpoint);
+
         LOG.info("Using zstd compression: {}", zstdCompression);
         LOG.info("Batch size: {}", batchSize);
         LOG.info("Max points per second: {}", maxPointsPerSecond);
 
         // Start a metrics exporter
         MetricsExporter metricsExporter = new MetricsExporter(MetricsUtil.metricRegistry());
         metricsExporter.init(ExporterOptions.newDefault());
-
-        GreptimeDB greptimeDB = DBConnector.connectTo(new String[] {endpoint}, dbName);
+        GreptimeDB greptimeDB = DBConnector.connect();
 
         Compression compression = zstdCompression ? Compression.Zstd : Compression.None;
         Context ctx = Context.newDefault().withCompression(compression);

ingester-example/src/main/java/io/greptime/bench/BulkWriteBenchmark.java renamed to ingester-example/src/main/java/io/greptime/bench/benchmark/BulkWriteBenchmark.java

@@ -14,11 +14,13 @@
  * limitations under the License.
  */
 
-package io.greptime.bench;
+package io.greptime.bench.benchmark;
 
 import io.greptime.BulkStreamWriter;
 import io.greptime.BulkWrite;
 import io.greptime.GreptimeDB;
+import io.greptime.bench.DBConnector;
+import io.greptime.bench.TableDataProvider;
 import io.greptime.common.util.MetricsUtil;
 import io.greptime.common.util.ServiceLoader;
 import io.greptime.common.util.SystemPropertyUtil;
@@ -37,8 +39,6 @@
  * BulkWriteBenchmark is a benchmark for the bulk write API of GreptimeDB.
  *
  * Env:
- * - db_endpoint: the endpoint of the GreptimeDB server
- * - db_name: the name of the database
  * - batch_size_per_request: the batch size per request
  * - zstd_compression: whether to use zstd compression
  */
@@ -47,19 +47,16 @@ public class BulkWriteBenchmark {
     private static final Logger LOG = LoggerFactory.getLogger(BulkWriteBenchmark.class);
 
     public static void main(String[] args) throws Exception {
-        String endpoint = SystemPropertyUtil.get("db_endpoint", "127.0.0.1:4001");
-        String dbName = SystemPropertyUtil.get("db_name", "public");
         boolean zstdCompression = SystemPropertyUtil.getBool("zstd_compression", true);
         int batchSize = SystemPropertyUtil.getInt("batch_size_per_request", 64 * 1024);
-        LOG.info("Connect to db: {}, endpoint: {}", dbName, endpoint);
         LOG.info("Using zstd compression: {}", zstdCompression);
         LOG.info("Batch size: {}", batchSize);
 
         // Start a metrics exporter
         MetricsExporter metricsExporter = new MetricsExporter(MetricsUtil.metricRegistry());
         metricsExporter.init(ExporterOptions.newDefault());
 
-        GreptimeDB greptimeDB = DBConnector.connectTo(new String[] {endpoint}, dbName);
+        GreptimeDB greptimeDB = DBConnector.connect();
 
         BulkWrite.Config cfg = BulkWrite.Config.newBuilder()
                 .allocatorInitReservation(0)

ingester-example/src/main/java/io/greptime/bench/StreamingWriteBenchmark.java renamed to ingester-example/src/main/java/io/greptime/bench/benchmark/StreamingWriteBenchmark.java

@@ -14,10 +14,12 @@
  * limitations under the License.
  */
 
-package io.greptime.bench;
+package io.greptime.bench.benchmark;
 
 import io.greptime.GreptimeDB;
 import io.greptime.StreamWriter;
+import io.greptime.bench.DBConnector;
+import io.greptime.bench.TableDataProvider;
 import io.greptime.common.util.MetricsUtil;
 import io.greptime.common.util.ServiceLoader;
 import io.greptime.common.util.SystemPropertyUtil;
@@ -37,8 +39,6 @@
  * StreamingWriteBenchmark is a benchmark for the streaming write API of GreptimeDB.
  *
  * Env:
- * - db_endpoint: the endpoint of the GreptimeDB server
- * - db_name: the name of the database
  * - batch_size_per_request: the batch size per request
  * - zstd_compression: whether to use zstd compression
  * - max_points_per_second: the max number of points that can be written per second, exceeding which may cause blockage
@@ -48,12 +48,9 @@ public class StreamingWriteBenchmark {
     private static final Logger LOG = LoggerFactory.getLogger(StreamingWriteBenchmark.class);
 
     public static void main(String[] args) throws Exception {
-        String endpoint = SystemPropertyUtil.get("db_endpoint", "127.0.0.1:4001");
-        String dbName = SystemPropertyUtil.get("db_name", "public");
         boolean zstdCompression = SystemPropertyUtil.getBool("zstd_compression", true);
         int batchSize = SystemPropertyUtil.getInt("batch_size_per_request", 64 * 1024);
         int maxPointsPerSecond = SystemPropertyUtil.getInt("max_points_per_second", Integer.MAX_VALUE);
-        LOG.info("Connect to db: {}, endpoint: {}", dbName, endpoint);
         LOG.info("Using zstd compression: {}", zstdCompression);
         LOG.info("Batch size: {}", batchSize);
         LOG.info("Max points per second: {}", maxPointsPerSecond);
@@ -62,7 +59,7 @@ public static void main(String[] args) throws Exception {
         MetricsExporter metricsExporter = new MetricsExporter(MetricsUtil.metricRegistry());
         metricsExporter.init(ExporterOptions.newDefault());
 
-        GreptimeDB greptimeDB = DBConnector.connectTo(new String[] {endpoint}, dbName);
+        GreptimeDB greptimeDB = DBConnector.connect();
 
         Compression compression = zstdCompression ? Compression.Zstd : Compression.None;
         Context ctx = Context.newDefault().withCompression(compression);

ingester-example/src/main/java/io/greptime/Cpu.java renamed to ingester-example/src/main/java/io/greptime/metric/Cpu.java

@@ -14,14 +14,14 @@
  * limitations under the License.
  */
 
-package io.greptime;
+package io.greptime.metric;
 
 import io.greptime.models.Column;
 import io.greptime.models.DataType;
 import io.greptime.models.Metric;
 
 /**
- *
+ * Memory metric class that represents CPU usage statistics.
  */
 @Metric(name = "cpu_metric")
 public class Cpu {

ingester-example/src/main/java/io/greptime/Memory.java renamed to ingester-example/src/main/java/io/greptime/metric/Memory.java

@@ -14,14 +14,14 @@
  * limitations under the License.
  */
 
-package io.greptime;
+package io.greptime.metric;
 
 import io.greptime.models.Column;
 import io.greptime.models.DataType;
 import io.greptime.models.Metric;
 
 /**
- *
+ * Memory metric class that represents memory usage statistics.
  */
 @Metric(name = "mem_metric")
 public class Memory {

ingester-example/src/main/java/io/greptime/TestConnector.java renamed to ingester-example/src/main/java/io/greptime/quickstart/TestConnector.java

@@ -14,13 +14,17 @@
  * limitations under the License.
  */
 
-package io.greptime;
+package io.greptime.quickstart;
 
+import io.greptime.GreptimeDB;
 import io.greptime.common.util.SerializingExecutor;
 import io.greptime.limit.LimitedPolicy;
 import io.greptime.models.AuthInfo;
 import io.greptime.options.GreptimeOptions;
+import io.greptime.quickstart.query.QueryJDBCQuickStart;
 import io.greptime.rpc.RpcOptions;
+import java.io.IOException;
+import java.util.Properties;
 
 /**
  *
@@ -30,11 +34,19 @@ public class TestConnector {
     public static GreptimeDB connectToDefaultDB() {
         // GreptimeDB has a default database named "public" in the default catalog "greptime",
         // we can use it as the test database
-        String database = "public";
+        Properties prop = new Properties();
+
+        try {
+            prop.load(QueryJDBCQuickStart.class.getResourceAsStream("/db-connection.properties"));
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+        String database = (String) prop.get("db.database");
         // By default, GreptimeDB listens on port 4001 using the gRPC protocol.
         // We can provide multiple endpoints that point to the same GreptimeDB cluster.
         // The client will make calls to these endpoints based on a load balancing strategy.
-        String[] endpoints = {"127.0.0.1:4001"};
+        String endpointsStr = prop.getProperty("db.endpoints");
+        String[] endpoints = endpointsStr.split(",");
         GreptimeOptions opts = GreptimeOptions.newBuilder(endpoints, database) // Optional, the default value is fine.
                 // Asynchronous thread pool, which is used to handle various asynchronous
                 // tasks in the SDK (You are using a purely asynchronous SDK). If you do not

ingester-example/src/main/java/io/greptime/QueryJDBC.java renamed to ingester-example/src/main/java/io/greptime/quickstart/query/QueryJDBCQuickStart.java

@@ -14,8 +14,11 @@
  * limitations under the License.
  */
 
-package io.greptime;
+package io.greptime.quickstart.query;
 
+import io.greptime.GreptimeDB;
+import io.greptime.metric.Cpu;
+import io.greptime.quickstart.TestConnector;
 import java.io.IOException;
 import java.sql.Connection;
 import java.sql.DriverManager;
@@ -33,9 +36,9 @@
 /**
  *
  */
-public class QueryJDBC {
+public class QueryJDBCQuickStart {
 
-    private static final Logger LOG = LoggerFactory.getLogger(QueryJDBC.class);
+    private static final Logger LOG = LoggerFactory.getLogger(QueryJDBCQuickStart.class);
 
     public static void main(String[] args) throws Exception {
         GreptimeDB greptimeDB = TestConnector.connectToDefaultDB();
@@ -82,7 +85,7 @@ public static void main(String[] args) throws Exception {
 
     public static Connection getConnection() throws IOException, ClassNotFoundException, SQLException {
         Properties prop = new Properties();
-        prop.load(QueryJDBC.class.getResourceAsStream("/db-connection.properties"));
+        prop.load(QueryJDBCQuickStart.class.getResourceAsStream("/db-connection.properties"));
 
         String dbName = (String) prop.get("db.database-driver");