feat: Added describe-parquet command to print info of parquet files

ice/src/main/java/com/altinity/ice/cli/Main.java

@@ -18,6 +18,7 @@
 import com.altinity.ice.cli.internal.cmd.DeleteNamespace;
 import com.altinity.ice.cli.internal.cmd.DeleteTable;
 import com.altinity.ice.cli.internal.cmd.Describe;
+import com.altinity.ice.cli.internal.cmd.DescribeParquet;
 import com.altinity.ice.cli.internal.cmd.Insert;
 import com.altinity.ice.cli.internal.cmd.InsertWatch;
 import com.altinity.ice.cli.internal.cmd.Scan;
@@ -142,6 +143,68 @@ void describe(
     }
   }
 
+  @CommandLine.Command(name = "describe-parquet", description = "Describe parquet file metadata.")
+  void describeParquet(
+      @CommandLine.Parameters(
+              arity = "1",
+              paramLabel = "<target>",
+              description = "Path to parquet file")
+          String target,
+      @CommandLine.Option(
+              names = {"-a", "--all"},
+              description = "Show everything")
+          boolean showAll,
+      @CommandLine.Option(
+              names = {"-s", "--summary"},
+              description = "Show size, rows, number of row groups, size, compress_size, etc.")
+          boolean showSummary,
+      @CommandLine.Option(
+              names = {"--columns"},
+              description = "Show columns")
+          boolean showColumns,
+      @CommandLine.Option(
+              names = {"-r", "--row-groups"},
+              description = "Show row groups")
+          boolean showRowGroups,
+      @CommandLine.Option(
+              names = {"-d", "--row-group-details"},
+              description = "Show column stats within row group")
+          boolean showRowGroupDetails,
+      @CommandLine.Option(
+              names = {"--json"},
+              description = "Output JSON instead of YAML")
+          boolean json,
+      @CommandLine.Option(names = {"--s3-region"}) String s3Region,
+      @CommandLine.Option(
+              names = {"--s3-no-sign-request"},
+              description = "Access S3 files without authentication")
+          boolean s3NoSignRequest)
+      throws IOException {
+    setAWSRegion(s3Region);
+    try (RESTCatalog catalog = loadCatalog()) {
+      var options = new ArrayList<DescribeParquet.Option>();
+      if (showAll || showSummary) {
+        options.add(DescribeParquet.Option.SUMMARY);
+      }
+      if (showAll || showColumns) {
+        options.add(DescribeParquet.Option.COLUMNS);
+      }
+      if (showAll || showRowGroups) {
+        options.add(DescribeParquet.Option.ROW_GROUPS);
+      }
+      if (showAll || showRowGroupDetails) {
+        options.add(DescribeParquet.Option.ROW_GROUP_DETAILS);
+      }
+
+      if (options.isEmpty()) {
+        options.add(DescribeParquet.Option.SUMMARY);
+      }
+
+      DescribeParquet.run(
+          catalog, target, json, s3NoSignRequest, options.toArray(new DescribeParquet.Option[0]));
+    }
+  }
+
   public record IceSortOrder(
       @JsonProperty("column") String column,
       @JsonProperty("desc") boolean desc,

ice/src/main/java/com/altinity/ice/cli/internal/cmd/DescribeParquet.java

@@ -0,0 +1,229 @@
+/*
+ * Copyright (c) 2025 Altinity Inc and/or its affiliates. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ */
+package com.altinity.ice.cli.internal.cmd;
+
+import com.altinity.ice.cli.internal.iceberg.io.Input;
+import com.altinity.ice.cli.internal.iceberg.parquet.Metadata;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.dataformat.yaml.YAMLFactory;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
+import org.apache.iceberg.io.FileIO;
+import org.apache.iceberg.io.InputFile;
+import org.apache.iceberg.rest.RESTCatalog;
+import org.apache.parquet.column.statistics.Statistics;
+import org.apache.parquet.hadoop.metadata.BlockMetaData;
+import org.apache.parquet.hadoop.metadata.ColumnChunkMetaData;
+import org.apache.parquet.hadoop.metadata.FileMetaData;
+import org.apache.parquet.hadoop.metadata.ParquetMetadata;
+import org.apache.parquet.schema.MessageType;
+import org.apache.parquet.schema.Type;
+import software.amazon.awssdk.services.s3.S3Client;
+import software.amazon.awssdk.services.s3.internal.crossregion.S3CrossRegionSyncClient;
+import software.amazon.awssdk.utils.Lazy;
+
+public final class DescribeParquet {
+
+  private DescribeParquet() {}
+
+  public enum Option {
+    ALL,
+    SUMMARY,
+    COLUMNS,
+    ROW_GROUPS,
+    ROW_GROUP_DETAILS
+  }
+
+  public static void run(
+      RESTCatalog catalog,
+      String filePath,
+      boolean json,
+      boolean s3NoSignRequest,
+      Option... options)
+      throws IOException {
+
+    Lazy<S3Client> s3ClientLazy =
+        new Lazy<>(
+            () ->
+                new S3CrossRegionSyncClient(
+                    com.altinity.ice.cli.internal.s3.S3.newClient(s3NoSignRequest)));
+    FileIO io = Input.newIO(filePath, null, s3ClientLazy);
+    InputFile inputFile = Input.newFile(filePath, catalog, io);
+    run(inputFile, json, options);
+  }
+
+  public static void run(InputFile inputFile, boolean json, Option... options) throws IOException {
+    ParquetMetadata metadata = Metadata.read(inputFile);
+
+    ParquetInfo info = extractParquetInfo(metadata, options);
+
+    ObjectMapper mapper = json ? new ObjectMapper() : new ObjectMapper(new YAMLFactory());
+    mapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
+    String output = mapper.writeValueAsString(info);
+    System.out.println(output);
+  }
+
+  private static ParquetInfo extractParquetInfo(ParquetMetadata metadata, Option... options) {
+    var optionsSet = Set.of(options);
+    boolean includeAll = optionsSet.contains(Option.ALL);
+
+    FileMetaData fileMetadata = metadata.getFileMetaData();
+
+    // Summary info
+    Summary summary = null;
+    if (includeAll || optionsSet.contains(Option.SUMMARY)) {
+      long totalRows = metadata.getBlocks().stream().mapToLong(BlockMetaData::getRowCount).sum();
+
+      long compressedSize =
+          metadata.getBlocks().stream().mapToLong(BlockMetaData::getCompressedSize).sum();
+
+      long uncompressedSize =
+          metadata.getBlocks().stream().mapToLong(BlockMetaData::getTotalByteSize).sum();
+
+      summary =
+          new Summary(
+              totalRows,
+              metadata.getBlocks().size(),
+              compressedSize,
+              uncompressedSize,
+              fileMetadata.getCreatedBy(),
+              fileMetadata.getSchema().getFieldCount());
+    }
+
+    // Column info
+    List<Column> columns = null;
+    if (includeAll || optionsSet.contains(Option.COLUMNS)) {
+      columns = extractColumns(fileMetadata.getSchema());
+    }
+
+    // Row group info
+    List<RowGroup> rowGroups = null;
+    if (includeAll
+        || optionsSet.contains(Option.ROW_GROUPS)
+        || optionsSet.contains(Option.ROW_GROUP_DETAILS)) {
+      boolean includeDetails = includeAll || optionsSet.contains(Option.ROW_GROUP_DETAILS);
+      rowGroups = extractRowGroups(metadata.getBlocks(), includeDetails);
+    }
+
+    return new ParquetInfo(summary, columns, rowGroups);
+  }
+
+  private static List<Column> extractColumns(MessageType schema) {
+    List<Column> columns = new ArrayList<>();
+    for (Type field : schema.getFields()) {
+      String logicalType = null;
+      if (field.isPrimitive()) {
+        var annotation = field.asPrimitiveType().getLogicalTypeAnnotation();
+        logicalType = annotation != null ? annotation.toString() : null;
+      }
+      columns.add(
+          new Column(
+              field.getName(),
+              field.isPrimitive() ? field.asPrimitiveType().getPrimitiveTypeName().name() : "GROUP",
+              field.getRepetition().name(),
+              logicalType));
+    }
+    return columns;
+  }
+
+  private static List<RowGroup> extractRowGroups(
+      List<BlockMetaData> blocks, boolean includeDetails) {
+    List<RowGroup> rowGroups = new ArrayList<>();
+
+    for (int i = 0; i < blocks.size(); i++) {
+      BlockMetaData block = blocks.get(i);
+
+      List<ColumnChunk> columnChunks = null;
+      if (includeDetails) {
+        columnChunks = new ArrayList<>();
+        for (ColumnChunkMetaData column : block.getColumns()) {
+          Statistics<?> stats = column.getStatistics();
+
+          ColumnStats columnStats = null;
+          if (stats != null && !stats.isEmpty()) {
+            long nulls = stats.isNumNullsSet() ? stats.getNumNulls() : 0;
+            String min = null;
+            String max = null;
+            if (stats.hasNonNullValue()) {
+              Object minVal = stats.genericGetMin();
+              Object maxVal = stats.genericGetMax();
+              min = minVal != null ? minVal.toString() : null;
+              max = maxVal != null ? maxVal.toString() : null;
+            }
+            columnStats = new ColumnStats(nulls, min, max);
+          }
+
+          columnChunks.add(
+              new ColumnChunk(
+                  column.getPath().toDotString(),
+                  column.getPrimitiveType().getName(),
+                  column.getEncodings().toString(),
+                  column.getCodec().name(),
+                  column.getTotalSize(),
+                  column.getTotalUncompressedSize(),
+                  column.getValueCount(),
+                  columnStats));
+        }
+      }
+
+      rowGroups.add(
+          new RowGroup(
+              i,
+              block.getRowCount(),
+              block.getTotalByteSize(),
+              block.getCompressedSize(),
+              block.getStartingPos(),
+              columnChunks));
+    }
+
+    return rowGroups;
+  }
+
+  @JsonInclude(JsonInclude.Include.NON_NULL)
+  public record ParquetInfo(Summary summary, List<Column> columns, List<RowGroup> rowGroups) {}
+
+  @JsonInclude(JsonInclude.Include.NON_NULL)
+  public record Summary(
+      long rows,
+      int rowGroups,
+      long compressedSize,
+      long uncompressedSize,
+      String createdBy,
+      int columnCount) {}
+
+  @JsonInclude(JsonInclude.Include.NON_NULL)
+  public record Column(String name, String type, String repetition, String logicalType) {}
+
+  @JsonInclude(JsonInclude.Include.NON_NULL)
+  public record RowGroup(
+      int index,
+      long rowCount,
+      long totalSize,
+      long compressedSize,
+      long startingPos,
+      List<ColumnChunk> columns) {}
+
+  @JsonInclude(JsonInclude.Include.NON_NULL)
+  public record ColumnChunk(
+      String path,
+      String type,
+      String encodings,
+      String codec,
+      long totalSize,
+      long uncompressedSize,
+      long valueCount,
+      ColumnStats stats) {}
+
+  @JsonInclude(JsonInclude.Include.NON_NULL)
+  public record ColumnStats(long nulls, String min, String max) {}
+}

ice/src/test/java/com/altinity/ice/cli/internal/cmd/DescribeParquetTest.java

@@ -0,0 +1,88 @@
+/*
+ * Copyright (c) 2025 Altinity Inc and/or its affiliates. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ */
+package com.altinity.ice.cli.internal.cmd;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import com.altinity.ice.test.Resource;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.PrintStream;
+import org.testng.annotations.Test;
+
+public class DescribeParquetTest {
+
+  @Test
+  public void testDescribeParquetSummary() throws IOException {
+    ByteArrayOutputStream outContent = new ByteArrayOutputStream();
+    PrintStream originalOut = System.out;
+    System.setOut(new PrintStream(outContent));
+
+    try {
+      var sampleFile =
+          Resource.asInputFile("com/altinity/ice/cli/internal/iceberg/parquet/sample-001.parquet");
+
+      DescribeParquet.run(sampleFile, false, DescribeParquet.Option.SUMMARY);
+
+      String output = outContent.toString();
+
+      assertThat(output).contains("rows:");
+      assertThat(output).contains("rowGroups:");
+      assertThat(output).contains("compressedSize:");
+      assertThat(output).contains("uncompressedSize:");
+    } finally {
+      System.setOut(originalOut);
+    }
+  }
+
+  @Test
+  public void testDescribeParquetColumns() throws IOException {
+    ByteArrayOutputStream outContent = new ByteArrayOutputStream();
+    PrintStream originalOut = System.out;
+    System.setOut(new PrintStream(outContent));
+
+    try {
+      var sampleFile =
+          Resource.asInputFile("com/altinity/ice/cli/internal/iceberg/parquet/sample-001.parquet");
+
+      DescribeParquet.run(sampleFile, false, DescribeParquet.Option.COLUMNS);
+
+      String output = outContent.toString();
+
+      assertThat(output).contains("columns:");
+      assertThat(output).contains("name:");
+      assertThat(output).contains("type:");
+    } finally {
+      System.setOut(originalOut);
+    }
+  }
+
+  @Test
+  public void testDescribeParquetJson() throws IOException {
+    ByteArrayOutputStream outContent = new ByteArrayOutputStream();
+    PrintStream originalOut = System.out;
+    System.setOut(new PrintStream(outContent));
+
+    try {
+      var sampleFile =
+          Resource.asInputFile("com/altinity/ice/cli/internal/iceberg/parquet/sample-001.parquet");
+
+      DescribeParquet.run(sampleFile, true, DescribeParquet.Option.SUMMARY);
+
+      String output = outContent.toString();
+
+      assertThat(output).contains("{");
+      assertThat(output).contains("}");
+      assertThat(output).contains("\"summary\"");
+    } finally {
+      System.setOut(originalOut);
+    }
+  }
+}