Extract file-finding for partition info reading.

src/hipscat/catalog/association_catalog/association_catalog.py

@@ -62,16 +62,9 @@ def _read_args(
         cls, catalog_base_dir: FilePointer, storage_options: Union[Dict[Any, Any], None] = None
     ) -> Tuple[CatalogInfoClass, PixelInputTypes, JoinPixelInputTypes]:  # type: ignore[override]
         args = super()._read_args(catalog_base_dir, storage_options=storage_options)
-        metadata_file = paths.get_parquet_metadata_pointer(catalog_base_dir)
-        if file_io.does_file_or_directory_exist(metadata_file, storage_options=storage_options):
-            partition_join_info = PartitionJoinInfo.read_from_file(
-                metadata_file, storage_options=storage_options
-            )
-        else:
-            partition_join_info_file = paths.get_partition_join_info_pointer(catalog_base_dir)
-            partition_join_info = PartitionJoinInfo.read_from_csv(
-                partition_join_info_file, storage_options=storage_options
-            )
+        partition_join_info = PartitionJoinInfo.read_from_dir(
+            catalog_base_dir, storage_options=storage_options
+        )
         return args + (partition_join_info,)
 
     @classmethod

src/hipscat/catalog/association_catalog/partition_join_info.py

@@ -7,7 +7,8 @@
 import pyarrow as pa
 from typing_extensions import Self
 
-from hipscat.io import FilePointer, file_io
+from hipscat.catalog.partition_info import PartitionInfo
+from hipscat.io import FilePointer, file_io, paths
 from hipscat.io.parquet_metadata import (
     read_row_group_fragments,
     row_group_stat_single_value,
@@ -91,6 +92,67 @@ def write_to_metadata_files(self, catalog_path: FilePointer, storage_options: di
 
         write_parquet_metadata_for_batches(batches, catalog_path, storage_options)
 
+    def write_to_csv(self, catalog_path: FilePointer, storage_options: dict = None):
+        """Write all partition data to CSV files.
+
+        Two files will be written::
+        - partition_info.csv - covers all primary catalog pixels, and should match the file structure
+        - partition_join_info.csv - covers all pairwise relationships between primary and
+          join catalogs.
+
+        Args:
+            catalog_path: FilePointer to the directory where the
+                `partition_join_info.csv` file will be written
+            storage_options (dict): dictionary that contains abstract filesystem credentials
+        """
+        partition_join_info_file = paths.get_partition_join_info_pointer(catalog_path)
+        file_io.write_dataframe_to_csv(
+            self.data_frame, partition_join_info_file, index=False, storage_options=storage_options
+        )
+
+        primary_pixels = self.primary_to_join_map().keys()
+        partition_info_pointer = paths.get_partition_info_pointer(catalog_path)
+        partition_info = PartitionInfo.from_healpix(primary_pixels)
+        file_io.write_dataframe_to_csv(
+            partition_info.as_dataframe(),
+            partition_info_pointer,
+            index=False,
+            storage_options=storage_options,
+        )
+
+    @classmethod
+    def read_from_dir(cls, catalog_base_dir: FilePointer, storage_options: dict = None) -> Self:
+        """Read partition join info from a file within a hipscat directory.
+
+        This will look for a `_metadata` file, and if not found, will look for
+        a `partition_join_info.csv` file.
+
+        Args:
+            catalog_base_dir: path to the root directory of the catalog
+            storage_options (dict): dictionary that contains abstract filesystem credentials
+
+        Returns:
+            A `PartitionInfo` object with the data from the file
+
+        Raises:
+            FileNotFoundError: if neither desired file is found in the catalog_base_dir
+        """
+        metadata_file = paths.get_parquet_metadata_pointer(catalog_base_dir)
+        partition_join_info_file = paths.get_partition_join_info_pointer(catalog_base_dir)
+        if file_io.does_file_or_directory_exist(metadata_file, storage_options=storage_options):
+            partition_join_info = PartitionJoinInfo.read_from_file(
+                metadata_file, storage_options=storage_options
+            )
+        elif file_io.does_file_or_directory_exist(partition_join_info_file, storage_options=storage_options):
+            partition_join_info = PartitionJoinInfo.read_from_csv(
+                partition_join_info_file, storage_options=storage_options
+            )
+        else:
+            raise FileNotFoundError(
+                f"_metadata or partition join info file is required in catalog directory {catalog_base_dir}"
+            )
+        return partition_join_info
+
     @classmethod
     def read_from_file(
         cls, metadata_file: FilePointer, strict=False, storage_options: Union[Dict[Any, Any], None] = None

src/hipscat/catalog/healpix_dataset/healpix_dataset.py

@@ -84,12 +84,7 @@ def _read_args(
         storage_options: Union[Dict[Any, Any], None] = None,
     ) -> Tuple[CatalogInfoClass, PartitionInfo]:
         args = super()._read_args(catalog_base_dir, storage_options=storage_options)
-        metadata_file = paths.get_parquet_metadata_pointer(catalog_base_dir)
-        if file_io.does_file_or_directory_exist(metadata_file, storage_options=storage_options):
-            partition_info = PartitionInfo.read_from_file(metadata_file, storage_options=storage_options)
-        else:
-            partition_info_file = paths.get_partition_info_pointer(catalog_base_dir)
-            partition_info = PartitionInfo.read_from_csv(partition_info_file, storage_options=storage_options)
+        partition_info = PartitionInfo.read_from_dir(catalog_base_dir, storage_options=storage_options)
         return args + (partition_info,)
 
     @classmethod

src/hipscat/catalog/partition_info.py

@@ -7,7 +7,7 @@
 import pandas as pd
 import pyarrow as pa
 
-from hipscat.io import FilePointer, file_io
+from hipscat.io import FilePointer, file_io, paths
 from hipscat.io.parquet_metadata import (
     read_row_group_fragments,
     row_group_stat_single_value,
@@ -75,6 +75,35 @@ def write_to_metadata_files(self, catalog_path: FilePointer, storage_options: di
 
         write_parquet_metadata_for_batches(batches, catalog_path, storage_options)
 
+    @classmethod
+    def read_from_dir(cls, catalog_base_dir: FilePointer, storage_options: dict = None) -> PartitionInfo:
+        """Read partition info from a file within a hipscat directory.
+
+        This will look for a `_metadata` file, and if not found, will look for
+        a `partition_info.csv` file.
+
+        Args:
+            catalog_base_dir: path to the root directory of the catalog
+            storage_options (dict): dictionary that contains abstract filesystem credentials
+
+        Returns:
+            A `PartitionInfo` object with the data from the file
+
+        Raises:
+            FileNotFoundError: if neither desired file is found in the catalog_base_dir
+        """
+        metadata_file = paths.get_parquet_metadata_pointer(catalog_base_dir)
+        partition_info_file = paths.get_partition_info_pointer(catalog_base_dir)
+        if file_io.does_file_or_directory_exist(metadata_file, storage_options=storage_options):
+            partition_info = PartitionInfo.read_from_file(metadata_file, storage_options=storage_options)
+        elif file_io.does_file_or_directory_exist(partition_info_file, storage_options=storage_options):
+            partition_info = PartitionInfo.read_from_csv(partition_info_file, storage_options=storage_options)
+        else:
+            raise FileNotFoundError(
+                f"_metadata or partition info file is required in catalog directory {catalog_base_dir}"
+            )
+        return partition_info
+
     @classmethod
     def read_from_file(
         cls, metadata_file: FilePointer, strict=False, storage_options: dict = None

tests/hipscat/catalog/association_catalog/test_association_catalog.py

@@ -89,8 +89,35 @@ def test_empty_directory(tmp_path, association_catalog_info_data, association_ca
 
     ## Now we create the needed _metadata and everything is right.
     part_info = PartitionJoinInfo(association_catalog_join_pixels)
-    part_info.write_to_metadata_files(
-        catalog_path=catalog_path,
-    )
+    part_info.write_to_metadata_files(catalog_path=catalog_path)
     catalog = AssociationCatalog.read_from_hipscat(catalog_path)
     assert catalog.catalog_name == association_catalog_info_data["catalog_name"]
+
+
+def test_csv_round_trip(tmp_path, association_catalog_info_data, association_catalog_join_pixels):
+    ## Path doesn't exist
+    with pytest.raises(FileNotFoundError):
+        AssociationCatalog.read_from_hipscat(os.path.join("path", "empty"))
+
+    catalog_path = os.path.join(tmp_path, "empty")
+    os.makedirs(catalog_path, exist_ok=True)
+
+    file_name = os.path.join(catalog_path, "catalog_info.json")
+    with open(file_name, "w", encoding="utf-8") as metadata_file:
+        metadata_file.write(json.dumps(association_catalog_info_data))
+
+    with pytest.raises(FileNotFoundError, match="partition"):
+        AssociationCatalog.read_from_hipscat(catalog_path)
+
+    file_name = os.path.join(catalog_path, "partition_info.csv")
+    with open(file_name, "w", encoding="utf-8") as metadata_file:
+        # dump some garbage in there - just needs to exist.
+        metadata_file.write(json.dumps(association_catalog_info_data))
+    with pytest.raises(FileNotFoundError, match="partition"):
+        AssociationCatalog.read_from_hipscat(catalog_path)
+
+    part_info = PartitionJoinInfo(association_catalog_join_pixels)
+    part_info.write_to_csv(catalog_path=catalog_path)
+
+    catalog = AssociationCatalog.read_from_hipscat(catalog_path)
+    pd.testing.assert_frame_equal(catalog.get_join_pixels(), association_catalog_join_pixels)

tests/hipscat/catalog/association_catalog/test_partition_join_info.py

@@ -55,6 +55,20 @@ def test_read_from_metadata_fail(tmp_path):
         PartitionJoinInfo.read_from_file(metadata_filename, strict=True)
 
 
+def test_load_partition_info_from_dir_fail(tmp_path):
+    empty_dataframe = pd.DataFrame()
+    metadata_filename = os.path.join(tmp_path, "empty_metadata.parquet")
+    empty_dataframe.to_parquet(metadata_filename)
+    with pytest.raises(FileNotFoundError, match="_metadata or partition join info"):
+        PartitionJoinInfo.read_from_dir(tmp_path)
+
+    # The file is there, but doesn't have the required content.
+    metadata_filename = os.path.join(tmp_path, "_metadata")
+    empty_dataframe.to_parquet(metadata_filename)
+    with pytest.raises(ValueError, match="missing columns"):
+        PartitionJoinInfo.read_from_dir(tmp_path)
+
+
 def test_primary_to_join_map(association_catalog_join_pixels):
     info = PartitionJoinInfo(association_catalog_join_pixels)
     pd.testing.assert_frame_equal(info.data_frame, association_catalog_join_pixels)
@@ -81,6 +95,16 @@ def test_metadata_file_round_trip(association_catalog_join_pixels, tmp_path):
     pd.testing.assert_frame_equal(new_info.data_frame, association_catalog_join_pixels)
 
 
+def test_csv_file_round_trip(association_catalog_join_pixels, tmp_path):
+    info = PartitionJoinInfo(association_catalog_join_pixels)
+    pd.testing.assert_frame_equal(info.data_frame, association_catalog_join_pixels)
+    info.write_to_csv(tmp_path)
+
+    file_pointer = file_io.get_file_pointer_from_path(os.path.join(tmp_path, "partition_join_info.csv"))
+    new_info = PartitionJoinInfo.read_from_csv(file_pointer)
+    pd.testing.assert_frame_equal(new_info.data_frame, association_catalog_join_pixels)
+
+
 def test_read_from_csv(association_catalog_partition_join_file, association_catalog_join_pixels):
     file_pointer = file_io.get_file_pointer_from_path(association_catalog_partition_join_file)
     info = PartitionJoinInfo.read_from_csv(file_pointer)

tests/hipscat/catalog/test_partition_info.py

@@ -55,6 +55,20 @@ def test_load_partition_info_from_metadata_fail(tmp_path):
         PartitionInfo.read_from_file(metadata_filename, strict=True)
 
 
+def test_load_partition_info_from_dir_fail(tmp_path):
+    empty_dataframe = pd.DataFrame()
+    metadata_filename = os.path.join(tmp_path, "empty_metadata.parquet")
+    empty_dataframe.to_parquet(metadata_filename)
+    with pytest.raises(FileNotFoundError, match="_metadata or partition info"):
+        PartitionInfo.read_from_dir(tmp_path)
+
+    # The file is there, but doesn't have the required content.
+    metadata_filename = os.path.join(tmp_path, "_metadata")
+    empty_dataframe.to_parquet(metadata_filename)
+    with pytest.raises(ValueError, match="missing Norder"):
+        PartitionInfo.read_from_dir(tmp_path)
+
+
 def test_load_partition_info_small_sky_order1(small_sky_order1_dir):
     """Instantiate the partition info for catalog with 4 pixels"""
     partition_info_file = paths.get_parquet_metadata_pointer(small_sky_order1_dir)