Use version-hint.text for StaticTable (apache#1887)

This change allow making use of the `version-hint.text` file when a
static table is instantiated with a `metadata_location` not ending with
'.metadata.json'.
User can just point to the table location, and metadata file path will
be read from `version-hint.text`.


Closes apache#763

# Rationale for this change

`version-hint.text` is useful in context where you does not want or need
a full-fledge catalog.
Our use case is sharing datasets publicly as Iceberg tables on S3.

# Are these changes tested?

No yet.

# Are there any user-facing changes?

Yes. User can now points `StaticTable` to the table location rather than
a specific version file.

Author: arnaudbriche

mkdocs/docs/api.md

@@ -215,6 +215,17 @@ static_table = StaticTable.from_metadata(
 
 The static-table is considered read-only.
 
+Alternatively, if your table metadata directory contains a `version-hint.text` file, you can just specify
+the table root path, and the latest metadata file will be picked automatically.
+
+```python
+from pyiceberg.table import StaticTable
+
+static_table = StaticTable.from_metadata(
+    "s3://warehouse/wh/nyc.db/taxis
+)
+```
+
 ## Check if a table exists
 
 To check whether the `bids` table exists:

pyiceberg/table/__init__.py

@@ -17,6 +17,7 @@
 from __future__ import annotations
 
 import itertools
+import os
 import uuid
 import warnings
 from abc import ABC, abstractmethod
@@ -1378,8 +1379,27 @@ def refresh(self) -> Table:
         """Refresh the current table metadata."""
         raise NotImplementedError("To be implemented")
 
+    @classmethod
+    def _metadata_location_from_version_hint(cls, metadata_location: str, properties: Properties = EMPTY_DICT) -> str:
+        version_hint_location = os.path.join(metadata_location, "metadata", "version-hint.text")
+        io = load_file_io(properties=properties, location=version_hint_location)
+        file = io.new_input(version_hint_location)
+
+        with file.open() as stream:
+            content = stream.read().decode("utf-8")
+
+        if content.endswith(".metadata.json"):
+            return os.path.join(metadata_location, "metadata", content)
+        elif content.isnumeric():
+            return os.path.join(metadata_location, "metadata", "v%s.metadata.json").format(content)
+        else:
+            return os.path.join(metadata_location, "metadata", "%s.metadata.json").format(content)
+
     @classmethod
     def from_metadata(cls, metadata_location: str, properties: Properties = EMPTY_DICT) -> StaticTable:
+        if not metadata_location.endswith(".metadata.json"):
+            metadata_location = StaticTable._metadata_location_from_version_hint(metadata_location, properties)
+
         io = load_file_io(properties=properties, location=metadata_location)
         file = io.new_input(metadata_location)
 

tests/conftest.py

@@ -1121,6 +1121,22 @@ def example_table_metadata_v3() -> Dict[str, Any]:
     return EXAMPLE_TABLE_METADATA_V3
 
 
+@pytest.fixture(scope="session")
+def table_location(tmp_path_factory: pytest.TempPathFactory) -> str:
+    from pyiceberg.io.pyarrow import PyArrowFileIO
+
+    metadata_filename = f"{uuid.uuid4()}.metadata.json"
+    metadata_location = str(tmp_path_factory.getbasetemp() / "metadata" / metadata_filename)
+    version_hint_location = str(tmp_path_factory.getbasetemp() / "metadata" / "version-hint.text")
+    metadata = TableMetadataV2(**EXAMPLE_TABLE_METADATA_V2)
+    ToOutputFile.table_metadata(metadata, PyArrowFileIO().new_output(location=metadata_location), overwrite=True)
+
+    with PyArrowFileIO().new_output(location=version_hint_location).create(overwrite=True) as s:
+        s.write(metadata_filename.encode("utf-8"))
+
+    return str(tmp_path_factory.getbasetemp())
+
+
 @pytest.fixture(scope="session")
 def metadata_location(tmp_path_factory: pytest.TempPathFactory) -> str:
     from pyiceberg.io.pyarrow import PyArrowFileIO

tests/table/test_init.py

@@ -383,6 +383,12 @@ def test_static_table_gz_same_as_table(table_v2: Table, metadata_location_gz: st
     assert static_table.metadata == table_v2.metadata
 
 
+def test_static_table_version_hint_same_as_table(table_v2: Table, table_location: str) -> None:
+    static_table = StaticTable.from_metadata(table_location)
+    assert isinstance(static_table, Table)
+    assert static_table.metadata == table_v2.metadata
+
+
 def test_static_table_io_does_not_exist(metadata_location: str) -> None:
     with pytest.raises(ValueError):
         StaticTable.from_metadata(metadata_location, {PY_IO_IMPL: "pyiceberg.does.not.exist.FileIO"})