ENH: Calculate hashes in memory if possible

src/fmu/dataio/_utils.py

@@ -7,6 +7,7 @@
 import json
 import os
 import uuid
+from io import BufferedIOBase, BytesIO
 from pathlib import Path
 from tempfile import NamedTemporaryFile
 from typing import Any, Final, Literal
@@ -85,20 +86,26 @@ def export_metadata_file(
 
 def export_file(
     obj: types.Inferrable,
-    filename: Path,
+    file: Path | BytesIO,
+    file_suffix: str | None = None,
     fmt: str = "",
-) -> str:
+) -> None:
     """
-    Export a valid object to file. If xtgeo is in the fmt string, xtgeo
-    xyz-column names will be preserved for xtgeo.Points and xtgeo.Polygons
+    Export a valid object to file or memory buffer. If xtgeo is in the fmt string,
+    xtgeo xyz-column names will be preserved for xtgeo.Points and xtgeo.Polygons
     """
 
-    # create output folder if not existing
-    filename.parent.mkdir(parents=True, exist_ok=True)
+    if isinstance(file, Path):
+        # create output folder if not existing
+        file.parent.mkdir(parents=True, exist_ok=True)
+        file_suffix = file.suffix
 
-    if filename.suffix == ".gri" and isinstance(obj, xtgeo.RegularSurface):
-        obj.to_file(filename, fformat="irap_binary")
-    elif filename.suffix == ".csv" and isinstance(obj, (xtgeo.Polygons, xtgeo.Points)):
+    elif not file_suffix:
+        raise ValueError("'suffix' must be provided when file is a BytesIO object")
+
+    if file_suffix == ".gri" and isinstance(obj, xtgeo.RegularSurface):
+        obj.to_file(file, fformat="irap_binary")
+    elif file_suffix == ".csv" and isinstance(obj, (xtgeo.Polygons, xtgeo.Points)):
         out = obj.copy()  # to not modify incoming instance!
         if "xtgeo" not in fmt:
             out.xname = "X"
@@ -109,72 +116,79 @@ def export_file(
                 out.get_dataframe(copy=False).rename(
                     columns={out.pname: "ID"}, inplace=True
                 )
-        out.get_dataframe(copy=False).to_csv(filename, index=False)
-    elif filename.suffix == ".pol" and isinstance(obj, (xtgeo.Polygons, xtgeo.Points)):
-        obj.to_file(filename)
-    elif filename.suffix == ".segy" and isinstance(obj, xtgeo.Cube):
-        obj.to_file(filename, fformat="segy")
-    elif filename.suffix == ".roff" and isinstance(
-        obj, (xtgeo.Grid, xtgeo.GridProperty)
-    ):
-        obj.to_file(filename, fformat="roff")
-    elif filename.suffix == ".csv" and isinstance(obj, pd.DataFrame):
+        out.get_dataframe(copy=False).to_csv(file, index=False)
+    elif file_suffix == ".pol" and isinstance(obj, (xtgeo.Polygons, xtgeo.Points)):
+        obj.to_file(file)
+    elif file_suffix == ".segy" and isinstance(obj, xtgeo.Cube):
+        obj.to_file(file, fformat="segy")
+    elif file_suffix == ".roff" and isinstance(obj, (xtgeo.Grid, xtgeo.GridProperty)):
+        obj.to_file(file, fformat="roff")
+    elif file_suffix == ".csv" and isinstance(obj, pd.DataFrame):
         logger.info(
             "Exporting dataframe to csv. Note: index columns will not be "
             "preserved unless calling 'reset_index()' on the dataframe."
         )
-        obj.to_csv(filename, index=False)
-    elif filename.suffix == ".parquet":
+        obj.to_csv(file, index=False)
+    elif file_suffix == ".parquet":
         from pyarrow import Table
 
         if isinstance(obj, Table):
-            from pyarrow import parquet
+            from pyarrow import output_stream, parquet
+
+            parquet.write_table(obj, where=output_stream(file))
 
-            parquet.write_table(obj, where=str(filename))
+    elif file_suffix == ".json":
+        if isinstance(obj, FaultRoomSurface):
+            serialized_json = json.dumps(obj.storage, indent=4)
+        else:
+            serialized_json = json.dumps(obj)
+
+        if isinstance(file, Path):
+            with open(file, "w") as stream:
+                stream.write(serialized_json)
+        else:
+            file.write(serialized_json.encode("utf-8"))
 
-    elif filename.suffix == ".json" and isinstance(obj, FaultRoomSurface):
-        with open(filename, "w") as stream:
-            json.dump(obj.storage, stream, indent=4)
-    elif filename.suffix == ".json":
-        with open(filename, "w") as stream:
-            json.dump(obj, stream)
     else:
-        raise TypeError(f"Exporting {filename.suffix} for {type(obj)} is not supported")
+        raise TypeError(f"Exporting {file_suffix} for {type(obj)} is not supported")
 
-    return str(filename)
 
+def md5sum(file: Path | BytesIO) -> str:
+    if isinstance(file, Path):
+        with open(file, "rb") as stream:
+            return md5sum_stream(stream)
+    return md5sum_stream(file)
+
+
+def md5sum_stream(stream: BufferedIOBase) -> str:
+    """Calculate the MD5 checksum of a stream."""
+    stream.seek(0)
 
-def md5sum(fname: Path) -> str:
-    """Calculate the MD5 checksum of a file."""
     hash_md5 = hashlib.md5()
-    with open(fname, "rb") as fil:
-        for chunk in iter(lambda: fil.read(4096), b""):
-            hash_md5.update(chunk)
+    while True:
+        chunk = stream.read(4096)
+        if not chunk:
+            break
+        hash_md5.update(chunk)
     return hash_md5.hexdigest()
 
 
-def export_file_compute_checksum_md5(
-    obj: types.Inferrable,
-    filename: Path,
-    fmt: str = "",
-) -> str:
-    """Export and compute checksum"""
-    export_file(obj, filename, fmt=fmt)
-    return md5sum(filename)
+def compute_md5(obj: types.Inferrable, file_suffix: str, fmt: str = "") -> str:
+    """Compute an MD5 sum for an object."""
+    memory_stream = BytesIO()
+    export_file(obj, memory_stream, file_suffix, fmt=fmt)
+    return md5sum(memory_stream)
 
 
 def compute_md5_using_temp_file(
-    obj: types.Inferrable, extension: str, fmt: str = ""
+    obj: types.Inferrable, file_suffix: str, fmt: str = ""
 ) -> str:
     """Compute an MD5 sum using a temporary file."""
-    if not extension.startswith("."):
-        raise ValueError("An extension must start with '.'")
-
-    with NamedTemporaryFile(buffering=0, suffix=extension) as tf:
-        logger.info("Compute MD5 sum for tmp file...: %s", tf.name)
-        return export_file_compute_checksum_md5(
-            obj=obj, filename=Path(tf.name), fmt=fmt
-        )
+    with NamedTemporaryFile(buffering=0, suffix=file_suffix) as tf:
+        logger.info("Compute MD5 sum for tmp file")
+        tempfile = Path(tf.name)
+        export_file(obj=obj, file=tempfile, fmt=fmt)
+        return md5sum(tempfile)
 
 
 def create_symlink(source: str, target: str) -> None:

src/fmu/dataio/aggregation.py

@@ -262,11 +262,20 @@ def _set_metadata(
 
         objdata = objectdata_provider_factory(obj=obj, dataio=etemp)
 
+        try:
+            checksum_md5 = _utils.compute_md5(obj, objdata.extension)
+        except Exception as e:
+            logger.debug(
+                f"Exception {e} occured when trying to compute md5 from memory stream "
+                f"for an object of type {type(obj)}. Will use tempfile instead."
+            )
+            checksum_md5 = _utils.compute_md5_using_temp_file(obj, objdata.extension)
+
         template["tracklog"] = [fields.Tracklog.initialize()[0]]
         template["file"] = {
             "relative_path": str(relpath),
             "absolute_path": str(abspath) if abspath else None,
-            "checksum_md5": _utils.compute_md5_using_temp_file(obj, objdata.extension),
+            "checksum_md5": checksum_md5,
         }
 
         # data section

src/fmu/dataio/dataio.py

@@ -821,7 +821,8 @@ def _export_without_metadata(self, obj: types.Inferrable) -> str:
         ).get_metadata()
 
         assert filemeta.absolute_path is not None  # for mypy
-        return export_file(obj, filename=filemeta.absolute_path, fmt=objdata.fmt)
+        export_file(obj, file=filemeta.absolute_path, fmt=objdata.fmt)
+        return str(filemeta.absolute_path)
 
     # ==================================================================================
     # Public methods:

src/fmu/dataio/providers/_filedata.py

@@ -15,9 +15,7 @@
 
 from fmu.dataio._logging import null_logger
 from fmu.dataio._model import enums, fields
-from fmu.dataio._utils import (
-    compute_md5_using_temp_file,
-)
+from fmu.dataio._utils import compute_md5, compute_md5_using_temp_file
 
 from ._base import Provider
 
@@ -108,11 +106,20 @@ def _get_share_folders(self) -> Path:
 
     def _compute_md5(self) -> str:
         """Compute an MD5 sum using a temporary file."""
-        if self.obj is None:
-            raise ValueError("Can't compute MD5 sum without an object.")
-        return compute_md5_using_temp_file(
-            self.obj, self.objdata.extension, fmt=self.objdata.fmt
-        )
+        try:
+            return compute_md5(
+                obj=self.obj,
+                file_suffix=self.objdata.extension,
+                fmt=self.objdata.fmt,
+            )
+        except Exception as e:
+            logger.debug(
+                f"Exception {e} occured when trying to compute md5 from memory stream "
+                f"for an object of type {type(self.obj)}. Will use tempfile instead."
+            )
+            return compute_md5_using_temp_file(
+                self.obj, self.objdata.extension, fmt=self.objdata.fmt
+            )
 
     def _add_filename_to_path(self, path: Path) -> Path:
         stem = self._get_filestem()