feat: offer GZIP support for Metric IO

fgpyo/util/metric.py

@@ -115,6 +115,7 @@
 
 import attr
 
+from fgpyo import io
 from fgpyo.util import inspect
 
 MetricType = TypeVar("MetricType")
@@ -161,7 +162,7 @@ def read(cls, path: Path, ignore_extra_fields: bool = True) -> Iterator[Any]:
             ignore_extra_fields: True to ignore any extra columns, False to raise an exception.
         """
         parsers = cls._parsers()
-        with path.open("r") as reader:
+        with io.to_reader(path) as reader:
             header: List[str] = reader.readline().rstrip("\r\n").split("\t")
             # check the header
             class_fields = set(cls.header())
@@ -234,7 +235,7 @@ def write(cls, path: Path, *values: MetricType) -> None:
             path: path to the output file
             values: zero or more metrics.
         """
-        with path.open("w") as writer:
+        with io.to_writer(path) as writer:
             writer.write("\t".join(cls.header()))
             writer.write("\n")
             for value in values:

fgpyo/util/tests/test_metric.py

@@ -1,4 +1,5 @@
 import enum
+import gzip
 from pathlib import Path
 from typing import Any
 from typing import Callable
@@ -158,6 +159,20 @@ def test_metrics_roundtrip(tmpdir: TmpDir) -> None:
     assert metrics == DUMMY_METRICS
 
 
+def test_metrics_roundtrip_gzip(tmp_path: Path) -> None:
+    path: Path = Path(tmp_path) / "metrics.txt.gz"
+
+    DummyMetric.write(path, *DUMMY_METRICS)
+
+    with gzip.open(path, "r") as handle:
+        handle.read(1)  # Will raise an exception if not a GZIP file.
+
+    metrics: List[DummyMetric] = list(DummyMetric.read(path=path))
+
+    assert len(metrics) == len(DUMMY_METRICS)
+    assert metrics == DUMMY_METRICS
+
+
 def test_metrics_read_extra_columns(tmpdir: TmpDir) -> None:
     person = Person(name="Max", age=42)
     path = Path(tmpdir) / "metrics.txt"