Merge pull request #451 from kmpaul/kpaul/issue-448

Allow for small GRIB files

kerchunk/grib2.py

@@ -49,13 +49,11 @@ def _split_file(f: io.FileIO, skip=0):
     while f.tell() < size:
         logger.debug(f"extract part {part + 1}")
         head = f.read(1024)
-        if len(head) < 1024:
-            break  # EOF
         if b"GRIB" not in head:
             f.seek(-4, 1)
             continue
         ind = head.index(b"GRIB")
-        start = f.tell() - 1024 + ind
+        start = f.tell() - len(head) + ind
         part_size = int.from_bytes(head[ind + 12 : ind + 16], "big")
         f.seek(start)
         yield start, part_size, f.read(part_size)

kerchunk/tests/test_grib.py

@@ -98,6 +98,12 @@ def test_subhourly():
     assert len(result) == 2, "Expected two grib messages"
 
 
+def test_tiny_grib():
+    fpath = os.path.join(here, "tinygrib.grb2")
+    result = scan_grib(fpath)
+    assert len(result) == 1, "Expected one grib message"
+
+
 def test_grib_tree():
     """
     End-to-end test from grib file to zarr hierarchy