Merge remote-tracking branch 'origin/develop'

Author: awdeorio

madoop/mapreduce.py

@@ -123,7 +123,7 @@ def prepare_input_files(input_dir, output_dir):
         st_size = inpath.stat().st_size
         total_size += st_size
         n_splits = math.ceil(st_size / MAX_INPUT_SPLIT_SIZE)
-        assert n_splits > 0
+        n_splits = 1 if not n_splits else n_splits  # Handle empty input file
         LOGGER.debug(
             "input %s size=%sB partitions=%s", inpath, st_size, n_splits
         )
@@ -278,13 +278,6 @@ def group_stage(input_dir, output_dir):
             last_two(inpath), outparent.name, ",".join(outnames),
         )
 
-    # Remove empty output files.  We won't always use the maximum number of
-    # reducers because some MapReduce programs have fewer intermediate keys.
-    for path in sorted(output_dir.iterdir()):
-        if path.stat().st_size == 0:
-            LOGGER.debug("empty partition: rm %s", last_two(path))
-            path.unlink()
-
     # Sort output files
     for path in sorted(output_dir.iterdir()):
         sort_file(path)

setup.py

@@ -14,7 +14,7 @@
     description="A light weight MapReduce framework for education.",
     long_description=LONG_DESCRIPTION,
     long_description_content_type="text/markdown",
-    version="0.3.0",
+    version="0.4.0",
     author="Andrew DeOrio",
     author_email="[email protected]",
     url="https://github.com/eecs485staff/madoop/",

tests/test_api.py

@@ -55,3 +55,18 @@ def test_missing_shebang(tmpdir):
             map_exe=TESTDATA_DIR/"word_count/map.py",
             reduce_exe=TESTDATA_DIR/"word_count/reduce_invalid.py",
         )
+
+
+def test_empty_inputs(tmpdir):
+    """Empty input files should not raise an error."""
+    with tmpdir.as_cwd():
+        madoop.mapreduce(
+            input_dir=TESTDATA_DIR/"word_count/input_empty",
+            output_dir="output",
+            map_exe=TESTDATA_DIR/"word_count/map.py",
+            reduce_exe=TESTDATA_DIR/"word_count/reduce.py",
+        )
+    utils.assert_dirs_eq(
+        TESTDATA_DIR/"word_count/correct/output",
+        tmpdir/"output",
+    )

tests/testdata/word_count/correct/grouper-output/part-00001

@@ -1,3 +0,0 @@
-Bye 1
-Hadoop 2
-World 2

tests/testdata/word_count/correct/output/part-00001

@@ -1 +1,3 @@
-Hello 2
+Bye 1
+Hadoop 2
+World 2

tests/testdata/word_count/correct/output/part-00002

@@ -0,0 +1 @@
+Hello 2

tests/testdata/word_count/correct/output/part-00003

@@ -1,3 +0,0 @@
-Bye 1
-Hadoop 2
-World 2

tests/testdata/word_count/correct/reducer-output/part-00001

@@ -1 +1,3 @@
-Hello 2
+Bye 1
+Hadoop 2
+World 2

tests/testdata/word_count/correct/reducer-output/part-00002

@@ -0,0 +1 @@
+Hello 2