def test_batch_errors(caplog):
pipeline = (_pipeline().set_error_manager(ErrorManager()).set_source(
RandomTextSource(22)).append_stage("reverser", BatchTextReverser(
size=5)).append_stage("error", BatchErrorStage(size=3)).build())
for item in pipeline.run():
assert item.has_errors()
assert item.get_timing("reverser")
assert item.get_timing("error")
error = next(item.soft_errors())
assert error.get_exception() is None
assert str(error) == "test pipeline error"
assert pipeline.count == 22
assert any(caplog.records)
pipeline = (_pipeline().set_error_manager(ErrorManager()).set_source(
RandomTextSource(28)).append_stage("reverser", BatchTextReverser(
size=8)).append_stage("error",
BatchErrorStage(size=7)).append_stage(
"duplicator",
BatchTextDuplicator(size=5)).build())
for item in pipeline.run():
assert item.has_errors()
assert item.get_timing("reverser")
assert item.get_timing("duplicator")
assert any(k.startswith("text_") for k in item.payload.keys())
assert item.get_timing("error")
error = next(item.soft_errors())
assert error.get_exception() is None
assert str(error) == "test pipeline error"
assert pipeline.count == 28
assert any(caplog.records)
pipeline = (_pipeline().set_error_manager(ErrorManager()).set_source(
RandomTextSource(10)).append_stage("reverser", BatchTextReverser(
size=3)).append_stage("error1",
BatchExceptionStage(size=7)).append_stage(
"error2",
BatchErrorStage(size=1)).build())
for item in pipeline.run():
assert item.has_critical_errors()
assert item.get_timing("reverser")
assert item.get_timing("error1") >= 0.0003
assert not item.get_timing("error2")
for error in item.critical_errors():
assert isinstance(error.get_exception(), Exception)
assert (str(error.get_exception()) == "test exception"
and str(error) != "test pipeline error")
assert pipeline.count == 10
assert any(caplog.records)
with pytest.raises(Exception):
pipeline = (_pipeline().set_source(RandomTextSource(10)).append_stage(
"reverser", BatchTextReverser(size=4)).append_stage(
"error", BatchExceptionStage(size=3)).build())
for _ in pipeline.run():
pass
assert pipeline.count == 1
def test_run_times():
pipeline = (_pipeline().set_source(RandomTextSource(10)).append_stage(
"waster0", TimeWaster(0.2), concurrency=1).append_stage(
"waster1", TimeWaster(0.2),
concurrency=1).append_stage("waster2",
TimeWaster(0.2),
concurrency=1).append_stage(
"waster3",
TimeWaster(0.2),
concurrency=1).build())
start_time = time.time()
items = list(pipeline.run())
_check(items, 10)
elapsed0 = time.time() - start_time
logger.debug("Time for multi-threading: {}".format(elapsed0))
pipeline = (_pipeline().set_source(RandomTextSource(10)).append_stage(
"waster0", TimeWaster(0.2), concurrency=1,
parallel=True).append_stage("waster1",
TimeWaster(0.2),
concurrency=1,
parallel=True).append_stage(
"waster2",
TimeWaster(0.2),
concurrency=1,
parallel=True).append_stage(
"waster3",
TimeWaster(0.2),
concurrency=1,
parallel=True).build())
start_time = time.time()
items = list(pipeline.run())
_check(items, 10)
elapsed1 = time.time() - start_time
logger.debug("Time for multi-process: {}".format(elapsed1))
pipeline = (_pipeline().set_source(RandomTextSource(10)).append_stage(
"waster0", TimeWaster(0.2), concurrency=0).append_stage(
"waster1", TimeWaster(0.2),
concurrency=0).append_stage("waster2",
TimeWaster(0.2),
concurrency=0).append_stage(
"waster3",
TimeWaster(0.2),
concurrency=0).build())
start_time = time.time()
items = list(pipeline.run())
_check(items, 10)
elapsed2 = time.time() - start_time
logger.debug("Time for sequential: {}".format(elapsed2))
assert elapsed2 > elapsed0
assert elapsed2 > elapsed1
def test_concurrency_errors():
with pytest.raises(Exception):
pipeline = (_pipeline().set_source(RandomTextSource(10)).append_stage(
"reverser", TextReverser(),
concurrency=1).append_stage("error",
ExceptionStage(),
concurrency=1).build())
try:
for _ in pipeline.run():
pass
except Exception:
tb = traceback.format_exc()
assert 'Exception("test exception")' in tb
assert "CriticalError" in tb
raise
assert pipeline.count == 1
with pytest.raises(Exception):
pipeline = (_pipeline().set_source(RandomTextSource(10)).append_stage(
"reverser", TextReverser(), concurrency=1,
parallel=True).append_stage("error",
ExceptionStage(),
concurrency=1,
parallel=True).build())
try:
for _ in pipeline.run():
pass
except Exception:
tb = traceback.format_exc()
assert 'Exception("test exception")' in tb
assert "CriticalError" in tb
raise
assert pipeline.count == 1
pipeline = (_pipeline().set_source(RandomTextSource(10)).append_stage(
"reverser", TextReverser(), concurrency=1).append_stage(
"error1", ErrorStage(), concurrency=1, parallel=True).append_stage(
"error2", ErrorStage(),
concurrency=2).append_stage("duplicator",
TextDuplicator(),
concurrency=1,
parallel=True).build())
for item in pipeline.run():
assert item.get_timing("reverser")
assert item.get_timing("duplicator")
assert any(k.startswith("text_") for k in item.payload.keys())
assert len(list(item.soft_errors())) == 2
assert item.get_timing("error1")
assert item.get_timing("error2")
assert pipeline.count == 10
def test_concurrent_constructions():
"""test `on_start` method"""
pipeline = (_pipeline().set_error_manager(
SerializableErrorManager()).set_source(
RandomTextSource(10)).append_stage(
"reverser1", TextReverser(), concurrency=1,
parallel=True).append_stage("stage",
SerializableStage(),
concurrency=2,
parallel=True).append_stage(
"reverser2",
TextReverser()).append_stage(
"error",
ErrorStage(),
concurrency=2,
parallel=True).build())
for item in pipeline.run():
assert item.payload.get("file")
assert item.get_timing("reverser1")
assert item.get_timing("reverser2")
assert item.has_errors()
assert pipeline.count == 10
pipeline = (_pipeline().set_error_manager(
SerializableErrorManager()).set_source(
RandomTextSource(10)).append_stage(
"stage", SerializableStage()).append_stage(
"reverser1", TextReverser(), concurrency=1,
parallel=True).append_stage("reverser2",
TextReverser(),
concurrency=1,
parallel=True).append_stage(
"error",
ErrorStage()).build())
for item in pipeline.run():
assert item.payload.get("file")
assert item.get_timing("reverser1")
assert item.get_timing("reverser2")
assert item.has_errors()
assert pipeline.count == 10
with pytest.raises(IOError):
(_pipeline().set_error_manager(SerializableErrorManager()).set_source(
RandomTextSource(10)).append_stage("stage",
ErrorSerializableStage(),
concurrency=1,
parallel=True).build())
def test_run():
pipeline = (_pipeline().set_source(RandomTextSource(10)).append_stage(
"reverser", TextReverser()).append_stage("duplicator",
TextDuplicator()).build())
for item in pipeline.run():
assert len([x for x in item.payload.keys()
if x.startswith("text")]) == 2
assert item.get_timing("reverser")
assert item.get_timing("duplicator")
assert pipeline.count == 10
def test_run_different_sizes():
pipeline = (_pipeline().set_source(RandomTextSource(2)).append_stage(
"reverser", BatchTextReverser(size=4)).append_stage(
"duplicator", BatchTextDuplicator(size=20)).build())
n = 0
for n, item in enumerate(pipeline.run()):
assert len([x for x in item.payload.keys()
if x.startswith("text")]) == 2
assert item.get_timing("reverser")
assert item.get_timing("duplicator")
assert n == 1 == pipeline.count - 1
pipeline = (_pipeline().set_source(RandomTextSource(6)).append_stage(
"reverser", BatchTextReverser(size=1)).append_stage(
"duplicator", BatchTextDuplicator(size=20)).build())
for n, item in enumerate(pipeline.run()):
assert len([x for x in item.payload.keys()
if x.startswith("text")]) == 2
assert item.get_timing("reverser")
assert item.get_timing("duplicator")
assert n == 5 == pipeline.count - 1
def test_run():
pipeline = (_pipeline().set_source(RandomTextSource(35)).append_stage(
"reverser",
BatchTextReverser()).append_stage("duplicator",
TextDuplicator()).append_stage(
"batch_duplicator",
BatchTextDuplicator()).build())
for item in pipeline.run():
assert len([x for x in item.payload.keys()
if x.startswith("text")]) == 3
assert item.get_timing("reverser")
assert item.get_timing("duplicator")
assert pipeline.count == 35
pipeline = (_pipeline().set_source(RandomTextSource(40)).append_stage(
"reverser", TextReverser()).append_stage(
"duplicator", TextDuplicator()).append_stage(
"batch_duplicator",
BatchTextDuplicator(check_batch=True)).build())
for _ in pipeline.run():
pass
assert pipeline.count == 40
def test_huge_run():
pipeline = (_pipeline().set_source(RandomTextSource(200)).append_stage(
"reverser0", BatchTextReverser(10000), concurrency=2,
parallel=True).append_stage("reverser1",
BatchTextReverser(10000),
concurrency=3,
parallel=True).append_stage(
"reverser2",
BatchTextReverser(10000),
concurrency=1,
parallel=True).append_stage(
"duplicator",
BatchTextDuplicator(10000),
concurrency=2,
parallel=True).build())
start_time = time.time()
items = list(pipeline.run())
elapsed1 = time.time() - start_time
logger.debug("Time for parallel: {}".format(elapsed1))
_check(items, 200)
pipeline = (_pipeline().set_source(RandomTextSource(200)).append_stage(
"reverser0", BatchTextReverser(10000),
concurrency=0).append_stage("reverser1",
BatchTextReverser(10000),
concurrency=0).append_stage(
"reverser2",
BatchTextReverser(10000),
concurrency=0).append_stage(
"duplicator",
BatchTextDuplicator(10000),
concurrency=0).build())
start_time = time.time()
items = list(pipeline.run())
elapsed2 = time.time() - start_time
logger.debug("Time for sequential: {}".format(elapsed2))
_check(items, 200)
assert elapsed2 > elapsed1
def test_timeouts():
pipeline = (_pipeline().set_source(RandomTextSource(100)).append_stage(
"reverser0", BatchTextReverser(timeout=1, size=120),
concurrency=0).append_stage("reverser1",
BatchTextReverser(timeout=1, size=120),
concurrency=0).append_stage(
"reverser2",
BatchTextReverser(timeout=0, size=120),
concurrency=0).append_stage(
"duplicator",
BatchTextDuplicator(timeout=1,
size=120),
concurrency=0).build())
start_time = time.time()
items = list(pipeline.run())
elapsed = time.time() - start_time
assert 3 <= round(elapsed)
_check(items, 100, pipeline)
pipeline = (_pipeline().set_source(RandomTextSource(100)).append_stage(
"reverser0", BatchTextReverser(timeout=1, size=120),
concurrency=1).append_stage("reverser1",
BatchTextReverser(timeout=2, size=120),
concurrency=1).append_stage(
"reverser2",
BatchTextReverser(timeout=0, size=120),
concurrency=1).append_stage(
"duplicator",
BatchTextDuplicator(timeout=1,
size=120),
concurrency=1).build())
start_time = time.time()
items = list(pipeline.run())
elapsed = time.time() - start_time
assert 4 <= round(elapsed)
_check(items, 100, pipeline)
pipeline = (_pipeline().set_source(RandomTextSource(100)).append_stage(
"reverser0",
BatchTextReverser(timeout=1, size=120),
concurrency=1,
parallel=True,
).append_stage(
"reverser1",
BatchTextReverser(timeout=0, size=120),
concurrency=1,
parallel=True,
).append_stage(
"reverser2",
BatchTextReverser(timeout=1, size=120),
concurrency=1,
parallel=True,
).append_stage(
"duplicator",
BatchTextDuplicator(timeout=0, size=120),
concurrency=1,
parallel=True,
).build())
start_time = time.time()
items = list(pipeline.run())
elapsed = time.time() - start_time
assert 2 <= round(elapsed)
_check(items, 100, pipeline)
def test_concurrent_initialization():
pipeline = (_pipeline().set_source(
RandomTextSource(100)).append_stage_concurrently(
"reverser0",
BatchTextReverser,
kwargs={
"cycles": 3
},
concurrency=2).append_stage_concurrently(
"reverser1", BatchTextReverser, args=[5],
concurrency=0).append_stage("reverser2",
BatchTextReverser(),
concurrency=1).append_stage(
"duplicator",
BatchTextDuplicator(),
concurrency=2).build())
items = list(pipeline.run())
_check(items, 100, pipeline)
pipeline = (_pipeline().set_source(
RandomTextSource(100)).append_stage_concurrently(
"reverser0", BatchTextReverser, concurrency=2,
parallel=True).append_stage_concurrently(
"reverser1",
BatchTextReverser,
args=[10],
concurrency=1,
parallel=True).append_stage_concurrently(
"reverser2", BatchTextReverser,
concurrency=0).append_stage_concurrently(
"duplicator",
BatchTextDuplicator,
args=[10],
concurrency=2,
parallel=True,
).build())
items = list(pipeline.run())
_check(items, 100, pipeline)
pipeline = (_pipeline().set_source(RandomTextSource(100)).append_stage(
"reverser0", BatchTextReverser(),
concurrency=0).append_stage_concurrently("reverser1",
BatchTextReverser,
concurrency=1).append_stage(
"duplicator",
BatchTextDuplicator(10),
concurrency=0).build())
items = list(pipeline.run())
_check(items, 100, pipeline)
pipeline = (_pipeline().set_source(
RandomTextSource(100)).append_stage_concurrently(
"duplicator0", BatchTextDuplicator, concurrency=0).append_stage(
"reverser", BatchTextReverser(),
concurrency=0).append_stage_concurrently(
"duplicator1", BatchTextDuplicator, concurrency=0).build())
items = list(pipeline.run())
_check(items, 100, pipeline)
pipeline = (_pipeline().set_source(RandomTextSource(100)).append_stage(
"reverser", BatchTextReverser(12),
concurrency=0).append_stage_concurrently("duplicator0",
BatchTextDuplicator,
concurrency=0).append_stage(
"duplicator1",
BatchTextDuplicator(),
concurrency=1).build())
items = list(pipeline.run())
_check(items, 100, pipeline)
pipeline = (_pipeline(max_init_workers=1).set_source(
RandomTextSource(100)).append_stage_concurrently(
"reverser0",
BatchTextReverser,
args=[20],
concurrency=1,
parallel=True).append_stage_concurrently(
"reverser1",
BatchTextReverser,
args=[20],
concurrency=1,
parallel=False).append_stage_concurrently(
"duplicator",
BatchTextDuplicator,
args=[20],
concurrency=1,
parallel=True,
).build())
items = list(pipeline.run())
_check(items, 100, pipeline)
def test_mixed_concurrent_run():
pipeline = (_pipeline().set_source(RandomTextSource(96)).append_stage(
"reverser0", TextReverser(),
concurrency=2).append_stage("reverser1",
BatchTextReverser(),
concurrency=0).append_stage(
"reverser2",
TextReverser(),
concurrency=1).append_stage(
"duplicator",
BatchTextDuplicator(),
concurrency=2).build())
items = list(pipeline.run())
_check(items, 96, pipeline)
pipeline = (_pipeline().set_source(RandomTextSource(81)).append_stage(
"reverser0", BatchTextReverser(), concurrency=2,
parallel=True).append_stage("reverser1",
TextReverser(),
concurrency=1,
parallel=True).append_stage(
"reverser2",
TextReverser(),
concurrency=0).append_stage(
"duplicator",
BatchTextDuplicator(),
concurrency=2,
parallel=True).build())
items = list(pipeline.run())
_check(items, 81, pipeline)
pipeline = (_pipeline().set_source(RandomTextSource(92)).append_stage(
"reverser0", BatchTextReverser(), concurrency=0).append_stage(
"reverser1", TextReverser(),
concurrency=1).append_stage("duplicator",
BatchTextDuplicator(),
concurrency=0).build())
items = list(pipeline.run())
_check(items, 92, pipeline)
pipeline = (_pipeline().set_source(RandomTextSource(83)).append_stage(
"reverser0", BatchTextReverser(), concurrency=1,
parallel=True).append_stage("reverser1",
BatchTextReverser(),
concurrency=1,
parallel=False).append_stage(
"duplicator",
TextDuplicator(),
concurrency=1,
parallel=True).build())
items = list(pipeline.run())
_check(items, 83, pipeline)
pipeline = (_pipeline().set_source(RandomTextSource(100)).append_stage(
"duplicator0", TextDuplicator(), concurrency=0).append_stage(
"reverser", TextReverser(),
concurrency=0).append_stage("duplicator1",
BatchTextDuplicator(check_batch=True),
concurrency=0).build())
items = list(pipeline.run())
_check(items, 100, pipeline)
pipeline = (_pipeline().set_source(RandomTextSource(100)).append_stage(
"duplicator0", TextDuplicator(), concurrency=2).append_stage(
"reverser", TextReverser(),
concurrency=2).append_stage("duplicator1",
BatchTextDuplicator(),
concurrency=2).build())
items = list(pipeline.run())
_check(items, 100, pipeline)
def test_queue_sizes():
pipeline = (_pipeline(max_queues_size=1).set_source(
RandomTextSource(93)).append_stage("reverser0",
BatchTextReverser(),
concurrency=2).append_stage(
"reverser1",
BatchTextReverser(),
concurrency=0).append_stage(
"reverser2",
BatchTextReverser(),
concurrency=1).append_stage(
"duplicator",
BatchTextDuplicator(),
concurrency=2).build())
items = list(pipeline.run())
_check(items, 93, pipeline)
pipeline = (_pipeline(max_queues_size=1).set_source(
RandomTextSource(79)).append_stage("reverser0",
BatchTextReverser(),
concurrency=2,
parallel=True).append_stage(
"reverser1",
BatchTextReverser(),
concurrency=1,
parallel=True).append_stage(
"reverser2",
BatchTextReverser(),
concurrency=0).append_stage(
"duplicator",
BatchTextDuplicator(),
concurrency=2,
parallel=True).build())
items = list(pipeline.run())
_check(items, 79, pipeline)
pipeline = (_pipeline(max_queues_size=2).set_source(
RandomTextSource(131)).append_stage(
"reverser0", BatchTextReverser(), concurrency=2,
parallel=True).append_stage("waster1",
TimeWaster(0.02),
concurrency=2,
parallel=True).append_stage(
"reverser1",
BatchTextReverser(),
concurrency=0).append_stage(
"waster2",
TimeWaster(0.03),
concurrency=2).build())
items = list(pipeline.run())
_check(items, 131, pipeline)
pipeline = (_pipeline(max_queues_size=0).set_source(
RandomTextSource(4)).append_stage("reverser0",
BatchTextReverser(),
concurrency=2).append_stage(
"reverser1",
BatchTextReverser(),
concurrency=0).append_stage(
"reverser2",
BatchTextReverser(),
concurrency=1).append_stage(
"duplicator",
BatchTextDuplicator(),
concurrency=2).build())
items = list(pipeline.run())
_check(items, 4, pipeline)
pipeline = (_pipeline(max_queues_size=0).set_source(
RandomTextSource(11)).append_stage("reverser0",
BatchTextReverser(),
concurrency=2,
parallel=True).append_stage(
"reverser1",
BatchTextReverser(),
concurrency=1,
parallel=True).append_stage(
"reverser2",
BatchTextReverser(),
concurrency=0).append_stage(
"duplicator",
BatchTextDuplicator(),
concurrency=2,
parallel=True).build())
items = list(pipeline.run())
_check(items, 11, pipeline)
def test_errors(caplog):
pipeline = (_pipeline().set_error_manager(ErrorManager()).set_source(
RandomTextSource(10)).append_stage("reverser",
TextReverser()).append_stage(
"error", ErrorStage()).build())
for item in pipeline.run():
assert item.has_errors()
assert item.get_timing("reverser")
assert item.get_timing("error")
error = next(item.soft_errors())
assert error.get_exception() is None
assert str(error) == "test pipeline error"
assert all("stage error has generated an error" in record.msg.lower()
for record in caplog.records if record.levelno == logging.ERROR)
assert pipeline.count == 10
pipeline = (_pipeline().set_error_manager(ErrorManager()).set_source(
RandomTextSource(10)).append_stage("reverser",
TextReverser()).append_stage(
"error",
ErrorStage()).append_stage(
"duplicator",
TextDuplicator()).build())
caplog.clear()
for item in pipeline.run():
assert item.has_errors()
assert item.get_timing("reverser")
assert item.get_timing("duplicator")
assert any(k.startswith("text_") for k in item.payload.keys())
assert item.get_timing("error")
error = next(item.soft_errors())
assert error.get_exception() is None
assert str(error) == "test pipeline error"
assert all("stage error has generated an error" in record.msg.lower()
for record in caplog.records if record.levelno == logging.ERROR)
assert pipeline.count == 10
pipeline = (_pipeline().set_error_manager(ErrorManager()).set_source(
RandomTextSource(10)).append_stage("reverser",
TextReverser()).append_stage(
"error1",
CriticalIOErrorStage()).build())
for item in pipeline.run():
assert item.has_critical_errors()
assert item.get_timing("reverser")
assert item.get_timing("error1")
for error in item.critical_errors():
assert isinstance(error.get_exception(), IOError)
assert str(error) == "test pipeline critical IO error"
pipeline = (_pipeline().set_error_manager(ErrorManager()).set_source(
RandomTextSource(10)).append_stage("reverser",
TextReverser()).append_stage(
"error1",
ExceptionStage()).append_stage(
"error2",
ErrorStage()).build())
caplog.clear()
for item in pipeline.run():
assert item.has_critical_errors()
assert item.get_timing("reverser")
assert item.get_timing("error1")
assert not item.get_timing("error2")
for error in item.critical_errors():
assert isinstance(error.get_exception(), Exception)
assert (str(error) == "test exception"
and str(error.get_exception()) == "test exception"
and str(error) != "test pipeline error")
assert all("stage error1 has generated an error" in record.msg.lower()
for record in caplog.records if record.levelno == logging.ERROR)
assert pipeline.count == 10
with pytest.raises(Exception):
pipeline = (_pipeline().set_source(RandomTextSource(10)).append_stage(
"reverser", TextReverser()).append_stage("error",
ExceptionStage()).build())
try:
for _ in pipeline.run():
pass
except Exception:
assert 'Exception("test exception")' in traceback.format_exc()
raise
assert pipeline.count == 1
pipeline = (_pipeline().set_error_manager(
ErrorManager().no_skip_on_critical_error()).set_source(
RandomTextSource(10)).append_stage(
"reverser1", TextReverser()).append_stage(
"error",
ExceptionStage()).append_stage("reverser2",
TextReverser()).build())
for item in pipeline.run():
assert item.get_timing("reverser1")
assert item.get_timing("error")
assert item.get_timing("reverser2")
assert pipeline.count == 10
def test_queue_sizes():
pipeline = (_pipeline(max_queues_size=1).set_source(
RandomTextSource(100)).append_stage(
"reverser0", TextReverser(),
concurrency=2).append_stage("reverser1",
TextReverser(),
concurrency=0).append_stage(
"reverser2",
TextReverser(),
concurrency=1).append_stage(
"duplicator",
TextDuplicator(),
concurrency=2).build())
items = list(pipeline.run())
_check(items, 100, pipeline)
pipeline = (_pipeline(max_queues_size=1).set_source(
RandomTextSource(100)).append_stage(
"reverser0", TextReverser(), concurrency=2,
parallel=True).append_stage("reverser1",
TextReverser(),
concurrency=1,
parallel=True).append_stage(
"reverser2",
TextReverser(),
concurrency=0).append_stage(
"duplicator",
TextDuplicator(),
concurrency=2,
parallel=True).build())
items = list(pipeline.run())
_check(items, 100, pipeline)
pipeline = (_pipeline(max_queues_size=3).set_source(
RandomTextSource(100)).append_stage("waster",
TimeWaster(0.02),
concurrency=2).append_stage(
"reverser",
TimeWaster(0.04),
concurrency=1,
parallel=True).build())
items = list(pipeline.run())
_check(items, 100, pipeline)
pipeline = (_pipeline(max_queues_size=0).set_source(
RandomTextSource(100)).append_stage(
"reverser0", TextReverser(),
concurrency=2).append_stage("reverser1",
TextReverser(),
concurrency=0).append_stage(
"reverser2",
TextReverser(),
concurrency=1).append_stage(
"duplicator",
TextDuplicator(),
concurrency=2).build())
items = list(pipeline.run())
_check(items, 100, pipeline)
pipeline = (_pipeline(max_queues_size=0).set_source(
RandomTextSource(100)).append_stage(
"reverser0", TextReverser(), concurrency=2,
parallel=True).append_stage("reverser1",
TextReverser(),
concurrency=1,
parallel=True).append_stage(
"reverser2",
TextReverser(),
concurrency=0).append_stage(
"duplicator",
TextDuplicator(),
concurrency=2,
parallel=True).build())
items = list(pipeline.run())
_check(items, 100, pipeline)
