Workflow: CSV to parquet

cluster_kwargs.yaml

@@ -66,3 +66,10 @@ test_work_stealing_on_straggling_worker:
 test_repeated_merge_spill:
   n_workers: 20
   worker_vm_types: [m6i.large]
+
+# For tests/workflows/test_from_csv_to_parquet.py
+from_csv_to_parquet:
+  n_workers: 10
+  worker_vm_types: [m6i.xlarge]  # 4 CPU, 16 GiB (preferred default instance)
+  backend_options:
+    region: "us-east-1"  # Same region as dataset

tests/workflows/test_from_csv_to_parquet.py

@@ -0,0 +1,102 @@
+from collections import OrderedDict
+
+import dask.dataframe as dd
+import pytest
+
+SCHEMA = OrderedDict(
+    [
+        ("GlobalEventID", "Int64"),
+        ("Day", "Int64"),
+        ("MonthYear", "Int64"),
+        ("Year", "Int64"),
+        ("FractionDate", "float64"),
+        ("Actor1Code", "string[pyarrow]"),
+        ("Actor1Name", "string[pyarrow]"),
+        ("Actor1CountryCode", "string[pyarrow]"),
+        ("Actor1KnownGroupCode", "string[pyarrow]"),
+        ("Actor1EthnicCode", "string[pyarrow]"),
+        ("Actor1Religion1Code", "string[pyarrow]"),
+        ("Actor1Religion2Code", "string[pyarrow]"),
+        ("Actor1Type1Code", "string[pyarrow]"),
+        ("Actor1Type2Code", "string[pyarrow]"),
+        ("Actor1Type3Code", "string[pyarrow]"),
+        ("Actor2Code", "string[pyarrow]"),
+        ("Actor2Name", "string[pyarrow]"),
+        ("Actor2CountryCode", "string[pyarrow]"),
+        ("Actor2KnownGroupCode", "string[pyarrow]"),
+        ("Actor2EthnicCode", "string[pyarrow]"),
+        ("Actor2Religion1Code", "string[pyarrow]"),
+        ("Actor2Religion2Code", "string[pyarrow]"),
+        ("Actor2Type1Code", "string[pyarrow]"),
+        ("Actor2Type2Code", "string[pyarrow]"),
+        ("Actor2Type3Code", "string[pyarrow]"),
+        ("IsRootEvent", "Int64"),
+        ("EventCode", "string[pyarrow]"),
+        ("EventBaseCode", "string[pyarrow]"),
+        ("EventRootCode", "string[pyarrow]"),
+        ("QuadClass", "Int64"),
+        ("GoldsteinScale", "float64"),
+        ("NumMentions", "Int64"),
+        ("NumSources", "Int64"),
+        ("NumArticles", "Int64"),
+        ("AvgTone", "float64"),
+        ("Actor1Geo_Type", "Int64"),
+        ("Actor1Geo_Fullname", "string[pyarrow]"),
+        ("Actor1Geo_CountryCode", "string[pyarrow]"),
+        ("Actor1Geo_ADM1Code", "string[pyarrow]"),
+        ("Actor1Geo_Lat", "float64"),
+        ("Actor1Geo_Long", "float64"),
+        ("Actor1Geo_FeatureID", "string[pyarrow]"),
+        ("Actor2Geo_Type", "Int64"),
+        ("Actor2Geo_Fullname", "string[pyarrow]"),
+        ("Actor2Geo_CountryCode", "string[pyarrow]"),
+        ("Actor2Geo_ADM1Code", "string[pyarrow]"),
+        ("Actor2Geo_Lat", "float64"),
+        ("Actor2Geo_Long", "float64"),
+        ("Actor2Geo_FeatureID", "string[pyarrow]"),
+        ("ActionGeo_Type", "Int64"),
+        ("ActionGeo_Fullname", "string[pyarrow]"),
+        ("ActionGeo_CountryCode", "string[pyarrow]"),
+        ("ActionGeo_ADM1Code", "string[pyarrow]"),
+        ("ActionGeo_Lat", "float64"),
+        ("ActionGeo_Long", "float64"),
+        ("ActionGeo_FeatureID", "string[pyarrow]"),
+        ("DATEADDED", "Int64"),
+        ("SOURCEURL", "string[pyarrow]"),
+    ]
+)
+
+
+@pytest.mark.client("from_csv_to_parquet")
+def test_from_csv_to_parquet(client, s3_factory, s3_url):
+    s3 = s3_factory(anon=True)
+    files = s3.ls("s3://gdelt-open-data/events/")[:1000]
+    files = [f"s3://{f}" for f in files]
+
+    df = dd.read_csv(
+        files,
+        sep="\t",
+        names=SCHEMA.keys(),
+        # 'dtype' and 'converters' cannot overlap
+        dtype={col: dtype for col, dtype in SCHEMA.items() if dtype != "float64"},
+        storage_options=s3.storage_options,
+        on_bad_lines="skip",
+        # Some bad files have '#' in float values
+        converters={
+            col: lambda v: float(v.replace("#", "") or "NaN")
+            for col, dtype in SCHEMA.items()
+            if dtype == "float64"
+        },
+    )
+
+    # Now we can safely convert the float columns
+    df = df.astype({col: dtype for col, dtype in SCHEMA.items() if dtype == "float64"})
+
+    df = df.map_partitions(
+        lambda xdf: xdf.drop_duplicates(subset=["SOURCEURL"], keep="first")
+    )
+    df["national_paper"] = df.SOURCEURL.str.contains(
+        "washingtonpost|nytimes", regex=True
+    )
+    df = df[df["national_paper"]]
+    df.to_parquet(f"{s3_url}/from-csv-to-parquet/", write_index=False)