Add example for file streaming (#1759)

Add example for directory streaming

Signed-off-by: DenChenn <aaaa102234@gmail.com>

examples/data_types_and_io/data_types_and_io/file_streaming.py

@@ -0,0 +1,44 @@
+from flytekit import task, workflow
+from flytekit.types.file import FlyteFile
+from flytekit.types.directory import FlyteDirectory
+import pandas as pd
+import os
+
+
+@task()
+def remove_some_rows(ff: FlyteFile) -> FlyteFile:
+    """
+    Remove the rows that the value of city is 'Seattle'.
+    This is an example with streaming support.
+    """
+    new_file = FlyteFile.new_remote_file("data_without_seattle.csv")
+    with ff.open("r") as r:
+        with new_file.open("w") as w:
+            df = pd.read_csv(r)
+            df = df[df["City"] != "Seattle"]
+            df.to_csv(w, index=False)
+    return new_file
+
+
+@task
+def process_folder(fd: FlyteDirectory) -> FlyteDirectory:
+    out_fd = FlyteDirectory.new_remote("folder-copy")
+    for base, x in fd.crawl():
+        src = str(os.path.join(base, x))
+        out_file = out_fd.new_file(x)
+        with FlyteFile(src).open("rb") as f:
+            with out_file.open("wb") as o:
+                o.write(f.read())
+    # The output path will be s3://my-s3-bucket/data/77/<execution-id>-<node-id>-0/folder-copy
+    return out_fd
+
+
+@workflow()
+def wf():
+    remove_some_rows(ff=FlyteFile("s3://custom-bucket/data.csv"))
+    process_folder(fd=FlyteDirectory("s3://my-s3-bucket/folder"))
+    return
+
+
+if __name__ == "__main__":
+    print(f"Running wf() {wf()}")