[WIP] Either refactoring

Propagate error and metadata

image_prediction/image_extractor/extractors/parsable.py

@@ -8,16 +8,18 @@ from typing import List, Union
 import fitz
 import numpy as np
 from PIL import Image
-from funcy import merge, compose, rcompose, keep, lfilter
+from funcy import merge, compose, rcompose, keep, lfilter, none
 from pymonad.either import Right, Left, Either
 from pymonad.tools import curry, identity
 
 from image_prediction.exceptions import InvalidBox, BadXref
+from image_prediction.formatter.formatters.enum import EnumFormatter
 from image_prediction.image_extractor.extractor import ImageExtractor, ImageMetadataPair
 from image_prediction.info import Info
 from image_prediction.stitching.stitching import stitch_pairs
 from image_prediction.stitching.utils import validate_box
 from image_prediction.utils import get_logger
+from image_prediction.utils.generic import bottom
 
 logger = get_logger()
 
@@ -58,8 +60,8 @@ class ParsablePDFImageExtractor(ImageExtractor):
 
 def right(pair: Either):
     if pair.is_right():
-        return pair.either(identity, identity)
-    logger.warning(f"Skipping bad image. reason: {pair.either(identity, identity)}")
+        return pair.either(bottom, identity)
+    logger.warning(f"Skipping bad image. {pair.either(identity, bottom)}")
 
 
 def extract_pages(doc, page_range):
@@ -127,8 +129,12 @@ def xref_to_maybe_image(doc, xref) -> Either:
 def make_maybe_image_metadata_pair(image: Either, metadata: Either):
     # haskell.org/tutorial/monads.html
     # (>>)             :: m a -> m b -> m b
-    return Right(make_image_metadata_pair).amap(image).amap(metadata)
-    # TODO: Somehow metadata needs to be added to Lefts for logging the reference to the invalid image
+    either = Right(make_image_metadata_pair).amap(image).amap(metadata)
+    return (
+        Left({"reason": either.either(identity, bottom), "metadata": EnumFormatter()(metadata.value)})
+        if either.is_left()
+        else either
+    )
 
 
 @curry(2)

image_prediction/utils/generic.py

@@ -13,3 +13,7 @@ def lift(fn):
 
 def starlift(fn):
     return curry(starmap)(fn)
+
+
+def bottom(*args, **kwargs):
+    return None