show more detail in readabiliity error messages

archivebox/extractors/readability.py

@@ -73,7 +73,7 @@ def save_readability(link: Link, out_dir: Optional[str]=None, timeout: int=TIMEO
             result_json = json.loads(result.stdout)
             assert result_json and 'content' in result_json, 'Readability output is not valid JSON'
         except json.JSONDecodeError:
-            raise ArchiveError('Readability was not able to archive the page', result.stdout + result.stderr)
+            raise ArchiveError('Readability was not able to archive the page (invalid JSON)', result.stdout + result.stderr)
 
         output_folder.mkdir(exist_ok=True)
         readability_content = result_json.pop("textContent") 
@@ -81,8 +81,6 @@ def save_readability(link: Link, out_dir: Optional[str]=None, timeout: int=TIMEO
         atomic_write(str(output_folder / "content.txt"), readability_content)
         atomic_write(str(output_folder / "article.json"), result_json)
 
-        # parse out number of files downloaded from last line of stderr:
-        #  "Downloaded: 76 files, 4.0M in 1.6s (2.52 MB/s)"
         output_tail = [
             line.strip()
             for line in (result.stdout + result.stderr).decode().rsplit('\n', 5)[-5:]
@@ -95,7 +93,7 @@ def save_readability(link: Link, out_dir: Optional[str]=None, timeout: int=TIMEO
 
         # Check for common failure cases
         if (result.returncode > 0):
-            raise ArchiveError('Readability was not able to archive the page', hints)
+            raise ArchiveError(f'Readability was not able to archive the page (status={result.returncode})', hints)
     except (Exception, OSError) as err:
         status = 'failed'
         output = err