Automate NLTK datapackage punkt_tab download for Analyzers

annif/analyzer/analyzer.py

@@ -6,6 +6,10 @@
 import functools
 import unicodedata
 
+import annif
+
+logger = annif.logger
+
 _KEY_TOKEN_MIN_LENGTH = "token_min_length"
 
 
@@ -21,6 +25,18 @@ def __init__(self, **kwargs) -> None:
         if _KEY_TOKEN_MIN_LENGTH in kwargs:
             self.token_min_length = int(kwargs[_KEY_TOKEN_MIN_LENGTH])
 
+        import nltk.data
+
+        try:
+            nltk.data.find("tokenizers/punkt_tab")
+        except LookupError as err:
+            logger.debug(str(err))
+            if "punkt_tab" in str(err):  # "punkt_tab" is surrounded by color code tags
+                logger.warning(
+                    'NLTK datapackage "punkt_tab" not found, downloading it now.'
+                )
+                nltk.download("punkt_tab")
+
     def tokenize_sentences(self, text: str) -> list[str]:
         """Tokenize a piece of text (e.g. a document) into sentences."""
         import nltk.tokenize

tests/test_analyzer.py

@@ -1,5 +1,7 @@
 """Unit tests for analyzers in Annif"""
 
+from unittest import mock
+
 import pytest
 
 import annif.analyzer
@@ -15,6 +17,15 @@ def test_get_analyzer_badspec():
         annif.analyzer.get_analyzer("()")
 
 
+@mock.patch("nltk.data.find", side_effect=LookupError("Resource punkt_tab not found"))
+@mock.patch("nltk.download")
+def test_nltk_data_missing(download, find):
+    annif.analyzer.get_analyzer("snowball(english)")
+    assert find.called
+    assert download.called
+    assert download.call_args == mock.call("punkt_tab")
+
+
 def test_english_analyzer_normalize_word():
     analyzer = annif.analyzer.get_analyzer("snowball(english)")
     assert analyzer._normalize_word("running") == "run"