Extract `Job.get_call_string` logic to `utils.get_call_string` (#1499)

* Extract `Job.get_call_string` logic to `utils.get_call_string`

* Remove an outdaded comment

* Move `truncate_long_string` to `utils`

* Remove `truncate` parameter in `get_call_string`

* Add a test for `get_call_string`

* Move `truncate_long_string` to module's top level

* Add a test case for `truncate_long_string` suite

rq/job.py

@@ -22,7 +22,7 @@ from .exceptions import DeserializationError, NoSuchJobError
 from .local import LocalStack
 from .serializers import resolve_serializer
 from .utils import (get_version, import_attribute, parse_timeout, str_to_date,
-                    utcformat, utcnow, ensure_list)
+                    utcformat, utcnow, ensure_list, get_call_string)
 
 # Serialize pickle dumps using the highest pickle protocol (binary, default
 # uses ascii)
@@ -45,12 +45,6 @@ class JobStatus(str, Enum):
 UNEVALUATED = object()
 
 
-def truncate_long_string(data, maxlen=75):
-    """ Truncates strings longer than maxlen
-    """
-    return (data[:maxlen] + '...') if len(data) > maxlen else data
-
-
 def cancel_job(job_id, connection=None):
     """Cancels the job with the given job ID, preventing execution.  Discards
     any job info (i.e. it can't be requeued later).
@@ -801,17 +795,7 @@ class Job:
         """Returns a string representation of the call, formatted as a regular
         Python function invocation statement.
         """
-        if self.func_name is None:
-            return None
-
-        arg_list = [as_text(truncate_long_string(repr(arg))) for arg in self.args]
-
-        kwargs = ['{0}={1}'.format(k, as_text(truncate_long_string(repr(v)))) for k, v in self.kwargs.items()]
-        # Sort here because python 3.3 & 3.4 makes different call_string
-        arg_list += sorted(kwargs)
-        args = ', '.join(arg_list)
-
-        return '{0}({1})'.format(self.func_name, args)
+        return get_call_string(self.func_name, self.args, self.kwargs, max_length=75)
 
     def cleanup(self, ttl=None, pipeline=None, remove_from_queue=True):
         """Prepare job for eventual deletion (if needed). This method is usually

rq/utils.py

@@ -297,3 +297,27 @@ def split_list(a_list, segment_size):
     """
     for i in range(0, len(a_list), segment_size):
         yield a_list[i:i + segment_size]
+
+
+def truncate_long_string(data, max_length=None):
+    """Truncate arguments with representation longer than max_length"""
+    if max_length is None:
+        return data
+    return (data[:max_length] + '...') if len(data) > max_length else data
+
+
+def get_call_string(func_name, args, kwargs, max_length=None):
+    """Returns a string representation of the call, formatted as a regular
+    Python function invocation statement. If max_length is not None, truncate
+    arguments with representation longer than max_length.
+    """
+    if func_name is None:
+        return None
+
+    arg_list = [as_text(truncate_long_string(repr(arg), max_length)) for arg in args]
+
+    kwargs = ['{0}={1}'.format(k, as_text(truncate_long_string(repr(v), max_length))) for k, v in kwargs.items()]
+    arg_list += sorted(kwargs)
+    args = ', '.join(arg_list)
+
+    return '{0}({1})'.format(func_name, args)

tests/test_utils.py

@@ -11,7 +11,7 @@ from redis import Redis
 
 from tests import RQTestCase, fixtures
 from rq.utils import backend_class, ensure_list, first, get_version, is_nonstring_iterable, parse_timeout, utcparse, \
-    split_list, ceildiv
+    split_list, ceildiv, get_call_string, truncate_long_string
 from rq.exceptions import TimeoutFormatError
 
 
@@ -113,3 +113,26 @@ class TestUtils(RQTestCase):
 
         expected_small_list_count = ceildiv(BIG_LIST_SIZE, SEGMENT_SIZE)
         self.assertEqual(len(small_lists), expected_small_list_count)
+
+    def test_truncate_long_string(self):
+        """Ensure truncate_long_string works properly"""
+        assert truncate_long_string("12", max_length=3) == "12"
+        assert truncate_long_string("123", max_length=3) == "123"
+        assert truncate_long_string("1234", max_length=3) == "123..."
+        assert truncate_long_string("12345", max_length=3) == "123..."
+
+        s = "long string but no max_length provided so no truncating should occur" * 10
+        assert truncate_long_string(s) == s
+
+    def test_get_call_string(self):
+        """Ensure a case, when func_name, args and kwargs are not None, works properly"""
+        cs = get_call_string("f", ('some', 'args', 42), {"key1": "value1", "key2": True})
+        assert cs == "f('some', 'args', 42, key1='value1', key2=True)"
+
+    def test_get_call_string_with_max_length(self):
+        """Ensure get_call_string works properly when max_length is provided"""
+        func_name = "f"
+        args = (1234, 12345, 123456)
+        kwargs = {"len4": 1234, "len5": 12345, "len6": 123456}
+        cs = get_call_string(func_name, args, kwargs, max_length=5)
+        assert cs == "f(1234, 12345, 12345..., len4=1234, len5=12345, len6=12345...)"