add image_name_from function and add deprecation warning to image_name

Signed-off-by: Tim van Katwijk <timvankatwijk@hotmail.com>

Author: tim-vk

dockerfile_parse/parser.py

@@ -238,6 +238,7 @@ def structure(self):
              "value": "yum -y update && yum clean all"}
         ]
         """
+
         def _rstrip_eol(text, line_continuation_char='\\'):
             text = text.rstrip()
             if text.endswith(line_continuation_char):
@@ -262,8 +263,8 @@ def _clean_comment_line(line):
         lineno = -1
         line_continuation_char = '\\'
         insnre = re.compile(r'^\s*(\S+)\s+(.*)$')  # matched group is insn
-        contre = re.compile(r'^.*\\\s*$')          # line continues?
-        commentre = re.compile(r'^\s*#')           # line is a comment?
+        contre = re.compile(r'^.*\\\s*$')  # line continues?
+        commentre = re.compile(r'^\s*#')  # line is a comment?
         directive_possible = True
         # escape directive regex
         escape_directive_re = re.compile(r'^\s*#\s*escape\s*=\s*(\\|`)\s*$', re.I)
@@ -354,7 +355,7 @@ def parent_images(self):
                         top_args[key] = value
             elif instr['instruction'] == 'FROM':
                 in_stage = True
-                image, _ = image_from(instr['value'])
+                image, _ = image_name_from(instr['value'])
                 if image is not None:
                     image = WordSplitter(image, args=top_args).dequote()
                     parents.append(image)
@@ -376,7 +377,7 @@ def parent_images(self, parents):
             if instr['instruction'] != 'FROM':
                 continue
 
-            old_image, stage = image_from(instr['value'])
+            old_image, stage = image_name_from(instr['value'])
             if old_image is None:
                 continue  # broken FROM, fixing would just confuse things
             if not parents:
@@ -393,7 +394,7 @@ def parent_images(self, parents):
 
         lines = self.lines
         for instr in reversed(change_instrs):
-            lines[instr['startline']:instr['endline']+1] = [instr['content']]
+            lines[instr['startline']:instr['endline'] + 1] = [instr['content']]
 
         self.lines = lines
 
@@ -416,7 +417,7 @@ def baseimage(self, new_image):
         images = []
         for instr in self.structure:
             if instr['instruction'] == 'FROM':
-                image, _ = image_from(instr['value'])
+                image, _ = image_name_from(instr['value'])
                 if image is not None:
                     images.append(image)
         if not images:
@@ -762,7 +763,7 @@ def add_lines(self, *lines, **kwargs):
         for stage in range(len(froms)-2, -1, -1):  # e.g. 0 for single or 2, 1, 0 for 3 stages
             start, finish = froms[stage], froms[stage+1]
             linenum = start['endline'] + 1 if at_start else finish['startline']
-            image, _ = image_from(froms[stage].get('value') or '')
+            image, _ = image_name_from(froms[stage].get('value') or '')
             if skip_scratch and image == 'scratch':
                 continue
             df_lines[linenum:linenum] = lines
@@ -862,6 +863,16 @@ def context_structure(self):
 
 
 def image_from(from_value):
+    """
+    :param from_value: string like "image:tag" or "image:tag AS name"
+    :return: tuple of the image and stage name, e.g. ("image:tag", None)
+    """
+    DeprecationWarning("Use image_name_from instead.")
+    image, name = image_name_from(from_value)
+    return str(image) if image else None, name
+
+
+def image_name_from(from_value):
     """
     :param from_value: string like "image:tag" or "image:tag AS name"
     :return: tuple of the image and stage name, e.g. ("image:tag", None)

tests/test_parser.py

@@ -17,7 +17,7 @@
 from textwrap import dedent
 
 from dockerfile_parse import DockerfileParser
-from dockerfile_parse.parser import image_from
+from dockerfile_parse.parser import image_from, image_name_from
 from dockerfile_parse.constants import COMMENT_INSTRUCTION
 from dockerfile_parse.util import b2u, u2b, Context, ImageName
 
@@ -573,9 +573,12 @@ def test_get_instructions_from_df(self, dfparser, instruction, instr_value,
             ('registry.example.com:5000/foo/bar:baz', None),
         )
     ])
-    def test_image_from(self, from_value, expect):
-        result = image_from(from_value)
+    def test_image_name_from(self, from_value, expect):
+        result = image_name_from(from_value)
+        # image_from is deprecated. But we still want to test it.
+        deprecated_result = image_from(from_value)
         assert result == expect
+        assert deprecated_result == expect
 
     def test_parent_images(self, dfparser):
         FROM = ('my-builder:latest', 'rhel7:7.5')