make 'path' and 'keywords' available in logging messages

Wrap all loggers used by job, extractor, downloader, and postprocessor
objects into a (custom) LoggerAdapter that provides access to the
underlying job, extractor, pathfmt, and kwdict objects and their
properties.

__init__() signatures for all downloader and postprocessor classes have
been changed to take the current Job object as their first argument,
instead of the current extractor or pathfmt.

(#574, #575)

test/test_downloader.py

@@ -14,21 +14,30 @@ from unittest.mock import Mock, MagicMock, patch
 
 import re
 import base64
+import logging
 import os.path
 import tempfile
 import threading
 import http.server
 
+
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
-from gallery_dl import downloader, extractor, config, util  # noqa E402
-from gallery_dl.downloader.common import DownloaderBase  # noqa E402
-from gallery_dl.output import NullOutput  # noqa E402
+from gallery_dl import downloader, extractor, output, config, util  # noqa E402
 
 
 class MockDownloaderModule(Mock):
     __downloader__ = "mock"
 
 
+class FakeJob():
+
+    def __init__(self):
+        self.extractor = extractor.find("test:")
+        self.pathfmt = util.PathFormat(self.extractor)
+        self.out = output.NullOutput()
+        self.get_logger = logging.getLogger
+
+
 class TestDownloaderModule(unittest.TestCase):
 
     @classmethod
@@ -96,11 +105,10 @@ class TestDownloaderBase(unittest.TestCase):
 
     @classmethod
     def setUpClass(cls):
-        cls.extractor = extractor.find("test:")
-        cls.extractor.log.job = None
         cls.dir = tempfile.TemporaryDirectory()
         cls.fnum = 0
         config.set((), "base-directory", cls.dir.name)
+        cls.job = FakeJob()
 
     @classmethod
     def tearDownClass(cls):
@@ -113,12 +121,13 @@ class TestDownloaderBase(unittest.TestCase):
         cls.fnum += 1
 
         kwdict = {
-            "category": "test",
+            "category"   : "test",
             "subcategory": "test",
-            "filename": name,
-            "extension": extension,
+            "filename"   : name,
+            "extension"  : extension,
         }
-        pathfmt = util.PathFormat(cls.extractor)
+
+        pathfmt = cls.job.pathfmt
         pathfmt.set_directory(kwdict)
         pathfmt.set_filename(kwdict)
 
@@ -159,7 +168,7 @@ class TestHTTPDownloader(TestDownloaderBase):
     @classmethod
     def setUpClass(cls):
         TestDownloaderBase.setUpClass()
-        cls.downloader = downloader.find("http")(cls.extractor, NullOutput())
+        cls.downloader = downloader.find("http")(cls.job)
 
         port = 8088
         cls.address = "http://127.0.0.1:{}".format(port)
@@ -196,7 +205,7 @@ class TestTextDownloader(TestDownloaderBase):
     @classmethod
     def setUpClass(cls):
         TestDownloaderBase.setUpClass()
-        cls.downloader = downloader.find("text")(cls.extractor, NullOutput())
+        cls.downloader = downloader.find("text")(cls.job)
 
     def test_text_download(self):
         self._run_test("text:foobar", None, "foobar", "txt", "txt")
@@ -208,29 +217,6 @@ class TestTextDownloader(TestDownloaderBase):
         self._run_test("text:", None, "", "txt", "txt")
 
 
-class FakeDownloader(DownloaderBase):
-    scheme = "fake"
-
-    def __init__(self, extractor, output):
-        DownloaderBase.__init__(self, extractor, output)
-
-    def connect(self, url, offset):
-        pass
-
-    def receive(self, file):
-        pass
-
-    def reset(self):
-        pass
-
-    def get_extension(self):
-        pass
-
-    @staticmethod
-    def _check_extension(file, pathfmt):
-        pass
-
-
 class HttpRequestHandler(http.server.BaseHTTPRequestHandler):
 
     def do_GET(self):