to support Nexus registry, add digest method flag

README.md

@@ -135,6 +135,13 @@ If you are using docker registry with a self signed ssl certificate, you can dis
   registry.py -l user:pass -r https://example.com:5000 --no-validate-ssl
 ```
 
+## Nexus docker registry
+
+Add --digest-method flag
+
+```
+registry.py -l user:pass -r https://example.com:5000 --digest-method GET
+```
 
 ## Important notes:
 
@@ -175,7 +182,7 @@ You are very welcome to contribute to this script. Of course, when making change
 please include your changes into `test.py` and run tests to check that your changes
 do not break existing functionality.
 
-For tests to work, install `mock` library
+For tests to work, more libraries are needed
 ```
   pip install -r requirements-ci.txt
 ```

registry.py

@@ -170,6 +170,7 @@ class Registry:
         self.no_validate_ssl = False
         self.http = None
         self.last_error = None
+        self.digest_method = "HEAD"
 
     def parse_login(self, login):
         if login is not None:
@@ -188,7 +189,7 @@ class Registry:
 
 
     @staticmethod
-    def create(host, login, no_validate_ssl):
+    def create(host, login, no_validate_ssl, digest_method = "HEAD"):
         r = Registry()
 
         (r.username, r.password) = r.parse_login(login)
@@ -199,6 +200,7 @@ class Registry:
         r.hostname = host
         r.no_validate_ssl = no_validate_ssl
         r.http = Requests()
+        r.digest_method = digest_method
         return r
 
 
@@ -262,10 +264,10 @@ class Registry:
 
     def get_tag_digest(self, image_name, tag):
         image_headers = self.send("/v2/{0}/manifests/{1}".format(
-            image_name, tag), method="HEAD")
+            image_name, tag), method=self.digest_method)
 
         if image_headers is None:
-            print("  tag digest not found: {0}".format(self.last_error))
+            print("  tag digest not found: {0}. Try --digest-method=GET".format(self.last_error))
             return None
 
         tag_digest = image_headers.headers['Docker-Content-Digest']
@@ -491,6 +493,13 @@ for more detail on garbage collection read here:
         nargs='?',
         metavar='Hours')
 
+    parser.add_argument(
+        '--digest-method',
+        help=('Use HEAD for standard docker registry or GET for NEXUS'),
+        default='HEAD',
+        metavar="HEAD|GET"
+    )
+
     return parser.parse_args(args)
 
 
@@ -620,7 +629,8 @@ def main_loop(args):
 
     args.login = username + ':' + password
 
-    registry = Registry.create(args.host, args.login, args.no_validate_ssl)
+    registry = Registry.create(args.host, args.login, args.no_validate_ssl,
+                               args.digest_method)
     
     registry.auth_schemes = get_auth_schemes(registry,'/v2/_catalog')
     

test.py

@@ -264,6 +264,35 @@ class TestListDigest(unittest.TestCase):
             response, 'sha256:85295b0e7456a8fbbc886722b483f87f2bff553fa0beeaf37f5d807aff7c1e52')
         self.assertEqual(self.registry.last_error, None)
 
+    def test_get_digest_nexus_ok(self):
+        self.registry.http.reset_return_value(status_code=200,
+                                              text=('{'
+                                                    '"schemaVersion": 2,\n '
+                                                    '"mediaType": "application/vnd.docker.distribution.manifest.v2+json"'
+                                                    '"digest": "sha256:357ea8c3d80bc25792e010facfc98aee5972ebc47e290eb0d5aea3671a901cab"'
+                                                    ))
+
+        self.registry.http.return_value.headers = {
+            'Content-Length': '4935',
+            'Docker-Content-Digest': 'sha256:85295b0e7456a8fbbc886722b483f87f2bff553fa0beeaf37f5d807aff7c1e52',
+            'X-Content-Type-Options': 'nosniff'
+        }
+
+        self.registry.digest_method = "GET"
+        response = self.registry.get_tag_digest('image1', '0.1.300')
+        self.registry.http.request.assert_called_with(
+            "GET",
+            "http://testdomain.com/v2/image1/manifests/0.1.300",
+            auth=(None, None),
+            headers=self.registry.HEADERS,
+            verify=True
+        )
+
+        self.assertEqual(
+            response, 'sha256:85295b0e7456a8fbbc886722b483f87f2bff553fa0beeaf37f5d807aff7c1e52')
+        self.assertEqual(self.registry.last_error, None)
+
+
     def test_invalid_status_code(self):
         self.registry.http.reset_return_value(400)
         response = self.registry.get_tag_digest('image1', '0.1.300')
@@ -660,7 +689,8 @@ class TestArgParser(unittest.TestCase):
                      "--no-validate-ssl",
                      "--delete-all",
                      "--layers",
-                     "--delete-by-hours", "24"]
+                     "--delete-by-hours", "24",
+                     "--digest-method", "GET"]
         args = parse_args(args_list)
         self.assertTrue(args.delete)
         self.assertTrue(args.layers)
@@ -674,6 +704,13 @@ class TestArgParser(unittest.TestCase):
         self.assertEqual(args.host, "hostname")
         self.assertEqual(args.keep_tags, ["keep1", "keep2"])
         self.assertEqual(args.delete_by_hours, "24")
+        self.assertEqual(args.digest_method, "GET")
+
+    def test_default_args(self):
+        args_list = ["-r", "hostname",
+                     "-l", "loginstring"]
+        args = parse_args(args_list)
+        self.assertEqual(args.digest_method, "HEAD")
 
 
 if __name__ == '__main__':