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Merged
xiekeyang merged 1 commit into from
Sep 11, 2017
Merged

oci_discovery/uri_template: Stub for URI Template expansion #7

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15 changes: 15 additions & 0 deletions README.md
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Expand Up @@ -22,6 +22,18 @@ The strategies in these specifications are inspired by some previous implementat
* [App Container Image Discovery](https://github.com/appc/spec/blob/v0.8.10/spec/discovery.md)
* [parcel](https://github.com/cyphar/parcel)

## Python dependencies

The [OCI Index Template Protocol](index-template.md) [implementation](oci_discovery/ref_engine/oci_index_template) depends on the [uritemplate][] package.
You can install the dependencies with [pip][]:

```
$ pip install -r requirements.txt
```

When uritemplate is not installed, a local implementation is used instead.
But the local stub supports only the most basic [URI Templates][rfc6570].

## Using the Python 3 ref-engine discovery tool

The individual components are usable as libraries, but the ref-engine discovery implementation can also be used from the command line:
Expand Down Expand Up @@ -258,5 +270,8 @@ location ~ ^/oci-image/.*/index.json$ {
[layout]: https://github.com/opencontainers/image-spec/blob/v1.0.0/image-layout.md
[location]: http://nginx.org/en/docs/http/ngx_http_core_module.html#location
[Nginx]: https://nginx.org/
[pip]: https://pip.pypa.io/en/stable/
[python3]: https://docs.python.org/3/
[rfc6570]: https://tools.ietf.org/html/rfc6570
[signed-name-assertions]: https://github.com/opencontainers/image-spec/issues/176
[uritemplate]: https://pypi.python.org/pypi/uritemplate
14 changes: 7 additions & 7 deletions oci_discovery/ref_engine/oci_index_template.py
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Expand Up @@ -15,6 +15,11 @@
import logging as _logging
import pprint as _pprint

try:
import uritemplate as _uritemplate
except ImportError as error:
from .. import uri_template as _uritemplate

from .. import fetch_json as _fetch_json
from .. import host_based_image_names as _host_based_image_names

Expand All @@ -30,16 +35,11 @@ def __str__(self):
self.uri_template)

def __init__(self, uri):
self.uri_template = uri
self.uri_template = _uritemplate.URITemplate(uri=uri)

def resolve(self, name):
name_parts = _host_based_image_names.parse(name=name)
try:
uri = self.uri_template.format(**name_parts)
except KeyError as error:
raise ValueError(
'failed to format {}'.format(self.uri_template)
) from error
uri = self.uri_template.expand(**name_parts)
_LOGGER.debug('fetching an OCI index for {} from {}'.format(name, uri))
index = _fetch_json.fetch(
uri=uri,
Expand Down
34 changes: 34 additions & 0 deletions oci_discovery/uri_template/__init__.py
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@@ -0,0 +1,34 @@
# Copyright 2017 oci-discovery contributors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

class URITemplate(object):
"""Stub implementation of uritemplate's URITemplate.

https://pypi.python.org/pypi/uritemplate
"""
def __init__(self, uri):
self.uri = uri

def __str__(self):
return self.uri

def expand(self, **kwargs):
# Basic URI Templates match Python's str.format() syntax, just
# try that.
try:
return self.uri.format(**kwargs)
except KeyError as error:
raise ValueError(
'failed to format {}'.format(self.uri)
) from error
294 changes: 294 additions & 0 deletions oci_discovery/uri_template/test.py
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# Copyright 2017 oci-discovery contributors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import collections
import unittest

try:
import uritemplate
except ImportError:
uritemplate = None


from . import URITemplate


class TestURITemplate(unittest.TestCase):
def _run(self, cls, exceptions=(), wrong_values=()):
"""Test against examples from RFC 6570.

https://tools.ietf.org/html/rfc6570
"""
# Defined in https://tools.ietf.org/html/rfc6570#section-3.2
# Other sections have their own definitions, but they're
# subsets of this set.
variables = {
'count': ('one', 'two', 'three'),
'dom': ('example', 'com'),
'dub': 'me/too',
'hello': 'Hello World!',
'half': '50%',
'var': 'value',
'who': 'fred',
'base': 'http://example.com/home/',
'path': '/foo/bar',
'list': ('red', 'green', 'blue'),
'keys': collections.OrderedDict((
('semi', ';'),
('dot', '.'),
('comma', ','),
)),
'v': '6',
'x': '1024',
'y': '768',
'empty': '',
'empty_keys': {},
#'undef': None.
}
for name, checks in (
(
'section 1.2, level 1',
(
('{var}', 'value'),
('{hello}', 'Hello%20World%21'),
),
),
(
'section 1.2, level 2',
(
('{+var}', 'value'),
('{+hello}', 'Hello%20World!'),
('{+path}/here', '/foo/bar/here'),
('here?ref={+path}', 'here?ref=/foo/bar'),
('X#{var}', 'X#value'),
('X#{hello}', 'X#Hello%20World!'),
),
),
(
'section 1.2, level 3',
(
('map?{x,y}', 'map?1024,768'),
('{x,hello,y}', '1024,Hello%20World%21,768'),
('{+x,hello,y}', '1024,Hello%20World!,768'),
('{+path,x}/here', '/foo/bar,1024/here'),
('{#x,hello,y}', '#1024,Hello%20World!,768'),
('{#path,x}/here', '#/foo/bar,1024/here'),
('X{.var}', 'X.value'),
('X{.x,y}', 'X.1024.768'),
('{/var}', '/value'),
('{/var,x}/here', '/value/1024/here'),
('{;x,y}', ';x=1024;y=768'),
('{;x,y,empty}', ';x=1024;y=768;empty'),
('{?x,y}', '?x=1024&y=768'),
('{?x,y,empty}', '?x=1024&y=768&empty='),
('?fixed=yes{&x}', '?fixed=yes&x=1024'),
('{&x,y,empty}', '&x=1024&y=768&empty='),
),
),
(
'section 1.2, level 4',
(
('{var:3}', 'val'),
('{var:30}', 'value'),
('{list}', 'red,green,blue'),
('{list*}', 'red,green,blue'),
('{keys}', 'semi,%3B,dot,.,comma,%2C'),
('{keys*}', 'semi=%3B,dot=.,comma=%2C'),
('{+path:6}/here', '/foo/b/here'),
('{+list}', 'red,green,blue'),
('{+list*}', 'red,green,blue'),
('{+keys}', 'semi,;,dot,.,comma,,'),
('{+keys*}', 'semi=;,dot=.,comma=,'),
('{#path:6}/here', '#/foo/b/here'),
('{#list}', '#red,green,blue'),
('{#list*}', '#red,green,blue'),
('{#keys}', '#semi,;,dot,.,comma,,'),
('{#keys*}', '#semi=;,dot=.,comma=,'),
('X{.var:3}', 'X.val'),
('X{.list}', 'X.red,green,blue'),
('X{.list*}', 'X.red.green.blue'),
('X{.keys}', 'X.semi,%3B,dot,.,comma,%2C'),
('X{.keys*}', 'X.semi=%3B.dot=..comma=%2C'),
('{/var:1,var}', '/v/value'),
('{/list}', '/red,green,blue'),
('{/list*}', '/red/green/blue'),
('{/list*,path:4}', '/red/green/blue/%2Ffoo'),
('{/keys}', '/semi,%3B,dot,.,comma,%2C'),
('{/keys*}', '/semi=%3B/dot=./comma=%2C'),
('{;hello:5}', ';hello=Hello'),
('{;list}', ';list=red,green,blue'),
('{;list*}', ';list=red;list=green;list=blue'),
('{;keys}', ';keys=semi,%3B,dot,.,comma,%2C'),
('{;keys*}', ';semi=%3B;dot=.;comma=%2C'),
('{?var:3}', '?var=val'),
('{?list}', '?list=red,green,blue'),
('{?list*}', '?list=red&list=green&list=blue'),
('{?keys}', '?keys=semi,%3B,dot,.,comma,%2C'),
('{?keys*}', '?semi=%3B&dot=.&comma=%2C'),
('{&var:3}', '&var=val'),
('{&list}', '&list=red,green,blue'),
('{&list*}', '&list=red&list=green&list=blue'),
('{&keys}', '&keys=semi,%3B,dot,.,comma,%2C'),
('{&keys*}', '&semi=%3B&dot=.&comma=%2C'),
),
),
(
'section 3.2.2',
(
('{var}', 'value'),
('{hello}', 'Hello%20World%21'),
('{half}', '50%25'),
('O{empty}X', 'OX'),
('O{undef}X', 'OX'),
('{x,y}', '1024,768'),
('{x,hello,y}', '1024,Hello%20World%21,768'),
('?{x,empty}', '?1024,'),
('?{x,undef}', '?1024'),
('?{undef,y}', '?768'),
('{var:3}', 'val'),
('{var:30}', 'value'),
('{list}', 'red,green,blue'),
('{list*}', 'red,green,blue'),
('{keys}', 'semi,%3B,dot,.,comma,%2C'),
('{keys*}', 'semi=%3B,dot=.,comma=%2C'),
),
),
):
with self.subTest(name=name):
for template, expected in checks:
with self.subTest(template=template):
if template in exceptions and template in wrong_values:
self.fail(
msg="entries in both 'exceptions' and 'wrong_values'. Pick one.")
obj = cls(uri=template)
try:
expanded = obj.expand(**variables)
except Exception as error:
if template in exceptions:
self.skipTest(
reason='expected failure: raised {}'
.format(error))
raise
if template in exceptions:
self.fail(
msg='expected a failure, but this no longer raises an exception')
if template in wrong_values:
self.assertNotEqual(expanded, expected)
else:
self.assertEqual(expanded, expected)

def test_stub(self):
self._run(
cls=URITemplate,
exceptions={
'?fixed=yes{&x}',
'?{undef,y}',
'?{x,empty}',
'?{x,undef}',
'O{undef}X',
'X{.keys*}',
'X{.keys}',
'X{.list*}',
'X{.list}',
'X{.var:3}',
'X{.var}',
'X{.x,y}',
'here?ref={+path}',
'map?{x,y}',
'{#keys*}',
'{#keys}',
'{#list*}',
'{#list}',
'{#path,x}/here',
'{#path:6}/here',
'{#x,hello,y}',
'{&keys*}',
'{&keys}',
'{&list*}',
'{&list}',
'{&var:3}',
'{&x,y,empty}',
'{+hello}',
'{+keys*}',
'{+keys}',
'{+list*}',
'{+list}',
'{+path,x}/here',
'{+path:6}/here',
'{+path}/here',
'{+var}',
'{+x,hello,y}',
'{/keys*}',
'{/keys}',
'{/list*,path:4}',
'{/list*}',
'{/list}',
'{/var,x}/here',
'{/var:1,var}',
'{/var}',
'{;hello:5}',
'{;keys*}',
'{;keys}',
'{;list*}',
'{;list}',
'{;x,y,empty}',
'{;x,y}',
'{?keys*}',
'{?keys}',
'{?list*}',
'{?list}',
'{?var:3}',
'{?x,y,empty}',
'{?x,y}',
'{keys*}',
'{list*}',
'{undef,y}',
'{x,hello,y}',
'{x,y}',
},
wrong_values={
'X#{hello}',
'{half}',
'{hello}',
'{keys}',
'{list}',
'{var:30}',
'{var:3}',
},
)

@unittest.skipIf(uritemplate is None, 'failed to import uritemplate')
def test_external(self):
self._run(
cls=uritemplate.URITemplate,
wrong_values={
'X#{hello}',
'X{.keys*}',
'X{.keys}',
'{#keys*}',
'{#keys}',
'{&keys*}',
'{&keys}',
'{+keys*}',
'{+keys}',
'{/keys*}',
'{/keys}',
'{;keys*}',
'{;keys}',
'{?keys*}',
'{?keys}',
'{keys*}',
'{keys}',
},
)
1 change: 1 addition & 0 deletions requirements.txt
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@@ -0,0 +1 @@
uritemplate>=3.0